this post was submitted on 15 Jul 2024
134 points (94.1% liked)
Climate - truthful information about climate, related activism and politics.
4953 readers
367 users here now
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:
How much each change to the atmosphere has warmed the world:
Recommended actions to cut greenhouse gas emissions in the near future:
Anti-science, inactivism, and unsupported conspiracy theories are not ok here.
founded 1 year ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
It's always important to remember that hydrogen is not harmless.
First, it normally comes from natural gas since it's less energy-intensive to produce it that way.
Second, even if we were to produce hydrogen from water, the cycle of electrolyzing, transporting and using hydrogen is associated with enormous energy losses, and we still have to get that extra energy from somewhere.
Third, even if renewables will fully cover the demands of such production, they are not completely harmless, either. They need to be manufactured and then discarded; they require intermittent energy storage, which either relies on batteries which are not eco-friendly, or again something like hydrogen which would necessitate a much more powerful source and commonly requires rare metals. Also, even in use, solar farms and windmills affect local ecosystems by the construction process, shadows, and, in case of windmills, noise pollution.
That's not to say renewables are bad - they are the best we've got - but any extra energy always comes at a cost, both financially and environmentally.
An air taxi is normally not a wise use of said energy.
Is it worse than hauling enormous batteries, though? I know hydrogen looses like half the energy on generation, but to me it sounds the same as if we do all-electric and spend the same amount of energy for just moving the batteries around. I'm too cooked atm, but is anyone up to do the research/math on this?
Batteries take up about 15-20% of the vehicle mass and have around 90% efficiency
Hydrogen cycle has, at best, 60% efficiency (assuming amazing logistics and fuel cell for hydrogen-to-energy conversion); also, hydrogen systems also weigh a lot, but even if they would weigh literally 0kg, they would lose on efficiency anyway.