NHPC Limited has commenced wet commissioning of the third generating unit at the Subansiri Lower Hydroelectric Project, marking a key step towards making India’s largest hydropower project fully operational. Unit 3, with an installed capacity of 250 megawatts, entered the commissioning phase after successfully completing underwater mechanical checks, confirming the readiness of critical components for testing under actual operating conditions.

During wet commissioning, water is allowed to flow through the turbine, enabling engineers to assess performance, safety systems and overall reliability before the unit is synchronised with the national power grid.

The Subansiri Lower project, a 2,000 megawatt run-of-river scheme located on the Assam–Arunachal Pradesh border, has seen steady progress in recent months. The first generating unit has already been commissioned, while trial operations on the second unit have been completed. The remaining units will be commissioned in phases to gradually ramp up generation while ensuring operational stability.

NHPC officials termed the start of wet commissioning for Unit 3 a significant milestone for both the company and India’s hydropower sector. They also acknowledged the support of the Ministry of Power and the governments of Arunachal Pradesh and Assam in advancing the project towards completion.

Once fully commissioned, the Subansiri Lower Hydroelectric Project is expected to add substantial renewable energy capacity to the national grid, improve power availability in the north-eastern region and strengthen overall energy security. The project is also projected to reduce carbon emissions by displacing a portion of electricity generation from fossil fuels.