They already do that with the existing system. It often happened in Spain (pre Iberian exception) that gas isn't even used, but the price of hydro was set to s

They already do that with the existing system. It often happened in Spain (pre Iberian exception) that gas isn't even used, but the price of hydro was set to something like (expected price of gas - 5 €) because they knew they could. So we end up paying the price of gas even when we don't use gas! Honestly, some people talk about the existing system as if it's this perfect free market... but in practice the bar is very low. The Iberian exception system is already showing in practice that it works better.