Comment by pfdietz
5 hours ago
You want a fuel that's chemically identical to current jet fuel, not one burdened with extra oxygen. Yes, this would require more energy, but it would be used more effectively in jets.
A drop-in compatible jet fuel can be made by hydrodeoxygenation of biomass, using Virent's process. The waste cellulose in current US waste streams would be more than enough to displace all current US jet fuel consumption. An extra source of hydrogen would be needed to do this, but hydrogen can be made renewably (and, indeed, that's a good way to provide dispatchable demand to help deal with renewable intermittency, and will have to be done anyway to displace the use of natural gas to make hydrogen.)
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.
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