Positive energy building in Nantes

[minguinhirigue]

I have only three caveats about this project (in addition to the desire to cut the cord ).

The first is hydrogen. I'm still not convinced by the fuel cell because the storage cycle via electrolysis is losing nearly a third of the energy received! I think that the impulse to give to new battery technologies would be more judicious. But it would take some numbers to really compare ... What capacity, what power and what cost the Abalone hydrogen fuel cell?

The second is the failure to take into account the storage system in the cost of a building who wants to be autonomous ... Not that I find this cost useless, or even too expensive (because if it is not put there, it is EDF which supports it with fuel plants!), but it's a bit dishonest.

The third is the gray energy cost of the building, I do not have it, but apart from the system of energy production, the building seems to me altogether classic, and there, you have to look at projects like the Green office of Conrad Lutz, to realize that it is possible to reduce by 70% the gray energy of a new building. This represents nothing less than 12,35 MWh for an office building of 1300m², enough to cover the needs of the building for 30 years!

Otherwise Christophe, I agree with you on the economic abbération of French photovoltaic at the moment, but we must remember:
1 - panel prices are more expensive than reality because of tax credit mechanisms
2 - the price of the French electric kWh is artificially low because of the operation of nuclear lobby
...
3 - in a few years, everything can be back to normal, by reducing the price of panels, AND an increase in the price of electricity *!

*Long live the revolution !

[nlc]

For hydrogen, yes, there are losses to conversion, but they have thought of everything: the losses involved in the heating of the building and the ECS.
The stack is an 12kW, I saw it and it's a big toy ....
The price I do not know, and the capacity all depends on the tank. But for a question of I know more what, they are limited to 100Kg of hydrogen storage. Above it must have specific permissions difficult to obtain.

For gray energy, I can not answer, inside everything is concrete, it is voluntary to have a big thermal inertia inside the building.

[Christophe]

The stack is an 12kW, I saw it and it's a big toy ....

Fat how? Because for the fuel cell that the liars of manufacturers "sold" to us between 1995 and 2005, it had to make 60 kW and fit under a hood ... Well, it's surely not the same technology but hey ... everything the same!

As their lie lasted a bit too long, they switched to biofuels there is 2 or 3 years old and now to the electric car ...

[nlc]

The fuel cell in cars I do not believe for a second.

It's big yes, 2m high and 1m by 1m about. But I did not see how it was fucked it was filmed on pallet, they had not unpacked yet.

[Christophe]

Yes, it's a lie for cars ...

Otherwise techno level, I think, like all the static batteries that it is a medium or high T ° CAP ... in cars it is MEP PAC (Proton Membrane Membranes), so the clutter must not be the same:



Here is a little doc I had done in 1999 on PACs, still valid because nothing has moved since or almost ...

https://www.econologie.com/cogeneration- ... nt-64.html

Excerpt:

2.3) High and Low temperature batteries and battery core
They are generally classified according to the nature of the electrolyte which gives the nominal operating temperature. Alkaline Fuel Cell (AFC) is distinguished from acid electrolyte cells which are divided into 2 subgroups:
• high temperature batteries (> 500 ° C), with molten carbonate (MCFC for Molten Carbonate Fuel Cell) or solid oxides (SOFC for Solid Oxide Fuel Cell) as electrolyte;
• batteries at low temperature (<200 ° C), with membranes as electrolyte
polymers (PEMFC for Proton Exchange Membrane Fuel Cell) or acid
phosphoric acid (PAFC for Phosphoric Acid Fuel Cell).
Low temperature batteries
They operate on the same general principle but they all tend to use a reformer that converts natural gas into hydrogen for various reasons:
• very well developed natural gas network
• storage and distribution of hydrogen still pose problems
• a priori negative for users regarding hydrogen storage (psychological aspect)
• Other means of producing expensive hydrogen, 4frs / kg by reforming compared to:
• 5 to 7 frs / kg by purification of petroleum products (oils ..)
• 25 frs / kg (!!) By electrolysis but can be greatly reduced by using renewable energies during times of low demand (mainly hydro-electricity, whose energy potential is almost constant)
Note: A thermal cracking of the ammonia (at about 600 ° C) is then enough to produce hydrogen, which will then have to be purified for sending in the acid piles. This seems to be one of the least expensive systems but what about the cost of producing ammonia (economic and environmental cost)?

(...)

High temperature batteries
MCFC: There is no reformer. The fuel is transformed into hydrogen in the heart. A fairly high temperature 650 ° C maintains the electrolyte (mixture of potassium carbonate and lithium) remains melted. Water vapor and CO2 are released and the exothermic reaction has the advantage of maintaining the temperature of the cell, which therefore requires only a primer heating. It is not an 100% ecological battery but allows the direct use of CH4.
SOFC: The electrolyte is composed of solid oxide (Zirconium) it works at about 1000 ° C. Here too, natural gas is transformed into H2 in the middle of the pile.

[nlc]

I will ask more details when I go to try the Tesla