EAC backs expansion of Dikchu hydro project to 110 MW in Sikkim
The Expert Appraisal Committee (EAC) of the Ministry of Environment, Forest and Climate Change has recommended environmental clearance for the expansion of the Dikchu Hydroelectric Project (HEP) in Sikkim from 96 MW to 110 MW. The recommendation was made on June 8.
The capacity increase will be achieved without any additional land acquisition, new civil construction, fresh forest diversion or hydro-mechanical modifications. The expansion is based on higher-than-expected river inflows recorded since the project became operational in 2018.
Capacity enhancement plan
The Dikchu HEP, located in Gangtok and Mangan districts of Sikkim, is a run-of-the-river project on the River Dikchu, a tributary of the Teesta River. The project currently operates with two Francis turbine generator units of 48 MW each.
According to the project proponent, Sneha Kinetic Power Projects Private Limited, discharge monitoring data from 2018-19 to 2022-23 showed that river inflows consistently exceeded the estimates used in the original Detailed Project Report (DPR). Based on an assessment of average 10-daily discharge data during this period, the company identified additional generation potential.
The existing turbines have an inbuilt overload capacity. By increasing discharge through the turbines from 15.23 m³/s to 17.5 m³/s during high-flow periods, the generating capacity of each unit can be increased from 48 MW to 55 MW, taking the total project capacity to 110 MW.
Project details
The expansion will add 14 MW of capacity and increase the project’s design energy generation to 455.44 MU annually.
The project occupies 55.5329 hectares of land, including 9.5319 hectares of forest land that has already received the necessary approvals. No additional land acquisition or forest diversion is proposed as part of the expansion.
Fambonglho Wildlife Sanctuary is located approximately 2 km from the project site. Environmental flow releases are being monitored by the Sikkim State Pollution Control Board.
Regulatory approvals
The Power Department of the Government of Sikkim approved the capacity enhancement proposal on June 17, 2025.
The EAC granted Terms of Reference (ToR) for the proposal on May 4, 2026. The committee also exempted the project from a fresh public hearing under Clause 7(ii) of the Environmental Impact Assessment (EIA) Notification, 2006, noting that a public hearing had already been conducted in November 2007 for the original project and that the expansion does not involve any physical changes on the ground.
Environmental conditions
While recommending environmental clearance, the EAC directed the project developer to comply with the recommendations of the Teesta River Basin Cumulative Impact Assessment and Carrying Capacity Study.
The committee also mandated periodic Glacial Lake Outburst Flood (GLOF) risk assessments through a reputed expert institution and continued implementation of the wildlife conservation plan in consultation with the Chief Wildlife Warden.
In addition, the project developer has been directed to provide community development measures, including solar panels, schools up to Class 12, 50-bed hospitals and skill development centres for tribal communities within a 10 km radius of the project area.
GLOF assessment
The EAC reviewed the GLOF assessment conducted for the project. The study identified and assessed 24 glacial lakes, with one lake, designated GL1, identified as the most critical.
Detailed breach modelling was carried out and the design GLOF of 616 cumecs at the project site was appraised and concurred with by the Central Water Commission.
The committee noted that the capacity enhancement would improve utilisation of surplus monsoon flows, increase renewable energy generation and provide additional peaking power support while resulting in negligible incremental environmental impacts.
The featured photograph is for representation only.
