Can China Make Hydrogen Electrolyzers Cheap as It Did for Solar?

https://macropolo.org/china-hydrogen-electrolyzers-cheap-solar/

by hunglee2 • 3 years ago

7 5 3 years ago

tuatoru• 3 years ago

There is little reason to believe we have fully explored the space of possible electrolyzers with the alkaline, solid oxide, and proton-exchange membrane types.

However, exploration will take time and a lot of computational brute force.

spaceywilly• 3 years ago

I have a house in NH that gets plenty of sun in the summer but uses barely any energy. Then, in the winter it requires a ton of energy to heat the house, but gets barely any sunlight. My dream setup would be to have solar panels that then use the excess solar power to generate and store hydrogen, then in the winter the hydrogen could be burned directly or mixed with propane for heating.

To have batteries storing the excess energy needed to serve the house’s energy needs for the entire winter doesn’t seem like it would ever be practical, but with more advances in Hydrogen tech I’m hoping it will open up more possibilities.

maartenh• 3 years ago

Have you considered a water based heating/cooling system that uses the earth itself as its storage buffer?

wesleyd• 3 years ago

I wish there was a cheap process for making methane or propane from excess solar. Unlike hydrogen, we have a lot of experience using and storing those.

credit_guy• 3 years ago

I did a back of the envelope, and maybe it's not quite so bad.

I read that a smallish, but not tiny, house needs about 500 gallons of propane to go through a winter. Yours will need more or less, but let's work with this. Propane has a pretty low density of about 0.5 g/cm3, so 500 gallons work out to be about 1000 kg. Hydrogen has more than twice the energy density of propane. Moreover, you'd probably use hydrogen to generate electricity via fuel cells, rather than to burn it like you burn propane. Heating via electricity and heat pumps is at least twice as efficient as via a furnace with propane, so let's say you need about 250 kg of Hydrogen.

It's difficult to find prices of large hydrogen tanks online, everyone puts a button with "Call for quote". But I found a study by the DoE [1] where it appears that the bulk cost for large hydrogen tanks of type IV that can hold 220 kg is about $75k. The best tanks are type III which have virtually zero leakage rate. I imagine those are more expensive. Type IV have some leakage rate, which should be proportional to the surface area of the tank. Because of the square-cube law, very large tanks like this one should have a lower leakage rate than smaller tanks like those used in a Toyota Mirai (which can hold only about 5kg of H2). Overall, I think you could expect less than 10% losses, maybe much less.

Of course, you'd need to add the cost of the electrolyzer, of the fuel cells, of the heat pumps etc. It looks quite expensive to me, but lots of things related to home improvement are expensive. This one, you actually get (some of) your money back in time.

[1] https://www.hydrogen.energy.gov/docs/hydrogenprogramlibrarie...

Can China Make Hydrogen Electrolyzers Cheap as It Did for Solar?

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