A new interstate transmission system (ISTS) scheme, titled “NERGS-III Siang Basin,” has been proposed to enable hydropower evacuation from upcoming projects in Arunachal Pradesh under the tariff-based competitive bidding (TBCB) route.

Estimated at Rs 1,804 crore, the project is scheduled for commissioning by February 2029. PFC Consulting (PFCCL) has been appointed as bid process coordinator, following clearance from the National Committee on Transmission (NCT), with final approval pending from the Union Power Ministry. The scheme aims to create evacuation infrastructure for two hydropower projects — Heo (3×80 MW) and Tato-I (3×62 MW) in Shi-Yomi district, being developed by NEEPCO, a subsidiary of NTPC.

Additionally, it will support future developments in the Siang sub-basin, where hydropower potential of about 5,600 MW may be harnessed by 2035. Key components include a 400/220kV GIS substation at Kaying, a 400kV GIS switching station at Niglok, and double-circuit (quad) transmission lines linking Kaying-Niglok (100 km) and Niglok-Gogamukh (125 km).