PM Green Secures Win in WBSEDCL's 250 MW/1,000 MWh Standalone BESS Auction, Boosting India's Energy Storage Push

In a pivotal development for India's burgeoning energy storage sector, PM Green, a wholly owned subsidiary of Hyderabad-based Power Mech Projects, has emerged as the winner of the West Bengal State Electricity Distribution Company Limited (WBSEDCL)'s auction for a 250 MW/1,000 MWh standalone Battery Energy Storage System (BESS). The project, set to be established at the Goaltore substation in Paschim Midnapore district, marks a significant step toward enhancing grid reliability and integrating renewable energy in West Bengal. Additionally, PM Green has exercised the greenshoe option for an extra 250 MW/1,000 MWh capacity at the Durgapur Projects campus, potentially doubling the project's scale and revenue potential.

The tender, floated by WBSEDCL in October 2025, invited bids for the development of a standalone BESS on a build-own-operate (BOO) basis. PM Green, leading a consortium, clinched the contract, underscoring its growing footprint in sustainable infrastructure. The base project is projected to generate revenues of approximately ₹15.63 billion (~$173.55 million) over its lifecycle, with the greenshoe addition pushing the total to ₹31.26 billion (~$347.08 million). The BESS will interconnect with WBSEDCL's network at the 132 kV bus of the Goaltore substation, ensuring seamless integration into the state's power grid.

Under the terms of the Battery Energy Storage Purchase Agreement (BESPA), the project must be commissioned within 18 months from signing, with the agreement spanning 15 years from the scheduled commissioning date. Developers are mandated to use only commercially established and operational technologies to minimize risks and facilitate timely rollout. The system must deliver a minimum AC-to-AC round-trip efficiency (RTE) of 90% monthly, with the capability for at least four hours of continuous discharge at rated power. Operational flexibility includes charging or discharging at or below rated capacity, as directed by WBSEDCL, with daily energy discharge limited by the agreed RTE.

To maintain high availability, the BESS allows for planned maintenance outages not exceeding 34 hours across any two consecutive months, requiring at least one month's advance notice. The maximum time to restore readiness between charge-discharge cycles is capped at one hour. WBSEDCL will not demand more than one full four-hour discharge per day at rated power, though sessions can be singular or segmented. These stipulations aim to balance operational efficiency with grid demands, particularly in supporting peak load management and renewable intermittency.

This auction comes amid a challenging landscape for India's energy storage market. According to Mercom India Research's India’s Energy Storage Landscape 1H 2025 Report, the country added only 48.4 MWh of storage capacity in the first half of 2025—a 74% decline from 186 MWh in the same period of 2024. Factors such as supply chain disruptions, high battery costs, and regulatory hurdles have slowed deployments, making WBSEDCL's initiative a timely catalyst for revival.

Deeper Analysis: Strategic Implications and Broader Market Dynamics

PM Green's victory highlights the strategic diversification of Power Mech Projects, traditionally known for engineering and construction in thermal power, into green energy solutions. As a subsidiary, PM Green leverages its parent's expertise in project execution, potentially accelerating commissioning and reducing costs. This win not only bolsters the company's portfolio but also positions it as a key player in India's BESS ecosystem, where standalone systems are increasingly vital for grid stabilization without direct ties to solar or wind generation.

Economically, the project's revenue projections reflect the growing viability of BESS in India, driven by falling lithium-ion battery prices and supportive policies like the National Electricity Plan's emphasis on storage for renewable integration. At full scale with the greenshoe, the initiative could power equivalent to thousands of households during outages or peaks, reducing reliance on fossil fuel backups and curbing transmission losses in West Bengal's rural and industrial belts. Paschim Midnapore's Goaltore and Durgapur's industrial hub are strategic locations, enhancing energy security in regions with high demand variability.

Environmentally, standalone BESS like this facilitates higher renewable penetration by storing excess green power and dispatching it during non-solar hours, aligning with India's net-zero by 2070 ambitions. It could avert significant CO2 emissions by displacing diesel generators and thermal plants, especially in a state like West Bengal, which relies heavily on coal. However, challenges persist: the 90% RTE guarantee demands advanced battery management systems, and any deviations could trigger penalties, underscoring the need for technological maturity.

On a broader scale, this auction signals a shift toward state-level storage tenders, complementing national efforts like SECI's hybrid auctions. With India's battery manufacturing ramping up under the Production Linked Incentive (PLI) scheme—aiming for 50 GWh by 2030—projects like this could ease import dependencies and foster domestic supply chains. Yet, the 74% drop in 2025 additions warns of potential bottlenecks; developers may face land acquisition delays, financing hurdles (with BESS capex around ₹4-6 crore per MWh), and evolving standards for grid codes.

Critics note the absence of disclosed tariffs in the announcement, which could indicate a focus on availability-based payments rather than competitive bidding rates seen in solar-storage hybrids (often ₹3-4/kWh). This model prioritizes reliability over cost minimization, suitable for standalone systems but potentially raising procurement expenses for discoms like WBSEDCL.

Overall, PM Green's success in this auction exemplifies the momentum building in India's storage sector, despite recent slowdowns. As global battery prices continue to decline and policy frameworks mature, such projects could pave the way for gigawatt-scale deployments, transforming West Bengal—and India—into a resilient, low-carbon energy powerhouse. Stakeholders will monitor commissioning timelines closely, as timely execution could inspire similar tenders across other states, accelerating the nation's clean energy transition.

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