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A comment on Ask HN: Is hydrogen likely to be a major source of power in the next 10 years?. Parent comment

Re:Ask HN: Is hydrogen likely to be a major source of power ... by cultus on Wednesday September 23, 2020 @03:17PM (#24570803)
Not to mention liquid H2 has quite a bit lower energy density than liquid fossil fuels. Many rockets have used kerosene in their first stages for this reason. Not the end of the world for aircraft, but certainly another major disadvantage.
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Re:Ask HN: Is hydrogen likely to be a major source of power ... by funcDropShadow on Wednesday September 23, 2020 @03:50PM (#24571131)
But the energy density per mass is still better than Li-ion batteries.
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Re:Ask HN: Is hydrogen likely to be a major source of power ... by nickik on Wednesday September 23, 2020 @07:09PM (#24573327)
Li-ion batteries are improving at a faster rate, and you can use your gravitational energy to recharge the battery.
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Re:Ask HN: Is hydrogen likely to be a major source of power ... by dmurray on Wednesday September 23, 2020 @08:22PM (#24573902)
How does that work? You run your propellor in reverse like a wind turbine?

This doesn't sound completely ridiculous but is there even any proof of concept for that? The gravitational potential energy doesn't seem all that high - most airplane fuel is burnt maintaining height, not gaining it - to justify the complexity of recovering some small fraction of it. Still, I once thought the same about regenerative braking in electric cars.

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Re:Ask HN: Is hydrogen likely to be a major source of power ... by 8note on Wednesday September 23, 2020 @10:37PM (#24574740)
Hydrogen is a storage mechanism; there'd be a way to reclaim your energy either way
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