By Rajesh Kumar Singh

India is counting on increasing investments in battery storage to help abate the mounting curtailments of solar power that the grid is currently unable to absorb.

Projects that are not equipped with battery storage are unlikely to find buyers, with almost 42 gigawatts of planned capacity yet to sign offtake contracts, Renewables Secretary Santosh Kumar Sarangi said on Friday.

Among the most at risk are about 18 gigawatts of solar-only projects and another 14 to 15 gigawatts of capacity awarded at high prices, he said at the BNEF Summit in New Delhi. 

In India, renewables additions have been led by photovoltaic, causing a day-time supply glut, particularly during summers when radiation is stronger. About 11% of solar power generated in India during the hottest months this year was lost to grid curtailments, even as demand hit a record. 

Grids around the globe are struggling to keep pace with the rapid expansion of solar and wind fleets, creating periods of excess electricity that force operators to shut down a portion of generation capacity to protect equipment and prevent blackouts. 

India’s transmission system failed to absorb more than 8 billion kilowatt-hours of power in April to June, when 63 billion actually reached the system. Peak curtailment was seen in May, when scorching heat sent electricity use to all-time high.  

Solar developers are now adding battery storage to attract buyers that need supplies throughout the day, Sarangi said.

Almost 21 gigawatts of the country’s renewable energy projects have only part-time access to the grid, putting them at a greater risk of curtailments, which is hampering expansion and threatening to slow energy transition.

States in the northern and western regions have struggled to build grid networks that match the expansion in solar energy.