@MattMastodon @BrianSmith950 @Ardubal @Pampa @AlexisFR @Wirrvogel @Sodis IIRC most studies show that long term storage is only a few percent of total energy, certainly well under 10%. So it is a viable option - if you can get past leaks, and other problems (e.g. the temptation to burn it, producing NOx pollution). And can store vast amounts of energy relatively cheaply.

Nuclear is of course a viable option. There are a few others e.g. iron-air batteries, or just building a lot more renewables than we need. Long range interconnectors help. Lithium is only helpful for short to medium term storage.

Re synthetic fuels, so far extremely expensive and limited scale. Might possibly be used for aviation in the long run (but it's easier just to fly less, and we still need a reliable, safe solution to the contrails problem). Maybe shipping too (possibly as ammonia).