Electricity price is a weird beast. Everyone has to pay the price of the most expensive electricity source (generally gas plants) that was recruited to respond to the power demand. It means that during a spike the electricity price can double or triple.
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.
That's for the spot price. If you have bought futures then that won't impact you
pay the difference only over their energy consumption, or pay the difference for the whole group?
Gas plants are only the most expensive in the simple cycle configuration. Combined cycle plants are competitive with other forms of baseload generation. The trouble is the response time.
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.