I have proven myself wrong

I keep working on a proof-of-concept paper for the idea I baptized ‘Energy Ponds’. You can consult two previous updates, namely ‘We keep going until we observe’ and ‘Ça semble expérimenter toujours’ to keep track of the intellectual drift I am taking. This time, I am focusing on the end of the technological pipeline, namely on the battery-powered charging station for electric cars. First, I want to make myself an idea of the market for charging.

I take the case of France. In December 2020, they had a total of 119 737 electric vehicles officially registered (matriculated), which made + 135% as compared to December 2019[1]. That number pertains only to 100% electrical ones, with plug-in hybrids left aside for the moment. When plug-in hybrids enter the game, France had, in December 2020, 470 295 vehicles that need or might need the services of charging stations. According to the same source, there were 28 928 charging stations in France at the time, which makes 13 EVs per charging station. That coefficient is presented for 4 other European countries: Norway (23 EVs per charging station), UK (12), Germany (9), and Netherlands (4).

I look up into other sources. According to Reuters[2], there was 250 000 charging stations in Europe by September 2020, as compared to 34 000 in 2014. That means an average increase by 36 000 a year. I find a different estimation with Statista[3]: 2010 – 3 201; 2011 – 7 018; 2012 – 17 498; 2013 – 28 824; 2014 – 40 910; 2015 – 67 064; 2016 – 98 669; 2017 – 136 059; 2018 – 153 841; 2019 – 211 438; 2020 – 285 796.

On the other hand, the European Alternative Fuels Observatory supplies their own data at https://www.eafo.eu/electric-vehicle-charging-infrastructure, as regards European Union.

Number of EVs per charging station (source: European Alternative Fuels Observatory):

EVs per charging station
201014
20116
20123
20134
20145
20155
20165
20175
20186
20197
20209

The same EAFO site gives their own estimation as regards the number of charging stations in Europe:

Number of charging stations in Europe (source: European Alternative Fuels Observatory):

High-power recharging points (more than 22 kW) in EUNormal charging stations in EUTotal charging stations
201225710 25010 507
201375117 09317 844
20141 47424 91726 391
20153 39644 78648 182
20165 19070 01275 202
20178 72397 287106 010
201811 138107 446118 584
201915 136148 880164 016
202024 987199 250224 237

Two conclusions jump to the eye. Firstly, there is just a very approximate count of charging stations. Numbers differ substantially from source to source. I can just guess that one of the reasons for that discrepancy is the distinction between officially issued permits to build charging points, on the one hand, and the actually active charging points, on the other hand. In Europe, building charging points for electric vehicles has become sort of a virtue, which governments at all levels like signaling. I guess there is some boasting and chest-puffing in the numbers those individual countries report.  

Secondly, high-power stations, charging with direct current, with a power of at least 22 kWh,  gain in importance. In 2012, that category made 2,45% of the total charging network in Europe, and in 2020 that share climbed to 11,14%. This is an important piece of information as regards the proof-of-concept which I am building up for my idea of Energy Ponds. The charging station I placed at the end of the pipeline in the concept of Energy Ponds, and which is supposed to earn a living for all the technologies and installations upstream of it, is supposed to be powered from a power storage facility. That means direct current, and most likely, high power.   

On the whole, the www.eafo.eu site seems somehow more credible that Statista, with all the due respect for the latter, and thus I am reporting some data they present on the fleet of EVs in Europe. Here it comes, in a few consecutive tables below:

Passenger EVs in Europe (source: European Alternative Fuels Observatory):

BEV (pure electric)PHEV (plug-in-hybrid)Total
20084 1554 155
20094 8414 841
20105 7855 785
201113 39516313 558
201225 8913 71229 603
201345 66232 47478 136
201475 47956 745132 224
2015119 618125 770245 388
2016165 137189 153354 290
2017245 347254 473499 820
2018376 398349 616726 014
2019615 878479 7061 095 584
20201 125 485967 7212 093 206

Light Commercial EVs in Europe (source: European Alternative Fuels Observatory):

BEV (pure electric)PHEV (plug-in-hybrid)Total
2008253253
2009254254
2010309309
20117 6697 669
20129 5279 527
201313 66913 669
201410 04910 049
201528 61028 610
201640 926140 927
201752 026152 027
201876 286176 287
201997 36311797 480
2020120 7111 054121 765

Bus EVs in Europe (source: European Alternative Fuels Observatory):

BEV (pure electric)PHEV (plug-in-hybrid)Total
20082727
20091212
2010123123
2011128128
2012286286
2013376376
201438940429
2015420145565
2016686304990
20178884451 333
20181 6084862 094
20193 6365254 161
20205 3115505 861

Truck EVs in Europe (source: European Alternative Fuels Observatory):

BEV (pure electric)PHEV (plug-in-hybrid)Total
200855
200955
201066
201177
201288
20134747
20145858
20157171
201611339152
2017544094
201822240262
201959538633
2020983291 012

Structure of EV fleet in Europe as regards the types of vehicles (source: European Alternative Fuels Observatory):

Passenger EVLight commercial EVBus EVTruck EV
200893,58%5,70%0,61%0,11%
200994,70%4,97%0,23%0,10%
201092,96%4,97%1,98%0,10%
201163,47%35,90%0,60%0,03%
201275,09%24,17%0,73%0,02%
201384,72%14,82%0,41%0,05%
201492,62%7,04%0,30%0,04%
201589,35%10,42%0,21%0,03%
201689,39%10,33%0,25%0,04%
201790,34%9,40%0,24%0,02%
201890,23%9,48%0,26%0,03%
201991,46%8,14%0,35%0,05%
202094,21%5,48%0,26%0,05%

Summing it up a bit. The market of Electric Vehicles in Europe seems being durably dominated by passenger cars. There is some fleet in other categories of vehicles, and there is even some increase, but, for the moment, in all looks more like an experiment. Well, maybe electric buses turn up sort of more systemically.

The proportion between the fleet of electric vehicles and the infrastructure of charging stations still seems to be in the phase of adjustment in the latter to the abundance of the former. Generally, the number of charging stations seems to be growing slower than the fleet of EVs. Thus, for my own concept, I assume that the coefficient of 9 EVs per charging station, on average, will stand still or will slightly increase. For the moment, I take 9. I assume that my charging stations will have like 9 habitual customers, plus a fringe of incidental ones.

From there, I think in the following terms. The number of times the average customer charges their car depends on the distance they cover. Apparently, there is like a 100 km  50 kWh equivalence. I did not find detailed statistics as regards distances covered by electric vehicles as such, however I came by some Eurostat data on distances covered by all passenger vehicles taken together: https://ec.europa.eu/eurostat/statistics-explained/index.php?title=Passenger_mobility_statistics#Distance_covered . There is a lot of discrepancy between the 11 European countries studied for that metric, but the average is 12,49 km per day. My average 9 customers would do, in total, an average of 410,27 of 50 kWh charging purchases per year. I checked the prices of fast charging with direct current: 2,3 PLN per 1 kWh in Poland[4],  €0,22 per 1 kWh in France[5], $0,13 per 1 kWh in US[6], 0,25 pence per 1 kWh in UK[7]. Once converted to US$, it gives $0,59 in Poland, $0,26 in France, $0,35 in UK, and, of course, $0,13 in US. Even at the highest price, namely that in Poland, those 410,27 charging stops give barely more than $12 000 a year.

If I want to have a station able to charge 2 EVs at the same time, fast charging, and counting 350 kW per charging pile (McKinsey 2018[8]), I need 700 kW it total. Investment in batteries is like $600 ÷ $800 per 1 kW (Cole & Frazier 2019[9]; Cole, Frazier, Augustine 2021[10]), thus 700 * ($600 ÷ $800) = $420 000 ÷ $560 000. There is no way that investment pays back with $12 000 a year in revenue, and I haven’t even started talking about paying off on investment in all the remaining infrastructure of Energy Ponds: ram pumps, elevated tanks, semi-artificial wetlands, and hydroelectric turbines.

Now, I revert my thinking. Investment in the range of $420 000 ÷ $560 000, in the charging station and its batteries, gives a middle-of-the-interval value of $490 000. I found a paper by Zhang et al. (2018[11]) who claim that a charging station has chances to pay off, as a business, when it sells some 5 000 000 kWh a year. When I put it back-to-back with the [50 kWh / 100 km] coefficient, it gives 10 000 000 km. Divided by the average annual distance covered by European drivers, thus by 4 558,55 km, it gives 2 193,68 customers per year, or some 6 charging stops per day. That seems hardly feasible with 9 customers. I assume that one customer would charge their electric vehicle no more than twice a week, and 6 chargings a day make 6*7 = 42 chargings, and therefore 21 customers.

I need to stop and think. Essentially, I have proven myself wrong. I had been assuming that putting a charging station for electric vehicles at the end of the internal value chain in the overall infrastructure of Energy Ponds will solve the problem of making money on selling electricity. Turns out it makes even more problems. I need time to wrap my mind around it.


[1] http://www.avere-france.org/Uploads/Documents/161011498173a9d7b7d55aef7bdda9008a7e50cb38-barometre-des-immatriculations-decembre-2020(9).pdf

[2] https://www.reuters.com/article/us-eu-autos-electric-charging-idUSKBN2C023C

[3] https://www.statista.com/statistics/955443/number-of-electric-vehicle-charging-stations-in-europe/

[4] https://elo.city/news/ile-kosztuje-ladowanie-samochodu-elektrycznego

[5] https://particulier.edf.fr/fr/accueil/guide-energie/electricite/cout-recharge-voiture-electrique.html

[6] https://afdc.energy.gov/fuels/electricity_charging_home.html

[7] https://pod-point.com/guides/driver/cost-of-charging-electric-car

[8] McKinsey Center for Future Mobility, How Battery Storage Can Help Charge the Electric-Vehicle Market?, February 2018,

[9] Cole, Wesley, and A. Will Frazier. 2019. Cost Projections for Utility-Scale Battery Storage.

Golden, CO: National Renewable Energy Laboratory. NREL/TP-6A20-73222. https://www.nrel.gov/docs/fy19osti/73222.pdf

[10] Cole, Wesley, A. Will Frazier, and Chad Augustine. 2021. Cost Projections for UtilityScale Battery Storage: 2021 Update. Golden, CO: National Renewable Energy

Laboratory. NREL/TP-6A20-79236. https://www.nrel.gov/docs/fy21osti/79236.pdf.

[11] Zhang, J., Liu, C., Yuan, R., Li, T., Li, K., Li, B., … & Jiang, Z. (2019). Design scheme for fast charging station for electric vehicles with distributed photovoltaic power generation. Global Energy Interconnection, 2(2), 150-159. https://doi.org/10.1016/j.gloei.2019.07.003

Ça semble expérimenter toujours

Je continue avec l’idée que j’avais baptisée « Projet Aqueduc ». Je suis en train de préparer un article sur ce sujet, du type « démonstration de faisabilité ». Je le prépare en anglais et je me suis dit que c’est une bonne idée de reformuler en français ce que j’ai écrit jusqu’à maintenant, l’histoire de changer l’angle intellectuel, me dégourdir un peu et prendre de la distance.

Une démonstration de faisabilité suit une logique similaire à tout autre article scientifique, sauf qu’au lieu d’explorer et vérifier une hypothèse théorique du type « les choses marchent de façon ABCD, sous conditions RTYU », j’explore et vérifie l’hypothèse qu’un concept pratique, comme celui du « Projet Aqueduc », a des fondements scientifiques suffisamment solides pour que ça vaille la peine de travailler dessus et de le tester en vie réelle. Les fondements scientifiques viennent en deux couches, en quelque sorte. La couche de base consiste à passer en revue la littérature du sujet pour voir si quelqu’un a déjà décrit des solutions similaires et là, le truc c’est explorer des différentes perspectives de similarité. Similaire ne veut pas dire identique, n’est-ce pas ? Cette revue de littérature doit apporter une structure logique – un modèle – applicable à la recherche empirique, avec des variables et des paramètres constants. C’est alors que vient la couche supérieure de démonstration de faisabilité, qui consiste à conduire de la recherche empirique proprement dite avec ce modèle.    

Moi, pour le moment, j’en suis à la couche de base. Je passe donc en revue la littérature pertinente aux solutions hydrologiques et hydroélectriques, tout en formant, progressivement, un modèle numérique du « Projet Aqueduc ». Dans cette mise à jour, je commence par une brève récapitulation du concept et j’enchaîne avec ce que j’ai réussi à trouver dans la littérature. Le concept de base du « Projet Aqueduc » consiste donc à placer dans le cours d’une rivière des pompes qui travaillent selon le principe du bélier hydraulique et qui donc utilisent l’énergie cinétique de l’eau pour pomper une partie de cette eau en dehors du lit de la rivière, vers des structures marécageuses qui ont pour fonction de retenir l’eau dans l’écosystème local. Le bélier hydraulique à la capacité de pomper à la verticale aussi bien qu’à l’horizontale et donc avant d’être retenue dans les marécages, l’eau passe par une structure similaire à un aqueduc élevé (d’où le nom du concept en français), avec des réservoirs d’égalisation de flux, et ensuite elle descend vers les marécages à travers des turbines hydroélectriques. Ces dernières produisent de l’énergie qui est ensuite emmagasinée dans une installation de stockage et de là, elle est vendue pour assurer la survie financière à la structure entière. On peut ajouter des installations éoliennes et/ou photovoltaïques pour optimiser la production de l’énergie sur le terrain occupé par la structure entière.  Vous pouvez trouver une description plus élaborée du concept dans ma mise à jour intitulée « Le Catch 22 dans ce jardin d’Eden ». La faisabilité dont je veux faire une démonstration c’est la capacité de cette structure à se financer entièrement sur la base des ventes d’électricité, comme un business régulier, donc de se développer et durer sans subventions publiques. La solution pratique que je prends en compte très sérieusement en termes de créneau de vente d’électricité est une station de chargement des véhicules électriques.   

L’approche de base que j’utilise dans la démonstration de faisabilité – donc mon modèle de base – consiste à représenter le concept en question comme une chaîne des technologies :

>> TCES – stockage d’énergie

>> TCCS – station de chargement des véhicules électriques

>> TCRP – pompage en bélier hydraulique

>> TCEW – réservoirs élevés d’égalisation

>> TCCW – acheminement et siphonage d’eau

>> TCWS – l’équipement artificiel des structures marécageuses

>> TCHE – les turbines hydroélectriques

>> TCSW – installations éoliennes et photovoltaïques     

Mon intuition de départ, que j’ai l’intention de vérifier dans ma recherche à travers la littérature, est que certaines de ces technologies sont plutôt prévisibles et bien calibrées, pendant qu’il y en a d’autres qui sont plus floues et sujettes au changement, donc moins prévisibles. Les technologies prévisibles sont une sorte d’ancrage pour the concept entier et celles plus floues sont l’objet d’expérimentation.

Je commence la revue de littérature par le contexte environnemental, donc avec l’hydrologie. Les variations au niveau de la nappe phréatiques, qui est un terme scientifique pour les eaux souterraines, semblent être le facteur numéro 1 des anomalies au niveau de rétention d’eau dans les réservoirs artificiels (Neves, Nunes, & Monteiro 2020[1]). D’autre part, même sans modélisation hydrologique détaillée, il y a des preuves empiriques substantielles que la taille des réservoirs naturels et artificiels dans les plaines fluviales, ainsi que la densité de placement de ces réservoirs et ma manière de les exploiter ont une influence majeure sur l’accès pratique à l’eau dans les écosystèmes locaux. Il semble que la taille et la densité des espaces boisés intervient comme un facteur d’égalisation dans l’influence environnementale des réservoirs (Chisola, Van der Laan, & Bristow 2020[2]). Par comparaison aux autres types de technologie, l’hydrologie semble être un peu en arrière en termes de rythme d’innovation et il semble aussi que des méthodes de gestion d’innovation appliquées ailleurs avec succès peuvent marcher pour l’hydrologie, par exemple des réseaux d’innovation ou des incubateurs des technologies (Wehn & Montalvo 2018[3]; Mvulirwenande & Wehn 2020[4]). L’hydrologie rurale et agriculturale semble être plus innovatrice que l’hydrologie urbaine, par ailleurs (Wong, Rogers & Brown 2020[5]).

Ce que je trouve assez surprenant est le manque apparent de consensus scientifique à propos de la quantité d’eau dont les sociétés humaines ont besoin. Toute évaluation à ce sujet commence avec « beaucoup et certainement trop » et à partir de là, le beaucoup et le trop deviennent plutôt flous. J’ai trouvé un seul calcul, pour le moment, chez Hogeboom (2020[6]), qui maintient que la personne moyenne dans les pays développés consomme 3800 litres d’eau par jour au total, mais c’est une estimation très holistique qui inclue la consommation indirecte à travers les biens et les services ainsi que le transport. Ce qui est consommé directement via le robinet et la chasse d’eau dans les toilettes, ça reste un mystère pour la science, apparemment, à moins que la science ne considère ce sujet comment trop terre-à-terre pour s’en occuper sérieusement.     

