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jandreseyesterday at 7:27 PM6 repliesview on HN

Bottom line: 40% efficiency, which is better than I expected but the competition is batteries at 80+% efficiency. It's a hard sell, especially as continual improvements in battery storage will continue to eat away at their niche.

5,000 W/kg sounds great on paper compared to 150 W/kg for batteries and is even in the same ballpark as gasoline at 12,000 W/kg, but I think that's just the figure for the fuel. I don't think it includes storage, the solar panels, the burner, etc... The cost is an open ended question as well. Maybe this will pan out for aircraft?


Replies

imglorpyesterday at 8:03 PM

The gasoline vs H2 ballpark is a little wider because storage is not trivial for H2 -- you need to carry around a cryogenic and/or high pressure vessel instead of a plastic box -- which will detract from your p/w ratio. It also wants to leak out, so H2 is maybe better for fleet vehicle applications where they can refill daily. Granted, anything is better than burning more hydrocarbons!

VBprogrammeryesterday at 7:41 PM

If that is 40% efficient as in 40% of the theoretical energy input comes out as electricity then it's quite incredible but I find that hard to believe. It would put it in the same range as diesel engines.

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datadrivenangelyesterday at 7:53 PM

The better comparison is Fuel Cells and vehicle based electrical generators. So you could put this in a vehicle or remote location, run it off hydrogen or natural gas, and get better efficiency. Potentially this could be a much better option for longer term storage in remote areas as well, where excess solar/wind could be used to crack hydrogen which then gets stored and later burned in one of these instead of a much much larger battery installation.

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tomrodyesterday at 11:34 PM

Rechargeables/battery packs have inefficiencies due to the grid and/or solar cells though, in terms of where to measure inefficiency?

cryptonectoryesterday at 11:32 PM

It might not be a hard sell compared to home generators. Forget hydrogen. Think natgas.

Tade0yesterday at 8:54 PM

Do you mean watts or watt-hours?