Running them almost never (predictions assume around 3 days per year for Germany) means we can use cheaper plants with lower efficiency. These plants will be op

Running them almost never (predictions assume around 3 days per year for Germany) means we can use cheaper plants with lower efficiency. These plants will be operated by the grid operators, not by power generation companies. Their cost will be factored into the grid fees since they provide "grid stability". It's going to cost a bit, but not nearly as much as the difference between nuclear or coal power and renewables.