Il y a un créneau de recherche intéressant, que certains de ses représentants appellent « la socio-hydrologie », qui étudie les comportements collectifs vis-à-vis de l’eau et des systèmes hydrologiques et qui est basée sur l’observation empirique que lesdits comportements collectifs s’adaptent, d’une façon profonde et pernicieuse à la fois, aux conditions hydrologiques que la société en question vit avec (Kumar et al. 2020[7]). Il semble que nous nous adaptons collectivement à la consommation accrue de l’eau par une productivité croissante dans l’exploitation de nos ressources hydrologiques et le revenu moyen par tête d’habitant semble être positivement corrélé avec cette productivité (Bagstad et al. 2020[8]). Il paraît donc que l’accumulation et superposition de nombreuses technologies, caractéristique aux pays développés, contribue à utiliser l’eau de façon de plus en plus productive. Dans ce contexte, il y a une recherche intéressante conduite par Mohamed et al. (2020[9]) qui avance la thèse qu’un environnement aride est non seulement un état hydrologique mais aussi une façon de gérer les ressources hydrologiques, sur ma base des données qui sont toujours incomplètes par rapport à une situation qui change rapidement.

Il y a une question qui vient plus ou moins naturellement : dans la foulée de l’adaptation socio-hydrologique quelqu’un a-t-il présenté un concept similaire à ce que moi je présente comme « Projet Aqueduc » ? Eh bien, je n’ai rien trouvé d’identique, néanmoins il y a des idées intéressement proches. Dans l’hydrologie descriptive il y a ce concept de pseudo-réservoir, qui veut dire une structure comme les marécages ou des nappes phréatiques peu profondes qui ne retiennent pas l’eau de façons statique, comme un lac artificiel, mais qui ralentissent la circulation de l’eau dans le bassin fluvial d’une rivière suffisamment pour modifier les conditions hydrologiques dans l’écosystème (Harvey et al. 2009[10]; Phiri et al. 2021[11]). D’autre part, il y a une équipe des chercheurs australiens qui ont inventé une structure qu’ils appellent par l’acronyme STORES et dont le nom complet est « short-term off-river energy storage » (Lu et al. 2021[12]; Stocks et al. 2021[13]). STORES est une structure semi-artificielle d’accumulation par pompage, où on bâtit un réservoir artificiel au sommet d’un monticule naturel placé à une certaine distance de la rivière la plus proche et ce réservoir reçoit l’eau pompée artificiellement de la rivière. Ces chercheurs australiens avancent et donnent des preuves scientifiques pour appuyer la thèse qu’avec un peu d’astuce on peut faire fonctionner ce réservoir naturel en boucle fermée avec la rivière qui l’alimente et donc de créer un système de rétention d’eau. STORES semble être relativement le plus près de mon concept de « Projet Aqueduc » et ce qui est épatant est que moi, j’avais inventé mon idée pour l’environnement des plaines alluviales de l’Europe tandis que STORES avait été mis au point pour l’environnement aride et quasi-désertique d’Australie. Enfin, il y a l’idée des soi-disant « jardins de pluie » qui sont une technologie de rétention d’eau de pluie dans l’environnement urbain, dans des structures horticulturales, souvent placées sur les toits d’immeubles (Bortolini & Zanin 2019[14], par exemple).

Je peux conclure provisoirement que tout ce qui touche à l’hydrologie strictement dite dans le cadre du « Projet Aqueduc » est sujet aux changements plutôt imprévisible. Ce que j’ai pu déduire de la littérature ressemble à un potage bouillant sous couvercle. Il y a du potentiel pour changement technologique, il y a de la pression environnementale et sociale, mais il n’y pas encore de mécanismes institutionnels récurrents pour connecter l’un à l’autre. Les technologies TCEW (réservoirs élevés d’égalisation), TCCW (acheminement et siphonage d’eau), et TCWS (l’équipement artificiel des structures marécageuses) démontrant donc un avenir flou, je passe à la technologie TCRP de pompage en bélier hydraulique. J’ai trouvé deux articles chinois, qui se suivent chronologiquement et qui semblent par ailleurs avoir été écrits par la même équipe de chercheurs : Guo et al. (2018[15]), and Li et al. (2021[16]). Ils montrent la technologie du bélier hydraulique sous un angle intéressant. D’une part, les Chinois semblent avoir donné du vrai élan à l’innovation dans ce domaine spécifique, tout au moins beaucoup plus d’élan que j’ai pu observer en Europe. D’autre part, les estimations de la hauteur effective à laquelle l’eau peut être pompée avec les béliers hydrauliques dernier cri sont respectivement de 50 mètres dans l’article de 2018 et 30 mètres dans celui de 2021. Vu que les deux articles semblent être le fruit du même projet, il y a eu comme une fascination suivie par une correction vers le bas. Quoi qu’il en soit, même l’estimation plus conservative de 30 mètres c’est nettement mieux que les 20 mètres que j’assumais jusqu’à maintenant.

Cette élévation relative possible à atteindre avec la technologie du bélier hydraulique est importante pour la technologie suivante de ma chaîne, donc celle des petites turbines hydroélectriques, la TCHE. L’élévation relative de l’eau et le flux par seconde sont les deux paramètres clés qui déterminent la puissance électrique produite (Cai, Ye & Gholinia 2020[17]) et il se trouve que dans le « Projet Aqueduc », avec l’élévation et le flux largement contrôlés à travers la technologie du bélier hydraulique, les turbines deviennent un peu moins dépendantes sur les conditions naturelles.

J’ai trouvé une revue merveilleusement encyclopédique des paramètres pertinents aux petites turbines hydroélectriques chez Hatata, El-Saadawi, & Saad (2019[18]). La puissance électrique se calcule donc comme : Puissance = densité de l’eau (1000 kg/m3) * constante d’accélération gravitationnelle (9,8 m/s2) * élévation nette (mètres) * Q (flux par seconde m3/s).

L’investissement initial en de telles installations se calcule par unité de puissance, donc sur la base de 1 kilowatt et se divise en 6 catégories : la construction de la prise d’eau, la centrale électrique strictement dite, les turbines, le générateur, l’équipement auxiliaire, le transformateur et enfin le poste extérieur. Je me dis par ailleurs que – vu la structure du « Projet Aqueduc » – l’investissement en la construction de prise d’eau est en quelque sorte équivalent au système des béliers hydrauliques et réservoirs élevés. En tout cas :

>> la construction de la prise d’eau, par 1 kW de puissance  ($) 186,216 * Puissance-0,2368 * Élévation -0,597

>> la centrale électrique strictement dite, par 1 kW de puissance  ($) 1389,16 * Puissance-0,2351 * Élévation-0,0585

>> les turbines, par 1 kW de puissance  ($)

@ la turbine Kaplan: 39398 * Puissance-0,58338 * Élévation-0,113901

@ la turbine Frances: 30462 * Puissance-0,560135 * Élévation-0,127243

@ la turbine à impulsions radiales: 10486,65 * Puissance-0,3644725 * Élévation-0,281735

@ la turbine Pelton: 2 * la turbine à impulsions radiales

>> le générateur, par 1 kW de puissance  ($) 1179,86 * Puissance-0,1855 * Élévation-0,2083

>> l’équipement auxiliaire, par 1 kW de puissance  ($) 612,87 * Puissance-0,1892 * Élévation-0,2118

>> le transformateur et le poste extérieur, par 1 kW de puissance 

($) 281 * Puissance0,1803 * Élévation-0,2075

Une fois la puissance électrique calculée avec le paramètre d’élévation relative assurée par les béliers hydrauliques, je peux calculer l’investissement initial en hydro-génération comme la somme des positions mentionnées ci-dessus. Hatata, El-Saadawi, & Saad (2019 op. cit.) recommandent aussi de multiplier une telle somme par le facteur de 1,13 (c’est donc un facteur du type « on ne sait jamais ») et d’assumer que les frais courants d’exploitation annuelle vont se situer entre 1% et 6% de l’investissement initial.

Syahputra & Soesanti (2021[19]) étudient le cas de la rivière Progo, dotée d’un flux tout à fait modeste de 6,696 mètres cubes par seconde et située dans Kulon Progo Regency (une region spéciale au sein de Yogyakarta, Indonesia). Le système des petites turbines hydroélectriques y fournit l’électricité aux 962 ménages locaux, et crée un surplus de 4 263 951 kWh par an d’énergie à revendre aux consommateurs externes. Dans un autre article, Sterl et al. (2020[20]) étudient le cas de Suriname et avancent une thèse intéressante, notamment que le développement d’installations basées sur les énergies renouvelables crée un phénomène d’appétit d’énergie qui croît à mesure de manger et qu’un tel développement en une source d’énergie – le vent, par exemple – stimule l’investissement en installations basées sur d’autres sources, donc l’hydraulique et le photovoltaïque.  

Ces études relativement récentes corroborent celles d’il y a quelques années, comme celle de Vilanova & Balestieri (2014[21]) ou bien celle de Vieira et al. (2015[22]), avec une conclusion générale que les petites turbines hydroélectriques ont atteint un degré de sophistication technologique suffisante pour dégager une quantité d’énergie économiquement profitable. Par ailleurs, il semble qu’il y a beaucoup à gagner dans ce domaine à travers l’optimisation de la distribution de puissance entre les turbines différentes. De retour aux publications les plus récentes, j’ai trouvé des études de faisabilité tout à fait robustes pour les petites turbines hydroélectriques, qui indiquent que – pourvu qu’on soit prêt à accepter un retour d’environ 10 à 11 ans sur l’investissement initial – le petit hydro peut être exploité profitablement même avec une élévation relative en dessous de 20 mètres (Arthur et al. 2020[23] ; Ali et al. 2021[24]).

C’est ainsi que j’arrive donc à la portion finale dans la chaîne technologique du « Projet Aqueduc », donc au stockage d’énergie (TCES) ainsi que TCCS ou la station de chargement des véhicules électriques. La puissance à installer dans une station de chargement semble se situer entre 700 et 1000 kilowatts (Zhang et al. 2018[25]; McKinsey 2018[26]). En dessous de 700 kilowatt la station peut devenir si difficile à accéder pour le consommateur moyen, due aux files d’attente, qu’elle peut perdre la confiance des clients locaux. En revanche, tout ce qui va au-dessus de 1000 kilowatts est vraiment utile seulement aux heures de pointe dans des environnements urbains denses. Il y a des études de concept pour les stations de chargement où l’unité de stockage d’énergie est alimentée à partir des sources renouvelables (Al Wahedi & Bicer 2020[27]). Zhang et al. (2019[28]) présentent un concept d’entreprise tout fait pour une station de chargement située dans le milieu urbain. Apparemment, le seuil de profitabilité se situe aux environs de 5 100 000 kilowatt heures vendues par an.  

En termes de technologie de stockage strictement dite, les batteries Li-ion semblent être la solution de base pour maintenant, quoi qu’une combinaison avec les piles à combustible ou bien avec l’hydrogène semble prometteuse (Al Wahedi & Bicer 2020 op. cit. ; Sharma, Panvar & Tripati 2020[29]). En général, pour le moment, les batteries Li-Ion montrent le rythme d’innovation relativement le plus soutenu (Tomaszewska et al. 2019[30] ; de Simone & Piegari 2019[31]; Koohi-Fayegh & Rosen 2020[32]). Un article récent par Elmeligy et al. (2021[33]) présente un concept intéressant d’unité mobile de stockage qui pourrait se déplacer entre plusieurs stations de chargement. Quant à l’investissement initial requis pour une station de chargement, ça semble expérimenter toujours mais la marge de manœuvre se rétrécit pour tomber quelque part entre $600 ÷ $800 par 1 kW de puissance (Cole & Frazier 2019[34]; Cole, Frazier, Augustine 2021[35]).


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[16] Li, J., Yang, K., Guo, X., Huang, W., Wang, T., Guo, Y., & Fu, H. (2021). Structural design and parameter optimization on a waste valve for hydraulic ram pumps. Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Puissance and Energy, 235(4), 747–765. https://doi.org/10.1177/0957650920967489

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[23] Arthur, E., Anyemedu, F. O. K., Gyamfi, C., Asantewaa-Tannor, P., Adjei, K. A., Anornu, G. K., & Odai, S. N. (2020). Potential for small hydroPuissance development in the Lower Pra River Basin, Ghana. Journal of Hydrology: Regional Studies, 32, 100757. https://doi.org/10.1016/j.ejrh.2020.100757

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[26] McKinsey Center for Future Mobility, How Battery Storage Can Help Charge the Electric-Vehicle Market?, February 2018,

[27] Al Wahedi, A., & Bicer, Y. (2020). Development of an off-grid electrical vehicle charging station hybridized with renewables including battery cooling system and multiple energy storage units. Energy Reports, 6, 2006-2021. https://doi.org/10.1016/j.egyr.2020.07.022

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[33] Elmeligy, M. M., Shaaban, M. F., Azab, A., Azzouz, M. A., & Mokhtar, M. (2021). A Mobile Energy Storage Unit Serving Multiple EV Charging Stations. Energies, 14(10), 2969. https://doi.org/10.3390/en14102969

[34] Cole, Wesley, and A. Will Frazier. 2019. Cost Projections for Utility-Scale Battery Storage.

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[35] Cole, Wesley, A. Will Frazier, and Chad Augustine. 2021. Cost Projections for UtilityScale Battery Storage: 2021 Update. Golden, CO: National Renewable Energy

Laboratory. NREL/TP-6A20-79236. https://www.nrel.gov/docs/fy21osti/79236.pdf.

Seasonal lakes

Once again, been a while since I last blogged. What do you want, I am having a busy summer. Putting order in my own chaos, and, over the top of that, putting order in other people’s chaos, this is all quite demanding in terms of time and energy. What? Without trying to put order in chaos, that chaos might take less time and energy? Well, yes, but order look tidier than chaos.

I am returning to the technological concept which I labelled ‘Energy Ponds’ (or ‘projet Aqueduc’ in French >> see: Le Catch 22 dans ce jardin d’Eden). You can find a description of that concept onder the hyperlinked titles provided. I am focusing on refining my repertoire of skills in scientific validation of technological concepts. I am passing in review some recent literature, and I am trying to find good narrative practices in that domain.

The general background of ‘Energy Ponds’ consists in natural phenomena observable in Europe as the climate change progresses, namely: a) long-term shift in the structure of precipitations, from snow to rain b) increasing occurrence of floods and droughts c) spontaneous reemergence of wetlands. All these phenomena have one common denominator: increasingly volatile flow per second in rivers. The essential idea of Energy Ponds is to ‘financialize’ that volatile flow, so to say, i.e. to capture its local surpluses, store them for later, and use the very mechanism of storage itself as a source of economic value.

When water flows downstream, in a river, its retention can be approached as the opportunity for the same water to loop many times over the same specific portion of the collecting basin (of the river). Once such a loop is created, we can extend the average time that a liter of water spends in the whereabouts. Ram pumps, connected to storage structures akin to swamps, can give such an opportunity. A ram pump uses the kinetic energy of flowing water in order to pump some of that flow up and away from its mainstream. Ram pumps allow forcing a process, which we now as otherwise natural. Rivers, especially in geological plains, where they flow relatively slowly, tend to build, with time, multiple ramifications. Those branchings can be directly observable at the surface, as meanders, floodplains or seasonal lakes, but much of them is underground, as pockets of groundwater. In this respect, it is useful to keep in mind that mechanically, rivers are the drainpipes of rainwater from their respective basins. Another basic hydrological fact, useful to remember in the context of the Energy Ponds concept, is that strictly speaking retention of rainwater – i.e. a complete halt in its circulation through the collecting basin of the river – is rarely possible, and just as rarely it is a sensible idea to implement. Retention means rather a slowdown to the flow of rainwater through the collecting basin into the river.

One of the ways that water can be slowed down consists in making it loop many times over the same section of the river. Let’s imagine a simple looping sequence: water from the river is being ram-pumped up and away into retentive structures akin to swamps, i.e. moderately deep spongy structures underground, with high capacity for retention, covered with a superficial layer of shallow-rooted vegetation. With time, as the swamp fills with water, the surplus is evacuated back into the river, by a system of canals. Water stored in the swamp will be ultimately evacuated, too, minus evaporation, it will just happen much more slowly, by the intermediary of groundwaters. In order to illustrate the concept mathematically, let’ s suppose that we have water in the river flowing at the pace of, e.g. 45 m3 per second. We make it loop once via ram pumps and retentive swamps, and, if as a result of that looping, the speed of the flow is sliced by 3. On the long run we slow down the way that the river works as the local drainpipe: we slow it from 43 m3 per second down to [43/3 = 14,33…] m3 per second.  As water from the river flows slower overall, it can yield more environmental services: each cubic meter of water has more time to ‘work’ in the ecosystem.  

When I think of it, any human social structure, such as settlements, industries, infrastructures etc., needs to stay in balance with natural environment. That balance is to be understood broadly, as the capacity to stay, for a satisfactorily long time, within a ‘safety zone’, where the ecosystem simply doesn’t kill us. That view has little to do with the moral concepts of environment-friendliness or sustainability. As a matter of fact, most known human social structures sooner or later fall out of balance with the ecosystem, and this is how civilizations collapse. Thus, here comes the first important assumption: any human social structure is, at some level, an environmental project. The incumbent social structures, possible to consider as relatively stable, are environmental projects which have simply hold in place long enough to grow social institutions, and those institutions allow further seeking of environmental balance.

