A monumental step towards India’s sustainable energy future has been taken as one of the eight units of the nation’s largest hydropower project, the Subansiri Lower Hydroelectric Project, officially began its test run. This significant milestone, unfolding on the border shared by Arunachal Pradesh and Assam, signals the imminent commissioning of this colossal power source.
Officials from NHPC Limited confirmed that the ‘wet commissioning’ of the first 250-megawatt unit of the impressive 2,000 MW project commenced on Friday, October 24, 2025. This critical phase involves a thorough test of the turbine’s various parameters using water flow, a process expected to take approximately four to five days. It’s a precursor to actual electricity generation, ensuring everything runs perfectly.
Currently, four of the project’s eight 250 MW units are ready for these vital test runs. The next crucial stage will involve synchronizing at least two of these units to enable the project to begin generating power for the grid.
The Subansiri Lower project, situated at Gerukamukh, initially broke ground in January 2005. However, its journey was not without challenges. Construction faced a prolonged suspension between 2011 and 2019 due to widespread protests from anti-dam activists in Assam, who voiced serious concerns regarding potential downstream environmental impacts.
Work finally resumed in October 2019, following a determined push from the Prime Minister’s Office. NHPC implemented enhanced mitigation and safety measures to address previous concerns, demonstrating a renewed commitment to the project’s completion.
Bhupender Gupta, Chairman and Managing Director of NHPC, underscored the profound importance of this achievement during the wet commissioning event. He hailed it as a “shining testament” to the corporation’s engineering prowess. “This is more than just a project milestone; it reflects India’s steady march toward a cleaner, greener, and self-reliant energy future,” Gupta stated, encapsulating the national aspiration tied to this ambitious hydropower venture.