Discussion
@strypey we've had quite a few interactions related to hydrogen as fuel, and as competition for batteries for transforming our transport fleet... I've written it off all along, and you've rightly called me on it... I notice there's been a bit of an resurgence of hydrogen-powered announcements recently, and this excellent video explains why that might be: https://www.youtube.com/watch?v=QsnGoAUS334
YouTube
The video mentions a 29% energy loss when converting electricity to hydrogen. Finally, some science. Fair point. But to compare apples with apples we have to consider the potential energy loss while charge batteries. Which can be almost as significant, especially when filling the last 80-100% of the battery.
Also, as I've said before, if all of this can be done with renewable energy that would otherwise be unused, how much does that matter? Whether we could realistically build enough batteries, etc, to store and use all that energy with better EROEI is an open question. Do we know the losses on charging and discharging grid-scale batteries, for example?
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The video also mentions 19% loss during hydrogen compression, transportation, etc. Some loss during compression is unavoidable, but again, that has to be compared against the losses involved in charging batteries.
More importantly, this 19% loss figure presumes that instead of green hydrogen being made at or close to where vehicles are filled, it's made at a handful of giant facilities and transported long distance. That may be necessary with current electrolysis tech, but it's worth noting as an area where technical innovation could change the EROEI (Energy Returned on Energy Invested) quite significantly.
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The next criticism is about hydrogen leakage from storage and transport. This is a challenge, and if it can't be solved, that is a strong argument against hydrogen as an energy carrier. Especially when the ozone layer damage from escaped hydrogen is factored in.
But waving leakage around in the absence of any careful scrutiny of storage tech and its progress is just FUD. One consultant interviewed in this video appears to seek out and highlight an incompetent worst case scenario, and compare it against traditional storage methods. This looks like confirmation bias at work, not a fair analysis of progress in the field, eg;
https://doi.org/10.3390/su16188270
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@lightweight
> I've written it off all along, and you've rightly called me on it
Very gracious of you to say so ☺️ You've made many good points about the potential downsides of hydrogen tech, all of which I try to take on board.
Speaking of which, I watched the video linked by @lightweight;
https://www.youtube.com/watch?v=QsnGoAUS334
... and took some notes.
The video opens by comparing sales of hydrogen-powered heavy vehicles to battery-electric ones. This was a common reputation laundering tactic of the fossil fuel industry back when EV batteries supported smaller ranges, charging tech was slower, and charging points were less available. It doesn't prove anything.
The low sales of hydrogen trucks could just as easily be explained by the fact that the tech is still new and unfamiliar, and fuel availability (especially of *green* hydrogen) is an open question. Even if It indicates that heavy vehicle buyers aren't sold on hydrogen yet, it doesn't prove there's no interest in it.
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YouTube
@strypey @lightweight We often forget the difference between an energy source and an energy currency IMO. Electricity and H2 are both energy currencies that by definition have to be created in a conversion process. The other thing that many renewable “just electrify everything” advocates forget is that electricity is a JIT currency so supply-load balances are very important not just total TWh. This becomes doubly important when you optimize energy systems for total carbon emissions and not just for price.
https://energyasicit.ca/Currencies/
https://energyasicit.ca/EnergyVision/
@icanbob @strypey I don't think many of us forget that. The thing is that batteries can provide 'on tap' balancing/peaking. Even better than gas turbines. Solar + wind + hydro + grid-scale (and V2G) batteries are a complete solution. Sure, generate H2 with excess energy, but I'd guess that pumping water back into hydro lakes is probably a) easier, and b) more efficient. Wonder if anyone's tested that hypothesis?
@lightweight @strypey it also kills the ozone layer on its way into space, 3H₂ + O₃ → 3H₂O
@jonathanharker
> it also kills the ozone layer on its way into space
That's another good reason to stop H2 leaking out of storage, beyond the obvious loss of potential energy whenever that happens. Not necessarily a good reason to completely avoid it as an energy carrier though.