I am starting my review of literature with an article by Phiri et al. (2021[1]), where the authors present a model for assessing the way that alluvial floodplains behave. I chose this one because my concept of Energy Ponds is supposed to work precisely in alluvial floodplains, i.e. in places where we have: a) a big river b) a lot of volatility in the amount of water in that river, and, as a consequence, we have (c) an alternation of floods and droughts. Normal stuff where I come from, i.e. in Northern Europe. Phiri et al. use the general model, acronymically called SWAT, which comes from ‘Soil and Water Assessment Tool’ (see also: Arnold et al. 1998[2]; Neitsch et al. 2005[3]), and with that general tool, they study the concept of pseudo-reservoirs in alluvial plains. In short, a pseudo-reservoir is a hydrological structure which works like a reservoir but does not necessarily look like one. In that sense, wetlands in floodplains can work as reservoirs of water, even if from the hydrological point of view they are rather extensions of the main river channel (Harvey et al. 2009[4]).

Analytically, the SWAT model defines the way a reservoir works with the following equation: V = Vstored + Vflowin − Vflowout + Vpcp − Vevap − Vseep . People can rightly argue that it is a good thing to know what symbols mean in an equation, and therefore V stands for the volume of water in reservoir at the end of the day, Vstored corresponds to the amount of water stored at the beginning of the day, Vflowin means the quantity of water entering reservoir during the day, Vflowout is the metric outflow of water during the day, Vpcp is volume of precipitation falling on the water body during the day, Vevap is volume of water removed from the water body by evaporation during the day, Vseep is volume of water lost from the water body by seepage.

This is a good thing to know, as well, once we have a nice equation, what the hell are we supposed to do with it in real life. Well, the SWAT model has even its fan page (http://www.swatusers.com ), and, as Phiri et al. phrase it out, it seems that the best practical use is to control the so-called ‘target release’, i.e. the quantity of water released at a given point in space and time, designated as Vtarg. The target release is mostly used as a control metric for preventing or alleviating floods, and with that purpose in mind, two decision rules are formulated. During the non-flood season, no reservation for flood is needed, and target storage is set at emergency spillway volume. In other words, in the absence of imminent flood, we can keep the reservoir full. On the other hand, when the flood season is on, flood control reservation is a function of soil water content. This is set to maximum and 50 % of maximum for wet and dry grounds, respectively. In the context of the V = Vstored + Vflowin − Vflowout + Vpcp − Vevap − Vseep equation, Vtarg is a specific value (or interval of values) in the Vflowout component.

As I am wrapping my mind around those conditions, I am thinking about the opposite application, i.e. about preventing and alleviating droughts. Drought is recognizable by exceptionally low values in the amount of water stored at the end of the given period, thus in the basic V, in the presence of low precipitation, thus low Vpcp, and high evaporation, which corresponds to high Vevap. More generally, both floods and droughts occur when – or rather after – in a given Vflowin − Vflowout balance, precipitation and evaporation take one turn or another.

I feel like moving those exogenous meteorological factors on one side of the equation, which goes like  – Vpcp + Vevap =  – V + Vstored + Vflowin − Vflowout − Vseep and doesn’t make much sense, as there are not really many cases of negative precipitation. I need to switch signs, and then it is more presentable, as Vpcp – VevapV – Vstored – Vflowin + Vflowout + Vseep . Weeell, almost makes sense. I guess that Vflowin is sort of exogenous, too. The inflow of water into the basin of the river comes from a melting glacier, from another river, from an upstream section of the same river etc. I reframe: Vpcp – Vevap + Vflowin V – Vstored + Vflowout + Vseep  . Now, it makes sense. Precipitations plus the inflow of water through the main channel of the river, minus evaporation, all that stuff creates a residual quantity of water. That residual quantity seeps into the groundwaters (Vseep), flows out (Vflowout), and stays in the reservoir-like structure at the end of the day (V – Vstored).

I am having a look at how Phiri et al. (2021 op. cit.) phrase out their model of pseudo-reservoir. The output value they peg the whole thing on is Vpsrc, or the quantity of water retained in the pseudo-reservoir at the end of the day. The Vpsrc is modelled for two alternative situations: no flood (V ≤ Vtarg), or flood (V > Vtarg). I interpret drought as particularly uncomfortable a case of the absence of flood.

Whatever. If V ≤ Vtarg , then Vpsrc = Vstored + Vflowin − Vbaseflowout + Vpcp − Vevap − Vseep  , where, besides the already known variables, Vbaseflowoutstands for volume of water leaving PSRC during the day as base flow. When, on the other hand, we have flood, Vpsrc = Vstored + Vflowin − Vbaseflowout − Voverflowout + Vpcp − Vevap − Vseep .

Phiri et al. (2021 op. cit.) argue that once we incorporate the phenomenon of pseudo-reservoirs in the evaluation of possible water discharge from alluvial floodplains, the above-presented equations perform better than the standard SWAT model, or V = Vstored + Vflowin − Vflowout + Vpcp − Vevap − Vseep

My principal takeaway from the research by Phiri et al. (2021 op. cit.) is that wetlands matter significantly for the hydrological balance of areas with characteristics of floodplains. My concept of ‘Energy Ponds’ assumes, among other things, storing water in swamp-like structures, including urban and semi-urban ones, such as rain gardens (Sharma & Malaviya 2021[5] ; Li, Liu & Li 2020[6] ; Venvik & Boogaard 2020[7],) or sponge cities (Ma, Jiang & Swallow 2020[8] ; Sun, Cheshmehzangi & Wang 2020[9]).  

Now, I have a few papers which allow me to have sort of a bird’s eye view of the SWAT model as regards the actual predictability of flow and retention in fluvial basins. It turns out that identifying optimal sites for hydropower installations is a very complex task, prone to a lot of error, and only the introduction of digital data such as GIS allows acceptable precision. The problem is to estimate accurately both the flow and the head of the waterway in question at an exact location (Liu et al., 2017[10]; Gollou and Ghadimi 2017[11]; Aghajani & Ghadimi 2018[12]; Yu & Ghadimi 2019[13]; Cai, Ye & Gholinia 2020[14]). My concept of ‘Energy Ponds’ includes hydrogeneration, but makes one of those variables constant, by introducing something like Roman siphons, with a constant head, apparently possible to peg at 20 metres. The hydro-power generation seems to be pseudo-concave function (i.e. it hits quite a broad, concave peak of performance) if the hydraulic head (height differential) is constant, and the associated productivity function is strongly increasing. Analytically, it can be expressed as a polynomial, i.e. as a combination of independent factors with various powers (various impact) assigned to them (Cordova et al. 2014[15]; Vieira et al. 2015[16]). In other words, by introducing, in my technological concept, that constant head (height) makes the whole thing more prone to optimization.

Now, I take on a paper which shows how to present a proof of concept properly: Pradhan, A., Marence, M., & Franca, M. J. (2021). The adoption of Seawater Pump Storage Hydropower Systems increases the share of renewable energy production in Small Island Developing States. Renewable Energy, https://doi.org/10.1016/j.renene.2021.05.151 . This paper is quite close to my concept of ‘Energy Ponds’, as it includes the technology of pumped storage, which I think about morphing and changing into something slightly different. Such as presented by Pradhan, Marence & Franca (2021, op. cit.), the proof of concept is structured in two parts: the general concept is presented, and then a specific location is studied  – the island of Curaçao, in this case – as representative for a whole category. The substance of proof is articulated around the following points:

>> the basic diagnosis as for the needs of the local community in terms of energy sources, with the basic question whether Seawater Pumped Storage Hydropower System is locally suitable as technology. In this specific case, the main criterium was the possible reduction of dependency on fossils. Assumptions as for the electric power required have been made, specifically for the local community.  

>> a GIS tool has been tested for choosing the optimal location. GIS stands for Geographic Information System (https://en.wikipedia.org/wiki/Geographic_information_system ). In this specific thread the proof of concept consisted in checking whether the available GIS data, and the software available for processing it are sufficient for selecting an optimal location in Curaçao.

At the bottom line, the proof of concept sums up to checking, whether the available GIS technology allows calibrating a site for installing the required electrical power in a Seawater Pumped Storage Hydropower System.

That paper by Pradhan, Marence & Franca (2021, op. cit.) presents a few other interesting traits for me. Firstly, the author’s prove that combining hydropower with windmills and solar modules is a viable solution, and this is exactly what I thought, only I wasn’t sure. Secondly, the authors consider a very practical issue: corrosion, and the materials recommended in order to bypass that problem. Their choice is fiberglass. Secondly, they introduce an important parameter, namely the L/H aka ‘Length to Head’ ratio. This is the proportion between the length of water conductors and the hydraulic head (i.e. the relative denivelation) in the actual installation. Pradhan, Marence & Franca recommend distinguishing two types of installations: those with L/H < 15, on the one hand, and those with 15 ≤ L/H ≤ 25. However accurate is that assessment of theirs, it is a paremeter to consider. In my concept of ‘Energy Ponds’, I assume an artificially created hydraulic head of 20 metres, and thus the conductors leading from elevated tanks to the collecting wetland-type structure should be classified in two types, namely [(L/H < 15) (L < 15*20) (L < 300 metres)], on the one hand, and [(15 ≤ L/H ≤ 25) (300 metres ≤ L ≤ 500 metres)], on the other hand.  

Still, there is bad news for me. According to a report by Botterud, Levin & Koritarov (2014[17]), which Pradhan, Marence & Franca quote as an authoritative source, hydraulic head for pumped storage should be at least 100 metres in order to make the whole thing profitable. My working assumption with ‘Energy Ponds’ is 20 metres, and, obviously, I have to work through it.

I think I have the outline of a structure for writing a decent proof-of-concept article for my ‘Energy Ponds’ concept. I think I should start with something I have already done once, two years ago, namely with compiling data as regards places in Europe, located in fluvial plains, with relatively the large volatility in water level and flow. These places will need water retention.

Out of that list, I select locations eligible for creating wetland-type structures for retaining water, either in the form of swamps, or as porous architectural structures. Once that second list prepared, I assess the local need for electrical power. From there, I reverse engineer. With a given power of X megawatts, I reverse to the storage capacity needed for delivering that power efficiently and cost-effectively. I nail down the storage capacity as such, and I pass in review the available technologies of power storage.

Next, I choose the best storage technology for that specific place, and I estimate the investment outlays necessary for installing it. I calculate the hydropower required in hydroelectric turbines, as well as in adjacent windmills and photovoltaic. I check whether the local river can supply the amount of water that fits the bill. I pass in review literature as regards optimal combinations of those three sources of energy. I calculate the investment outlays needed to install all that stuff, and I add the investment required in ram pumping, elevated tanks, and water conductors.  

Then, I do a first approximation of cash flow: cash from sales of electricity, in that local installation, minus the possible maintenance costs. After I calculate that gross margin of cash,  I compare it to the investment capital I had calculated before, and I try to estimate provisionally the time of return on investment. Once this done, I add maintenance costs to my sauce. I think that the best way of estimating these is to assume a given lifecycle of complete depreciation in the technology installed, and to count maintenance costs as the corresponding annual amortization.         


[1] Phiri, W. K., Vanzo, D., Banda, K., Nyirenda, E., & Nyambe, I. A. (2021). A pseudo-reservoir concept in SWAT model for the simulation of an alluvial floodplain in a complex tropical river system. Journal of Hydrology: Regional Studies, 33, 100770. https://doi.org/10.1016/j.ejrh.2020.100770.

[2] Arnold, J.G., Srinivasan, R., Muttiah, R.S., Williams, J.R., 1998. Large area hydrological modelling and assessment: Part I. Model development. J. Am. Water Resour. Assoc. 34, 73–89.

[3] Neitsch, S.L., Arnold, J.G., Kiniry, J.R., Williams, J.R., 2005. “Soil and Water Assessment Tool Theoretical Documentation.” Version 2005. Blackland Research Center, Texas.

[4] Harvey, J.W., Schaffranek, R.W., Noe, G.B., Larsen, L.G., Nowacki, D.J., O’Connor, B.L., 2009. Hydroecological factors governing surface water flow on a low-gradient floodplain. Water Resour. Res. 45, W03421, https://doi.org/10.1029/2008WR007129.

[5] Sharma, R., & Malaviya, P. (2021). Management of stormwater pollution using green infrastructure: The role of rain gardens. Wiley Interdisciplinary Reviews: Water, 8(2), e1507. https://doi.org/10.1002/wat2.1507

[6] Li, J., Liu, F., & Li, Y. (2020). Simulation and design optimization of rain gardens via DRAINMOD and response surface methodology. Journal of Hydrology, 585, 124788. https://doi.org/10.1016/j.jhydrol.2020.124788

[7] Venvik, G., & Boogaard, F. C. (2020). Infiltration capacity of rain gardens using full-scale test method: effect of infiltration system on groundwater levels in Bergen, Norway. Land, 9(12), 520. https://doi.org/10.3390/land9120520

[8] Ma, Y., Jiang, Y., & Swallow, S. (2020). China’s sponge city development for urban water resilience and sustainability: A policy discussion. Science of the Total Environment, 729, 139078. https://doi.org/10.1016/j.scitotenv.2020.139078

[9] Sun, J., Cheshmehzangi, A., & Wang, S. (2020). Green infrastructure practice and a sustainability key performance indicators framework for neighbourhood-level construction of sponge city programme. Journal of Environmental Protection, 11(2), 82-109. https://doi.org/10.4236/jep.2020.112007

[10] Liu, Yan, Wang, Wei, Ghadimi, Noradin, 2017. Electricity load forecasting by an improved forecast engine for building level consumers. Energy 139, 18–30. https://doi.org/10.1016/j.energy.2017.07.150

[11] Gollou, Abbas Rahimi, Ghadimi, Noradin, 2017. A new feature selection and hybrid forecast engine for day-ahead price forecasting of electricity markets. J. Intell. Fuzzy Systems 32 (6), 4031–4045.

[12] Aghajani, Gholamreza, Ghadimi, Noradin, 2018. Multi-objective energy manage- ment in a micro-grid. Energy Rep. 4, 218–225.

[13] Yu, Dongmin, Ghadimi, Noradin, 2019. Reliability constraint stochastic UC by considering the correlation of random variables with Copula theory. IET Renew. Power Gener. 13 (14), 2587–2593.

[14] Cai, X., Ye, F., & Gholinia, F. (2020). Application of artificial neural network and Soil and Water Assessment Tools in evaluating power generation of small hydropower stations. Energy Reports, 6, 2106-2118. https://doi.org/10.1016/j.egyr.2020.08.010.

[15] Cordova M, Finardi E, Ribas F, de Matos V, Scuzziato M. Performance evaluation and energy production optimization in the real-time operation of hydropower plants. Electr Pow Syst Res 2014;116:201–7.   http://dx.doi.org/ 10.1016/j.epsr.2014.06.012  

[16] Vieira, D. A. G., Guedes, L. S. M., Lisboa, A. C., & Saldanha, R. R. (2015). Formulations for hydroelectric energy production with optimality conditions. Energy Conversion and Management, 89, 781-788.

[17] Botterud, A., Levin, T., & Koritarov, V. (2014). Pumped storage hydropower: benefits for grid reliability and integration of variable renewable energy (No. ANL/DIS-14/10). Argonne National Lab.(ANL), Argonne, IL (United States). https://publications.anl.gov/anlpubs/2014/12/106380.pdf

Le Catch 22 dans ce jardin d’Eden

Ça fait un sacré bout de temps depuis ma dernière mise à jour en français sur ce blog, « Discover Social Sciences ». Je n’avais pas écrit en français depuis printemps 2020. Pourquoi je recommence maintenant ? Probablement parce que j’ai besoin d’arranger les idées dans ma tête. Il se passe beaucoup de choses, cette année, et j’avais découvert, déjà en 2017, qu’écrire en français m’aide à mettre de l’ordre dans le flot de mes pensées.

Je me concentre sur un sujet que j’avais déjà développé dans le passé et que je vais présenter à une conférence, ce vendredi. Il s’agit du concept que j’avais nommé « Étangs énergétiques » auparavant et que je présente maintenant comme « Projet aqueduc ». Je commence avec une description générale du concept et ensuite je vais passer en revue un peu de littérature récente sur le sujet.

Oui, bon, le sujet. Le voilà. Il s’agit d’un concept technologique qui combine la rétention contrôlée de l’eau dans les écosystèmes placés le long des fleuves et des rivières avec de la génération d’électricité avec les turbines hydrauliques, le tout sur la base des structures marécageuses. Du point de vue purement hydrologique, une rivière est une gouttière qui collecte l’eau de pluie qui tombe sur la surface de son bassin. Le lit de la rivière est une vallée inclinée qui connecte les points le moins élevés du terrain en question et de de fait l’eau de pluie converge des tous les points du bassin fluvial vers l’embouchure de la rivière.

La civilisation humaine sédentaire est largement basée sur le fait que les bassins fluviaux ont la capacité de retenir l’eau de pluie pour un certain temps avant qu’elle s’évapore ou coule dans la rivière. Ça se retient à la surface – en forme des lacs, étangs ou marécages – et ça se retient sous terre, en forme des couches et des poches aquifères diverses. La rétention souterraine dans les poches aquifères rocheuses est naturellement permanente. L’eau retenue dans une couche aquifère reste là jusqu’au moment où nous la puisons. En revanche, la rétention superficielle ainsi que celle dans les couches aquifères souterraines est essentiellement temporaire. L’eau y est ralentie dans sa circulation, aussi bien dans son mouvement physique vers les points les plus bas du bassin local (la rivière du coin) que dans son évaporation vers l’atmosphère. L’existence même des fleuves et des rivières est aussi une manifestation de circulation ralentie. Le lit de la rivière n’arrive pas à évacuer en temps réel toute l’eau qui s’y agglomère et c’est ainsi que les rivières ont de la profondeur : cette profondeur est la mesure de rétention temporaire de l’eau de pluie.

