NHPC to Launch Second Unit of Subansiri Hydroelectric Project

The NHPC is preparing to launch the second unit of the Subansiri Lower Hydroelectric Project, marking a significant step in India's renewable energy efforts. With a capacity of 250 MW, this unit will contribute to the project's total capacity of 2,000 MW. The project, located at Gerukamukh, has faced numerous challenges over the years, including protests and legal issues, but is now on track for completion. The initiative aims to generate substantial electricity while minimizing environmental impact, aligning with India's commitment to sustainable energy development. Stay tuned for more updates on this pivotal project.

By Narendra Chaudhary Dec 21, 2025, 14:02 IST

Commencement of Commercial Operations

New Delhi, Dec 21: The NHPC, a state-owned enterprise, is set to initiate commercial operations for the second unit of the Subansiri Lower Hydroelectric Project, which boasts a total capacity of 2,000 MW, starting Tuesday.

In a recent filing, NHPC announced that Unit-2, with a capacity of 250 MW, will officially commence operations at 00:00 hours on December 23, 2025.

This run-of-the-river project, featuring eight units of 250 MW each, is situated at Gerukamukh near North Lakhimpur, straddling the border between Arunachal Pradesh and Assam, and utilizes water from the Subansiri River.

Developed at an estimated investment of around Rs 27,000 crore under the Ministry of Power, the facility will ultimately house eight Francis-type turbines, making it the largest hydroelectric power station in India upon full commissioning.

Sanjay Kumar Singh, NHPC's Director (Projects), was present at the site to oversee the launch of commercial operations.

During his visit, he evaluated critical infrastructure elements, including the main dam, diversion tunnel, and spillway structures, while engaging with contractors and stakeholders to discuss outstanding tasks.

The first unit, with a capacity of 250 MW, was successfully synchronized with the national grid on December 3, confirming its operational readiness.

NHPC anticipates that the project will produce approximately 7,421.59 million units of electricity in a year with 90% dependability.

The remaining four units are expected to be connected sequentially during 2026–27, further bolstering energy supply and supporting national infrastructure.

Construction of the concrete gravity dam, which stands 116 meters high and spans 284 meters in length, commenced over two decades ago.

The project faced significant delays due to various technical, environmental, and social issues, including an eight-year halt from 2011 to 2019 caused by protests in Assam and legal disputes concerning dam safety and ecological concerns downstream.

However, with enhanced mitigation strategies in place, construction resumed in October 2019, turning initial skepticism into tangible progress.

NHPC representatives noted that the Subansiri project is designed as a run-of-the-river scheme, which utilizes the river's natural flow while minimizing construction scale and environmental impact compared to traditional large-reservoir projects.

This approach aligns with India's broader initiative for scalable and environmentally conscious hydropower development.