this post was submitted on 15 Jul 2024
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Discussion of climate, how it is changing, activism around that, the politics, and the energy systems change we need in order to stabilize things.

As a starting point, the burning of fossil fuels, and to a lesser extent deforestation and release of methane are responsible for the warming in recent decades: Graph of temperature as observed with significant warming, and simulated without added greenhouse gases and other anthropogentic changes, which shows no significant warming

How much each change to the atmosphere has warmed the world: IPCC AR6 Figure 2 - Thee bar charts: first chart: how much each gas has warmed the world. About 1C of total warming. Second chart: about 1.5C of total warming from well-mixed greenhouse gases, offset by 0.4C of cooling from aerosols and negligible influence from changes to solar output, volcanoes, and internal variability. Third chart: about 1.25C of warming from CO2, 0.5C from methane, and a bunch more in small quantities from other gases. About 0.5C of cooling with large error bars from SO2.

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A hydrogen-powered air taxi flew 523 miles emitting only water vapor (www.popsci.com)
submitted 4 months ago by [email protected] to c/[email protected]
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"Joby took a pre-production prototype of one of its battery-electric aircraft and outfitted it with a liquid hydrogen fuel tank and fuel system. The modified, hydrogen-powered VTOL was able to complete a 523 mile flight above Marina, California..."

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[โ€“] [email protected] 1 points 4 months ago (1 children)

So as far as I know, the benefit of LOHC is that compression/cooling is no longer required. Transporting/storing hydrogen becomes as easy as transporting any oil. There is an energy cost in the binding reaction, which is endothermic, but the unbinding reaction is exothermic so you get some of that energy back.

Unless you mean some other conversion?

[โ€“] [email protected] 1 points 4 months ago* (last edited 4 months ago)

I mean obtaining and using. You have energy losses converting water to hydrogen and hydrogen to energy, and those two compound nastily, even while using the most efficient tech.

Also, safety is a concern that can be addressed, but that was beyond my point. You still need to transfer hydrogen from point A to point B, and it is way more expensive and eco-unfriendly than moving electricity around. Or, if you want to put electrolyzers on each petrol station, you need to make sure the water supply is adequate and hydrogen storage is large enough to supply for peak demand, and that your station gets enough electricity, too (and you'll need more of it compared to a regular charging station).