NHPC Teesta V resumes hydel power generation after 2023 GLOF

LALIT DAHAL

GANGTOK,: Nearly three years after a catastrophic glacial lake outburst flood crippled hydropower infrastructure across Sikkim, State-run NHPC has restored commercial operations at two generating units of its Teesta Stage V Hydroelectric Power Station, returning 340 megawatts of capacity to India’s electricity grid.

The revival marks one of the most significant milestones in the reconstruction of the eastern Himalayan State’s power infrastructure since the October 2023 disaster, which devastated the Teesta River basin and forced several hydropower projects offline.

NHPC said Units One and Two, each with an installed capacity of 170 megawatts, resumed commercial operation at 5 p.m. on July 13 following successful synchronisation with the national grid. The third generating unit, which will restore the station to its full 510-megawatt capacity, will be commissioned separately, the company said.

The Teesta Stage V project was among the major assets affected when South Lhonak Lake breached during the night of Oct. 3-4, 2023, unleashing a destructive surge through the Teesta basin. The flood destroyed the Teesta Stage III dam at Chungthang, damaged roads and bridges, disrupted communities and power infrastructure, and caused widespread loss of life and property across Sikkim.

NHPC has estimated direct losses from the flood at Rs 1,075.97 crore. Restoration efforts suffered a further setback in August 2024, when a landslide damaged the outlet structure of the project’s Tail Race Tunnel, resulting in additional losses estimated at Rs 327.67 crore.

Engineers spent the intervening period carrying out extensive civil reconstruction, repairing hydro-mechanical systems, restoring electrical equipment and rehabilitating critical infrastructure required to return the station to commercial service.

With two of its three generating units now back in operation, the project has restored 340 megawatts of generation capacity, strengthening electricity supply while signalling a broader recovery of strategic infrastructure in one of India’s most important hydropower corridors.

The commissioning of the remaining 170-megawatt unit will complete the restoration of the station’s original 510-megawatt installed capacity.

The restart carries significance beyond electricity generation. It underscores the gradual rehabilitation of the Teesta Valley after one of the most destructive hydrological disasters in the Himalayas in recent decades, restoring a critical source of renewable energy while highlighting the resilience of infrastructure rebuilding in a region increasingly exposed to climate-driven extreme events.