The commissioning of Unit‑2 sets the pace for Subansiri’s next three units, with full capacity by FY2026‑27.
Union Minister for Power Manohar Lal has hailed the Subansiri Lower Hydroelectric Project as a testament to India’s clean energy commitment.
Virtually inaugurating the commercial operation of the 250 MW first unit (Unit‑2) of the 2,000 MW Subansiri Lower Hydroelectric Project on the River Subansiri in Arunachal Pradesh-Assam border region on Tuesday, Lal said, “The commissioning of this unit is not just a technical achievement, but a testament to years of hard work, dedication, and teamwork.”
He added that the project stands as a symbol of India’s commitment to clean and sustainable energy, supporting Northeast India’s growth, strengthening the national grid, and advancing India’s ambitious net-zero goals.
The event was also attended by Pankaj Agarwal, Secretary, Power, Bhupender Gupta, Chairman & Managing Director, NHPC, and other officers of the Ministry of Power and NHPC.
Lauding NHPC’s achievement as the project’s developer, Agarwal noted, “The Subansiri Lower Project will greatly improve energy supply in the Northeast and serve as a testament to India’s commitment to state‑of‑the‑art, sustainable power systems.”
He urged the timely commissioning of the remaining units, noting that the project will continue to play a pivotal role in India’s transition to a net-zero energy future while generating substantial socioeconomic benefits for local communities.
Bhupender Gupta, Chairman & Managing Director, NHPC, thanked the Ministry of Power, the governments of Arunachal Pradesh and Assam, former NHPC leadership, the Subansiri Project team, and all stakeholders, stating, “The project will strengthen the national grid, support sustainable development in the Northeast, and provide reliable renewable energy to meet growing demand.”
With the commissioning of Unit‑2, the project is moving swiftly towards the commissioning of three units of 250 MW each shortly, followed by phased commissioning of the remaining four units during FY2026‑27.
As India’s largest hydropower project, the Subansiri Lower scheme comprises eight units of 250 MW each and is designed as a run‑of‑the‑river project with small pondage, diverting water through eight head race tunnels (HRTs) to generate 7,422 million units (MU) of renewable electricity annually. The project features the largest dam in Northeast India—a 116‑metre‑high concrete gravity dam—which not only strengthens regional infrastructure and grid resilience but also enhances flood moderation and water management in the Subansiri River basin.
Power & Community Gains
The Subansiri Lower Hydroelectric Project features India’s heaviest hydro generator rotors, largest stators, and biggest main inlet valves, along with innovations such as the nation’s largest aggregate processing plants, highest‑capacity batching plant, and first‑ever use of Rotec’s tower belt for dam concreting in India.
As the first cascaded dam on the River Subansiri, it provides flood moderation with a 442 million cubic metre flood cushion. With a gross reservoir storage of 1,365 million cubic metres at full reservoir level (FRL), about one‑third remains empty during floods to absorb excess water and protect downstream communities.
NHPC has implemented extensive riverbank protection and erosion control measures along the Subansiri River, completing works up to 30 km downstream and extending them up to 60 km with an investment of about ₹522 crore. This has effectively stabilised the riverbanks for over five years.
Apart from supplying electricity to 16 beneficiary states across India, the Subansiri Lower Hydroelectric Project will provide free power allocations to Arunachal Pradesh and Assam, while the Northeast region will receive 1,000 MW from the project, significantly strengthening regional energy availability.
The project has engaged around 7,000 local people daily during its construction phase and creating numerous direct and indirect jobs through contractors, service providers, and local markets.