> It's not terribly difficult (or expensive, comparatively) to store energy when size and weight are not a concern. You can use huge tanks of molten salt, for e

> It's not terribly difficult (or expensive, comparatively) to store energy when size and weight are not a concern. You can use huge tanks of molten salt, for example. Yet, PG&E pumps water uphill at night so it can get more hydro during the day. Maybe they made a big mistake, but I'd like to see some actual numbers. PG&E isn't perfect, but they're not obviously incompetent either, so .... To put it another way, if you're correct, you're ignoring gobs of money. > The nice thing is that in a lot of places where it's hot and sunny often, electricity use tracks sunlight due to air conditioning. Most places don't have air conditioning.