Ces mécanismes fondamentaux fonctionnent différemment en fonction des conditions géologiques. Maintenant, je me concentre sur les conditions que je connais dans mon environnement à moi, donc sur les écosystèmes des plaines et des vallées de l’Europe du Nord, soit grosso modo au nord des Alpes. Ces écosystèmes sont pour la plupart des moraines post-glaciales de fond, donc c’est de la terre littéralement labourée, sculptée et dénivelée par les glaciers. Il n’y a pas vraiment beaucoup de poches aquifères profondes dans la roche de base, en revanche nous avons beaucoup de couches aquifères relativement proches de la surface. Par conséquent, il n’y a pas beaucoup d’accumulation durable de l’eau, à la différence de l’Europe du Sud et de l’Afrique du Nord, où les poches aquifères rocheuses peuvent retenir des quantités importantes d’eau pendant des décennies, voir des siècles. La circulation de l’eau dans ces écosystèmes des plaines est relativement lente – beaucoup plus lente que dans la montagne – ce qui favorise la présence des rivières larges et pas vraiment très profondes ainsi que la formation des marécages.

Dans ces plaines post-glaciales de l’Europe du Nord, l’eau coule lentement, s’accumule peu et s’évapore vite. La forme idéale des précipitations dans ces conditions géologiques c’est de la neige abondante en hiver – qui fond lentement, goutte par goute, au printemps – ainsi que des pluies lentes en longues. La moraine post-glaciale absorbe bien de l’eau qui arrive lentement, mais n’est pas vraiment faite pour absorber des pluies torrentielles. Avec le changement climatique, les précipitations ont changé. Il y a beaucoup moins de neige en hiver en beaucoup plus des pluies violentes. Si nous voulons avoir du contrôle de notre système hydrologique, il nous faut des technologies de rétention d’eau pour compenser des variations temporaires.

Bon, ça c’est le contexte de mon idée et voilà l’idée elle-même. Elle consiste à créer des structures marécageuses semi-artificielles dans la proximité des rivières et les remplir avec de l’eau pompée desdites rivières. La technologie de pompage est celle du bélier hydraulique : une pompe qui utilise l’énergie cinétique de l’eau courante. Le principe général est un truc ancien. D’après ce que j’ai lu à ce sujet, le principe de base, sous la forme de la roue à aubes , fût déjà en usage dans la Rome ancienne, était très utilisé dans les villes Européennes jusqu’à la fin du 18ème siècle. La technologie du bélier hydraulique – une pompe qui utilise ladite énergie cinétique de l’eau dans un mécanisme similaire au muscle cardiaque – fût victime des aléas de l’histoire. Inventée en 1792 par Joseph de Montgolfier (oui, l’un des fameux frères-ballon), cette technologie n’avait jamais eu l’occasion de montrer tous ses avantages. en 1792 (le même qui, quelques années plus tôt, fit voler, avec son frère Étienne, le premier ballon à air chaud). Au 19ème siècle, avec la création des systèmes hydrauliques modernes avec l’eau courante dans les robinets, les technologies de pompage devaient offrir assez de puissance pour assurer une pression suffisante au niveau des robinets et c’est ainsi que les pompes électriques avaient pris la relève. Néanmoins, lorsqu’il s’agit de pomper lentement de l’eau courante des rivières vers les marécages artificiels, le bélier hydraulique est suffisant.

« Suffisant pour faire quoi exactement ? », peut-on demander. Voilà donc le reste de mon idée. Un ou plusieurs béliers hydrauliques sont plongés dans une rivière. Ils pompent l’eau de la rivière vers des structures marécageuses semi-artificielles. Ces marécages servent à retenir l’eau de pluie (qui coule déjà dans le cours de la rivière). L’eau de la rivière que je pompe vers les marécages c’est l’eau de pluie qui avait gravité, en amont, vers le lit de la rivière. Une fois dans les marécages, cette eau va de toute façon finir par graviter vers le lit de la rivière à quelque distance en amont. Pompage et rétention dans les marécages servent à ralentir la circulation de l’eau dans l’écosystème local. Circulation ralentie veut dire que plus d’eau va s’accumuler dans cet écosystème, comme une réserve flottante. Il y aura plus d’eau dans les couches aquifères souterraines, donc plus d’eau dans les puits locaux et – à la longue – plus d’eau dans la rivière elle-même, puisque l’eau dans la rivière c’est l’eau qui y avait coulé depuis et à travers les réservoirs locaux.

Jusqu’à ce point-là, l’idée se présente donc de façon suivante : rivière => bélier hydraulique => marécages => rivière. Je passe plus loin. Le pompage consiste à utiliser l’énergie cinétique de l’eau courante. L’énergie, ça se conserve par transformation. L’énergie cinétique de l’eau courante se transforme en énergie cinétique de la pompe, qui à son tour se transforme en énergie cinétique du flux vers les marécages.

La surface des marécages est placée au-dessus du lit de la rivière, à moins qu’ils ne soient un polder, auquel cas il n’y a pas besoin de pompage. Une fois l’eau est déversée dans les marécages, ceux-là absorbent donc, dans leur masse, l’énergie cinétique du flux qui se transforme en énergie potentielle de dénivellation. Et si nous amplifions ce phénomène ? Si nous utilisions l’énergie cinétique captée par le bélier hydraulique de façon à minimiser la dispersion dans la masse des marécages et de créer un maximum d’énergie potentielle ? L’énergie potentielle et proportionnelle à l’élévation relative. Plus haut je pompe l’eau de la rivière, plus d’énergie potentielle je récupère à partir de l’énergie cinétique du flux pompé. La solution la plus évidente serait une installation de pompage-turbinage, donc le réservoir de rétention devrait être placé sérieusement plus haut que la rivière. Quoi qu’apparemment la plus évidente et porteuse des principes de base intéressants, cette solution a ses défauts en ce qui concerne sa flexibilité et son coût.

Le principe de base à retenir c’est l’idée d’utiliser l’énergie potentielle de l’eau pompée à une certaine élévation comme un de facto réservoir d’énergie électrique. Il suffit de placer des turbines hydro-électriques en aval de l’eau stockée en élévation. En revanche, les installations de pompage-turbinage sont très coûteuses et très exigeantes en termes d’espace. Le réservoir supérieur dans les installations de pompage-turbinage est censé être soit un lac semi-artificiel soit un réservoir complètement artificiel en de tour, certainement pas un marécage. Il est donc temps que j’explique pourquoi je suis tant attaché à cette forme hydrologique précise. Les marécages sont relativement peu chers à créer et à maintenir, tout en étant relativement faciles à placer près de et de combiner avec les habitations humaines. Par « relativement » je veux dire en comparaison au pompage-turbinage.

Le marécage est un endroit symboliquement négatif dans notre culture. Le mal est tapi dans les marécages. Les marécages sont malsains. Ma théorie tout à fait privée à ce sujet est que dans le passé les colonies humaines, fréquemment celles qui ont finalement donné naissance à des villes, étaient localisées près des marécages. Probablement c’était parce que le niveau d’eau souterraine dans des tels endroits est favorablement haut. Il est facile d’y creuser des puits, d’épandre des fossés d’irrigation, petit gibier y abonde. Seulement voilà, lorsque les homo sapiens abondent, ils se différencient inévitablement en hominides rustiques d’une part et les citadins d’autre part. Ce partage est un mécanisme de base de la civilisation humaine. La campagne produit de la nourriture, la ville produit des nouveaux rôles sociaux, à travers interaction intense dans un espace densément peuplé. L’un des aspects fondamentaux de la ville est qu’elle sert de laboratoire expérimental permanent pour nos technologies, à travers la construction et la reconstruction d’immeubles. Oui, l’architecture, en compagnie du textile, du bâtiment naval et de la guerre, ont toujours été les activités humaines par excellence orientées sur l’innovation technologique.

La ville veut donc dire le bâtiment et le bâtiment a besoin de terre vraiment ferme. Les marécages deviennent ennemis. Il faut les assécher et les séparer durablement de la circulation hydrologique naturelle qui les eût formés pendant des millénaires. Les humains et les marécages ce fût donc un mariage naturel au début, suivie par une crise conjugale due à la nécessité d’apprendre comment faire de la technologie nouvelle et maintenant la technologie vraiment nouvelle rend possible une médiation conjugale dans ce couple. Il y a tout un courant de recherche et innovation architecturale, concentré autour des concepts tels que « les jardins de pluie » (Sharma & Malaviya 2021[1] ; Li, Liu & Li 2020[2] ; Venvik & Boogaard 2020[3]) ou « les villes éponges » (Ma, Jiang & Swallow2020[4] ; Sun, Cheshmehzangi & Wang 2020[5]). Nous sommes en train de développer des technologies qui rendent la cohabitation entre villes et marécages non seulement possible mais bénéfique pour l’environnement et pour les citadins en même temps.

Question : comment utiliser le principe de base de pompage-turbinage, donc le stockage d’énergie potentielle de l’eau placée en élévation, sans construire des structures de pompage-turbinage et en présence des structures marécageuses à la limite de la ville et de la campagne ? Réponse : à travers la construction des tours relativement petites et légères, avec des petits réservoirs d’égalisation au sommet de chaque tour. Un bélier hydraulique bien construit rend possible d’élever l’eau par 20 mètres environ. On peut imaginer donc un réseau des béliers hydrauliques installés dans le cours d’une rivière et connectés à des petites tours de 20 mètres chacune, où chaque tour est équipée d’un tuyau de descente vers les marécages et le tuyau est équipé des petites turbines hydro-électriques.

L’idée complète se présente donc comme suit : rivière => bélier hydraulique => l’eau monte => tours légères de 20 mètres avec des petits réservoirs d’égalisation au sommet => l’eau descend => petites turbines hydro-électriques => marécages => l’eau s’accumule => circulation hydrologique naturelle à travers le sol => rivière.

Bon, où est le Catch 22 dans ce jardin d’Eden ? Dans l’aspect économique. Les béliers hydrauliques de bonne qualité, tels qu’ils sont produits aujourd’hui, sont chers. Il y a très peu de fournisseurs solides de cette technologie. La plupart des béliers hydrauliques en utilisation sont des machins artisanaux à faible puissance et petit débit. L’infrastructure des tours de siphonage avec les turbines hydro-électriques de bonne qualité, ça coûte aussi. Si on veut être sérieux côté électricité, faut équiper tout ce bazar avec des magasins d’énergie. Toute l’infrastructure aurait besoin des frais de maintenance que je ne sais même pas comment calculer. Selon mes calculs, la vente d’électricité produite dans ce circuit hydrologique pourrait assurer un retour sur l’investissement pas plus court que 8 – 9 ans et encore, c’est calculé avec des prix d’électricité vraiment élevés.

Faut que j’y pense (plus).    


[1] Sharma, R., & Malaviya, P. (2021). Management of stormwater pollution using green infrastructure: The role of rain gardens. Wiley Interdisciplinary Reviews: Water, 8(2), e1507. https://doi.org/10.1002/wat2.1507

[2] Li, J., Liu, F., & Li, Y. (2020). Simulation and design optimization of rain gardens via DRAINMOD and response surface methodology. Journal of Hydrology, 585, 124788. https://doi.org/10.1016/j.jhydrol.2020.124788

[3] Venvik, G., & Boogaard, F. C. (2020). Infiltration capacity of rain gardens using full-scale test method: effect of infiltration system on groundwater levels in Bergen, Norway. Land, 9(12), 520. https://doi.org/10.3390/land9120520

[4] Ma, Y., Jiang, Y., & Swallow, S. (2020). China’s sponge city development for urban water resilience and sustainability: A policy discussion. Science of the Total Environment, 729, 139078. https://doi.org/10.1016/j.scitotenv.2020.139078

[5] Sun, J., Cheshmehzangi, A., & Wang, S. (2020). Green infrastructure practice and a sustainability key performance indicators framework for neighbourhood-level construction of sponge city programme. Journal of Environmental Protection, 11(2), 82-109. https://doi.org/10.4236/jep.2020.112007

Alois in the middle

 

I am returning to my syllabuses for the next academic year. I am focusing more specifically on microeconomics. Next year, I am supposed to give lectures in Microeconomics at both the Undergraduate, and the Master’s level. I feel like asking fundamental questions. My fundamental question, as it comes to teaching any curriculum, is the same: what can my students do with it? What is the function and the purpose of microeconomics? Please, notice that I am not asking that frequently stated, rhetorical question ‘What are microeconomics about?’. Well, buddy, microeconomics are about the things you are going to lecture about. Stands to reason. I want to know, and communicate, what is the practical utility, in one’s life, of those things that microeconomics are about.

The basic claim I am focusing on is the following: microeconomics are the accountancy of social structures. They serve exactly the same purpose that any kind of bookkeeping has ever served: to find and exploit patterns in human behaviour, by the means of accurately applied measures. Them ancients, who built those impressive pyramids (who builds a structure without windows and so little free space inside?), very quickly gathered that in order to have one decent pyramid, you need an army of clerks who do the accounting. They used to count stone, people, food, water etc. This is microeconomics, basically.

Thus, you can do with microeconomics if you want to build an ancient pyramid. Now, I am dividing the construction of said ancient pyramid in two stages: Undergraduate, and Master’s. An Undergraduate ancient pyramid requires the understanding of what do you need to keep the accounts of if you don’t want to be thrown to crocodiles. At the Master’s level, you will want to know what are the odds that you find yourself in a social structure, where inaccurate accounting, in connection with a pyramid, will have you thrown to crocodiles.

Good, now some literature, and a little turn by my current scientific work on the EneFin concept (see « Which salesman am I? » and « Sans une once d’utopisme » for sort of a current account of that research). I have just read that sort of transitional form of science, between an article and a book, basically a report, by Bleich and Guimaraes 2016[1]. It regards investment in renewable energies, mostly from the strictly spoken view of investment logic. Return on investment, net present value – that kind of thing. As I was making my notes out of that reading, my mind made a jump, and it landed on the cover of the quite-well-known book by Joseph Schumpeter: ‘Business Cycles’.

Joseph Schumpeter is an intriguing classic, so to say. Born in 1883, he published ‘Business Cycles’ in 1939, being 56 year-old, after the hell of a ride both for him and for the world, and right at the beginning of another ride (for the world). He was studying economics in Austria, in the early 1900, when social sciences in general were sort of different from their today’s version. They were the living account of a world that used to be changing at a breath-taking pace. Young Joseph (well, Alois in the middle) Schumpeter witnessed the rise of Marxism, World War I, the dissolution of his homeland, the Austro-Hungarian Empire, the rise of the German Reich. He moved from academia to banking, and from European banking to American academia.

I deeply believe that whatever kind of story I am telling, whether I am lecturing about economics, discussing a business concept, or chatting about philosophy, at the bottom line I am telling the story of my own existence. I also deeply believe that the same is true for anyone who goes to any lengths in telling a story. We tell stories in order to rationalize that crazy, exciting, unique and deadly something called ‘life’. To me, those ‘Business Cycles’ by Joseph Schumpeter look very much like a rationalized story of quite turbulent a life.

So, here come a few insights I have out of re-reading ‘Business Cycles’ for the n-th time, in the context of research on my EneFin business concept. Any technological change takes place in a chain of value added. Innovation in one tier of the chain needs to overcome the status quo both upstream and downstream of the chain, but once this happens, the whole chain of technologies and goods changes. I wonder how it can apply specifically to EneFin, which is essentially an institutional scheme. In terms of value added, this scheme is situated somewhere between the classical financial markets, and typical social entrepreneurship. It is social to the extent that it creates that quasi-cooperative connexion between the consumers of energy, and its suppliers. Still, as my idea assumes a financial market for those complex contracts « energy + shares in the supplier’s equity », there is a strong capitalist component.

I guess that the resistance this innovation would have to overcome would consist, on one end, in distrust from the part of those hardcore activists of social entrepreneurship, like ‘Anything that has anything to do with money is bad!’, and, on the other hand, there can be resistance from the classical financial market, namely the willingness to forcibly squeeze the EneFin scheme into some kind of established structure, like the stock market.

The second insight that Joseph has just given me is the following: there is a special type of business model and business action, the entrepreneurial one, centred on innovation rather than on capitalizing on the status quo. This is deep, really. What I could notice, so far, in my research, is that in every industry there are business models which just work, and others which just don’t. However innovative you think you are, most of the times either you follow the field-tested patterns or you simply fail. The real, deep technological change starts when this established order gets a wedge stuffed up its ass, and the wedge is, precisely, that entrepreneurial business model. I wonder how entrepreneurial is the business model of EneFin. Is it really as innovative as I think it is?

In the broad theoretical picture, which comes handy as it comes to science, the incidence of that entrepreneurial business model can be measured and assessed as a probability, and that probability, in turn, is a factor of change. My favourite mathematical approach to structural change is that particular mutation that Paul Krugman[2] made out of the classical production function, as initially formulated by Prof Charles W. Cobb and Prof Paul H. Douglas, in their common work from 1928[3]. We have some output generated by two factors, one of which changes slowly, whilst the other changes quickly. In other words, we have one quite conservative factor, and another one that takes on the crazy ride of creative destruction.

