Comment by spaceywilly
3 hours ago
I agree, I wish more work was being done on building a hydrogen economy. Hydrogen can be generated sustainably, is a great way to store excess energy from renewable sources, can be transported, and as a bonus can be mixed with hydrocarbon fuels to be used directly as a heating source.
As an example, a house in NH can generate a lot of excess solar power in the summer months when it uses hardly any electricity. If all that energy could be stored as hydrogen, in the winter (when solar power is less due to the far northern latitude and snow covering the panels) it could draw down on the hydrogen to generate electricity and also use it for a backup heat fuel.
I'm in Northern Europe and am in that situation. I have an electric heat pump, so would need around 3 MWh over the winter period. Apparently that would need a tank around 4m3 at 700 bar (typical pressure of hydrogen vehicle tanks). Plus the fuel cell actually generate heat, so that could be used for heating too. Doesn't seem terribly unrealistic.
I'm skeptical of any application for hydrogen where electricity could be used directly. In your case, I think hydrogen would better be used in a more centralized power plant as a backup for renewable sources (perhaps with the waste heat then used for district heating), and the power used to drive your heat pump.
The issue is long term, high capacity storage. To store enough energy to last an entire winter using batteries just isn’t practical today. I think you’d need around 100 power walls at today’s capacity to make a house completely off grid, meaning you store excess solar from the summer and draw it down in the winter. With hydrogen stored in pressurized tanks, a 20 m3 tank could be enough to last the whole winter, which seems much more practical than 100 powerwalls.
I think this could be a solution if you wanted a fully off grid, solar powered house, or perhaps if we collectively decide to generate more electricity at home and not rely so much on the grid.