India proposes battery storage rules for new renewables

India's Central Electricity Authority has proposed mandatory battery storage for new government solar and onshore wind projects. The draft rules would apply to projects commissioned after July 1, 2027. Storage would need to equal at least 10% of the plant's installed capacity. The minimum duration would be two hours. From July 2029, the duration would increase to four hours while the 10% capacity requirement would remain. A 100 MW renewable project would therefore require at least 10 MW of storage. This equals 20 MWh under the first phase and 40 MWh under the second. The draft also proposes grid-forming inverter capabilities. At least 15% of renewable plant inverters would need grid-forming control. All BESS power conversion systems would also need this capability. The proposal aims to manage renewable fluctuations and surplus generation.