As India rapidly scales up its renewable energy capacity to meet its climate goals, a key challenge is emerging for its power system — electricity supply that is abundant in some hours but insufficient in others.

This is because renewable power generation sources come with a fundamental limitation: They are intermittent. Solar power generation drops to zero after sunset and wind output fluctuates with changing weather.

But electricity demand does not always align with these patterns. This creates a growing mismatch between when electricity is generated and when it is needed. This mismatch can stretch the grid and even threaten its stability if not managed properly.

This challenge is particularly relevant for India, where renewable sources account for 53% (283 gigawatts) of the total installed power generation capacity of 532 GW. Solar power alone contributes over 150 GW, making it the largest source in the renewable energy mix.

This is where deploying systems that “store” energy becomes critical — and where India has fallen short so far.

So how does such energy get stored? Here’s a look at the different types of systems in use around the world and what India is doing to build up its storage capacity.

Energy storage refers to systems that can store excess renewable electricity during periods of high generation and discharge it when demand rises but power generation remains low.

At its core, energy storage systems convert electricity from renewable sources such as solar and wind, when it is available, into forms that can be stored. Later, it converts these back into electricity when need arises.

A range of energy storage technologies are being deployed globally. Among them, pumped hydro storage (PHS) and battery energy storage systems (BESS) are currently the most widely used. A look at these two systems:

Beyond these technologies, several other storage solutions are also being deployed globally, though at a smaller scale.

The deployment of energy storage systems in India has not kept pace with the rapid addition of renewable energy capacity. This widening gap is raising concerns over whether the grid will be able to efficiently absorb and manage the rising share of renewable power in the years ahead.

The government is primarily focusing on the two major systems mentioned above: PHS and BESS.

At present, India has an installed BESS capacity of around 0.27 GW. PHS capacity stands at about 7.2 GW. There are plans, however, for a massive scale-up over the next decade.

A Central Electricity Authority (CEA) plan projects the country’s total energy storage capacity to reach 174 GW/888 gigawatt hours by 2035-36. This includes 80 GW/321 GWh of BESS and 94 GW/567 GWh of PHS.

The top power planning agency noted that storage systems with durations of around four to six hours would become increasingly critical for integrating larger volumes of renewable energy into the grid beyond 2030. This requirement is expected to grow alongside India’s non-fossil fuel installed capacity, which is projected to rise from the current 283 GW to 786 GW by 2035-36.

“The storage requirement can be met either through Hydro Pumped Storage Projects (PSP) or BESS or a combination of both. BESS is suitable for short-duration storage, and PSPs are suitable for long-duration storage. Long-duration energy storage will also be crucial for the supply of round-the-clock renewable energy power to Commercial & Industrial (C&I) consumers,” the CEA plan said.

The project pipeline for both technologies is already expanding rapidly.

 Currently, 13,120 MW/78,720 MWh of PHS capacity is under construction. Another 9,580 MW/57,480 MWh has received concurrence and is awaiting construction. In addition, pumped storage projects totalling nearly 75,000 MW are under survey and investigation.

On the battery storage side, 10,658.94 MW/28,739.32 MWh of BESS capacity is currently under construction. Projects totalling 22,347.15 MW/69,836.70 MWh are at the tendering stage.

However, the CEA’s long-term resource adequacy plan also flagged a major concern: India’s heavy dependence on imports for battery storage systems. India currently imports nearly 75-80% of its lithium-ion cells, which account for roughly 80% of the total cost of a battery storage system.

“One of the Asian countries dominates over 75-80% of global battery manufacturing, exposing India to geopolitical risks, trade frictions and price volatility,” it noted.

 Globally, PHS and BESS are the two most widely deployed electricity storage technologies. According to the International Renewable Energy Agency, global installed PHS capacity currently stands at around 160 GW.

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 China leads with nearly 66 GW of installed capacity, followed by Japan at 21.8 GW and the US at 18.9 GW. Europe collectively accounts for around 28 GW of pumped hydro capacity.

Battery energy storage deployment is accelerating rapidly. Some estimates place the total installed global battery storage capacity at around 270 GW. According to the International Energy Agency, 108 GW of new battery storage capacity was added globally in 2025 alone – a 40% increase over 2024.

China continued to dominate battery storage deployment in 2025, accounting for nearly 60% of global additions, followed by the US and Europe. The technology, however, is also expanding quickly beyond the largest markets.

“Deployment is widening beyond the largest markets, with strong momentum in Australia and parts of the Middle East, where storage is increasingly seen as a key building block for electricity security and renewables integration,” the IEA noted in its Global Energy Review 2026.