Flood halts power generation of 1,420 MW at 4 plants

The cloudburst on June 25 unleashed floods across remote Sainj valley, crippling nearly the entire hydropower corridor. Within hours, raging waters—laden with boulders, silt and uprooted trees—overran intakes, penstocks and turbine halls, forcing a complete shutdown of four major plants with a combined capacity of 1,420 MW.

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The fallout is stark, operators are now grappling with daily revenue losses running into several crores of rupees. A multi-month restoration race against time is already under way.

Two National Hydroelectric Power Corporation (NHPC) projects bore the brunt. The 800 MW Parbati Hydroelectric Project Phase II (PHEP-II) saw its entire powerhouse floor inundated with sludge, clogging draft tubes and disabling all four turbines.

Just downstream, the 520 MW Parbati Project Phase III (PHEP-III) was similarly incapacitated—its trash racks buried beneath metres of debris, halting some 30 million units’ generation of electricity per day. The 100 MW Himachal Pradesh Power Corporation Limited (HPPCL) Sainj hydel project and a private 1 MW mini-hydel plant in the same valley also collapsed under the deluge, with the latter’s dam and powerhouse structures suffering damage.

Rehabilitation teams have mobilised heavy earth-moving equipment from NHPC’s adjoining sites. As river levels subside, contractors are carving temporary bypass channels around the jammed intakes and shoring up damaged sections of the headrace tunnels.

“Once the flow eases,” explains PHEP-II head Ranjeet Singh, “we’ll divert the Jivah nullah spill into a new alignment. Only then can we accurately assess the structural damage inside the powerhouse.” He cautions, however, that clearing compacted debris, much of it lodged beneath the turbines and draft tubes, could take time.

Meanwhile, at PHEP-III, General Manager Prakash Chand Azad remains cautiously optimistic. He said, “With specialised equipment, we expect to restore at least two units within a short time. Full generation might take some more time, provided there are no further rain-triggered surges.”

Though this timeline is aggressive, the region’s power planners are under immense pressure. These hills contribute key peaking power for northern India’s summer grid. Any prolonged outage risks grid instability and forces reliance on costly thermal plants.

Beyond repairs, the disaster underscores a growing vulnerability. Experts warn that Himalayan cloudbursts, once rare, are spiking in frequency and intensity, driven by shifting monsoon patterns and glacial melt. As restoration teams race to bring units back online, state authorities are also conducting post-mortems on slope stabilisation, upstream catchment management and early-warning systems to safeguard the valley’s lifeblood — its rivers.