That second factor is innovation, or, if you want, the entrepreneurial business model. If it is to be powerful, then, mathematically, incremental change in that innovative factor should bring much greater a result on the side of output than numerically identical an increment in the conservative factor. The classical notation by Cobb and Douglas fits the bill. We have Y = A*F1a*F21-a and a > 0,5. Any change in F1 automatically brings more Y than the identical change in F2. Now, the big claim by Paul Krugman is that if F1 changes functionally, i.e. if its changes really increase the overall Y, resources will flow from F2 to F1, and a self-reinforcing spiral of change forms: F1 induces faster a change than F2, therefore resources are being transferred to F1, and it induces even more incremental change in F1, which, in turn, makes the Y jump even higher etc.

I can apply this logic to my scientific approach of the EneFin concept. I assume that introducing the institutional scheme of EneFin can improve the access to electricity in remote, rural locations, in the developing countries, and, consequently, it can contribute to creating whole new markets and social structures. Those local power systems organized in the lines of EneFin are the factor of innovation, the one with the a > 0,5 exponent in the Y = A*F1a*F21-a function. The empirical application of this logic requires to approximate the value of ‘a’, somehow. In my research on the fundamental link between population and access to energy, I had those exponents nailed down pretty accurately for many countries in the world. I wonder to what extent I can recycle them intellectually for the purposes of my present research.

As I am thinking on this issue, I will keep talking on something else, and the something else in question is the creation of new markets. I go back to the Venerable Man of microeconomics, the Source of All Wisdom, who used to live with his mother when writing the wisdom which he is so reputed for, today. In other words, I am referring to Adam Smith. Still, just to look original, I will quote his ‘Lectures on Justice’ first, rather than going directly to his staple book, namely ‘The Inquiry Into The Nature And Causes of The Wealth of Nations’.

So, in the ‘Lectures on Justice’, Adam Smith presents his basic considerations about contracts (page 130 and on): « That obligation to performance which arises from contract is founded on the reasonable expectation produced by a promise, which considerably differs from a mere declaration of intention. Though I say I have a mind to do such thing for you, yet on account of some occurrences I do not do it, I am not guilty of breach of promise. A promise is a declaration of your desire that the person for whom you promise should depend on you for the performance of it. Of consequence the promise produces an obligation, and the breach of it is an injury. Breach of contract is naturally the slightest of all injuries, because we naturally depend more on what we possess that what is in the hands of others. A man robbed of five pounds thinks himself much more injured than if he had lost five pounds by a contract ».

People make markets, and markets are made of contracts. A contract implies that two or more people want to do some exchange of value, and they want to perform the exchange without coercion. A contract contains a value that one party engages to transfer on the other party, and, possibly, in the case of mutual contracts, another value will be transferred the other way round. There is one thing about contracts and markets, a paradox as for the role of the state. Private contracts don’t like the government to meddle, but they need the government in order to have any actual force and enforceability. This is one of the central thoughts by another classic, Jean-Jacques Rousseau, in his ‘Social Contract’: if we want enforceable contracts, which can make the intervention of the government superfluous, we need a strong government to back up the enforceability of contracts.

If I want my EneFin scheme to be a game-changer in developing countries, it can work only in countries with relatively well-functioning legal systems. I am thinking about using the metric published by the World Bank, the CPIA property rights and rule-based governance rating.

Still another insight that I have found in Joseph Schumpeter’s ‘Business Cycles’ is that when the entrepreneur, introducing a new technology, struggles against the first inertia of the market, that struggle in itself is a sequence of adaptation, and the strategy(ies) applied in the phases of growth and maturity in the new technology, later on, are the outcome of patterns developed during that early struggle. There is some sort of paradox in that struggle. When the early entrepreneur is progressively building his or her presence in the market, they operate under high uncertainty, and, almost inevitably, do a lot of trial and error, i.e. a lot of adjustments to the initially inaccurate prediction of the future. The developed, more mature version of the newly introduced technology is the outcome of that somehow unique sequence of trials, errors, and adjustments.

Scientifically, that insight means a fundamental uncertainty: once the actual implementation of an entrepreneurial business model, such as EneFin, gets inside that tunnel of learning and struggle, it can take on so many different mutations, and the response of the social environment to those mutations can be so idiosyncratic that we get into really serious economic modelling here.

I am consistently delivering good, almost new science to my readers, and love doing it, and I am working on crowdfunding this activity of mine. As we talk business plans, I remind you that you can download, from the library of my blog, the business plan I prepared for my semi-scientific project Befund  (and you can access the French version as well). You can also get a free e-copy of my book ‘Capitalism and Political Power’ You can support my research by donating directly, any amount you consider appropriate, to my PayPal account. You can also consider going to my Patreon page and become my patron. If you decide so, I will be grateful for suggesting me two things that Patreon suggests me to suggest you. Firstly, what kind of reward would you expect in exchange of supporting me? Secondly, what kind of phases would you like to see in the development of my research, and of the corresponding educational tools?

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[1] Bleich, K., & Guimaraes, R. D. (2016). Renewable Infrastructure Investment Handbook: A Guide for Institutional Investors. In World Economic Forum, Geneva.

[2] Krugman, P. (1991). Increasing returns and economic geography. Journal of political economy, 99(3), 483-499.

[3] Charles W. Cobb, Paul H. Douglas, 1928, A Theory of Production, The American Economic Review, Volume 18, Issue 1, Supplement, Papers and Proceedings of the Fortieth Annual Meeting of the American Economic Association (March 1928), pp. 139 – 165

Fire and ice. A real-life business case.

I keep going along the frontier between my scientific research, my small investment business, and my teaching. In this update, I bring you two typically educational pieces of content, one sort of astride educational and practical investment decisions of my own, and finally I give slightly educational an account of a current business decision I am taking.  

In the video entitled ‘My investment experience, my teaching and my science #3  BMW, Daimler and Volkswagen’ [ Invest 3 2020-08-26 14-02-22 ; https://youtu.be/Vot6QMXp7UA  ], I discuss those three investment positions in my portfolio. Three German automotive companies. Same industry, same country, same macroeconomic environment, and yet three different performances in terms of return on investment. In this video, you can see me developing on the distinction between long term-trends and short-term variations, as well as trying to connect technical analysis of price trends with fundamental analysis of their half-annual reports.

I have place on You Tube two pieces of content in the stream of teaching designated as ‘Urban Economics and City Management’. ‘Urban Economics and City Management #1 Lockdowns in pandemic and the role of cities’ [ Cities 1 2020-08-27 08-57-15; https://youtu.be/fYIz_6JVVZk  ] recounts and restates my starting point in this path of research. I browse through the main threads of connection between the pandemic of COVID-19 and the civilisational role of cities. The virus, which just loves densely populated places, makes us question the patterns of urban life, and makes us ask question as for the future of cities.

In ‘Urban Economics and City Management #2 Case study of REIT: Urban Edge and Atrium [Cities 2 2020-08-27 11-00-52 ; https://youtu.be/BURimdfpxcY ], I study the cases of two REITs, i.e. Real Estate Investment Trusts, namely Urban Edge (U.S.) and Atrium (Central Europe), with two assumptions. Firstly, cities can grow and evolve, when the local humans master the craft of agglomerating in one, relatively tiny place, the technologies of construction, sanitation, transportation, energy supply etc., and to parcel those technologies into marketable goods. Secondly, rental and lease of real estate are parcelled, marketable urban technologies.

In the video ‘My investment experience, my teaching and my science #4 The Copernic project’, [ Invest 4 Copernic 2020-08-30 08-57-54 ; https://youtu.be/_6klh0AwJAM  ], I am developing on a topic exactly at the intersection of those three: the Copernic project. Honestly, this is complex stuff. I hesitated to choose this topic as educational material, yet I have that little intuition that good teachers teach useful skills. I want to be a good teacher, and the s**t I teach, I want it to be useful for my students. Life is complex and brutal, business is complex and brutal, and, as a matter of fact, each of us, humans, is complex and brutal. Fake simplicity is for pussies.

Thus, whoever among my students reads this update and watches the accompanying video material, is going to deal with real stuff, far beyond textbooks. This is a business which I am thinking about engaging in, and I am just starting to comprehend its patterns. This update is a living proof and test how good I am, or how I suck, at grasping business models of the digital economy.

In educational terms, I am locating the content relative to Copernic project in the path of teaching which I labelled ‘My investment experience, my teaching and my science’, as I am entertaining the idea of investing in the Copernic project. The subject cuts comprehensively across and into many aspects of economics and management. It can be considered as useful material for any educational path in these major fields.

It started when I reacted to a piece of advertising on Facebook. Yes, many interesting stories start like that, nowadays. It was an ad for the Copernic project itself. Here you have a link to Copernic’s website – https://copernic.io/ – but keep in mind that it is only Polish version, at least for the moment. I will do my best to describe the project in English.

Copernic is both the name of the project, and the name of an LLP (Limited Liability Partnership), incorporated under Polish law, in Krakow, Poland. The commonly used Polish acronym for an LLP is ‘sp. Z o.o.’, however, as I write in English, I will keep using the name ‘Copernic LLP’. I checked this company in the Judicial Register (of incorporated entities) run by the Ministry of Justice of the Republic of Poland, under the link https://ekrs.ms.gov.pl/web/wyszukiwarka-krs/strona-glowna/index.html . A business story emerges. On December 6th, 2019, Copernic LLP is founded, under the register #817764, in Gdansk, Poland, technically by two partners: a physical person and another LLP, i.e. TTC Trade LLP (register #788023). Yet, after scratching the surface, the surface being the Judicial Register, I discovered that TTC Trade LLP is wholly owned by the same physical person who was its partner in Copernic LLP. Anyway, the physical person apported 1000 PLN and took 1 partner share, whilst her LLP paid in 4000 PLN in exchange of 4 partner shares. By the way, PLN stands for Polish zloty and it comes like PLN 1 = $0,27.

On May 6th, 2020, the physical person who founded Copernic LLP steps out of the partnership, and her own LLP, TTC Trade, sells two of its two partner shares in Copernic LLP, to Sapiency LLP (https://sapiency.io/en/, register #789717) incorporated in Krakow, Poland, at their face value of 2000 PLN. On the same day, the partnership contract is being reformulated entirely and signed anew, including a change of headquarters, which move from Gdansk to Krakow, Poland. By the same occasion, another corporate partner steps in, namely Reset Sun Energy LLP (Konin, Poland, register #802147) and takes 2 partner shares in Copernic LLP, for a price of 2000 PLN. By the same means, the total partners’ equity in Copernic LLP moves from 5000 PLN to 6000 PLN.

On July 20th, 2020, TTC Trade LLP and Reset Sun Energy LLP both sell their partner shares in Copernic LLP to Sapiency LLP, at face value, i.e. 6000 PLN. We have an interesting legal structure, when one Limited Liability Partnership (Copernic) is wholly owned by another Limited Liability Partnership (Sapiency), which, in turn, is 50/50 owned by two gentlemen, one of whom I had the honour to meet in person. Cool guy. Fire and ice in one. A bit like me.   

Sapiency is mostly active in cryptocurrencies. They make Blockchain-based tokens for whoever asks, and I think their main technological platform is Ethereum (https://ethereum.org/en/). The marketing model is membership-based, thus oriented on long-term relations with customers. The business model of Copernic LLP is logically connected to that of Sapiency LLP. Copernic builds solar farms in Poland, and markets Blockchain-based tokens labelled Copernic1, at a face value of 4 PLN apiece. Each such token corresponds to a share in the future leasing of solar farms, and those farms, by now, are under actual or planned construction. Later on, i.e. after the solar farms become operational, those lease-connected Copernic1 tokens are supposed to give their holders a claim on secondary tokens CopernicKWH, which, in turn, correspond to claims on electricity generated in those solar farms. The first attribution of CopernicKWH tokens to the holders of Copernic1 tokens is supposed to take place within 14 days after the first photovoltaic farm becomes operational with Copernic LLP, with a standing power of at least 1 MW. That day of operational capacity can be a movable feast, and thus the official statute of those tokens stipulates that the first attribution of CopernicKWH will take place not later than January 1st 2021. After the first attribution of  CopernicKWH, subsequent attributions to the holders of Copernic1 are supposed to take place at least once a week.

The CopernicKWH tokens can be used as means of payment at the Kanga Exchange (https://kanga.exchange ), which looks cool, on the whole, with one exception. According to Kanga’s own statement, ‘Kanga Exchange is operated by Good Investments Ltd, registered in accordance with the International Business Companies Act of the Republic of Seychelles, Company Number 192185’ (https://support.kanga.exchange/company-information/ ). Just for your information: I can incorporate a business in Seychelles without getting up from my desk, 100% online, for the modest sum of 399 British Pounds (https://www.offshoreformations247.com/offshore-jurisdictions/seychelles). I am fully aware how bloody hard it is to set up any business structure connected to cryptocurrencies in the European legal environment, however… Seychelles? Seriously?

The average price of electricity in Poland, when I am writing those words, is around 0,617 PLN per 1 kWh. One Copernic1 token, with its current price of 4 PLN, corresponds to 4/0,617 = 6,48 kWh of energy. Assuming that every week, starting from the day 0 of operations at the solar farm, Copernic LLP attributes me 1 CopernicKWH token for each Copernic1 token in my possession, I break even after 7 weeks, and each consecutive week brings me a net profit.

I do my maths according to the logic of the capital balance sheet. First of all, I want to compute the book value of assets that corresponds to the planned solar farm of 1 megawatt in standing power. In a report published by the International Renewable Energy Agency (IRENA https://irena.org ), entitled ‘Renewable Power Generation Costs in 2019’ (https://irena.org/publications/2020/Jun/Renewable-Power-Costs-in-2019 ), I can read that the average investment needed for 1 watt of power in a photovoltaic installation can be cautiously estimated at $0,38, thus PLN 1,40.

Building a solar farm of 1 MW, thus of a million watts in terms of electric power, means an investment of at least PLN 1,40 * 106 = PLN 1 400 000. To that, you need to add the price of acquiring land. At the end of the day, I would tentatively put a PLN 2 million capital tag on the project. Supposing that capital for the project comes from the sales of Copernic1 tokens, Copernic LLP needs to sell at least 2 000 000 PLN/ 4 PLN = 500 000 of them Copernic1.

Looks like a lot, especially for a Limited Liability Partnership with partner equity at 6000 PLN. Assets worth PLN 2 000 000 minus PLN 6000 in partner equity means PLN 1 994 000 = $ 538 919  in capital which is not clear at all where it is supposed to come from. The sole partner in Copernic LLP, namely Sapiency LLP could pay in additional equity. Happens all the time. Still, Sapiency LLP as a partner equity of PLN 5000. See what I mean? Another option is a massive loan, and, finally, the whole balance sheet could rely mostly on those Copernic1 tokens. Only those tokens are supposed to embody claims on the lease of the solar farm. Now, legally, a lease is a contract which gives to the lessee (the one who physically exploits), the right to exploit things or rights owned by the lessor (the one who graciously allows others to exploit). In exchange, the lessee pays a rent to the lessor.

There are two things about that lease of solar farms. A lease is not really divisible, as it is the right to exploit something. If you divide that something into smaller somethings, you split the initial lease into as many separate leases. If I buy one Copernic1 token and that token embodies claims derived from a lease contract, what specifically is the object of leasing? There is another thing. If I buy Copernic1 tokens, it gives me claims on the future CopernicKWH tokens. In other words, Copernic will pay me in the future. If they pay me, on the basis of a lease contract, it is as if they were paying me a rent, i.e. as if they were leasing that solar farm from me. Only I don’t have that solar farm. They will have it. Yes, indeed, WTF? This is the moment to ask that rhetorical question.

A few paragraphs ago, I wrote that I am entertaining the idea of investing in those Copernic1 tokens. I think the idea has become much less attractive, business-wise, whilst becoming much more entertaining. There is an important question, though. Isn’t it ethically advisable to invest in renewable energies, even if the legal scheme is a bit sketchy, just to push forward those renewables? I can give an answer in two parts to that question. Firstly, renewables grow like hell, both in terms of power supplied, and in terms of attractiveness in financial markets. They really don’t need any exceptional push. They walk, and even run on their own legs. Secondly, I worked through my own ideas for implementing new technologies in the field of renewable energies, and, notably, I worked a lot with a tool called ‘Project Navigator’, run by the same International Renewable Energy Agency which I quoted earlier. The link is here: https://irena.org/navigator . There is one sure takeaway I have from working with that tool: a good project needs a solid, transparent, 100% by-the-book institutional base. Wobbly contracts translate into wobbly financing, and that, in turn, means grim prospects for the project in question.     

Another doubt arises in my mind, as I do flows instead of balances. A solar farm needs to earn money, i.e. to make profit, in order to assure a return on investment. The only asset which can earn value over time is land in itself. In practical terms, as long as we want that solar farm to work, it needs to generate a positive operational cash flow. Photovoltaic equipment ages inexorably, by physical wear and tear as well as by relative moral obsolescence. That aging can assure substantial amortization, yet you need some kind of revenue which you can write that amortization off from. If all or a substantial part of energy produced in the solar farm is tokenized and attributed to the holders of Copernic1, lease-based tokens, there could be hardly any energy left for sale, hence not much of a revenue. In other words, the system of initial financing with tokens can jeopardize economic payoff from the project, and that’s another thing I learnt with the Project Navigator: you need a solid economic base, and there is no way around it.

