Tackling grid challenges increasingly important as German solar PV booms – report

The increasing use of new rooftop installations is quickening the expansion of solar PV in Germany, meaning the technology’s efficient integration into the energy system becomes increasingly important, said the German Institute for Economic Research (DIW). In a report on the state of solar in Germany’s energy transition, DIW said that the widely fluctuating quantities of solar electricity over the course of the day and year currently lead to temporary bottlenecks - especially at the distribution grid level.

Periods of negative prices on the wholesale electricity market have increased, showing the need for more and improved use of storages. DIW calls for incentives to ensure that battery storages in homes or businesses serve the overall system. Currently, for example, PV storage systems are already fully charged in the summer months during the hours of peak PV generation, and the PV systems feed all electricity into the grid. Smart electricity metres are key to making use of the full potential of storages, but their expansion is lagging behind in Germany.

There are currently about 91 gigawatts (GW) of photovoltaics installed across the country, already surpassing the government goal of 88 GW by the end of 2024. The DIW said the government should consider increasing the auctioned volumes for large-scale ground-mounted PV farms, where there was still "a lot of potential”. This could also "help to keep expansion costs down, as ground-mounted systems are cheaper than rooftop systems," report author Felix Schmidt said. As Germany is very dependent on Chinese solar modules, DIW suggests setting up a reserve equal to one or two years’ worth of expansion to protect plans against possible supply bottlenecks.