But unused capacity in nuclear overspeeds the turbines, you can't allow that to happen -- generation and frequency are both controlled by the same steam valve.

But unused capacity in nuclear overspeeds the turbines, you can't allow that to happen -- generation and frequency are both controlled by the same steam valve. Unused capacity in solar just sits there basking in the sun. The frequency is controlled by software in an inverter. To make solar demand-responsive, you just build more of it. It's really that simple.