Commissioning of Unit Two
Subansiri Lower Hydroelectric Project Strengthening North East Power Supply: India has strengthened its clean energy infrastructure with the commissioning of Unit-2 (250 MW) of the Subansiri Lower Hydroelectric Project. The project is located on the Subansiri River along the Arunachal Pradesh–Assam border and represents a major milestone in India’s renewable energy journey.
The commissioning was virtually inaugurated by Manohar Lal, Union Minister of Power, Housing and Urban Affairs. With this step, India adds significant renewable capacity to the national grid while addressing regional power imbalances.
Strategic Importance of the Project
The Subansiri Lower Hydroelectric Project is India’s largest hydropower project with a total installed capacity of 2,000 MW. It is being developed by NHPC, India’s premier hydropower public sector enterprise.
The project directly supports India’s Net Zero emissions commitment by reducing reliance on fossil fuels. It also plays a crucial role in meeting rising electricity demand in eastern and north-eastern India, regions that have historically faced power deficits.
Static GK fact: Hydropower is classified as a renewable energy source because it relies on the natural water cycle driven by solar energy.
Design and Engineering Features
The project is a run of the river scheme with limited pondage, ensuring minimal environmental disruption. It comprises eight generating units, each with a capacity of 250 MW.
One of its most notable features is the 116-metre-high concrete gravity dam, the largest dam in North-East India. The project is also the first cascaded dam on the Subansiri River, marking a major engineering achievement in the region.
Static GK Tip: Concrete gravity dams rely on their own weight to resist water pressure and are commonly used in large river valley projects.
Flood Moderation Role
Apart from power generation, the Subansiri Lower Project plays a vital role in flood moderation. Around one-third of the reservoir capacity, approximately 442 million cubic metres, is intentionally kept vacant during monsoon months.
This design allows the reservoir to absorb excess floodwaters, significantly reducing flood risks in downstream areas of Assam, which are frequently affected by monsoon flooding.
Project Timeline and Future Expansion
With Unit-2 operational, the project is steadily moving toward full commissioning. Three additional units are planned to be commissioned in the near term, while the remaining four units will be brought online in phases during 2026–27.
Once fully operational, the project is expected to generate around 7,422 million units of electricity annually, greatly enhancing grid stability and renewable energy availability in the region.
Socio Economic Benefits
The project has delivered substantial socio-economic gains for the North-East. During construction, nearly 7,000 local workers were employed daily, boosting regional livelihoods.
Electricity from the project will be supplied to 16 beneficiary states, with free power allocation to Arunachal Pradesh and Assam. Additionally, 1,000 MW has been specifically reserved for the North-East region, ensuring local energy security.
NHPC has also invested in riverbank protection, community development, and CSR initiatives, strengthening long-term regional growth.
Static Usthadian Current Affairs Table
Subansiri Lower Hydroelectric Project Strengthening North East Power Supply:
| Topic | Detail |
| Project Name | Subansiri Lower Hydroelectric Project |
| Total Capacity | 2,000 MW |
| Unit Capacity | 250 MW each |
| Number of Units | Eight |
| Commissioned Unit | Unit-2 in December 2025 |
| Developer | NHPC |
| River | Subansiri River |
| Location | Arunachal Pradesh–Assam border |
| Dam Height | 116 metres |
| Annual Generation | 7,422 million units |
| Key Benefits | Renewable power, flood moderation, regional development |
