IESA Sees Long-Duration Storage as Key to India’s 500 GW Goal

India’s target of achieving 500 GW of non-fossil fuel energy capacity by 2030 will require accelerated deployment of long-duration energy storage (LDES), with the proposed FY2028 viability gap funding (VGF) framework expected to play a key role, according to a report by the India Energy Storage Alliance (IESA), prepared in association with Customized Energy Solutions (CES).

The report, titled, 'Long-Duration Energy Storage: Global Outlook and India’s Deployment Pathway,' highlights the need to expand storage capacity to manage renewable energy variability, improve grid stability and reduce the curtailment of clean electricity.

India curtailed 2.3 TWh of solar energy over eight months in 2025 because of grid and storage constraints, the report states. With solar and wind generation increasing, longer-duration storage could help capture surplus electricity and supply it during periods of high demand or lower renewable generation.

Globally, the Long Duration Energy Storage Council estimates that around 8 terawatts (TW) of LDES capacity, equivalent to 140 TWh of storage, will be required by 2040. Against this requirement, global operational capacity stood at 117 GW in 2025. Deployment would need to increase nearly 50-fold to meet the projected demand.

Meeting the global requirement would involve an estimated USD 4 trillion in capital investment, potentially generating approximately USD 540 billion in annual system-wide savings. However, the current global project pipeline stands at 0.22 TW, or about 3 percent of the projected 8 TW requirement, indicating the scale of investment and deployment needed.

“Long-duration energy storage is the linchpin that will enable us to maximise renewable utilisation, enhance grid stability, and build resilience into our power system,” said Debmalya Sen, president of IESA. He added that policy support, innovative business models and technology-neutral investment could help India establish a benchmark for renewable energy integration and power system reliability.

In India, the Central Electricity Authority (CEA) projects a battery energy storage system (BESS) requirement of 34.5 GWh by FY2027. According to the report, 9.3 GWh had been commissioned, while another 195 GWh of projects had been awarded or were under tender. The report notes that much of this pipeline is concentrated on short-duration storage, highlighting the need to diversify into technologies capable of providing electricity over longer periods.

The report identifies several technologies suited to different storage requirements. Flow batteries can support daily storage cycles of eight to 12 hours, while iron-air batteries offer the potential for multi-day storage. Pumped hydro, compressed air and thermal energy storage could also serve large-scale grid and industrial applications. The choice of technology would depend on grid requirements, project economics and deployment conditions.

IESA also points to policy and financing gaps that could slow adoption. These include the absence of a formal statutory definition of long-duration energy storage and a dedicated funding mechanism for projects offering eight hours or more of storage.

The alliance has called for coordinated action by policymakers, regulators, industry participants and investors to establish suitable policy frameworks, develop commercially viable business models and extend technology-neutral support. It identifies the anticipated FY2028 VGF framework as a potential enabler for attracting investment and accelerating deployment.

The report argues that expanding long-duration storage will be important as India moves beyond adding renewable generation capacity towards improving its integration, dispatchability and contribution to power system reliability.