India will test battery storage in coal-fired power plants to absorb surging midday solar and hold some thermal energy in reserve during the evening peak—without disrupting the grid.
The relocation aims at an increasing cycle: coal units are now forced by the sun to retreat in the daytime, but the demand still points to them in the evening. That tension is only increasing with a non-fossil capacity target of 500 GW by 2030.
“At times there are only two choices. Either you shut down the coal plant (during excess solar generation) or lose the thermal capacity in the evening, which we don’t want,” said Ghanshyam Prasad, chairman of the Central Electricity Authority (CEA), at PowerGen India 2025 in New Delhi. “We are just trying this as an experiment.”
As a test of whether a way out exists, the CEA has requested NTPC, the largest coal generator in India, to put in place batteries in a few of its plants with financial assistance. The concept is not very complex: pay now when renewable production is high and pay later when the coal units can operate more continuously, reduce cycling costs, and, perhaps, increase the lifespan of the assets.
NTPC has already given a tender of 1.7 GW of battery across 11 coal plants—one of the largest in the world. It has 300 MW of four-hour systems (1,200 MWh) and 1,400 MW of two-hour systems (2,800 MWh), which are to be cycled twice a day over a period of 12 years.
The balance is relevant since the process of transition in India is a balancing act. The pace of renewables is increasing, but coal is still at the heart of 24-hour supply. The government is considering adding 97 GW of coal generation by 2035, which will take the fleet to about 307 GW, though flexibility and storage will continue to increase.
“If we maintain operations at that level for extended durations, the anticipated lifespan of a plant—usually around 25 years—could be reduced by a third or more,” said NTPC director of operations Ravinder Kumar.
This is the direction in which regulation is driving. Coal plants now have to work at a minimum load of 55 percent and have to comply with certain ramp rates. A 40 percent target is being considered, but NTPC has reported durability concerns and is maintaining its technical minimum at 55 percent in the meantime.
All this is going on against a stark shortage of storage. Even the current number of 500 MWh of operating batteries in India is only a fraction of the multi-gigawatt need by the early 2030s. Despite the fact that approximately 12.5 GW of projects are currently under tender with an additional 3.3 GW under review, supported by the Viability Gap Funding scheme of the Union government, which pays about 30 percent of the capital costs.
When the pilot is working
Coal-plus-batteries might be a viable solution—stretching the thermal resources already available and supporting the very quick uptake of renewable resources. It would also provide a model to other economies that rely on coal to absorb variable renewables without impacting reliability.
