With two units of the Lower Subansiri Hydro Power Project already generating commercial electricity and a third unit set to come online shortly, NHPC has received all necessary clearances from the Central Government to begin construction of the Middle Subansiri Hydroelectric Project. At the same time, preliminary studies are underway for the proposed Upper Subansiri project. Official sources confirmed that the Government of India has granted investment clearance for the Middle Subansiri project, which is expected to generate more than 1,600 MW of power. Environmental clearance has also been secured, and the tendering process for construction has already begun.
Regarding the Lower Subansiri project, two units are currently in commercial operation, producing a combined 500 MW of electricity. The third unit is likely to start commercial generation within the next few days. If work progresses as scheduled, all eight units of the project are expected to become operational by March 2027. However, officials acknowledged that reduced river flow during the dry season will make it difficult to operate all eight units continuously. During the monsoon, when water levels rise, full-capacity generation is expected to be possible. At present, the Subansiri river is already experiencing low water flow.
Sources explained that during the dry months, only one or two units are run during the daytime to conserve water, allowing all units to operate during peak demand periods. At least one unit must remain operational at all times to ensure the river does not dry up. Responding to concerns about downstream flooding, officials stated that the Lower Subansiri project includes flood moderation measures, with flood cushioning and storage capacity of up to 15 meters. After assessing historical peak flood levels of the Subansiri river, authorities believe there should be no major flood-related issues during the rainy season.