NHPC’s Subansiri Lower hydel project has begun commercial operation of its fifth 250 MW generating unit, taking the 2,000 MW project’s operational capacity to 1,250 MW, or 62.5% of its installed capacity.
Located at Gerukamukh, the project achieved the Commercial Operation Date for the fifth unit at midnight on October 23, according to the Times of India report. The unit had been synchronised with the National Grid on October 12 in the presence of Diwakar Nath Mishra, additional secretary in the Union Ministry of Power.
The commissioning means that five of the project’s eight 250 MW units are now commercially operational. The first four units entered commercial operation between December 2025 and May 2026, according to the report. The latest unit adds another 250 MW to the project’s generating capacity and marks the latest stage in the completion of NHPC’s largest project.
The Subansiri Lower project has a planned installed capacity of 2,000 MW. Its progress is therefore being measured not only by the number of units commissioned but also by the proportion of its planned capacity available for commercial generation. With five units operational, the project has crossed the three-fifths mark of its total capacity, while work continues on the remaining three units.
NHPC chairperson and managing director Bhupender Gupta described the commissioning of the fifth unit as a milestone for the company’s efforts to develop the hydropower potential of the North-Eastern Region. He said the project represented NHPC’s engineering capabilities and its commitment to national development.
The unit’s synchronisation with the National Grid preceded its Commercial Operation Date, indicating the sequence through which the new capacity was brought into the electricity system. Synchronisation connects a generating unit to the grid, while commercial operation marks the point at which the unit is recognised as commercially operational.
The project’s operational expansion is significant for the region’s electricity system because it adds renewable generation capacity while increasing the amount of power available from a major northeastern facility. NHPC said that, once fully operational, the project is expected to support electricity generation, grid stability and the availability of renewable power in the region and beyond.
The remaining units are still under construction and commissioning work. The report does not specify a completion date for the full 2,000 MW project. Further progress will therefore depend on the completion and commercial operation of the three units that are not yet operational.
