Comment by Leherenn

They're not really solutions if they're not achievable in practice though. Otherwise why not add nuclear fusion to the mix?

To give some example: Switzerland is roughly electricity neutral over a year, but there's a significant winter/summer imbalance of about 5TWh. To add enough storage to compensate this imbalance, you would need to:

- cover about 2% of the country in batteries

- build about a thousand pump storage stations: despite the Alps covering about 40% of the country, it's not clear if you would have enough valleys to flood

- hydrogen looks a bit more reasonable, if we don't look at the costs, you only need to store a few millions m3 of liquid hydrogen. The gas storage in Germany for instance are quite a bit larger than that, but hydrogen is also significantly harder to store.

And all of this is to use once a year essentially! None of it looks practical or affordable (a pump storage station costs a few billions a piece for instance).