India accelerates long-duration storage amid solar curtailment woes

By mid-2026, India’s energy planners had moved decisively beyond the initial two-hour battery storage models, recognizing that short-duration systems were insufficient to handle the growing variability of solar power and peak demand fluctuations. This shift was driven by the realization that the grid’s needs had evolved from simply measuring megawatts of capacity to quantifying 'hours of stored sunshine,' reflecting a more nuanced approach to energy storage that prioritizes duration alongside power. The urgency of this transition was underscored by the staggering 2.3 terawatt-hours of solar electricity wasted between May and December 2025, as inflexible coal plants failed to ramp down quickly enough to absorb excess solar generation during low demand periods, highlighting the critical role longer-duration storage plays in optimizing renewable integration and grid stability.

This early pivot towards longer-duration battery systems—extending storage capacity from two to four hours or more—illustrates a deeper engineering understanding within India’s energy sector. By maintaining the same power output, such as 500 MW, but increasing energy capacity to 2,000 MWh, these systems effectively double the duration, enabling more sustained energy delivery that better matches the intermittent nature of solar generation. This nuanced approach reflects a strategic evolution from simply adding capacity to enhancing the quality and flexibility of storage solutions, a critical step as India’s renewable energy footprint expands and the grid demands more sophisticated balancing mechanisms.

By mid-2026, India’s rapid rise in peak electricity demand—reaching 270.8 GW in May, a 90 GW jump since 2019—exposed critical grid reliability challenges, particularly during nighttime when air conditioning load surges. Despite ambitious plans for 80 GW of battery and 94 GW of pumped hydro storage by 2035-36, these solutions offer only 4 to 6 hours of discharge, falling short of addressing prolonged low renewable generation periods and peak demand fluctuations.

The summer of 2026 starkly revealed systemic grid constraints as India curtailed approximately 11% of its solar power—equivalent to around 8 billion kWh—due to transmission bottlenecks and limited storage capacity. This not only forced operators to ramp up fossil fuel plants, undermining emissions goals, but also highlighted the inflexibility of the grid, with about 21 GW of variable renewable energy capacity operating under Temporary General Network Access and facing peak period restrictions.

In response to these challenges, government and industry leaders, including MNRE Secretary Santosh Kumar Sarangi, have emphasized the urgent need for expanding transmission infrastructure at both interstate and intrastate levels alongside scaling battery storage capacity. Initiatives like potential-based transmission planning and the Green Energy Corridor aim to alleviate synchronization and evacuation bottlenecks, while calls for improved forecasting, regional coordination, and market reforms intensify to better harness India’s soaring solar capacity.

The stakes remain high as up to 42 GW of solar projects—particularly 18 GW of solar-only capacity—face curtailment or lack of grid access, threatening to stall renewable expansion, especially in northern and western states where grid development lags behind installations. The Ministry of New and Renewable Energy is advocating immediate investment in at least 10 GWh of battery storage to mitigate these losses, with experts warning that without rapid upgrades in storage and transmission infrastructure, India’s renewable ambitions risk being undermined by persistent grid inflexibility and transmission bottlenecks.

In July 2026, India took a decisive leap in its long-duration energy storage ambitions by awarding 1,344MW of pumped hydro storage contracts through SECI’s competitive reverse auction, with Greenko securing 720MW, Tata Power 324MW, and Torrent Energy Storage Solutions 300MW. These 40-year build-own-operate agreements mandate eight-hour discharge durations and set the first publicly benchmarked tariffs for large-scale pumped hydro, aligning with India’s target of 74GW/411.4GWh storage capacity by 2031–32 and underscoring a strategic commitment to grid stability during solar surplus and evening peak demand.

Alongside pumped hydro, India signaled a diversification in storage technologies by awarding Delectrik Systems the country’s first utility-scale vanadium redox flow battery contract—a 100MWh system integrated into the 30GW Gujarat Hybrid Renewable Energy Park. This milestone reflects a broader national strategy to expand and streamline regulatory processes for both pumped hydro and advanced battery storage pipelines, accelerating renewable integration and grid resilience.

By mid-August 2026, the government further advanced its storage agenda through SECI’s award of a 230MW hybrid renewable project to Juniper Green Energy Limited under a 25-year PPA at ₹5.26 per unit. This project, combining solar, wind, and Battery Energy Storage Systems (BESS), exemplifies the strategic push toward long-duration hybrid solutions designed to deliver at least 90% firm power during peak hours, addressing intermittency and reliability challenges with a clear 24-month commercial operation timeline.

India's energy storage landscape is rapidly evolving beyond the lithium-ion paradigm, embracing a diversified portfolio that includes sodium-ion, vanadium redox flow, iron flow, and innovative CO2-based batteries. NTPC’s strategic pivot, underscored by Chairman Gurdeep Singh's assertion that “Battery doesn't just mean lithium,” reflects a maturing technology ecosystem where projects like the 3 MWh vanadium flow battery and a 144 MWh CO2 battery at Kudgi exemplify this shift. This diversification is complemented by the commissioning of India’s first utility-scale 100 MWh vanadium flow battery at the Gujarat Hybrid Renewable Energy Park by Delectrik Systems, signaling a tangible move toward hybrid and long-duration storage solutions.

Pumped hydro storage (PSP) remains a cornerstone of India’s long-duration energy strategy, with major players like Greenko, Tata Power, and Torrent securing 1,344 MW of PSP capacity under SECI’s PSP-I tender, structured as 40-year build-own-operate contracts demanding eight-hour discharge durations. NTPC’s ambitious scaling plans, targeting over 18 GW of PSP capacity—including 13.2 GW allocated across multiple states and operational assets like the 1 GW Tehri PSP—highlight the complementary role of PSP in stabilizing the grid and integrating renewables. These efforts are aligned with India’s broader goal of achieving 74 GW/411.4 GWh of energy storage by 2031–32, with 156 GWh already underway, underscoring a strategic blend of battery and hydro storage to meet diverse grid needs.

