In a significant development for India's renewable energy sector, NHPC Limited has achieved another major milestone with the successful synchronization of generating unit-3 of the Subansiri Lower Hydroelectric Project with the National Grid. This 250 MW unit was connected on Wednesday, January 21, marking continued progress toward the commissioning of what will become India's largest hydroelectric power project upon completion.
Accelerated Progress on Ambitious Project
This achievement comes less than two months after the successful synchronization of Unit-2 on December 2, 2025, demonstrating the accelerated pace of commissioning for this ambitious project that spans across Arunachal Pradesh and Assam. The 2,000 MW SLHEP comprises eight generating units of 250 MW each, representing a substantial addition to India's renewable energy infrastructure.
Leadership Acknowledges Stakeholder Support
Bhupender Gupta, Chairman and Managing Director of NHPC, conveyed his gratitude to multiple stakeholders for their continued support in this challenging endeavor. "The successful synchronization reflects NHPC's technical capabilities and contributes to grid stability," Gupta stated, while expressing appreciation to the Ministry of Power, Government of India, the governments of Arunachal Pradesh and Assam, and former NHPC leadership.
The CMD specifically lauded the Subansiri team led by Rajendra Prasad, executive director and head of project, emphasizing that "the achievement will facilitate the phased commissioning of the remaining units." He encouraged the project team to continue working steadily toward completion of the project and commissioning of the balance units.
Overcoming Historical Challenges
The Subansiri project's journey has been marked by significant challenges that threatened its completion. Though construction began in 2005 following central government approval in 2003, the project faced complete disruption in December 2011 due to intense opposition from anti-dam organizations raising environmental and social concerns.
This eight-year suspension finally ended in October 2019 when the National Green Tribunal granted environmental clearance after exhaustive assessments, allowing work to resume on what has become a flagship project for India's renewable energy ambitions.
Innovative Technology Minimizes Environmental Impact
The project distinguishes itself through innovative run-of-the-river technology, which utilizes the natural flow of water to generate electricity without requiring large reservoirs. This approach significantly minimizes environmental impact compared to traditional dam-based projects, addressing core concerns raised during earlier protests while maintaining efficient power generation capabilities.
Strategic Cross-State Infrastructure
The infrastructure strategically spans both Arunachal Pradesh and Assam, with the main dam positioned 2.3 km upstream of the Subansiri river in Arunachal Pradesh. This cross-state positioning enables the project to serve multiple regions while optimizing water flow utilization, creating a model for cooperative development between neighboring states.
National Significance and Future Impact
Upon full commissioning of all eight units, the 2,000 MW Subansiri Lower Hydroelectric Project will emerge as India's largest hydropower generating station. The project is expected to:
- Substantially strengthen the nation's renewable energy portfolio
- Significantly enhance electricity access throughout the northeastern region
- Support national energy requirements and sustainable development goals
- Align with India's commitment to reducing dependence on fossil fuel generation
This milestone represents more than just technical achievement—it symbolizes India's growing capabilities in large-scale renewable energy infrastructure and demonstrates how persistent effort can overcome significant challenges to deliver projects of national importance.
