Germany registers 130 hours of negative day-ahead power prices in May

In May, Germany experienced 130 hours of negative day-ahead power prices due to an oversupply of solar energy, leading to prices dropping below €1/MWh for 160 hours, as reported by the Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE). This trend was driven by the fact that photovoltaic output consistently exceeded demand during midday hours. Negative prices were recorded on 21 out of 31 days in May, particularly when solar systems were operating at maximum capacity. The longest stretch of negative prices occurred on May 11, lasting nine hours and reaching as low as -€250/MWh. Retail customers with variable tariffs received credits for their consumption during these periods. Additionally, there were nine hours with prices at exactly €0/MWh and 19 hours with prices between €0 and €1/MWh. The month also saw price peaks, with the highest reaching €229.11/MWh on May 19 during peak household consumption times. Operators of large battery storage systems took advantage of these price fluctuations for revenue generation through arbitrage, despite limited storage capacity compared to generation peaks. Germany’s installed PV output stands at around 105 GW, supported by only 2 GW/2.7 GWh of large-scale battery storage. Total installed capacity, including residential and commercial systems, reaches 13 GW/20.3 GWh. Germany recorded 457 hours of negative prices in 2024, showing a 50% increase from the previous year. As of the end of May 2025, the country had already experienced 250 hours of negative prices, with the summer months, characterized by high solar energy production, still ahead.