A test pitch of my ‘Energy Ponds’ business concept

I am returning to a business concept I have been working on for many months, and which I have provisionally labelled ‘Energy Ponds’. All that thinking about new economic solutions for a world haunted by insidious pathogens – no, not selfie sticks, I am talking about the other one, COVID-19 – pushed me to revisit fundamentally the concept of Energy Ponds, and you, my readers, you are my rubber duck.

The rubber duck (Latin: anas flexilis), also known as bath duck (anas balneum) is a special semi-aquatic avian species, whose valour I know from my son, IT engineer by profession. Every now and then, he says, on the phone: ‘Dad, focus, you are going to be my rubber duck’. The rubber duck is an imaginary animal. It feeds on discursive waters. You talk to it in order to get your own thoughts straight. When I am my son’s rubber duck, he explains me some programming problems and solutions, he checks if I understand what he says, and when I test positive, it means that he can get the message across to any moderately educated hominid.

I am going to proceed along the path of discursive equilibrium, in a cycle made of three steps. First, I will try to describe my idea in 1 – 2 sentences, in a simple and intelligible way. Then, I develop on that short description, with technical details. In the third step, I look for gaps and holes in the so-presented concept, and then I go again: short description, development, critical look etc. I think I will repeat the cycle until I reach the Subjective Feeling of Having Exhausted the Matter. Nelson Goodman and John Rawls proposed something slightly similar (Goodman 1955[1]; Rawls 1999[2]): when I talk long enough to myself, and to an imaginary audience, my concepts sharpen.   

Here I go. First attempt. I synthesize. The concept of ‘Energy Ponds’ consists in ram-pumping water from rivers into retentive, semi-natural wetlands, so as to maximize the retention of water, and, in the same time, in using the elevation created through ram-pumping so as to generate hydroelectricity. At the present stage of conceptual development, ‘Energy Ponds’ require optimization at two levels, namely that of adequately choosing and using the exact geographical location, and that of making the technology of ram-pumping economically viable.  

I develop. We are increasingly exposed to hydrological effects of climate change, namely to recurrent floods and droughts, and it starts being a real pain in the ass. We need to figure out new ways of water management, so as to retain a maximum of rainwater, whilst possibly alleviating occasional flood-flows. Thus, we need to figure out good ways of capturing rainwater, and of retaining it. Rivers are the drainpipes of surrounding lands, whence the concept of draining basin: this is the expanse of land, adjacent to a river, where said river collects (drains) water from. That water comes from atmospheric precipitations. When we collect water from rivers, we collect rainwater, which fell on the ground, trickled underground, and then, under the irresistible force of grandpa Newton, flew towards the lowest point in the whereabouts, that lowest point being the river.

Thus, when we collect water from the river, we collect rainwater, just drained through land. We can collect it in big artificial reservoirs, which has been done for decades. An alternative solution is to retain water in wetlands. This is something that nature has been doing for millions of years. We have sort of a ready-made recipe from. Wetlands are like sponges covered with towels. A layer of spongy ground, allowing substantial accumulation of water, is covered with a dense, yet not very thick layer of shallowly rooted vegetation. That cover layer prevents the evaporation of water.  

Now, I go into somehow novel a form of expression, i.e. novel for me. The age I am, 52, I have that slightly old school attachment to writing, and for the last 4 years, I have been mostly writing on my blog. Still, as a university professor, I work with young people – students – and those young people end up, every now and then, by teaching me something. I go more visual in my expression, which this whole written passage can be considered as an introduction to. Under the two links below, you will find:

  1. The Power Point Presentation with a regular pitch of my idea

That would be all in this update. Just as with my other ideas, in the times we have, i.e. with the necessity to figure out new s**t in the presence of pathogens, you are welcome to contact me with any intellectual contribution you feel like supplying.  

If you want to contact me directly, you can mail at: goodscience@discoversocialsciences.com .


[1] Goodman, N. (1955) Fact, Fiction, and Forecast, Cambridge, Mass., Harvard University Press, pp. 65–68

[2] Rawls J. (1999) A Theory of Justice. Revised Edition, President and Fellows of Harvard College, ISBN 0-674-00078-1, p. 18

The mind-blowing hydro

My editorial on You Tube

There is that thing about me: I am a strange combination of consistency and ADHD. If you have ever read one of Terry Pratchett’s novels from the ‘Discworld’ series, you probably know the imaginary character of golems: made of clay, with a logical structure – a ‘chem’ – put in their heads, they can work on something endlessly. In my head, there are chems, which just push me to do things over and over and over again. Writing and publishing on that research blog is very much in those lines. I can stop whenever I want, I just don’t want right now. Yet, when I do a lot about one chem, I start craving for another one, like nearby but not quite in the same intellectual location.

Right now, I am working on two big things. Firstly, I feel like drawing a provisional bottom line under those two years of science writing on my blog. Secondly, I want to put together an investment project that would help my city, my country and my continent, thus Krakow, Poland, and Europe, to face one of the big challenges resulting from climate change: water management. Interestingly, I started to work on the latter first, and only then I began to phrase out the former. I explain. As I work on that project of water management, which I provisionally named « Energy Ponds » (see, for example, « All hope is not lost: the countryside is still exposed »), I use the « Project Navigator », made available by the courtesy of the International Renewable Energy Agency (IRENA). The logic built into the « Project Navigator » makes me return, over and over again, to one central question: ‘You, Krzysztof Wasniewski, with your science and your personal energy, how are you aligned with that idea of yours? How can you convince other people to put their money and their personal energy into developing on your concept?’.

And so I am asking myself: ‘What’s your science, bro? What can you get people interested in, with rational grounds and intelligible evidence?’.

As I think about it, my first basic claim is that we can do it together in a smart way. We can act as a collective intelligence. This statement can be considered as a manifestation of the so-called “Bignetti model” in cognitive sciences (Bignetti 2014[1]; Bignetti et al. 2017[2]; Bignetti 2018[3]): for the last two years, I have been progressively centering my work around the topic of collective intelligence, without even being quite aware of it. As I was working on another book of mine, entitled “Capitalism and Political Power”, I came by that puzzling quantitative fact: as a civilization, we have more and more money per unit of real output[4], and, as I reviewed some literature, we seem not to understand why is that happening. Some scholars complain about the allegedly excessive ‘financialization of the economy’ (Krippner 2005[5]; Foster 2007[6]; Stockhammer 2010[7]), yet, besides easy generalizations about ‘greed’, or ‘unhinged race for profit’, no scientifically coherent explanation is offered regarding this phenomenon.

As I was trying to understand this phenomenon, shades of correlations came into my focus. I could see, for example, that growing an amount of money per unit of real output has been accompanied by growing an amount of energy consumed per person per year, in the global economy[8]. Do we convert energy into money, or the other way around? How can it be happening? In 2008, the proportion between the global supply of broad money, and the global real output passed the magical threshold of 100%. Intriguingly, the same year, the share of urban population in the total human population passed the threshold of 50%[9], and the share of renewable energy in the total final consumption of energy, at the global scale, took off for the first time since 1999, and keeps growing since then[10]. I started having that diffuse feeling that, as a civilization, we are really up to something, right now, and money is acting like a social hormone, facilitating change.

We change as we learn, and we learn as we experiment with the things we invent. How can I represent, in a logically coherent way, collective learning through experimentation? When an individual, or a clearly organized group learns through experimentation, the sequence is pretty straightforward: we phrase out an intelligible definition of the problem to solve, we invent various solutions, we test them, we sum up the results, we select seemingly the best solution among those tested, and we repeat the whole sequence. As I kept digging the topic of energy, technological change, and the velocity of money, I started formulating the outline of a complex hypothesis: what if we, humans, are collectively intelligent about building, purposefully, and semi – consciously, social structures supposed to serve as vessels for future collective experiments?

My second claim is that one of the smartest things we can do about climate change is, besides reducing our carbon footprint, to take proper care of our food and energy base. In Europe, climate change is mostly visible as a complex disruption to our water system, and we can observe it in our local rivers. That’s the thing about Europe: we have built our civilization, on this tiny, mountainous continent, in close connection with rivers. Right, I can call them scientifically ‘inland waterways’, but I think that when I say ‘river’, anybody who reads it understands intuitively. Anyway, what we call today ‘the European heritage’ has grown next to EVENLY FLOWING rivers. Once again: evenly flowing. It means that we, Europeans, are used to see the neighbouring river as a steady flow. Streams and creeks can overflow after heavy rains, and rivers can swell, but all that stuff had been happening, for centuries, very recurrently.

Now, with the advent of climate change, we can observe three water-related phenomena. Firstly, as the English saying goes, it never rains but it pours. The steady rhythm and predictable volume of precipitations we are used to, in Europe (mostly in the Northern part), progressively gives ground to sudden downpours, interspersed with periods of drought, hardly predictable in their length. First moral of the fairy tale: if we have less and less of the kind of water that falls from the sky slowly and predictably, we need to learn how to capture and retain the kind of water that falls abruptly, unscheduled. Secondly, just as we have adapted somehow to the new kind of sudden floods, we have a big challenge ahead: droughts are already impacting, directly and indirectly, the food market in Europe, but we don’t have enough science yet to predict accurately neither their occurrence nor their local impact. Yet, there is already one emerging pattern: whatever happens, i.e. floods or droughts, rural populations in Europe suffer more than the urban ones (see my review of literature in « All hope is not lost: the countryside is still exposed »). Second moral of the fairy tale: whatever we do about water management in these new conditions, in Europe, we need to take care of agriculture first, and thus to create new infrastructures so as to shield farms against floods and droughts, cities coming next in line.

Thirdly, the most obviously observable manifestation of floods and droughts is variation in the flow of local rivers. By the way, that variation is already impacting the energy sector: when we have too little flow in European rivers, we need to scale down the output of power plants, as they have not enough water to cool themselves. Rivers are drainpipes of the neighbouring land. Steady flow in a river is closely correlated with steady a level of water in the ground, both in the soil, and in the mineral layers underneath. Third moral of the fairy tale: if we figure out workable ways of retaining as much rainfall in the ground as possible, we can prevent all the three disasters in the same time, i.e. local floods, droughts, and economically adverse variations in the flow of local rivers.           

I keep thinking about that ownership-of-the-project thing I need to cope with when using the « Project Navigator » by IRENA. How to make local communities own, as much as possible, both the resources needed for the project, and its outcomes? Here, precisely, I need to use my science, whatever it is. People at IRENA have experience in such project, which I haven’t. I need to squeeze my brain and extract thereof any useful piece of coherent understanding, to replace experience. I am advancing step by step. I intuitively associate ownership with property rights, i.e. with a set of claims on something – things or rights – together with a set of liberties of action regarding the same things or rights. Ownership from the part of a local community means that claims and liberties should be sort of pooled, and the best idea that comes to my mind is an investment fund. Here, a word of explanation is due: an investment fund is a general concept, whose actual, institutional embodiment can take the shape of a strictly speaking investment fund, for one, and yet other legal forms are possible, such as a trust, a joint stock company, a crowdfunding platform, or even a cryptocurrency operating in a controlled network. The general concept of an investment fund consists in taking a population of investors and making them pool their capital resources over a set of entrepreneurial projects, via the general legal construct of participatory titles: equity-based securities, debt-based ones, insurance, futures contracts, and combinations thereof. Mind you, governments are investment funds too, as regards their capacity to move capital around. They somehow express the interest of their respective populations in a handful of investment projects, they take those populations’ tax money and spread it among said projects. That general concept of investment fund is a good expression of collective intelligence. That thing about social structure for collective experimentation, which I mentioned a few paragraphs ago, an investment fund is an excellent example. It allows spreading resources over a number of ventures considered as local experiments.

Now, I am dicing a few ideas for a financial scheme, based on the general concept of an investment fund, as collectively intelligent as possible, in order to face the new challenges of climate change, through new infrastructures for water management. I start with reformulating the basic technological concept. Water powered water pumps are immersed in the stream of a river. They use the kinetic energy of that stream to pump water up and further away, more specifically into elevated water towers, from which that water falls back to the ground level, as it flows down it powers relatively small hydroelectric turbines, and ends up in a network of ponds, vegetal complexes and channel-like ditches, all that made with a purpose of retaining as much water as possible. Those structures can be connected to others, destined directly to capture rainwater. I was thinking about two setups, respectively for rural environments and for the urban ones. In the rural landscape, those ponds and channels can be profiled so as to collect rainwater from the surface of the ground and conduct it into its deeper layers, through some system of inverted draining. I think it would be possible, under proper geological conditions, to reverse-drain rainwater into deep aquifers, which the neighbouring artesian wells can tap into. In the urban context, I would like to know more about those Chinese technologies used in their Sponge Cities programme (see Jiang et al. 2018[11]).

The research I have done so far suggests that relatively small, local projects work better, for implementing this type of technologies, than big, like national scale endeavours. Of course, national investment programmes will be welcome as indirect support, but at the end of the day, we need a local community owning a project, possibly through an investment-fund-like institutional arrangement. The economic value conveyed by any kind of participatory title in such a capital structure sums up to the Net Present Value of three cash flows: net proceeds from selling hydroelectricity produced in small water turbines, reduction of the aggregate flood-related risk, as well as of the drought-related risk. I separate risks connected to floods from those associated with droughts, as they are different in nature. In economic and financial terms, floods are mostly a menace to property, whilst droughts materialize as more volatile prices of food and basic agricultural products.

In order to apprehend accurately the Net Present Value of any cash flow, we need to set a horizon in time. Very tentatively, by interpreting data from 2012, presented in a report published by IRENA (the same IRENA), I assume that relatively demanding investors in Europe expect to have a full return on their investment within 6,5 years, which I make 7 years, for the sake of simplicity. Now, I go a bit off the beaten tracks, at least those I have beaten so far. I am going to take the total atmospheric precipitations falling on various European countries, which means rainfall + snowfall, and then try to simulate what amount of ‘NPV = hydroelectricity + reduction of risk from floods and droughts’(7 years) could the retention of that water represent.

Let’s walse. I take data from FAOSTAT regarding precipitations and water retention. As a matter of fact, I made a query of that data regarding a handful of European countries. You can have a look at the corresponding Excel file UNDER THIS LINK. I rearranged bit the data from this Excel file so as to have a better idea of what could happen, if those European countries I have on my list, my native Poland included, built infrastructures able to retain 2% of the annual rainfall. The coefficient of 2% is vaguely based on what Shao et al. (2018[12]) give as the target retention coefficient for the city of Xiamen, China, and their Sponge-City-type investment. I used the formulas I had already phrased out in « Sponge Cities », and in « La marge opérationnelle de $1 539,60 par an par 1 kilowatt », to estimate the amount of electricity possible to produce out of those 2% of annual rainfall elevated, according to my idea, into 10-metres-high water towers. On the top of all that, I added, for each country, data regarding the already existing capacity to retain water. All those rearranged numbers, you can see them in the Excel file UNDER THIS OTHER LINK (a table would be too big for inserting into this update).   

The first provisional conclusion I have to make is that I need to revise completely my provisional conclusion from « Sponge Cities », where I claimed that hydroelectricity would have no chance to pay for any significant investment in sponge-like structures for retaining water. The calculations I have just run show just the opposite: as soon as we consider whole countries as rain-retaining basins, the hydroelectric power, and the cash flow dormant in that water is just mind-blowing. I think I will need to get a night of sleep just to check on the accuracy of my calculations.

Deranging as they are, my calculations bear another facet. I compare the postulated 2% of retention in annual precipitations with the already existing capacity of these national basins to retain water. That capacity is measured, in that second Excel file, by the ‘Coefficient of retention’, which denominates the ‘Total internal renewable water resources (IRWR)’ over the annual precipitation, both in 10^9 m3/year. My basic observation is that European countries have a capacity to retain water very similar in disparity to the intensity of precipitations, measured in mm per year. Both coefficients vary in a similar proportion, i.e. their respective standard deviations make around 0,4 of their respective means, across the sample of 37 European countries. When I measure it with the Pearson coefficient of correlation between the intensity of rainfall and the capacity to retain it , it yields r = 0,63. In general, the more water falls from the sky per 1 m2, the greater percentage of that water is retained, as it seems. Another provisional conclusion I make is that the capacity to retain water, in a given country, is some kind of response, possibly both natural and man-engineered, to a relatively big amount of water falling from the sky. It looks as if our hydrological structures, in Europe, had been built to do something with water we have momentarily plenty of, possibly even too much of, and which we should save for later.

I am consistently delivering good, almost new science to my readers, and love doing it, and I am working on crowdfunding this activity of mine. You can communicate with me directly, via the mailbox of this blog: goodscience@discoversocialsciences.com. As we talk business plans, I remind you that you can download, from the library of my blog, the business plan I prepared for my semi-scientific project Befund  (and you can access the French version as well). You can also get a free e-copy of my book ‘Capitalism and Political Power’ You can support my research by donating directly, any amount you consider appropriate, to my PayPal account. You can also consider going to my Patreon page and become my patron. If you decide so, I will be grateful for suggesting me two things that Patreon suggests me to suggest you. Firstly, what kind of reward would you expect in exchange of supporting me? Secondly, what kind of phases would you like to see in the development of my research, and of the corresponding educational tools?


[1] Bignetti, E. (2014). The functional role of free-will illusion in cognition:“The Bignetti Model”. Cognitive Systems Research, 31, 45-60.

[2] Bignetti, E., Martuzzi, F., & Tartabini, A. (2017). A Psychophysical Approach to Test:“The Bignetti Model”. Psychol Cogn Sci Open J, 3(1), 24-35.

