>>_tk_+(OP)
There are flexible consumer energy tariffs based on the spot market + fee now. But although you even get negative prices, I was surprised that those tariffs are not economical for me. I have 2 heat pumps that are responsible for 75% of my energy consumption. I could optimize their working hours to low/negative hours by software and work with the thermal inertia of the house / water tank.
At the moment it is not worth the effort, a monthly floating tariff is more or less the same. Especially because the net fees are not based on the spot market and are 50% of the energy bill. This is a political failure.