Mongabay · Natuur

Nepal's flood disaster tests hydropower strategy and exports

Recent flash floods in Nepal have caused significant damage to the country's hydropower infrastructure, raising questions about its reliance on hydropower for economic growth and exports. The disaster has highlighted the need for more resilient project designs and has spurred discussions about diversifying the energy mix.

The Aug. 26 flash floods on the Nepal-China border severely damaged or destroyed 281 megawatts of installed hydropower capacity and affected 388 MW under construction, with estimated losses in the hundreds of billions of Nepali rupees. Additionally, 150 MW of power was disconnected from the national grid due to washed-away transmission lines. Surface-built powerhouses, dams, and desanders were the most affected, while underground facilities fared better, suggesting that project location, longer access tunnels, and early-warning systems are crucial for resilience, though these upgrades may increase costs by 10-12%.

Some experts suggest that the flood should prompt Nepal to prioritize domestic energy consumption over its export-oriented hydropower strategy, citing both the physical risks of disasters and declining electricity prices in India. This disaster jeopardizes Nepal's recent achievement of net-exporter status (18.75 billion rupees in FY2025) as winter approaches, accelerating calls to increase solar power generation.

The floods crippled 281 MW of installed generation capacity, including a solar plant, and damaged four under-construction projects totaling 700 MW. The 42-year-old Devighat Hydroelectric Plant was destroyed, and a 25-MW solar plant was badly damaged. Transmission lines and a substation on the Trishuli River were also destroyed, cutting off another 150 MW. Hundreds of engineers and workers are feared missing.

The 100-MW Super Trishuli Hydropower Project, located downstream and away from the river, survived the flood due to its location and pre-construction flood-probability assessments, offering lessons for making hydropower plants more resilient within the existing export model.

The flood exposed a pattern where surface-built powerhouses, dams, and desanders suffered the most damage, while newer underground facilities were more resilient. Experts emphasize the need for flood-resilient designs, early warning systems, robust evacuation measures, and longer access tunnels to powerhouses. These design changes are estimated to increase project costs by 10-12%.

The increased risk to hydropower on snow-fed rivers has led some to advocate for a shift in strategy, prioritizing domestic consumption over exports. This disaster could also delay Nepal's clean energy transition targets. The export-focused strategy faces a dual risk: physical disasters and market risks like falling electricity prices in India.

While Nepal has ambitious targets for electricity exports and domestic consumption, the flood's impact, particularly on winter supply, could force the country to import more power from India, reversing recent export gains. The government has not yet revised its energy targets in response to the flood.

The flood has also highlighted the potential of solar power as a less risky alternative. With falling installation costs and advancements in battery storage, solar power could potentially contribute up to 20% of Nepal's energy mix, compensating for reduced hydropower generation, especially during winter.

The economic fallout is expected to increase electricity costs by at least 10-12%, with developers needing to build stronger infrastructure, passing the costs to consumers. A proposal for a loss-and-damage fund for hydropower projects has been suggested. The recent achievement of net-exporter status is now at risk due to potential winter import needs.

The disaster has also raised concerns about the "haphazard permissions" for hydropower projects in river basins without adequate risk assessments, suggesting the need for basin-level planning to designate safe locations for power plants.

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