3 ms·
You are confusing energy storage and fuel storage. I am talking about CAES, it uses electricity to compress air and feed that into a container, like a metal cyl
by ClumsyPilot 4y ago
You are confusing energy storage and fuel storage. I am talking about CAES, it uses electricity to compress air and feed that into a container, like a metal cylinder or caverns lined with impermeable material. When you need electricity, you release the air through a generator and produce electricity.
Hydroelectric, compressed air and batteries have round trip efficiency of ~80%.
https://www.sciencedirect.com/topics/engineering/compressed-air-energy-storage https://www.sciencedirect.com/topics/engineering/compressed-...
The facility you linked produces and stores chemical fuel, and can't even convert it back into electricity. It is really easy to store insane quantity of fuel, just like we can store loads of oil.
The kicker is that production of Hydrogen and other e-fuelds is less than 50% efficient, and converting them back to electricity is another 50% loss. Compression for storage and transportation mean further losses. So the overall round-trip efficiency is expected to be about 25% or lower.
It is probably possible to build an economy based on e-fuels, and that's what many oil companies are pushing for. They are probably the only viable way to achieve seasonal storage. It's a different set of tradeoffs.
- philipkglass 4y agoThe facility you linked produces and stores chemical fuel, and can't even convert it back into electricity. The project includes using Mitsubishi M501JAC combined-cycle gas turbines to turn the hydrogen back into electricity: https://www.powermag.com/aces-deltas-giant-utah-salt-cavern-hydrogen-storage-project-gets-504m-conditional-doe-loan-guarantee/ https://www.powermag.com/aces-deltas-giant-utah-salt-cavern-... https://power.mhi.com/products/gasturbines/lineup/m501j https://power.mhi.com/products/gasturbines/lineup/m501j This turbine has a rated combined-cycle efficiency of 64%. Production of hydrogen is more than 70% efficient in the best current commercial electrolyzers: https://www.nrel.gov/docs/fy04osti/36705.pdf https://www.nrel.gov/docs/fy04osti/36705.pdf Round-trip efficiency is much lower than 80%, but not as low as you have written here.
- pencilguin 4y agoIndustrial-scale electrolysers will soon be well over 90% efficient.
- nomel 4y agoAny terms I can search to understand these advances? I seemed to remember learning that boring old electrolysis was around 30% efficient!
- pencilguin 4y agohttps://www.nature.com/articles/s41467-022-32652-y https://www.nature.com/articles/s41467-022-32652-y Presuming I understood correctly. Another system used a hydrogen-side electrode made of foamed metal immersed in water, where the surface area presented to the water was therefore very large, and the small pore size limited the hydrogen bubbles' interference with contact between water and electrode surface.
- ClumsyPilot 4y agowhy are turbines used in place of potentially more efficient fule cells?
- AstralStorm 4y agoCost. Fuel cells require quality manufactured membranes that also require regular maintenance and replacement. Getting volume with them is also a hard problem.
- scythe 4y agoThermochemical hydrogen offers the best prospect for hydrogen production if it can be worked out, because the whole-process efficiency from solar or nuclear heat can exceed the practical limits of water electrolysis. Most recent work focuses on the copper chloride process (which uses an electrolytic step) [1]. The best purely thermal cycle is sulfur-iodine, but running the process sustainably has yet to be achieved due to the corrosive nature of the intermediates. 1: https://www.sciencedirect.com/science/article/pii/S0196890419311884 https://www.sciencedirect.com/science/article/pii/S019689041...
- rdtwo 4y agoRussians did that at some point in the 70s 80s. They pumped compressed air into some salt mines and that worked well until one of the mines sprung a leak and blew the mountain up