NHPC Commissions 250 MW Unit 4 of Subansiri Lower Project, Total Operational Capacity Reaches 1,000 MW – Indian PSU
State-run NHPC Limited has declared the commercial operation of Unit 4 (250 MW) of its flagship 2,000 MW Subansiri Lower Hydroelectric Project (SLHEP), marking a key milestone in India’s hydropower expansion.
The unit commenced commercial operations at midnight on May 8, adding 250 MW of clean energy to the national grid, the company said in an official release.
With this development, the Subansiri Lower project has now achieved an operational capacity of 1,000 MW—half of its total planned capacity—reflecting steady progress in its phased commissioning strategy.
The project, located on the Subansiri River, is expected to play a crucial role in enhancing grid stability, meeting peak electricity demand, and enabling smoother integration of renewable energy sources into the national grid.
Unit 4 had successfully completed its trial run on May 1, prior to its commercial declaration. The remaining units (5 to 8) are scheduled to be commissioned in phases by the end of 2026.
Once fully operational, the 2,000 MW project is expected to generate around 7,421 million units of electricity annually. It is also projected to contribute significantly to India’s climate goals by reducing carbon emissions by nearly 7 million tonnes each year.
The Subansiri Lower Hydroelectric Project has had a long and complex journey. While construction began in 2005 following forest clearance in 2004, work was halted between December 2011 and October 2019 due to protests in Assam over safety concerns and downstream environmental impacts.
Construction resumed on October 15, 2019, after resolution of legal challenges, including those raised before the National Green Tribunal, and incorporation of key design modifications.
NHPC reiterated that the project has been implemented in line with statutory requirements and government guidelines, with a strong focus on environmental safeguards, safety measures, and socioeconomic welfare.
