Dibrugarh: NHPC Limited, a Navratna Public Sector Undertaking under the Ministry of Power, has announced the commercial operation of the fourth unit (Unit 4 of 250 MW) of its flagship 2,000 MW Subansiri Lower Hydroelectric Project (SLHEP). This brings the project to half of its total intended capacity.
The unit commenced commercial operation on Friday, adding another 250 MW of clean, renewable energy to the national grid and pushing the project's total operational capacity to a landmark 1,000 MW.
Project Background and Challenges
The Subansiri Lower Hydroelectric Project, located on the Arunachal Pradesh–Assam border, is one of India's largest hydroelectric developments. Construction began in January 2005 after obtaining forest clearance on October 12, 2004. However, due to agitations and protests by local stakeholders, construction was stalled from December 2011 to October 2019 — a delay of nearly eight years that significantly pushed back the project's commissioning timeline.
Phased Commissioning Progress
The project's first unit (Unit 2) was commercially commissioned on December 23, 2025, marking the inaugural milestone in the project's phased rollout. The second unit (Unit 3) followed on February 1, 2026, taking the project's contribution to 500 MW of the national grid. The third unit came online on March 20, 2026, raising total operational capacity to 750 MW.
Friday's commissioning of the fourth unit completes a rapid sequence of activations over the past several months, reaching the symbolic 1,000 MW halfway mark.
Official Statements
Bhupender Gupta, Chairman and Managing Director of NHPC, said, "The successful commissioning of this unit highlights NHPC's strong technical expertise and project execution capabilities, and further reinforces its pivotal role in strengthening India's energy security in line with the Centre's vision of a sustainable and self-reliant power sector."
He conveyed gratitude to the Ministry of Power and the governments of Arunachal Pradesh and Assam for their continued support, while acknowledging the dedicated efforts of the project team led by Executive Director Rajendra Prasad and the contributions of various departments at NHPC's corporate office. He expressed confidence that the remaining units would be commissioned within their targeted timelines.
