> With enough overcapacity from renewables we could also produce hydrogen and store that for example and run it through fuel cells or gas plants when needed.
Aren't lithium-ion batteries more efficient than hydrogen fuel cells?
Aren't lithium-ion batteries more efficient than hydrogen fuel cells?
To expand battery capacity you need to dig up lithium and half a dozen other rare elements, deal with the toxic byproducts (or dump them in a lake), manufacture batteries, control circuits and run ongoing maintenance.
To expand hydrogen capacity, you need more pressure vessels. These can be made of steel or aluminum, two of the cheapest materials in existence, and with practically zero pollution. Ongoing maintenance amounts to checking for rust and occasionally replacing valves, so it scales far better.
Hydrogen has serious downsides, but there's definitely a case to be made.
I think converting H2 to methane and storing that is far more realistic than storing H2. Methane slots into all of our current natural gas infrastructure. Liquid natural gas cars are more practical than H2 cars.
However, we're going to be harvesting TWh-worth of lithium for our car batteries anyway, so we're going to have a huuuuuge secondary market of used car batteries that still have a consistent 50%-80% charge capacity that could be used for grid storage.
I think it's too early to see exactly how the technology will work out, but a huge lithium-ion economy seems inevitable. I truly hope that electricity -> H2 -> methane (or a carbon chain) happens though. Because that is carbon sequestration, and I think that in 2050 we're going to want to start paying people to do that and not let the result get emitted again.
Even simpler, you can store it in salt domes which are currently used for natural gas reserves. The pipes and related infrastructure may need to be replaced due to hydrogen embrittlement, but the storage itself is already there.
Which is why I'm more interested in Redox Flow than Lithium Ion, for grid-scale applications anyway. Lithium Ion's efficiency is necessary for cars or other mobile applications. But if you're building it on the ground, you just build a bunch of cheap heavy tanks all over the place.
If this infrastructure is built out, it may also provide the path to pulling CO2 out of the atmosphere or ocean and permanently sequestering it. That is something that I think we'll probably be very interested in doing in coming decades. Having affordable technology for that (perhaps $20-80/ton?) would enable CO2 emissions for those cases that really require it, and possibly also some clawing back of the worst parts of anthropogenic climate change.