The push toward diversified storage technologies is driven by a nuanced understanding of grid flexibility requirements, emphasizing energy capacity and duration over mere power output. NTPC’s leadership stresses that storage solutions must be evaluated in terms of megawatt-hours to effectively manage renewable variability, with Gurdeep Singh noting the integration of solar and wind “along with the storage.” This paradigm shift is further supported by the recent achievement of Technology Readiness Level 7 for sodium-ion batteries, signaling imminent commercial production within two to three years, and reinforcing India’s commitment to a multi-technology storage ecosystem that balances innovation with scalability.

NTPC's strategic pivot into battery energy storage systems (BESS) and hybrid renewable projects marks a significant evolution from its traditional thermal power roots, underscoring a diversified approach to India's energy transition. By mid-2026, NTPC had incorporated a dedicated 5 GWh BESS capacity under the PSDF Viability Gap Funding Scheme across 15 thermal stations, while its group-level renewable capacity surged from 82,646 MW to 90,904 MW within a year, driven primarily by subsidiaries. Chairman Gurdeep Singh's emphasis on energy capacity measured in megawatt-hours rather than just megawatts highlights NTPC's recognition that storage investments could rival or exceed those in generation, reflecting a nuanced understanding of the financial scale and complexity involved in integrating storage with renewables.

The regulatory landscape is evolving in tandem with industry ambitions, as exemplified by the Central Electricity Regulatory Commission's issuance of BESS tariff determination regulations in March 2026, which provide a critical framework for storage project viability. This regulatory support has catalyzed a wave of private sector investments, with Serentica Renewables—backed by KKR—commissioning a 200 MWh BESS in Bikaner as the first phase of a planned 1 GWh facility. Their ambitious pipeline to deploy 7 GWh of battery storage over the next two years, supported by over US$650 million in investment and a broader INR1 trillion commitment in Rajasthan, signals robust commercial momentum and a maturing financial ecosystem underpinning India's long-duration storage ambitions.

NTPC Green Energy's recent award of a 200 MW/800 MWh standalone BESS project in West Bengal, secured through a competitive e-reverse auction at INR 4.35 lakh per MW per month, exemplifies the commercial scaling and strategic deployment of grid-firming storage assets. Operating on a build-own-operate model integrated into the state's distribution network, this project reflects a broader shift in procurement trends favoring sophisticated battery storage solutions designed to enhance grid resilience and manage peak demand fluctuations. Such developments underscore the growing engagement of both public and private sectors in India's energy storage market, reinforcing the financial ecosystem's maturation.

The infusion of green financing into hybrid renewable projects with integrated storage is gaining traction, as demonstrated by AMPIN Energy's securing of $195 million from Sumitomo Mitsui Banking Corporation and Rabobank for a 100 MW hybrid wind-solar project with battery storage. This deal, structured under Green Loan and Equator Principles, highlights the increasing sophistication of India's renewable energy financing landscape and the critical role of storage in delivering reliable, dispatchable clean power. AMPIN's expanding portfolio—now boasting 6 GW of renewable capacity alongside 5.5 GWh of storage—mirrors the broader trend of private sector investment driving the commercial scaling of India's energy storage transition.

By mid-2026, India had achieved a significant milestone with 297.36 GW of non-fossil fuel installed capacity, constituting 54.18% of its total generation capacity, backed by over Rs 5.08 lakh crore in investments from public sector banks and institutions. However, the rapid growth in variable renewable energy (VRE) generation exposed critical mismatches with transmission system readiness, resulting in approximately 6,900 GWh of power being restricted from evacuation in FY26. This bottleneck underscores the urgent need to synchronize renewable capacity additions with robust transmission infrastructure to fully harness India's clean energy potential.

Recognizing these challenges, the Indian government is aggressively expanding transmission infrastructure through a potential-based planning approach and scaling up intra-state projects under the Green Energy Corridor program. With plans to seek Union cabinet approval for a ₹50,000 crore third phase focused on renewable-rich states like Gujarat, Rajasthan, and Karnataka, the initiative aims to unclog grids and enable higher renewable power evacuation. This expansion is designed as a public-private partnership with competitive bidding to ensure accountability and timely commissioning of transmission corridors ahead of renewable plant rollouts, which is critical to meeting the ambitious 2030 target of 500 GW non-fossil capacity.

Parallel to transmission upgrades, India is scaling its battery energy storage systems (BESS) to enable reliable 24/7 renewable power supply. NTPC is leading this charge with plans to expand its BESS portfolio to 38.9 GWh by FY32, diversifying beyond lithium-ion to include sodium-ion, vanadium redox flow, iron flow, CO2-based batteries, and large-scale pumped storage projects. Chairman Gurdeep Singh emphasized that 'battery doesn't just mean lithium,' highlighting upcoming projects like a 144 MWh CO2 battery at Kudgi and a 3 MWh vanadium flow battery, reflecting a strategic push to balance grid variability and reduce renewable curtailment.

Looking ahead, India is on track to meet or exceed its ambitious 411 GWh energy storage target by 2031-32, with 156 GWh already under implementation. The transition to commercial-scale sodium-ion battery manufacturing is expected within two to three years, while large-scale orders for vanadium flow batteries, such as NTPC Green Energy Limited's 100 MW contract, signal a maturing domestic supply chain. This multi-technology storage expansion, combined with enhanced transmission coordination and collaborative Resource Adequacy Plans, is pivotal to overcoming current bottlenecks and ensuring that the country's renewable capacity additions translate into dependable, round-the-clock clean power.