India’s largest hydropower project achieves major milestone with wet commissioning of Subansiri Unit

In a landmark development for India’s hydropower sector, NHPC Limited has successfully commenced wet commissioning of Unit-I (250 MW) of the 2,000 MW Subansiri Lower Hydroelectric Project (HEP) on October 24, 2025, marking the first step toward bringing the nation’s largest hydroelectric project into operation.

Wet commissioning refers to the phase when water is first allowed to flow through the turbine system to test the mechanical and electrical components under real conditions—verifying that the equipment runs safely and efficiently before full power generation begins.

The successful mechanical run of the first machine signals the synchronization process with the national power grid, paving the way for power generation trials. Three more 250 MW units are expected to follow this year,