[3] Bignetti, E. (2018). New Insights into “The Bignetti Model” from Classic and Quantum Mechanics Perspectives. Perspective, 4(1), 24.

[4] https://data.worldbank.org/indicator/FM.LBL.BMNY.GD.ZS last access July 15th, 2019

[5] Krippner, G. R. (2005). The financialization of the American economy. Socio-economic review, 3(2), 173-208.

[6] Foster, J. B. (2007). The financialization of capitalism. Monthly Review, 58(11), 1-12.

[7] Stockhammer, E. (2010). Financialization and the global economy. Political Economy Research Institute Working Paper, 242, 40.

[8] https://data.worldbank.org/indicator/EG.USE.PCAP.KG.OE last access July 15th, 2019

[9] https://data.worldbank.org/indicator/SP.URB.TOTL.IN.ZS last access July 15th, 2019

[10] https://data.worldbank.org/indicator/EG.FEC.RNEW.ZS last access July 15th, 2019

[11] Jiang, Y., Zevenbergen, C., & Ma, Y. (2018). Urban pluvial flooding and stormwater management: A contemporary review of China’s challenges and “sponge cities” strategy. Environmental science & policy, 80, 132-143.

[12] Shao, W., Liu, J., Yang, Z., Yang, Z., Yu, Y., & Li, W. (2018). Carbon Reduction Effects of Sponge City Construction: A Case Study of the City of Xiamen. Energy Procedia, 152, 1145-1151.

All hope is not lost: the countryside is still exposed

My editorial on You Tube

I am focusing on the possible benefits of transforming urban structures of at least some European cities into sponge-like structures, such as described, for example, by Jiang et al. (2018) as well as in my recent updates on this blog (see Sponge Cities). In parallel to reporting my research on this blog, I am developing a corresponding project with the « Project Navigator », made available by the courtesy of the International Renewable Energy Agency (IRENA). Figuring out my way through the « Project Navigator » made me aware of the importance that social cohesion has in the implementation of such infrastructural projects. Social cohesion means a set of common goals, and an institutional context that allows the appropriation of outcomes. In « Sponge Cities », when studying the case of my hometown, Krakow, Poland, I came to the conclusion that sales of electricity from water turbines incorporated into the infrastructure of a sponge city could hardly pay off for the investment needed. On the other hand, significant reduction of the financially quantifiable risk connected to floods and droughts can be an argument. Especially the flood-related risks, in Europe, already amount to billions of euros, and we seem to be just at the beginning of the road (Alfieri et al. 2015[1]). Shielding against such risks can possibly make a sound base for social coherence, as a common goal. Hence, as I am structuring the complex concept of « Energy Ponds », I start with assessing risks connected to climate change in European cities, and the possible reduction of those risks through sponge-city-type investments.

I start with comparative a review of Alfieri et al. 2015[2] as regards flood-related risks, on the one hand, and Naumann et al. (2015[3]) as well as Vogt et al. (2018[4]) regarding the drought-related risks. As a society, in Europe, we seem to be more at home with floods than with droughts. The former is something we kind of know historically, and with the advent of climate change we just acknowledge more trouble in that department, whilst the latter had been, until recently, something that happens essentially to other people on other continents. The very acknowledgement of droughts as a recurrent risk is a challenge.

Risk is a quantity: this is what I teach my students. It is the probability of occurrence multiplied by the magnitude of damage, should the s**t really hit the fan. Why adopting such an approach? Why not to assume that risk is just the likelihood of something bad happening? Well, because risk management is practical. There is any point in bothering about risk if we can do something about it: insure and cover, hedge, prevent etc. The interesting thing about it is that all human societies show a recurrent pattern: as soon as we organise somehow, we create something like a reserve of resources, supposed to provide for risk. We are exposed to a possible famine? Good, we make a reserve of food. We risk to be invaded by a foreign nation/tribe/village/alien civilisation? Good, we make an army, i.e. a group of people, trained and equipped for actions with no immediate utility, just in case. The nearby river can possibly overflow? Good, we dig and move dirt, stone, wood and whatnot so as to build stopbanks. In each case, we move along the same path: we create a pooled reserve of something, in order to minimize the long-term damage from adverse events.

Now, if we wonder how much food we need to have in stock in case of famine, sooner or later we come to the conclusion that it is individual need for food multiplied by the number of people likely to be starving. That likelihood is not evenly distributed across the population: some people are more exposed than others. A farmer, with a few pigs and some potatoes in cultivation is less likely to be starving than a stonemason, busy to build something and not having time or energy to care for producing food. Providing for the risk of flood works according to the same scheme: some structures and some people are more likely to suffer than others.

We apprehend flood and drought-related risks in a similar way: those risks amount to a quantity of resources we put aside, in order to provide for the corresponding losses, in various ways. That quantity is the arithmetical product of probability times magnitude of loss.    

Total risk is a complex quantity, resulting from events happening in causal, heterogeneous chains. A river overflows and destroys some property: this is direct damage, the first occurrence in the causal chain. Among the property damaged, there are garbage yards. As water floods them, it washes away and further into the surrounding civilisation all kinds of crap, properly spoken crap included. The surrounding civilisation gets contaminated, and decontamination costs money: this is indirect damage, the second tier of the causal chain. Chemical and biological contamination by floodwater causes disruptions in the businesses involved, and those disruptions are costly, too: here goes the third tier in the causal chain etc.

I found some interesting insights, regarding the exposure to flood and drought-related risks in Europe, with Paprotny et al. (2018[5]). Firstly, this piece of research made me realized that floods and droughts do damage in very different ways. Floods are disasters in the most intuitive sense of the term: they are violent, and they physically destroy man-made structures. The magnitude of damage from floods results from two basic variables: the violence and recurrence of floods themselves, on the one hand, and the value of human structures affected. In a city, a flood does much more damage because there is much more property to destroy. Out there, in the countryside, damages inflicted by floods change from the disaster-type destruction into more lingering, long-term impediments to farming (e.g. contamination of farmed soil), as the density of man-made structures subsides. Droughts work insidiously. There is no spectacular disaster to be afraid of. Adverse outcomes build up progressively, sometimes even year after year. Droughts affect directly the countryside much more than the cities, too. It is rivers drying out first, and only in a second step, cities experiencing disruptions in the supply of water, or of the rivers-dependent electricity. It is farm soil drying out progressively, and farmers suffering some damage due to lower crops or increased costs of irrigation, and only then the city dwellers experiencing higher prices for their average carrot or an organic cereal bar. Mind you, there is one type of drought-related disaster, which sometimes can directly affect our towns and cities: forest fires.

Paprotny et al. (2018) give some detailed insights into the magnitude, type, and geographical distribution of flood-related risks in Europe. Firstly, the ‘where exactly?’. France, Spain, Italy, and Germany are the most affected, with Portugal, England, Scotland, Poland, Czech Republic, Hungary, Romania and Portugal following closely behind. As to the type of floods, France, Spain, and Italy are exposed mostly to flash floods, i.e. too much rain falling and not knowing where to go. Germany and virtually all of Central Europe, my native Poland included, are mostly exposed to river floods. As for the incidence of human fatalities, flash-floods are definitely the most dangerous, and their impact seems to be the most serious in the second half of the calendar year, from July on.

Besides, the research by Paprotny et al. (2018) indicates that in Europe, we seem to be already on the path of adaptation to floods. Both the currently observed losses –human and financial – and their 10-year, moving average had their peaks between 1960 and 2000. After 2000, Europe seems to have been progressively acquiring the capacity to minimize the adverse impact of floods, and this capacity seems to have developed in cities more than in the countryside. It truly gives a man a blow, to their ego, when they learn the problem they want to invent a revolutionary solution to does not really exist. I need to return on that claim I made in the « Project Navigator », namely that European cities are perfectly adapted to a climate that does no longer exist. Apparently, I was wrong: European cities seem to be adapting quite well to the adverse effects of climate change. Yet, all hope is not lost. The countryside is still exposed. Now, seriously. Whilst Europe seem to be adapting to greater an occurrence of floods, said occurrence is most likely to increase, as suggested, for example, in the research by Alfieri et al. (2017[6]). That sends us to the issue of limits to adaptation and the cost thereof.

Let’s rummage through more literature. As I study the article by Lu et al. (2019[7]), which compares the relative exposure to future droughts in various regions of the world, I find, first of all, the same uncertainty which I know from Naumann et al. (2015), and Vogt et al. (2018): the economically and socially important drought is a phenomenon we just start to understand, and we are still far from understanding it sufficiently to assess the related risks with precision. I know that special look that empirical research has when we don’t really have a clue what we are observing. You can see it in the multitude of analytical takes on the same empirical data. There are different metrics for detecting drought, and by Lu et al. (2019) demonstrate that assessment of drought-related losses heavily depends on the metric used. Once we account for those methodological disparities, some trends emerge. Europe in general seems to be more and more exposed to long-term drought, and this growing exposure seems to be pretty consistent across various scenarios of climate change. Exposure to short-term episodes of drought seems to be growing mostly under the RCP 4.5 and RCP 6.0 climate change scenarios, a little bit less under the RCP 8.5 scenario. In practical terms it means that even if we, as a civilisation, manage to cut down our total carbon emissions, as in the RCP 4.5. climate change scenario, the incidence of drought in Europe will be still increasing. Stagge et al. (2017[8]) point out that exposure to drought in Europe diverges significantly between the Mediterranean South, on the one hand, and the relatively colder North. The former is definitely exposed to an increasing occurrence of droughts, whilst the latter is likely to experience less frequent episodes. What makes the difference is evapotranspiration (loos of water) rather than precipitation. If we accounted just for the latter, we would actually have more water

I move towards more practical an approach to drought, this time as an agricultural phenomenon, and I scroll across the article on the environmental stress on winter wheat and maize, in Europe, by Webber et al. (2018[9]). Once again, I can see a lot of uncertainty. The authors put it plainly: models that serve to assess the impact of climate change on agriculture violate, by necessity, one of the main principles of statistical hypotheses-testing, namely that error terms are random and independent. In these precise models, error terms are not random, and not mutually independent. This is interesting for me, as I have that (recent) little obsession with applying artificial intelligence – a modest perceptron of my own make – to simulate social change. Non-random and dependent error terms are precisely what a perceptron likes to have for lunch. With that methodological bulwark, Webber et al. (2018) claim that regardless the degree of the so-called CO2 fertilization (i.e. plants being more active due to the presence of more carbon dioxide in the air), maize in Europe seems to be doomed to something like a 20% decline in yield, by 2050. Winter wheat seems to be rowing on a different boat. Without the effect of CO2 fertilization, a 9% decline in yield is to expect, whilst with the plants being sort of restless, and high on carbon, a 4% increase is in view. With Toreti et al. (2019[10]), more global a take is to find on the concurrence between climate extremes, and wheat production. It appears that Europe has been experiencing increasing an incidence of extreme heat events since 1989, and until 2015 it didn’t seem to affect adversely the yield of wheat. Still, since 2015 on, there is a visible drop in the output of wheat. Even stiller, if I may say, less wheat is apparently compensated by more of other cereals (Eurostat[11], Schills et al. 2018[12]), and accompanied by less potatoes and beets.

When I first started to develop on that concept, which I baptised “Energy Ponds”, I mostly thought about it as a way to store water in rural areas, in swamp-and-meadow-like structures, to prevent droughts. It was only after I read a few articles about the Sponge Cities programme in China that I sort of drifted towards that more urban take on the thing. Maybe I was wrong? Maybe the initial concept of rural, hydrological structures was correct? Mind you, whatever we do in Europe, it always costs less if done in the countryside, especially regarding the acquisition of land.

Even in economics, sometimes we need to face reality, and reality presents itself as a choice between developing “Energy Ponds” in urban environment, or in rural one. On the other hand, I am rethinking the idea of electricity generated in water turbines paying off for the investment. In « Sponge Cities », I presented a provisional conclusion that it is a bad idea. Still, I was considering the size of investment that Jiang et al. (2018) talk about in the context of the Chinese Sponge-Cities programme. Maybe it is reasonable to downsize a bit the investment, and to make it sort of lean and adaptable to the cash flow possible to generate out of selling hydropower.    

I am consistently delivering good, almost new science to my readers, and love doing it, and I am working on crowdfunding this activity of mine. You can communicate with me directly, via the mailbox of this blog: goodscience@discoversocialsciences.com. As we talk business plans, I remind you that you can download, from the library of my blog, the business plan I prepared for my semi-scientific project Befund  (and you can access the French version as well). You can also get a free e-copy of my book ‘Capitalism and Political Power’ You can support my research by donating directly, any amount you consider appropriate, to my PayPal account. You can also consider going to my Patreon page and become my patron. If you decide so, I will be grateful for suggesting me two things that Patreon suggests me to suggest you. Firstly, what kind of reward would you expect in exchange of supporting me? Secondly, what kind of phases would you like to see in the development of my research, and of the corresponding educational tools?


[1] Alfieri, L., Feyen, L., Dottori, F., & Bianchi, A. (2015). Ensemble flood risk assessment in Europe under high end climate scenarios. Global Environmental Change, 35, 199-212.

[2] Alfieri, L., Feyen, L., Dottori, F., & Bianchi, A. (2015). Ensemble flood risk assessment in Europe under high end climate scenarios. Global Environmental Change, 35, 199-212.

[3] Gustavo Naumann et al. , 2015, Assessment of drought damages and their uncertainties in Europe, Environmental Research Letters, vol. 10, 124013, DOI https://doi.org/10.1088/1748-9326/10/12/124013

[4] Vogt, J.V., Naumann, G., Masante, D., Spinoni, J., Cammalleri, C., Erian, W., Pischke, F., Pulwarty, R., Barbosa, P., Drought Risk Assessment. A conceptual Framework. EUR 29464 EN, Publications Office of the European Union, Luxembourg, 2018. ISBN 978-92-79-97469-4, doi:10.2760/057223, JRC113937

[5] Paprotny, D., Sebastian, A., Morales-Nápoles, O., & Jonkman, S. N. (2018). Trends in flood losses in Europe over the past 150 years. Nature communications, 9(1), 1985.

[6] Alfieri, L., Bisselink, B., Dottori, F., Naumann, G., de Roo, A., Salamon, P., … & Feyen, L. (2017). Global projections of river flood risk in a warmer world. Earth’s Future, 5(2), 171-182.

[7] Lu, J., Carbone, G. J., & Grego, J. M. (2019). Uncertainty and hotspots in 21st century projections of agricultural drought from CMIP5 models. Scientific reports, 9(1), 4922.

[8] Stagge, J. H., Kingston, D. G., Tallaksen, L. M., & Hannah, D. M. (2017). Observed drought indices show increasing divergence across Europe. Scientific reports, 7(1), 14045.

[9] Webber, H., Ewert, F., Olesen, J. E., Müller, C., Fronzek, S., Ruane, A. C., … & Ferrise, R. (2018). Diverging importance of drought stress for maize and winter wheat in Europe. Nature communications, 9(1), 4249.

[10] Toreti, A., Cronie, O., & Zampieri, M. (2019). Concurrent climate extremes in the key wheat producing regions of the world. Scientific reports, 9(1), 5493.

[11] https://ec.europa.eu/eurostat/statistics-explained/index.php/Agricultural_production_-_crops last access July 14th, 2019

[12] Schils, R., Olesen, J. E., Kersebaum, K. C., Rijk, B., Oberforster, M., Kalyada, V., … & Manolov, I. (2018). Cereal yield gaps across Europe. European journal of agronomy, 101, 109-120.

Sponge cities

My editorial on You Tube

I am developing on the same topic I have already highlighted in « Another idea – urban wetlands », i.e. on urban wetlands. By the way, I have found a similar, and interesting concept in the existing literature: the sponge city. It is being particularly promoted by Chinese authors. I am going for a short review of the literature on this specific topic, and I am starting with correcting a mistake I made in my last update in French, « La ville – éponge » when discussing the article by Shao et al. (2018[1]). I got confused in the conversion of square meters into square kilometres. I forgot that 1 km2 = 106 m2, not 103. Thus, correcting myself now, I rerun the corresponding calculations. The Chinese city of Xiamen, population 3 500 000, covers an area of 1 865 km2, i.e. 1 865 000 000 m2. In that, 118 km2 = 118 000 000 m2 are infrastructures of sponge city, or purposefully arranged urban wetlands. Annual precipitations in Xiamen, according to Climate-Data.org, are 1131 millimetres per year, thus 1131 m3 of water per 1 m2. Hence, the entire city of Xiamen receives 1 865 000 000 m2 * 1 131 m3/m2 =  2 109 315 000 000 m3 of precipitation a year, and the sole area of urban wetlands, those 118 square kilometres, receives 118 000 000 m2 * 1 131 m3/m2 =  133 458 000 000 m3. The infrastructures of sponge city in Xiamen have a target capacity of 2% regarding the retention of rain water, which gives  2 669 160 000 m3.

Jiang et al. (2018[2]) present a large scale strategy for the development of sponge cities in China. The first takeaway I notice is the value of investment in sponge city infrastructures across a total of 30 cities in China. Those 30 cities are supposed to absorb $275,6 billions in the corresponding infrastructural investment, thus an average of $9,19 billion per city. The first on the list is Qian’an, population 300 000, are 3 522 km2, total investment planned I = $5,1 billion. That gives $17 000 per resident, and $1 448 041 per 1 km2 of urban area. The city of Xiamen, whose case is discussed by the previously cited Shao et al. (2018[3]), has already got $3,3 billion in investment, with a target at I = $14,14 billion, thus at $4800 per resident, and $7 721 180 per square kilometre. Generally, the intensity of investment, counted per capita or per unit of surface, is really disparate. This is, by the way, commented by the authors: they stress the fact that sponge cities are so novel a concept that local experimentation is norm, not exception.

