Grid storage is different from powering EVs though. You don’t provide a week of grid backup via battery. You do stuff like pump 100 million gallons of water into a dam with a hydro plant ready.
I think water is more efficient then hydrogen even.
I think water is more efficient then hydrogen even.
m * g * h -> you either need lots of water or lots of height. Best is to have both. You only get that in the Alps and you need some special geoprgaphic features to make it work. Europe is also densely populated and the nature we have left, we want to preserve, so we can't flood all of it.
Do the math, figure out how big of damn we would need to store 3TWh.
My result: at 1000m pump height, you would need 3000 billion liters, which is cube of water with a length 1.5km. Double check this tough, I'm not sure if I did all the conversion correctly
For what it is worth, in Europe, Switzerland is doing a lot of pumped hydro powered by surplus French nuclear power in the summer time. Norway has huge amounts of hydro and only pumps a little, but it doesn't matter much: The Scandinavian grid is so well connected, that hydro will ramp down when power is available elsewhere, in effect providing on-demand provider for the whole region.
I guess that plant doesn't have an extreme amount of head or a particularly large reservoir.
It's about 7 minutes at https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Sta... , which has a lot more head.
So you need a lot more pumped storage if you want to start talking about days of backup, and we already used quite a few of the best sites.