Hydrogen storage

[User963]

I read an article about ewf or eon generating hydrogen and then storing it in an underground cave in Yorkshire. It seems that hydrogen can be stored underground and could then be burnt to generate electricity when necessary.
This Seems ideal to me. Invest in wind power and on windy days generate hydrogen which is stored. This can then be burnt for electricity generation instead of gas on cold windless days.
why isn’t this more widely talked about as a solution? What are the downsides?

It is a good idea but like everything it's not a perfect solution.

I'm only an interested amateur - no specialist knowledge but this is what I think:

Converting electricity to hydrogen will result in energy loss (probably around 50 percent though might be a lot better than this if you had serious economy of scale. Or could be worse). Either way if there's no other way to store the electricity a 50 percent yield is better than a 0 percent yield so maybe worth doing.

Burning hydrogen is not necessarily a clean burn. Burning hydrogen in air risks creating nitrogen oxides which are a pollutant and contribute to warming. You can control this with carefully maintained flame (or by burning in pure oxygen but I don't think this would be viable for power generation because of the additional risks and expense). In a large facility you could probably ensure that minimal nox pollution is made so not too problematic. Unless you have unscrupulous governments willing to relax environmental controls in the name of profits of course.....

Short term energy storage is most likely best done with batteries (this is widespread and there are lots of innovative projects around battery storage eg vehicle to grid and grid balancing using battery storage at EV charging sites) I don't think there is much energy loss putting electricity in and out of batteries.

We currently use pumped storage to store electricity - ie water is pushed uphill and when you let it down it releases the stored energy. I don't know how much scope there is to expand pumped storage and how it compares to hydrogen storage in terms of efficiency and/or side benefits.

I think nitrogen oxide settles to the ground very quickly though so is only a problem in built up spaces. As most power stations would likely be in the countryside I'm not sure if that would be an issue.

The other benefit compared to battery storage would be that it wouldn't require as many minerals as battery generation. I'm not sure there are sufficient resources in world for batteries for EV, home storage and power station storage of power.

My understanding is that on a windy day there is often vast amounts of electricity generated that is unused. So I'm not sure if it would matter if 50% of it was wasted when generating hydrogen?

I think this is very unlikely. Hydrogen storage is actually quite difficult, it is the smallest molecule in the universe, and has very low gravimetric and volumetric energy density. Most storage solutions are either cryogenic, i.e liquid, or high pressure. LH2 is at 16k, HPH2 is at 350 or 700bar. High pressure hydrogen can transpire through metal so rock isn't going to contain it very well. Having said that hydrogen is definitely going to be part of the future energy mix.

We are expecting H2 generation at renewable energy sites but current thinking is that hydrolysis will sit alongside carbon capture and storage to generate "power to liquid" fuels, e.g. green ethanol, methanol, butanol. Ultimately these could (big could) be drop in fuels for existing technologies. There's a really good graphic on the FlyZero Roadshow ppt showing how different propulsion technologies are likely to pan out.

I realize I haven't really answered your question, I post again in due course.

Re burning H2 to make electricity.

(Name change fail, 80%= daft) So I'm going to start with the premise that where we are now is not where we are going to be in 2050.

It's really important that we are realistic in what we can achieve and in which time frame. There will be a lot of baby steps along the way.

There are a couple of really big issues with this principally "why turn electricity into H2 and then back to electricity"?

Also, topping up LNG power station with H2 is all very well but that means replying on fossil fuels for the majority of demand.