Friday 31 / October / 2025
New Delhi: One of the units of India’s largest hydropower project, along the Arunachal Pradesh-Assam border, started a test run, signalling its commissioning soon.
Officials of the NHPC Limited said the wet commissioning of the first 250 MW unit of the 2,000 MW Subansiri Lower Hydroelectric Project was done on October 24, 2025.
“Wet commissioning is basically a test run of the turbine to check several parameters without generating electricity. The test run with water flow may take four to five days,” a NHPC official said.
The Subansiri Lower project has eight units of 250 MW each. “Four of these units are ready for test runs. The next step involves synchronisation of at least two units for the project to start generating power,” he said.
The Subansiri Lower project, located at Gerukamukh on the inter-State boundary, was launched in January 2005. Work on the project was suspended in 2011 following protests by anti-dam activists in Assam and concerns over downstream environmental impacts.
The work resumed in October 2019 after the Prime Minister’s Office pushed for its completion, and the NHPC adopted enhanced mitigation and safety measures.
On completion, the Subansiri Lower Hydroelectric Project will generate approximately 7,500 million kilowatt-hours of power annually, in a 90%-dependable year.
NHPC Limited commenced construction work of Subansiri Lower Hydroelectric Project in January 2005 after obtaining forest clearance on October 12, 2004. However, due to agitations and protests by local stakeholders, the project construction work was stalled from December 2011 to October 2019. The project construction resumed from October 15, 2019, after the clearance by National Green Tribunal.
