NHPC Declares Commercial Operation of it’s first Unit (Unit Number 2 of 250 MW) of India’s Largest Hydropower Project- 2000 MW Subansiri Lower H.E. Project
NHPC Declares Commercial Operation of it’s first Unit (Unit Number 2 of 250 MW) of India’s Largest Hydropower Project- 2000 MW Subansiri Lower H.E. Project
In a landmark milestone for India’s clean energy sector, NHPC Limited, a “Navratna” Enterprise under the Government of India, has declared the Commercial Operation Date (COD) of it’s first Unit (Unit Number 2 of 250 MW) of the 2000 MW (8 X 250 MW) Subansiri Lower H.E. Project, located on the Arunachal Pradesh/Assam border. The unit successfully commenced commercial operation on 23rd December 2025, marking a significant step in commissioning India’s largest hydropower project.
Hon’ble Union Minister of Power, Housing & Urban Affairs Manohar Lal inaugurated the commercial operation of Unit Number 2 (250 MW) of the 2000 MW (8×250 MW) Subansiri Lower Hydroelectric Project through virtual mode on 23rd December 2025, marking a landmark milestone in the project’s progress. Hon’ble Minister lauded the achievement as a proud milestone in NHPC’s journey. He stated that the commissioning of this unit is “not just a technical achievement, but a testament to years of hard work, dedication, and teamwork.” He further emphasized that the Subansiri Project stands as a symbol of India’s commitment to clean and sustainable energy, supporting North-East India’s growth, strengthening the national grid and advancing India’s ambitious Net Zero goals.
The momentous event was graced by Shri Pankaj Agarwal, Secretary (Power), Govt. of India; Shri Mohd. Afzal, Joint Secretary (Hydro), Ministry of Power, Govt. of India alongwith Shri Bhupender Gupta, CMD, NHPC; Shri Uttam Lal, Director (Personnel); Shri Sanjay Kumar Singh Director (Projects); Shri Suprakash Adhikari Director (Technical); Shri Mahesh Kumar Sharma, Director (Finance) and Shri Santosh Kumar, Chief Vigilance Officer.
Shri Pankaj Agarwal, Secretary (Power) lauded NHPC’s achievement, highlighting that the Subansiri Lower Project will greatly improve energy supply in the North-East and serve as a testament to India’s commitment to state-of-the-art, sustainable power systems. Shri Agarwal emphasized timely commissioning of the remaining units, noting that the Subansiri Project will continue to play a pivotal role in India’s transition to a Net Zero energy future while generating substantial socio-economic benefits for local communities.
Shri Bhupender Gupta, CMD, NHPC, expressed his heartfelt gratitude to the Ministry of Power, Govt. of India, the Governments of Arunachal Pradesh and Assam, former NHPC leadership, the entire Subansiri Project team, all key stakeholders and partners for their dedicated support in making this milestone achievement possible. He further stated that the project will strengthen the national grid, support sustainable development in the North-East and provide reliable renewable energy to meet growing demand. Shri Rajendra Prasad, Executive Director and Head of the Subansiri Lower Project, affirmed that the project team is fully committed to achieving commissioning of the remaining units of the project as per the stipulated schedule.
With the commissioning of Unit # 2, the Project is moving swiftly towards commissioning of 3 more units of 250 MW each shortly, followed by phased commissioning of the remaining four units during 2026-27. Upon full commissioning, the 2000 MW Subansiri Lower Hydroelectric Project will make a significant contribution to India’s renewable energy capacity, enhance national grid resilience and usher in a new era in massive clean energy contribution.
As India’s largest hydropower project, the Subansiri Lower Project comprises 8 units of 250 MW each and is designed as a Run-of-the-River scheme with small pondage, diverting water through eight Head Race Tunnels (HRTs) to generate 7,422 million units (MU) of renewable electricity annually contributing significantly to India’s green energy future. The project features the largest dam in North-East 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.
The Subansiri Lower H.E. Project is a showcase of engineering excellence and determination, housing India’s heaviest hydro generator rotors, largest stators and biggest main inlet valves. The project also features pioneering construction innovations, including the nation’s largest aggregate processing plants, the highest-capacity batching plant and the first-ever use of Rotec’s Tower Belt for dam concreting in India, underscoring NHPC’s commitment to technological advancement in large-scale hydropower development.
The Subansiri Lower H.E. Project is the first of the cascaded dams on the Subansiri River and plays a critical role in flood moderation. The project provides a dedicated 442 million cubic metre flood cushion for safer management during the monsoon season. With a gross reservoir storage of 1,365 million cubic metres at Full Reservoir Level (FRL), the project ensures that approximately one-third of the reservoir remains empty during flood periods, enabling it to absorb excess floodwaters 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 stabilized the riverbanks for over five years. In addition, NHPC is supporting downstream community development through livelihood programs in piggery, sericulture and handloom, developed with IRMA. These initiatives, now in production, benefit around 5,000 women farmers and promote sustainable socio-economic development in the region.
Apart from supplying electricity to 16 beneficiary states across India, the Subansiri Lower H.E. Project will provide free power allocations to Arunachal Pradesh and Assam, while the North-East region will receive 1,000 MW from the project, significantly strengthening regional energy availability.
The project has generated strong socio-economic benefits for the region by engaging around 7,000 local people daily during its construction phase and creating numerous direct and indirect jobs through contractors, service providers and local markets. With the commissioning of the project and the availability of continuous power, new small-scale industries are expected to emerge, further expanding employment and business opportunities while helping reduce outmigration. Additionally, the project is expected to boost tourism and enhance river navigation, contributing to long-term regional development and prosperity.
NHPC has invested around ₹155 crore in CSR initiatives across Arunachal Pradesh and Assam. Key works include constructing 3,129 toilets under Swachh Vidyalaya Abhiyaan, establishing a Vivekananda Kendra Vidyalaya in Dollungmukh serving 250 students, providing safe drinking water facilities at 1,841 locations and RO water with sanitation at 9 locations and executing multiple rural development projects such as community halls, meeting halls, causeways and water supply schemes in nearby areas.
Over the last five decades, NHPC has successfully executed hydropower projects in some of the most challenging terrains and has diversified into solar, wind, and green hydrogen, reinforcing its position as a 100% Green Energy Company. With an installed capacity of 8333 MW from 30 power stations and 14 projects totaling 9704 MW currently under construction, NHPC continues to play a vital role in advancing India’s clean energy transition and strengthening national energy security.
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Faridabad
23.12.2025