Solar power developers in India have begun adding battery storage to their photovoltaic projects in an effort to attract buyers and reduce the large share of curtailments for power supply that the grids are unable to absorb, Santosh Sarangi, Secretary of India's Ministry of New and Renewable Energy, said on Friday.

As many as 42 gigawatts (GW) of solar projects are still struggling to find offtakers, Sarangi said at the BNEF Summit in New Delhi, in comments carried by Bloomberg. Of these, about 18 GW of solar-only projects without batteries are most at risk of continuing to struggle, while another up to 15 GW of projects awarded at high prices also risk failing to secure buyers, according to the official.

Without battery backup, solar projects face curtailments during the hottest months and peak daytime hours. Pairing batteries with solar allows operators to store surplus midday generation and dispatch it after sunset, when solar output fades but demand remains high, flexibility that makes storage-equipped projects more attractive to buyers such as distribution companies seeking firm evening supply.

The underlying challenge is one of pace: India's electricity grid is expanding more slowly than the boom in renewable energy installations, leading to a rising share of clean energy curtailments and threatening to slow the solar and wind boom in the world's most populous country. The stakes extend beyond the power sector: India has committed to installing 500 GW of non-fossil fuel capacity by 2030 and to reaching net zero by 2070, targets that depend on the grid's ability to absorb an ever-larger share of variable renewable energy.

Grid and transmission constraints accounted for nearly two-thirds of all renewable energy curtailment, which totaled 300 gigawatt-hours (GWh) in the first quarter of the year, according to a May report by clean energy think tank Ember.

In a separate analysis in June, Ember said that India needs around 10 GWh of battery storage immediately in order to stop renewable energy curtailment when the coal fleet cannot ramp down below its technical minimum.

"Without sufficient flexibility, including storage, this could become a constraint on the next phase of renewable energy growth," said the report's author, Neshwin Rodrigues, Senior Energy Analyst at Ember.

Between April and June, the hottest months of the year in India, the national grid wasted 11% of solar power output even as electricity demand jumped to a new record high. The national grid failed to absorb 8 billion kilowatt-hours (kWh) of solar energy, compared with 63 billion kWh that reached the grid, said Shripad Yesso Naik, Minister of State in the New and Renewable Energy Ministry.

The economics of storage have also shifted in developers' favor as global battery prices have fallen in recent years, and New Delhi has separately thrown policy weight behind the technology, approving a federal viability gap funding scheme in 2023 to support battery energy storage projects.

By Charles Kennedy for OilPrice.com