The Central Electricity Authority (CEA) has finalized a Transmission System Master Plan for the evacuation of power from the vast hydroelectric potential in the Brahmaputra Basin. The plan addresses a total exploitable capacity of 76,075.2 MW, including existing hydro projects and planned Pumped Storage Plants (PSPs).
The total estimated expenditure for the required new and augmented transmission system is approximately ₹6,42,944 crore.
Hydro Potential and Phasing
The CEA’s reassessment identified 64,945.2 MW of exploitable hydroelectric potential (for projects >25 MW), excluding Pumped Storage, across the Brahmaputra Basin. The major sub-basins contributing to this capacity are Siang (29%), Subansiri (19%), and Dibang (14%). Arunachal Pradesh accounts for the largest share of this potential at 81% (52,230.5 MW).
The total capacity planned for evacuation, including new hydro and pumped storage, is 76,075.2 MW. The plan is divided into two time frames:
| Capacity Type | Existing / Under Construction (MW) | Additional Capacity by 2035 (MW) | Additional Capacity Beyond 2035 (MW) | Total (MW) |
| HEPs (>25 MW) | 6,807 | 19,552 | 38,586.2 | 64,945.2 |
| PSPs | 0 | 3,720 | 7,410 | 11,130 |
| Grand Total | 6,807 | 23,272 | 45,996.2 | 76,075.2 |
Pumped Storage Potential
A total of 11,130 MW of Pumped Storage Plants (PSPs) were included, with significant projects planned in:
- Mizoram: 6,150 MW (including Leiva Lui, Tuiphai Lui, and Daizo Lui PSPs).
- Assam: 2,380 MW (including Kopili, Ouguri, and Tharakunji PSPs).
Transmission System Requirement
The master plan envisages the addition of extensive transmission infrastructure, heavily utilizing High Voltage Direct Current (HVDC) technology for long-distance, bulk power transfer out of the Northeast Region (NER).
- Total Infrastructure Addition: 31,397 ckm of transmission lines (including 21,000 ckm of HVDC corridor) and 109,935 MVA+MW of capacity addition.
- Phasing of Expenditure:
- Upto 2035: Requires 9,922 ckm of line additions (including 6,000 ckm HVDC) at an estimated cost of ₹1,91,009 crore.
- Beyond 2035: Requires 21,475 ckm of line additions (including 15,000 ckm HVDC) at an estimated cost of ₹4,51,935 crore.
Pooling and Evacuation Summary
Overall, 94% of the total hydroelectric capacity (60,900.5 MW) is planned to be pooled at the Inter-State Transmission System (ISTS) level.
74% of the total PSP capacity (8,210 MW) is planned to be pooled at the ISTS level.
The master plan is intended to provide hydro project developers with visibility regarding power evacuation infrastructure. The CEA noted that while the overall system has been planned, specific transmission elements will be implemented based on applications received and the latest available technology at the time of execution.