Grid expansion lag forces Germany to increase winter power plant backup reserve

Germany has raised its power plant backup reserve to ensure a stable winter electricity supply due to grid extensions not keeping pace with the country's renewables rollout. "The delays in grid expansion continue to make it necessary to ensure grid stability with the help of the grid reserve," the head of the country's grid agency BNetzA, Klaus Müller, said . "With the expected progress in grid expansion, we can assume a decreasing need for grid reserve in the future. This shows once again that rapid grid expansion increases grid security." The agency said a reserve capacity of 8.3 gigawatts (GW) was necessary, without taking into account possible gas shortages as a result of the Ukraine war.

Germany will partly rely on foreign power suppliers to ensure its supply security. Of the total reserve capacity, domestic power plants will provide 6.8 GW, an increase of 1.4 GW compared to last winter. "The reasons for this increase are the continued expansion of renewable energies and the European-mandated expansion of cross-border trading capacities, which are not being followed by grid expansion to the necessary extent," BNetzA said with reference to a lack of connections between the windy north and industrial centres in the south. It added that foreign plants will need to provide 1.4 GW of backup capacity, given that Germany's reserve capacities are exhausted. By winter 2023 /2024, the required grid reserve can be reduced to 5.4 GW if extensions are built according to current plans.

The agency said possible gas shortages would require a recalculation of reserve requirements. "We are constantly monitoring the risk of a gas shortage and examining possible effects on the secure supply of electricity. Should this have an impact on the grid reserve requirement, we will react to it directly," Müller said. His agency is in the process of evaluating the effects of gas shortages and will present its calculations in the summer. 

Germany's grid reserve is composed of power plants that are meant to be decommissioned, but are kept on stand-by for use in case of emergency. These plants are not allowed to operate on the electricity market. They mostly run only a few hours per year once called upon by grid operators to ensure supply security.