The National Hydroelectric Power Corporation (NHPC) declared the commercial operation of Unit-2 (250 MW) of the 2,000 MW Subansiri Lower Hydroelectric Project (SLHEP) from 00:00 hours on December 23, 2025. Union Minister of Power, Housing and Urban Affairs Manohar Lal inaugurated the commercial operation virtually. Located on the Subansiri River — a tributary of the Brahmaputra — on the Assam-Arunachal Pradesh border, the SLHEP is designed as a run-of-the-river scheme with an installed capacity of 2,000 MW across eight units of 250 MW each. Once fully commissioned, it will be India's largest hydropower project, generating approximately 7,422 million units (MU) of renewable electricity annually. Unit-1 had been commissioned earlier in December 2025, and Unit-2's commissioning follows within days. The remaining six units are scheduled for phased commissioning through 2026-27. The project, developed by NHPC, faced over two decades of delays due to environmental protests, especially from downstream communities in Assam who raised concerns about flood risk and seismic vulnerability of the dam. It is classified under India's 50,000 MW hydropower initiative and aligns with India's target of achieving 500 GW of non-fossil fuel energy capacity by 2030. The commissioning of SLHEP units represents a significant step in harnessing India's hydropower potential in the Northeast, where approximately 40 percent of India's hydropower resources are concentrated.
Subansiri Lower Hydroelectric Project: NHPC Commissions 250 MW Unit-2 of India's Largest Hydropower Project on December 23, 2025
The National Hydroelectric Power Corporation (NHPC) declared the commercial operation of Unit-2 (250 MW) of the 2,000 MW Subansiri Lower Hydroelectric Project (SLHEP) from 00:00 hours on December 23, 2025. Union Minister of Power, Housing and Urban Affairs Manohar Lal inaugurated the commercial operation virtually. Located on the Subansiri River — a tributary of the Brahmaputra — on the Assam-Arunachal Pradesh border, the SLHEP is designed as a run-of-the-river scheme with an installed capacity of 2,000 MW across eight units of 250 MW each. Once fully commissioned, it will be India's largest hydropower project, generating approximately 7,422 million units (MU) of renewable electricity annually. Unit-1 had been commissioned earlier in December 2025, and Unit-2's commissioning follows within days. The remaining six units are scheduled for phased commissioning through 2026-27. The project, developed by NHPC, faced over two decades of delays due to environmental protests, especially from downstream communities in Assam who raised concerns about flood risk and seismic vulnerability of the dam. It is classified under India's 50,000 MW hydropower initiative and aligns with India's target of achieving 500 GW of non-fossil fuel energy capacity by 2030. The commissioning of SLHEP units represents a significant step in harnessing India's hydropower potential in the Northeast, where approximately 40 percent of India's hydropower resources are concentrated.
Key facts
- NHPC commissioned Unit-2 (250 MW) of the 2,000 MW Subansiri Lower Hydroelectric Project on December 23, 2025.
- Once fully commissioned, it will be India's largest hydropower project generating 7,422 MU annually.
- The project is a run-of-the-river scheme on the Subansiri River at the Assam-Arunachal Pradesh border.
- It consists of eight units of 250 MW each, with phased commissioning through 2026-27.
- The project faced over two decades of delays due to environmental protests from downstream communities.
- Northeast India concentrates approximately 40% of India's total hydropower resources.
Mains angle
Q: Evaluate the significance of NHPC's Subansiri Lower Hydroelectric Project commissioning for India's 500 GW non-fossil fuel energy target by 2030.
Answer (50 words):
On December 23, 2025, NHPC commissioned Unit-2 (250 MW) of the 2,000 MW Subansiri Lower Hydroelectric Project on the Assam-Arunachal border. Union Minister Manohar Lal inaugurated virtually. Designed as run-of-the-river across eight 250 MW units generating 7,422 MU annually, it will be India's largest hydropower project, advancing the 500 GW non-fossil target.
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The Subansiri Lower Hydroelectric Project, once fully commissioned, will have a total installed capacity of how many MW?
The Subansiri Lower Hydroelectric Project (SLHEP) has a total installed capacity of 2,000 MW across eight units of 250 MW each, making it India's largest hydropower project.
Source: Social News XYZ / Assam Tribune / The News Mill / Energy Watch / Border Lens
Frequently asked questions
Which unit of the Subansiri Lower Hydroelectric Project was commissioned on December 23, 2025, and by whom?
NHPC (National Hydroelectric Power Corporation) commissioned Unit-2 (250 MW) of the Subansiri Lower Hydroelectric Project on December 23, 2025, inaugurated virtually by Union Minister Manohar Lal.
What is the total installed capacity of the Subansiri Lower Hydroelectric Project and its annual power generation?
The Subansiri Lower Hydroelectric Project has a total installed capacity of 2,000 MW (8 units of 250 MW each) and will generate approximately 7,422 million units (MU) of electricity annually when fully commissioned.
On which river and at which inter-state border is the Subansiri Lower Hydroelectric Project located?
The project is located on the Subansiri River — a tributary of the Brahmaputra — at the border of Assam and Arunachal Pradesh. It is designed as a run-of-the-river scheme.
Why did the Subansiri Lower Hydroelectric Project face significant delays?
The project faced over two decades of delays primarily due to environmental protests from downstream communities in Assam who raised concerns about ecological impact and dam safety.
What percentage of India's hydropower resources are concentrated in Northeast India?
Northeast India concentrates approximately 40% of India's total hydropower resources, making the region strategically significant for renewable energy development.
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