Ember says India urgently requires battery storage to help integrate rising solar generation and reduce renewable energy losses
Coal plants operating near their technical limits are creating new challenges for grid management during peak solar hours
The think tank identifies regulatory barriers that slow the expansion of battery energy storage capacity in India
India needs around 10 GWh of battery energy storage capacity ‘immediately’ to reduce renewable energy curtailment caused by operational constraints at coal-fired power plants, according to a new analysis by energy think tank Ember.
Ember's analysis finds that several coal-fired power plants are already operating at or near their minimum technical load (MTL), the lowest level at which they can safely and reliably function. Because these plants cannot reduce generation any further, excess solar electricity is increasingly being curtailed, or prevented from entering the grid.
In FY2025-26, close to 2.1 TWh of renewable electricity was curtailed to enable coal power plants to operate at their technical minimum loads (MTL), leading to an estimated INR 629 crore worth of electricity not generated or sold.
Solar and wind together account for around 17% of India’s annual electricity generation on an average. As more and more solar energy demands space on the grid, coal must be backed down by tens of GWs within the span of a few hours.
Grid operators continue to keep coal plants online to ensure sufficient power is available during the evening demand peak and to maintain reserve capacity for system stability.
Ember shares an example. On March 6, 2026, at midnight coal supplied 87% of India’s electricity, by midday solar and wind pushed down coal’s share to 54% by taking 41% of the mix. This translated into a reduction of around 49 GW in 6 hours. Coal then had to climb back up to 85% in the evening when solar output collapsed in the afternoon, recovering 51 GW in 3 hours.
“Around 10 GWh of storage charging during the midday window would have been sufficient to absorb surplus renewable generation, keep coal above its minimum technical load, and avoid curtailment,” adds Ember.
According to Neshwin Rodrigues, Senior Energy Analyst at Ember underlines that renewable energy generation curtailment is required purely to keep coal power plants at their MTL.
According to Ember, deploying approximately 10 GWh of battery energy storage would help address this issue by storing surplus solar generation during the day and supplying it back to the grid when demand rises later. This would enable greater utilization of renewable energy. Battery storage, the think tank notes, can provide a faster and more flexible solution than relying solely on coal plants to balance the grid.
Ember recommends adding battery storage since it can be built far faster than any other form of power sector infrastructure. Within 5 to 7 months, a site-ready project can move from financial close to commissioning. The country saw 3.37 GWh Khavda BESS project commissioned within 10 months. Hence, as Ember explains, deploying battery storage capacity is not a constraint in India (see ‘World’s Largest’ Single Location BESS Outside China, In India).
According to Ember, current grid connection rules are a key barrier to expanding battery storage capacity in India, as they require battery projects to be linked with renewable energy plants before they can charge from the grid. This requirement can slow down project deployment and limit their scalability.
“The current framework has the default the wrong way around, restricting the very operation that would help the grid most,” added Rodrigues. “Correcting it would allow storage to charge when it reduces curtailment, lowers system stress, and improves flexibility. In doing so, it would unlock the next phase of India’s renewable energy growth.”
Ember’s report Bottleneck to the next phase of renewable energy growth in India is available for free download on its website.
Recently, Mercom India Research reported that India’s battery energy storage capacity grew 941% quarter-on-quarter (QoQ) in Q1 2026 with 4.6 GWh, reaching a cumulative 5.9 GWh (see India’s Battery Storage Capacity Surges 941% QoQ In Q1 2026).