[205guy]

I don't think the electric grid follows a traditional supply-and-demand curve. Every kilowatt used must be generated at the same time. Generation comes in tiers: cheap baseload (coal or nuclear, each with their issues), expensive peaker plants (nat. gas), and cheap but unpredictably intermittent renewables. Prices are highly regulated and agreed to in long-term contracts that take into account peak usage and minimal generation capacity. If demand increases, it is really expensive to supply until the level is enough to build a new baseload plant, but even those are expensive now.

Big users such as Google with its datacenters will of course negociate their own electricity contracts. I think renewables are the cheapest to buy right now, so by moving load around to be able to maximize use of cheap renewable electricity, they will definitely save money.