A 37-megawatt-peak solar plant in Thuringia has become the first ground-mounted photovoltaic facility in Germany to be prequalified for the secondary balancing market, according to grid operator 50Hertz and partners Sunnic Lighthouse and Entelios.
50Hertz said the Schkölen project is now authorised to deliver both positive and negative secondary control reserve. The operator said additional Sunnic Lighthouse assets in Mecklenburg-Vorpommern and Saxony-Anhalt are expected to follow once they complete the prequalification process.
The companies said the approval demonstrates that weather-dependent solar and wind assets can contribute to system balancing, a requirement that traditionally relied on conventional generation. Secondary balancing services must be deployable within five minutes, with bids from 1 MW accepted daily on regelleistung.net, 50Hertz said.
Dr. Dirk Biermann, chief operations officer at 50Hertz, said the milestone marks a step toward integrating renewables into system-stability responsibilities. “In the power system of the future, wind and solar will not only be the backbone of electricity generation, but with the phase-out of conventional power plants they will also have to gradually assume responsibility for system stability,” he said. “The prequalification of the PV parks is an important first step in this direction.” He added that, through cooperation with Sunnic Lighthouse and Entelios, “we will gain valuable practical experience for the successful participation of renewables in the balancing market.”
50Hertz said integrating solar and wind facilities into the balancing market requires high-quality forecasting, strong data systems and resilient technical processes. The partners developed a combined concept covering technical and regulatory needs, including metering systems, data management and an AI-supported forecasting model deployed at the PV sites.
According to 50Hertz, the newly qualified plants will be able to curtail output during periods of high solar generation to provide negative automatic frequency restoration reserve (aFRR), and increase output during shortfalls or periods of negative wholesale electricity prices to provide positive aFRR.
Sunnic Lighthouse, a subsidiary of ENERPARC, markets more than 4.8 GW of installed renewable capacity. Entelios specialises in flexibility services through participation in balancing markets and intraday trading, the companies said.
