If one has grid-scale storage, there are many more efficient ways to do electricity generation. Hydroelectric, in existing geological reservoirs, are the only

If one has grid-scale storage, there are many more efficient ways to do electricity generation. Hydroelectric, in existing geological reservoirs, are the only grid-scale "battery" that currently exists. The primary reason they are not more popular is because not many reservoirs exist right next to major power consuming locales.