What I infer from Anthropic post is that they will estimate the energy price as if they weren't using it and pay the difference if their use upped the price.
With day ahead forecasting, we can try to turn that peak load into base load. Grid operations are a non trivial part in how this AI energy situation plays out.
First of all, the resources those tiny batteries use are less than a drop in the bucket of what we ideally would like to add to the grid, and secondly, we're currently nowhere close to being limited by battery capacity. China alone had the industrial capacity to produce more than 2 TWh of new batteries last year, but they actually produced a bit less than 1 TWh because there was no market demand for this many batteries.
They just overbuilt production capacity by over 100%, per their industrial policy.