NHPC has began partial commercial operations at the 2,000 MW Subansiri Lower Hydroelectric Project, located on the Assam-Arunachal Pradesh border, more than 13 years after its originally scheduled commissioning in December 2012.
Union Power Minister Manohar Lal inaugurated Unit-2 of the project virtually from New Delhi on Tuesday, describing the development as a “proud milestone” achieved through sustained effort over the years. The project comprises eight units of 250 MW each, with three additional units expected to become operational shortly and full commissioning targeted by 2026-27.
India’s largest hydropower facility, the run-of-the-river project with minimal pondage is expected to generate 7,422 million units of clean electricity annually. Power from the project will be supplied to 16 states, with 1,000 MW allocated to the Northeast, while Assam and Arunachal Pradesh will receive free power as host states.
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The project features a 116-metre-high concrete gravity dam, the tallest in Northeast India, which provides flood moderation through a 442 million cubic metre water cushion. NHPC has also invested ₹522 crore in riverbank protection works extending up to 60 km downstream.
Construction began in January 2005 after forest clearance but remained stalled between December 2011 and October 2019 following protests over safety and downstream impact concerns. Work resumed after clearance from the National Green Tribunal and expert committees.
The project cost has escalated to ₹26,075 crore from an initial estimate of ₹6,285 crore. It currently employs around 7,000 local workers daily and incorporates major engineering milestones, including India’s heaviest hydropower rotors and largest stators.
Full commissioning by May 2026 is expected to significantly boost renewable energy generation and strengthen India’s journey towards its Net Zero targets.
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