French Nuclear Fleet's Flexibility for Renewables Under Scrutiny
The French nuclear fleet's ability to accommodate significant shares of wind and solar power is under scrutiny. While it can reduce output by a third in less than 30 minutes, this is insufficient for effective integration of renewables.
Existing nuclear reactors face challenges in ramping up and down to match the variable output of wind and solar. French reactors, for instance, are inflexible a third of the time due to fuel cycle constraints. Even when ramping, their technical limits are not regularly reached.
Only one reactor worldwide, Germany's Brokdorf, has reported damage from ramping, highlighting potential risks. In Germany, fossil-fired power plants, not nuclear, have done most of the ramping to accommodate around 20% wind and solar. The technical capability of nuclear reactors to ramp is unclear and has not been demonstrated on a fleet-wide scale. Statements about their ramping capability are contradictory, even among proponents of nuclear.
Ramping is crucial in an energy system that includes renewables. More research and open discussion are needed about the particular behavior of nuclear reactors during ramping and potential wear and tear.
A reduction of even a third of the French nuclear fleet's output twice a day is not enough to integrate wind and solar power effectively. While nuclear reactors can adjust output, their flexibility and safety during ramping need further investigation. Germany's focus on rapidly expanding gas power capacity, aiming for about 20 gigawatts, underscores the importance of flexible power plants in managing variability in renewable generation.
