New solar, wind plants may need battery storage from 2027

CHENNAI: New solar and wind power projects may soon have to install battery storage along with their plants to help ensure a steady supply of electricity to the power grid.

The Central Electricity Authority (CEA) has proposed new rules under which renewable energy plants commissioned after July 1, 2027 will have to ensure that at least 15% of their inverters, devices that convert electricity generated by solar panels or wind turbines into a form that can be supplied to the grid, can work in a "grid-forming" mode. Battery storage systems will also have to have this capability.

For new ground-mounted solar and on-shore wind projects commissioned after July 1, 2027, the CEA has proposed a minimum battery storage capacity equal to 10% of the project's installed capacity. The batteries should be able to store electricity for at least two hours.

For example, a 100 MW solar plant would need a battery system capable of storing 10 MW of electricity for two hours.

The requirement will become stricter for projects commissioned after July 1, 2029 and up to June 30, 2031. These projects will have to provide storage for at least four hours, while the storage capacity will remain at 10% of the plant's installed capacity. A 100 MW project, for example, would need 10 MW of storage for four hours.

The CEA said it may change the required percentage of grid-forming inverters or the storage capacity from time to time.

The draft rules have been issued for public comments. Stakeholders and members of the public can send their suggestions and objections to the CEA by October 4, 2026.