Tamil Nadu government releases three-year BESS policy

Tamil Nadu’s three-year Battery Energy Storage Systems Policy 2026 is designed to expand battery storage across the state. It targets deployment of 2.5 GW/10 GWh and supports renewable-energy integration, peak management, grid support, and energy security. The policy covers standalone and co-located BESS projects.

Existing solar and wind projects of one MW or more will be encouraged to install storage. New solar or solar-hybrid projects meeting that size threshold must install BESS equal to at least 10% of their solar capacity. Eligible projects can also receive a complete waiver of applicable transmission and wheeling charges attributable to their storage.

TNPDC will procure 2,500 MW/10,000 MWh in the first phase from eligible projects using the policy benefits. Tamil Nadu Green Energy Corporation Limited will coordinate and monitor implementation through a single-window system. The policy therefore combines a target, a project requirement, financial support, and central coordination.

Tamil Nadu’s policy envisages 2.5 GW/10 GWh of Battery Energy Storage System deployment over three years. In its first phase, TNPDC will procure 2,500 MW/10,000 MWh from eligible BESS projects that receive policy benefits. These figures show the intended scale of storage expansion across the state.

Four BESS projects are currently being developed. They include a 500 MW/1,000 MWh project under the Viability Gap Funding for Development of Battery Energy Storage System scheme. Another is a 375 MW/1,500 MWh project under a Viability Gap Funding scheme supported through the Power System Development Fund.

The remaining two projects combine solar and storage. Each has a capacity of 15 MW/45 MWh. Together, the four listed projects amount to 905 MW/2,590 MWh. They provide an existing base as Tamil Nadu moves toward the larger policy target.

A Battery Energy Storage System, or BESS, is a facility that stores electrical energy in batteries and releases it when required. In practical terms, it acts as a timing tool for electricity. Power can be held instead of being used immediately, then delivered later for grid support or peak management.

For a solar project, a BESS can charge when solar generation is available and discharge when the project or grid needs power. A wind project can use the same basic arrangement when wind output is available. The battery is connected to equipment that manages charging, storage, and delivery to the electricity system.

The policy specifically promotes BESS for renewable-energy integration, peak management, and grid support. It encourages existing solar and wind projects of one MW or more to install storage. It also supports standalone systems, which can provide storage without being located beside a generation project.

The requirement applies to new solar or solar-hybrid renewable-energy projects with installed capacity of one MW or more. The project must have applied on or after the policy’s notification date, or be commissioned on or after April 1, 2027. This links the storage rule to both project size and timing.

The minimum is BESS capacity equal to 10% of the solar project’s installed capacity. For example, a 100 MW solar project would need storage capacity of at least 10% of that installed capacity. The policy text states the percentage requirement, but it does not specify a storage duration for this rule.

Existing solar and wind renewable-energy projects of one MW and above are encouraged, rather than required, to install BESS. They may use storage for renewable-energy integration, peak management, or grid support. The policy therefore imposes a requirement on qualifying new projects while encouraging additions at existing sites.

Eligible co-located and standalone BESS projects will receive a 100% waiver of applicable transmission and wheeling charges attributable to the eligible storage. Transmission charges relate to moving electricity through the power network, while wheeling charges apply to using distribution networks. The waiver removes those applicable network charges for the qualifying BESS portion.

The benefit can reduce the cost of moving stored electricity through the network. It applies whether the BESS is located alongside a renewable-energy project or operates as a standalone facility. The policy links the waiver specifically to charges attributable to eligible BESS, rather than describing a general waiver for every project cost.

The article does not provide a rupee estimate for the savings. Even so, the full waiver is a significant project incentive because it lowers applicable network-related costs. Alongside the first-phase procurement plan, it is intended to encourage more standalone and co-located storage projects.

Two state agencies have distinct responsibilities under the policy. Tamil Nadu Green Energy Corporation Limited is the State Nodal Agency. It will coordinate, facilitate, and monitor BESS project implementation and operate a single-window system for these projects.

The Tamil Nadu Power Distribution Corporation, or TNPDC, will handle procurement. In the first phase, it will procure BESS capacity aggregating to 2,500 MW/10,000 MWh from eligible projects that avail themselves of the policy’s benefits. This gives the policy a defined buyer as well as an implementation coordinator.

The arrangement is intended to connect project development with public procurement. Developers can use the single-window system for coordination and facilitation, while TNPDC creates demand for qualifying storage. The procurement target forms the first phase of the broader three-year plan to deploy 2.5 GW/10 GWh of BESS across Tamil Nadu.

Solar and wind generation can vary because their electricity output depends on available sunlight and wind. A grid must keep electricity supply and demand balanced. Adding batteries gives the system a way to shift some electricity across time instead of relying only on generation at the exact moment power is needed.

A battery can charge when renewable generation is available and discharge during periods of higher demand or lower renewable output. This can reduce sudden mismatches between supply and demand. It can also help manage peak periods and provide support close to renewable projects or elsewhere on the network.

The policy identifies renewable-energy integration, peak management, and grid support as uses for BESS. Tamil Nadu has 29.8 GW of installed renewable capacity, including 14.5 GW of solar and 11.6 GW of wind. Its storage target is therefore intended to support grid stability as renewable generation forms a large part of the state’s capacity.