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The government has set a target of generating 17,000 megawatts of hydropower within the next three years and 30,000 megawatts within the next decade. However, experts and recent studies warn that Nepal's hydropower sector must treat climate change not merely as an environmental issue but as the single biggest threat to the long-term success of its projects.

According to experts, changing rainfall patterns, rising temperatures, glacier melt, floods and landslides are likely to significantly affect the productivity, lifespan and economic viability of hydropower projects. They stress that climate variability must be factored into investment decisions involving hydropower and related infrastructure.

"Hydropower projects undertaken while ignoring climate-related risks may end up becoming more of a burden than an opportunity," said Arun Bhakta Shrestha, Senior Climate Change Specialist and senior advisor on climate and environmental risks at ICIMOD.

Shrestha said three successive monsoon seasons - in 2021, 2023 and 2024 - caused an estimated Rs 15 billion in damage to hydropower infrastructure.

"These losses are not merely the result of natural disasters; they also reflect our failure to make scientific climate risk assessments mandatory in project planning and implementation," he said.

"The climate and hydrological conditions on which Nepal has based its infrastructure development have changed significantly, making it essential to update existing planning and design standards."

He added that projects that determine site selection, capacity and design without comprehensive climate risk assessments expose developers, banks and the insurance sector to substantial financial risks.

"Climate resilience is not an environmental luxury; it is the foundation of Nepal's hydropower development," Shrestha said.

Dr Divas Basnyat, a researcher at the Nepal Development Research Institute specializing in hydropower and climate change, said the lack of reliable long-term data on climate, river flow and sediment remains one of the sector's biggest challenges.

"Without sufficient data, it becomes difficult to accurately assess risks and scientifically design hydropower projects," he said.

Referring to the institute's study, Adaptation to Climate Change in the Hydroelectricity Sector in Nepal, Basnyat said climate risk must be incorporated into both ongoing projects and those planned for the coming decade. He noted that many projects currently under development continue to rely primarily on existing climatic conditions and economic assumptions, paying insufficient attention to future climate scenarios.

Climate change, however, does not affect every hydropower project in the same way. Run-of-river (RoR) projects, which depend on a river's natural flow, are considered the most vulnerable.

Irregular rainfall and fluctuating river flows can sharply reduce electricity generation during the dry season. Reservoir-based projects, on the other hand, can store water and regulate flows, enabling them to better withstand seasonal fluctuations. Experts therefore believe reservoir-based hydropower will play a crucial role in strengthening Nepal's climate resilience.

A study by the Nepal Development Research Institute analyzed 90 hydropower projects with installed capacities exceeding five megawatts, including projects in operation, under construction preparation and at the proposal stage.

The study recommends revising hydropower design standards from now on, warning that the impacts of climate change will become even more pronounced in projects developed after 2030. It also emphasizes that a single design approach cannot be applied to every project and calls for adaptive strategies tailored to each project's location and risk profile.

For projects already in operation, the study recommends modern weather and river monitoring systems, early warning mechanisms, effective sediment management, turbine protection technologies, regular climate risk assessments and adequate insurance coverage.

For new projects, it recommends making climate-smart design, climate risk assessments based on future climate scenarios and resilient infrastructure mandatory. It also advises giving priority to capable project developers and strengthening monitoring and adaptation measures, particularly for small run-of-river projects, which face greater climate risks.

Another study, Identification of Safe Hydropower Project Sites in Nepal in the Context of Climate Change, conducted by researcher Suraksha Paudel during her postgraduate research at Tribhuvan University's Department of Environmental Science, found that although most existing hydropower projects remain technically suitable, many are inadequately prepared for climate-related risks.

The study argues that hydropower planning should not focus solely on engineering feasibility but should equally consider climate risks, watershed conditions and the safety of local communities.

Based on an assessment of 36 hydropower projects in the Trishuli watershed, the research concludes that safer and more climate-resilient hydropower systems are essential, particularly in glacier-fed river basins. Paudel said the findings could help planners, engineers and policymakers identify safer and more suitable sites before project construction begins.

Sandip Kumar Dev, spokesperson for the Ministry of Energy, Water Resources and Irrigation, said the government is aware of the growing impact of climate change on hydropower generation and is working with stakeholders to minimize the risks through improved planning and adaptation measures.