The Solar Energy Corporation of India (SECI) has started planning for its biggest solar-plus-storage project, two sources familiar told Infralogic.

The central authority intends to build a 13 GW solar farm with 5 GWh- 7 GWh of associated battery capacity, the sources said.

The project’s planning is in its early stages with approvals pending from the Prime Minister’s office.

Consultants will subsequently be appointed to prepare a detailed project report, likely through a competitive bid process, one of the sources said.

It will take at least 18 months for the SECI to start considering publishing a tender for the development contract, he added.

The project will also be eligible for grant funding, both sources said.

India requires more battery storage projects because transmission capacity has not kept up with power generation growth, said Shantanu Gupta, a partner at law firm Khaitan & Co.

Gupta has experience in private equity, mergers and acquisitions, and general corporate advisory, with a special focus on energy, infrastructure, real estate, and manufacturing.

One of the main reasons for the slower growth in transmission capacity is securing right of way as projects require huge land parcels, and acquisition of land and securing grid corridors remains a challenge, he added.

A report by JMK Research and Analytics in September stated that more than 50 GW of renewable energy capacity is currently stranded nationwide due to transmission constraints, increasing per-unit transmission costs, weakening project viability, and deterring private investment.

In the financial year through March 2025, India added 8,830 circuit kilometres (ckm) of new transmission lines against a target of 15,253ckm, reflecting a 42% shortfall.

SECI’s biggest battery project commissioned so far is in Chhattisgarh state. The project has a capacity of 40 MW/120 MWh with a solar plant, which has an installed capacity of 152.325 MWh.

Last month, Hindustan Power secured a contract from SECI for a solar and battery project with a capacity of 150 MW, according to a report by the Press Trust of India. It involves the installation of about 300 MWp of solar and a 300 MWh battery.

SECI did not respond to a request for comment.