Tant de passionantes discussions avec Gregor il y a quelques années. Des tonnes et des tonnes d'échanges. Gregor est l'un des meilleurs spécialistes mondiaux dans le domaine des super-grids EnR.
Gregor avait fini par claquer la porte face à l'idéologie pro-thermosolaire qui polluait le think-tank DESERTEC. Les gens intellectuellement rigoureux et authentiques, c'est rare.
Cela fait plaisir de le lire de nouveau aujourd'hui, interviewé par un autre ami, Dave Andrew, fondateur du réseau Claverton. Gregor propose d'abandonner les projets hydrogène, ce scientifique les estime absurdes, ceci pour des raisons physiques (et par ricochet économiques et écologiques) de base.
Tout comme avec l'EPR ou encore avec la route solaire, la France se lance tête baissée dans l'hydrogène, cela va coûter monstrueusement cher. Une machine à siphoner l'argent public. Le naufrage n'est pas seulement probable mais certain.
Elon Musk n'est pas un dieu mais il fait partie des gens qui réfléchissent en profondeur. Il arrive aux mêmes conclusions que Gregor.
Il y a un énorme problème de stratégie énergétique en France.
"In Germany much is now talked about methane generation…
Storage techniques for longer periods could be based on the electrochemical production of hydrogen or methane and its storage. Yes, methane production is currently being discussed in detail in Germany. A total efficiency of less than 60 percent is cited for the steps of methane gas generation by electrochemical means, compression to pressures with which efficient storage is possible, as well as the storage and transport of the gas.
Reconversion to electricity is possible in small units with efficiencies of about 40 percent and in the case of the most efficient large gas power plants with efficiencies of up to 60 percent.
Thus, with these already very generous estimates, the overall efficiency – from electricity to gas and back to electricity – is in small systems around 24 percent (and 36 percent when using the most efficient large power plants). This corresponds to an overall loss of some 76 percent."
"(...) This is the only way to explain the fact that the inefficient “power to gas technology” in the form of using hydrogen or methane as storage mediums is once again greeted so euphorically. Only at an extremely high ecological and economic price, can it be used to compensate for all – especially long term – mismatch of demand and renewable supply, which is why this idea should be abandoned.
(...) For the same quantity of electricity used by the end user, then in the case of utilizing the previously mentioned storage methods almost four times the primary production and thus also approximately fourfold production potential – fourfold material expenditure, and fourfold land consumption etc. – are required. This naturally incurs a corresponding additional economic and ecological cost. By the way, in the few electricity-to-gas-to-electricity systems realized so far, the achieved efficiencies of electricity via gas and storage back to electricity are once again significantly lower and the expenditure for the resulting necessary primary production is correspondingly higher. The additional technical equipment in the chain also entails additional costs which we did not consider yet in this discussion.
As shown above, even in the case of the above-mentioned optimistic assumptions for large-scale plants, the expenditure would be around three times that needed for the direct use of the electrical energy without intermediate storage plus the costs of the equipment. The use of these large scale facilities would, however, lead to a significant break in the logic of decentralization, which has gained so many supporters happily ignoring many crucial aspects.
The considerations just pointed out exemplarily show how important the avoidance of storage steps is and what importance should be given to it in the system design. (...)
In large-scale networks, storage facilities could be used in the form of existing hydroelectric storage power plants causing no additional storage losses. Then furthermore shared large-scale pumped-storage power plants with efficiencies of roughly 80 percent could also be used for this purpose. (...)"