Wu et al. (2019[4]) present another case study, from among the cities listed in Jiang et al. (2018), namely the city of Wuhan. Wuhan is probably the biggest project of sponge city in terms of capital invested: $20,04 billion, distributed across 293 detailed initiatives. Started after a catastrophic flood in 2016, the project has also proven its value in protecting the city from floods, and, apparently, it is working. As far as I could understand, the case of Wuhan was the first domino block in the chain, the one that triggered the whole, nation-wide programme of sponge cities.

Shao et al. (2016[5]) present an IT approach to organizing sponge-cities, focusing on the issue of data integration. The corresponding empirical field study had been apparently conducted in Fenghuang County, province Hunan. The main engineering challenge consists in integrating geographical data from geographic information systems (GIS) with data pertinent to urban infrastructures, mostly CAD-based, thus graphical. On the top of that, spatial data needs to be integrated with attribute data, i.e. with the characteristics of both infrastructural objects, and their natural counterparts. All that integrated data is supposed to serve efficient application of the so-called Low Impact Development (LID) technology. With the Fenghuang County, we can see the case of a relatively small area: 30,89 km2, 350 195 inhabitants, with a density of population of 200 people per 1 km2. The integrated data system was based on dividing that area into 417 sub-catchments, thus some 74 077 m2 per catchment.         

Good, so this is like a cursory review of literature on the Chinese concept of sponge city. Now, I am trying to combine it with another concept, which I first read about in a history book, namely Civilisation and Capitalism by Fernand Braudel, volume 1: The Structures of Everyday Life[6]: the technology of lifting and pumping water from a river with the help of kinetic energy of waterwheels propelled by the same river. Apparently, back in the day, in cities like Paris, that technology was commonly used to pump river water onto the upper storeys of buildings next to the river, and even to the further-standing buildings. Today, we are used to water supply powered by big pumps located in strategic nodes of large networks, and we are used to seeing waterwheels as hydroelectric turbines. Still, that old concept of using directly the kinetic energy of water seems to pop up again, here and there. Basically, it has been preserved in a slightly different form. Do you know that image in movies, with that windmill in the middle of a desert? What is the point of putting a windmill in the middle of a desert? To pump water from a well. Now, let’s make a little jump from wind power to water power. If we can use the force of wind to pump water from underground, we can use the force of water in a river to pump water from that river.  

In scientific literature, I found just one article making reference to it, namely Yannopoulos et al. (2015[7]). Still, in the less formal areas, I found some more stuff. I found that U.S. patent, from 1951, for a water-wheel-driven brush. I found more modern a technology of the spiral pump, created by a company called PreScouter. Something similar is being proposed by the Dutch company Aqysta. Here are some graphics to give you an idea:


Now, I put together the infrastructure of a sponge city, and the technology of pumping water uphill using the energy of the water. I have provisionally named the thing « Energy Ponds ». Water wheels power water pumps, which convey water to elevated tanks, like water towers. From water towers, water falls back down to the ground level, passes through small hydroelectric turbines on its way down, and lands in the infrastructures of a sponge city, where it is being stored. Here below, I am trying to make a coherent picture of it. The general concept can be extended, which I present graphically further below: infrastructure of the sponge city collects excess water from rainfall or floods, and partly conducts it to the local river(s). What limits the river from overflowing or limits the degree of overflowing is precisely the basic concept of Energy Ponds, i.e. those water-powered water pumps that pump water into elevated tanks. The more water flows in the river – case of flood or immediate threat thereof – the more power in those pumps, the more flow through the elevated tanks, and the more flow through hydroelectric turbines, hence the more electricity. As long as the whole infrastructure physically holds the environmental pressure of heavy rainfall and flood waves, it can work and serve.

My next step is to outline the business and financial framework of the « Energy Ponds » concept, taking the data provided by Jiang et al. (2018) about 29 sponge city projects in China, squeezing as much information as I can from it, and adding the component of hydroelectricity. I transcribed their data into an Excel file, and added some calculations of my own, together with data about demographics and annual rainfall. Here comes the Excel file with data as of July 5th 2019. A pattern emerges. All the 29 local clusters of projects display quite an even coefficient of capital invested per 1 km2 of construction area in those projects: it is $320 402 571,51 on average, with quite a low standard deviation, namely $101 484 206,43. Interestingly, that coefficient is not significantly correlated neither with the local amount of rainfall per 1 m2, nor with the density of population. It looks like quite an autonomous variable, and yet as a recurrent proportion.      

Another interesting pattern is to find in the percentage of the total surface, in each of the cities studied, devoted to being filled with the sponge-type infrastructure. The average value of that percentage is 0,61% and is accompanied by quite big a standard deviation: 0,63%. It gives an overall variability of 1,046. Still, that percentage is correlated with two other variables: annual rainfall, in millimetres per square meter, as well as with the density of population, i.e. average number of people per square kilometre. Measured with the Pearson coefficient of correlation, the former yields r = 0,45, and the latter is r = 0,43: not very much, yet respectable, as correlations come.

From underneath those coefficients of correlation, common sense pokes its head. The more rainfall per unit of surface, the more water there is to retain, and thus the more can we gain by installing the sponge-type infrastructure. The more people per unit of surface, the more people can directly benefit from installing that infrastructure, per 1 km2. This one stands to reason, too.

There is an interesting lack of correlations in that lot of data taken from Jiang et al. (2018). The number of local projects, i.e. projects per one city, is virtually not correlated with anything else, and, intriguingly, is negatively correlated, at Pearson r = – 0,44, with the size of local populations. The more people in the city, the less local projects of sponge city are there.    

By the way, I have some concurrent information on the topic. According to a press release by Voith, this company has recently acquired a contract with the city of Xiamen, one of the sponge-cities, for the supply of large hydroelectric turbines in the technology of pumped storage, i.e. almost exactly the thing I have in mind.

Now, the Chines programme of sponge cities is a starting point for me to reverse engineer my own concept of « Energy Ponds ». I assume that four economic aggregates pay off for the corresponding investment: a) the Net Present Value of proceedings from producing electricity in water turbines b) the Net Present Value of savings on losses connected to floods c) the opportunity cost of tap water available from the retained precipitations, and d) incremental change in the market value of the real estate involved.

There is a city, with N inhabitants, who consume R m3 of water per year, R/N per person per year, and they consume E kWh of energy per year, E/N per person per year. R divided by 8760 hours in a year (R/8760) is the approximate amount of water the local population needs to have in current constant supply. Same for energy: E/8760 is a good approximation of power, in kW, that the local population needs to have standing and offered for immediate use.

The city collects F millimetres of precipitation a year. Note that F mm = F m3/m2. With a density of population D people per 1 km2, the average square kilometre has what I call the sponge function: D*(R/N) = f(F*106). Each square kilometre collects F*106 cubic meters of precipitation a year, and this amount remains is a recurrent proportion to the aggregate amount of water that D people living on that square kilometre consume per year.

The population of N residents spend an aggregate PE*E on energy, and an aggregate PR*R on water, where PE and PR are the respective prices of energy and water. The supply of water and energy happens at levelized costs per unit. The reference math here is the standard calculation of LCOE, or Levelized Cost of Energy in an interval of time t, measured as LCOE(t) = [IE(t) + ME(t) + UE(t)] / E, where IE is the amount of capital invested in the fixed assets of the corresponding power installations, ME is their necessary cost of current maintenance, and UE is the cost of fuel used to generate energy. Per analogy, the levelized cost of water can be calculated as LCOR(t) = [IR(t) + MR(t) + UR(t)] / R, with the same logic: investment in fixed assets plus cost of current maintenance plus cost of water strictly speaking, all that divided by the quantity of water consumed. Mind you, in the case of water, the UR(t) part could be easily zero, and yet it does not have to be.  Imagine a general municipal provider of water, who buys rainwater collected in private, local installations of the sponge type, at UR(t) per cubic metre, that sort of thing.

The supply of water and energy generates gross margins: E(t)*(PE(t) – LCOE(t)) and R(t)*(PR(t) – LCOR(t)). These margins are possible to rephrase as, respectively, PE(t)*E(t)IE(t) – ME(t) – UE(t), and R(t)*PR(t) – IR(t) – MR(t) – UR(t). Gross margins are gross cash flows, which finance organisations (jobs) attached to the supply of, respectively, water and energy, and generate some net surplus. Here comes a little difficulty with appraising the net surplus from the supply of water and energy. Long story short: the levelized values of the « LCO-whatever follows » type explicitly incorporate the yield on capital investment. Each unit of output is supposed to yield a return on investment I. Still, this is not how classical accounting defines a cost. The amounts assigned to costs, both variable and fixed, correspond to the strictly speaking current expenditures, i.e. to payments for the current services of people and things, without any residual value sedimenting over time. It is only after I account for those strictly current outlays that I can calculate the current margin, and a fraction of that margin can be considered as direct yield on my investment. In standard, basic accounting, the return on investment is the net income divided by the capital invested. The net income is calculated as π = Q*P – Q*VC – FC – r*I – T, where Q and P are quantity and price, VC is the variable cost per unit of output Q, FC stands for the fixed costs, r is the price of capital (interest rate) on the capital I invested in the given business, and T represents taxes. In the same standard accounting, Thus calculated net income π is then put into the formula of internal rate of return on investment: IRR = π / I.     

When I calculate my margin of profit on the sales of energy or water, I have those two angles of approach. Angle #1 consists in using the levelized cost, and then the margin generated over that cost, i.e. P – LC (price minus levelized cost) can be accounted for other purposes than the return on investment. Angle #2 comes from traditional accounting: I calculate my margin without reference to the capital invested, and only then I use some residual part of that margin as return on investment. I guess that levelized costs work well in the accounting of infrastructural systems with nicely predictable output. When the quantity demanded, and offered, in the market of energy or water is like really recurrent and easy to predict, thus in well-established infrastructures with stable populations around, the LCO method yields accurate estimations of costs and margins. On the other hand, when the infrastructures in question are developing quickly and/or when their host populations change substantially, classical accounting seems more appropriate, with its sharp distinction between current costs and capital outlays.

Anyway, I start modelling the first component of the possible payoff on investment in the infrastructures of « Energy Ponds », i.e.  the Net Present Value of proceedings from producing electricity in water turbines. As I generally like staying close to real life (well, most of the times), I will be wrapping my thinking around my hometown, where I still live, i.e. Krakow, Poland, area of the city: 326,8 km2, area of the metropolitan area: 1023,21 km2. As for annual precipitations, data from Climate-Data.org[1] tells me that it is a bit more than the general Polish average of 600 mm a year. Apparently, Krakow receives an annual rainfall of 678 mm, which, when translated into litres received by the whole area, makes a total rainfall on the city of  221 570 400 000 litres, and, when enlarged to the whole metropolitan area, makes

693 736 380 000 litres.

In the generation of electricity from hydro turbines, what counts is the flow, measured in litres per second. The above-calculated total rainfall is now to be divided by 365 days, then by 24 hours, and then by 3600 seconds in an hour. Long story short, you divide the annual rainfall in litres by the constant of 31 536 000 seconds in one year. Mind you, on odd years, it will be 31 622 400 seconds. This step leads me to an estimate total flow of 7 026 litres per second in the city area, and 21 998 litres per second in the metropolitan area. Question: what amount of electric power can I get with that flow? I am using a formula I found at Renewables First.co.uk[2] : flow per second, in kgs per second multiplied by the gravitational constant a = 9,81, multiplied by the average efficiency of a hydro turbine equal to 75,1%, further multiplied by the net head – or net difference in height – of the water flow. All that gives me electric power in watts. All in all, when you want to calculate the electric power dormant in your local rainfall, take the total amount of said rainfall, in litres falling on the entire place where you can possibly collect that rainwater from, and multiply it by 0,076346*Head of the waterflow. You will get power in kilowatts, with that implied efficiency of 75,1% in your technology.

For the sake of simplicity, I assume that, in those installations of elevated water tanks, the average elevation, thus the head of the subsequent water flow through hydro turbines, will be H = 10 m. That leads me to P = 518 kW available from the annual rainfall on the city of Krakow, when elevated to H = 10 m, and, accordingly, P = 1 621 kW for the rainfall received over the entire metropolitan area.

In the next step, I want to calculate the market value of that electric power, in terms of revenues from its possible sales. I take the power, and I multiply it by 8760 in a year (8784 hours in an odd year). I get the amount of electricity for sale equal to E = 4 534 383 kWh from the rainfall received over the city of Krakow strictly spoken, and E = 14 197 142 kWh if we hypothetically collect rainwater from the entire metro area.

Now, the pricing. According to data available at GlobalPetrolPrices.com[3], the average price of electricity in Poland is PE = $0,18 per kWh. Still, when I get, more humbly, to my own electricity bill, and I crudely divide the amount billed in Polish zlotys by the amount used in kWh, I get to something like PE = $0,21 per kWh. The discrepancy might be coming from the complexity of that price: it is the actual price per kWh used plus all sorts of constant stuff per kW of power made available. With those prices, the market value of the corresponding revenues from selling electricity from rainfall used smartly would be like $816 189  ≤ Q*PE  $952 220 a year from the city area, and $2 555 485 ≤ Q*PE  $2 981 400 a year from the metropolitan area.

I transform those revenues, even before accounting for any current costs, into a stream, spread over 8 years of average lifecycle in an average investment project. Those 8 years are what is usually expected as the time of full return on investment in those more long-term, infrastructure-like projects. With a technological lifecycle around 20 years, those projects are supposed to pay for themselves over the first 8 years, the following 12 years bringing a net overhead to investors. Depending on the pricing of electricity, and with a discount rate of r = 5% a year, it gives something like $5 275 203 ≤ NPV(Q*PE ; 8 years) ≤ $6 154 403 for the city area, and $16 516 646 ≤ NPV(Q*PE ; 8 years) ≤  $19 269 421 for the metropolitan area.

When I compare that stream of revenue to what is being actually done in the Chinese sponge cities, discussed a few paragraphs earlier, one thing jumps to the eye: even with the most optimistic assumption of capturing 100% of rainwater, so as to make it flow through local hydroelectric turbines, there is no way that selling electricity from those turbines pays off for the entire investment. This is a difference in the orders of magnitude, when we compare investment to revenues from electricity.

I am consistently delivering good, almost new science to my readers, and love doing it, and I am working on crowdfunding this activity of mine. You can communicate with me directly, via the mailbox of this blog: goodscience@discoversocialsciences.com. As we talk business plans, I remind you that you can download, from the library of my blog, the business plan I prepared for my semi-scientific project Befund  (and you can access the French version as well). You can also get a free e-copy of my book ‘Capitalism and Political Power’ You can support my research by donating directly, any amount you consider appropriate, to my PayPal account. You can also consider going to my Patreon page and become my patron. If you decide so, I will be grateful for suggesting me two things that Patreon suggests me to suggest you. Firstly, what kind of reward would you expect in exchange of supporting me? Secondly, what kind of phases would you like to see in the development of my research, and of the corresponding educational tools?


[1] https://en.climate-data.org/europe/poland/lesser-poland-voivodeship/krakow-715022/ last access July 7th 2019

[2] https://www.renewablesfirst.co.uk/hydropower/hydropower-learning-centre/how-much-power-could-i-generate-from-a-hydro-turbine/ last access July 7th, 2019

[3] https://www.globalpetrolprices.com/electricity_prices/ last access July 8th 2019

[1] Shao, W., Liu, J., Yang, Z., Yang, Z., Yu, Y., & Li, W. (2018). Carbon Reduction Effects of Sponge City Construction: A Case Study of the City of Xiamen. Energy Procedia, 152, 1145-1151.

[2] Jiang, Y., Zevenbergen, C., & Ma, Y. (2018). Urban pluvial flooding and stormwater management: A contemporary review of China’s challenges and “sponge cities” strategy. Environmental science & policy, 80, 132-143.

[3] Shao, W., Liu, J., Yang, Z., Yang, Z., Yu, Y., & Li, W. (2018). Carbon Reduction Effects of Sponge City Construction: A Case Study of the City of Xiamen. Energy Procedia, 152, 1145-1151.

[4] Wu, H. L., Cheng, W. C., Shen, S. L., Lin, M. Y., & Arulrajah, A. (2019). Variation of hydro-environment during past four decades with underground sponge city planning to control flash floods in Wuhan, China: An overview. Underground Space, article in press

[5] Shao, W., Zhang, H., Liu, J., Yang, G., Chen, X., Yang, Z., & Huang, H. (2016). Data integration and its application in the sponge city construction of China. Procedia Engineering, 154, 779-786.

[6] Braudel, F., & Reynolds, S. (1979). Civilization and capitalism 15th-18th Century, vol. 1, The structures of everyday life. Civilization, 10(25), 50.

[7] Yannopoulos, S., Lyberatos, G., Theodossiou, N., Li, W., Valipour, M., Tamburrino, A., & Angelakis, A. (2015). Evolution of water lifting devices (pumps) over the centuries worldwide. Water, 7(9), 5031-5060.