India’s largest hydropower project begins wet commissioning of first 250 MW unit at Subansiri

In a landmark moment for India’s hydropower sector, NHPC Limited has commenced the wet commissioning of the first 250 MW unit of its 2,000 MW Subansiri Lower Hydroelectric Project (HEP). 

The process follows the successful mechanical run of the turbine, marking a decisive step toward the operational launch of India’s largest hydroelectric project and NHPC’s most powerful unit to date.

Located at Gerukamukh on the Arunachal Pradesh–Assam border, the Subansiri Lower HEP was launched in January 2005. The project had faced an eight-year suspension between 2011 and 2019 due to protests in Assam and legal hurdles concerning downstream environmental impacts. Work resumed in October 2019 after NHPC adopted enhanced mitigation and safety measures, leading to this major breakthrough.

The milestone ceremony was attended by NHPC Chairman and Managing Director Shri Bhupender Gupta, Executive Director and Project Head Shri Rajendra Prasad, along with NHPC Directors and senior officials from both the corporate and project sites.

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Expressing his gratitude, Shri Gupta extended thanks to the Ministry of Power, Government of India, and the governments of Arunachal Pradesh and Assam, as well as past NHPC leaders, the Subansiri project team, and all stakeholders. 

“This achievement is a shining testament to NHPC’s engineering excellence and India’s growing strength in world-class infrastructure,” he said. “It represents more than just a project milestone—it reflects India’s steady march towards a cleaner, greener, and self-reliant energy future.”

With Unit-1 now in the wet commissioning phase, grid synchronisation is expected shortly. NHPC aims to commission three more 250 MW units within this year, adding 1,000 MW to the national grid. Once all eight units (8 × 250 MW) are operational, the Subansiri Lower HEP will emerge as India’s largest hydroelectric facility, lighting millions of homes and strengthening the nation’s energy security.