India’s 500 GW Clean Energy Ambition Hinges on LDES Scale-Up, with FY28 Viability Gap Funding as the Key Enabler: IESA Report

India’s path to achieving 500 GW of non-fossil fuel energy capacity by 2030 now critically depends on scaling up long-duration energy storage (LDES) technologies, according to a new report by the India Energy Storage Alliance (IESA) in association with Customized Energy Solutions (CES). The report, ‘Long-Duration Energy Storage: Global Outlook and India’s Deployment Pathway,’ identifies the anticipated FY2028 Viability Gap Funding (VGF) framework as a key enabler for accelerating LDES deployment and unlocking the full value of India’s clean energy transition. As the focus shifts from capacity addition to optimisation and integration of renewable resources, scaling up LDES is essential to support grid stability, renewable integration, and energy resilience on the path to net zero.

The report highlights that , over eight months in 2025, India curtailed 2.3 terawatt-hours (TWh) of solar energy due to grid and storage constraints, underscoring the urgent need to enhance grid flexibility and maximise renewable generation. With increasing penetration of variable renewable energy, the ability to capture surplus electricity and dispatch it during periods of high demand or low generation is vital for grid reliability and economic efficiency.

According to the LDES Council, by 2040, the world will require around 8 terawatts (TW) of LDES capacity, equivalent to 140 TWh of storage. In comparison, just 117 GW was operational globally in 2025, indicating that deployment rates must increase nearly 50-fold to meet future requirements. Achieving this will require an estimated $4 trillion in capital investment, with the potential to unlock approximately $540 billion in annual system-wide savings. Despite these benefits, the current global project pipeline stands at only 0.22 TW, about 3% of the 8 TW target, signalling significant growth potential and the need for accelerated action.

Debmalya Sen, President, India Energy Storage Alliance, said, “India’s journey toward a clean and reliable energy future depends on our ability to integrate renewables efficiently and flexibly. 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. With the right policy support, innovative business models, and technology-neutral investment, India can set a global benchmark for sustainable energy integration and system reliability.”

Within India, the Central Electricity Authority (CEA) projects a battery energy storage system (BESS) requirement of 34.5 GWh by FY2027. To date, 9.3 GWh has been commissioned, with another 195 GWh of projects awarded or under tender. However, most of this pipeline is concentrated on short-duration solutions, underscoring the need to diversify towards long-duration technologies that can provide grid balancing and resource adequacy over extended periods.

The report highlights a spectrum of emerging storage technologies positioned to address these requirements. Flow batteries are suited for daily storage cycles of eight to twelve hours, iron-air batteries offer multi-day flexibility, and solutions such as pumped hydro, compressed air, and thermal energy storage address large-scale and industrial needs. The optimal technology mix will depend on specific grid applications, project economics, and deployment environments.

Policy and financing frameworks will be instrumental in accelerating LDES adoption. The report notes the absence of a formal statutory definition for long-duration storage and a dedicated funding mechanism for projects providing eight hours or more of storage in India.

IESA recommends that policymakers, regulators, industry leaders, and investors collaborate to establish adaptive policies, create viable commercial models, and provide technology-neutral support. By accelerating investment in long-duration storage solutions, India can ensure the reliability, resilience, and economic viability of its evolving power system, unlocking the full value of its renewable energy transition.