Itanagar/Dhemaji: The Subansiri Lower Hydroelectric Project (SLHEP), India’s largest under-construction hydroelectric project, has reached a significant milestone with the commencement of wet commissioning of its Unit 4 (250 MW).
The wet commissioning process — a critical pre-synchronisation phase — began successfully on April 1, 2026. During this stage, the unit undergoes rigorous testing with water flow to verify the performance of turbines, generators, control systems, and associated equipment under actual operating conditions.
NHPC Limited, the executing agency, confirmed that all necessary preparatory works, including dry commissioning and system checks, were completed successfully before initiating the wet commissioning. Engineers and technical teams are closely monitoring the process to ensure safety and efficiency.
Once Unit 4 is successfully synchronised with the grid, it will add 250 MW of clean power to the national grid. The project has a total installed capacity of 2,000 MW (8 units of 250 MW each). With Units 1, 2, and 3 already under various stages of testing and commissioning, the start of wet commissioning for Unit 4 marks steady progress toward full project completion.
Located on the Subansiri River on the border of Arunachal Pradesh and Assam, the mega project is expected to play a vital role in meeting India’s growing energy demand and supporting the country’s renewable energy targets. It will also bring substantial economic benefits to the region through employment generation, infrastructure development, and revenue sharing with the states.
Arunachal Pradesh and Assam governments have been closely coordinating with NHPC to address local concerns and ensure smooth implementation. The project is considered a game-changer for the Northeast’s power sector.
The successful wet commissioning of Unit 4 is being seen as a positive development that boosts confidence in the timely commissioning of the remaining units in the coming months.
Tags: Subansiri Lower Hydroelectric Project, SLHEP Unit 4, Wet Commissioning, NHPC Arunachal, 2000 MW Hydro Project, Arunachal Pradesh Power, Northeast Hydro Power, Mega Hydel Project, Clean Energy Arunachal, India’s Largest Hydro Project
Hashtags: #SubansiriLower #SLHEP #NHPC #HydroPower #ArunachalPradesh #CleanEnergy #NortheastPower #Unit4Commissioning #2000MWHydro #AssamArunachal
