Solar power poses no risk to German grid stability even at peak feed-in times – industry

Necessary regulatory and technical precautions have been taken in Germany to prevent blackouts or power cuts resulting from grid overloads when there are high levels of sunshine and therefore solar PV output and low levels of power demand, the German Solar Industry Association (BSW-Solar) has said. Reforms to the Energy Industry Act (EnWG) that passed through parliament at the end of January had brought regulations that keep the risk down, the association said. The integration of renewable energies into the grid has been optimised and distribution grid operators will be obliged to regularly check the controllability of photovoltaic systems in the future, among other interventions, said BSW Solar.

The act builds on the System Stability Ordinance from 2012, which mandated that photovoltaic systems are not turned off when the frequency of the grid is exceeded. Instead,  “the output is continuously throttled by the inverters, the control instruments of a solar system,” said Professor Bernd Engel, grid integration expert at the Technical University  Braunschweig. “The higher the frequency rises, the more the inverter reduces its feed-in power.”

Rather than switching off strictly at 50.2 Hertz, photovoltaic systems now switch off in stages at different frequencies. Since 2018, this system-friendly behaviour has been mandatory across Europe for photovoltaic inverters. There have already been cases where progressive power reduction by inverters has worked well and led to a stabilised grid frequency.

The Federal Office for Information Security recently warned that the Solar Peaks Act could leave the German energy supply vulnerable to Chinese interference, as the country manufactures many inverters. Internationally, Germany has one of the most stable power supplies.