Climate change and global warming are significantly altering natural systems worldwide, and Nepal is among the most vulnerable countries. Rising temperatures have disrupted precipitation patterns and accelerated the melting of snow and glaciers in the Himalayas. Nepal's major rivers originate from the Himalayas, the Mahabharat range, and the Chure hills, with approximately 32% of river flow coming from snow and glacier melt, and 68% from rainfall, both of which are directly influenced by climate variability.

Nepal's energy sector relies heavily on hydropower, which supplies over 90% of the country's electricity, and most of it is ROR type. This makes the sector particularly sensitive to climate-related disruptions, including irregular river flows, extreme rainfall, and glacial hazards. The country is home to over 3,250 glaciers, and rising temperatures are increasing the frequency of Glacial Lake Outburst Floods (GLOFs). Nepal has recorded 25 GLOF events so far, five of which occurred in the past decade.

A recent GLOF triggered by a glacier outburst in China severely impacted multiple hydropower projects in Nepal, including the 111 MW Rasuwagadhi, 60 MW Trishuli-3A, 25 MW Trishuli Hydropower Center, 22 MW Chilime, 14 MW Upper Mailung, 14 MW Devighat, and 5 MW Mailung Khola projects, as well as the Trishuli-3B hub substation. This event led to the shutdown of approximately 250 MW of electricity generation.

Likewise, in September 2024, persistent rainfall caused floods and landslides that damaged 11 operational hydropower plants with a combined capacity of 625.96 MW. According to the Ministry of Water Resources and Irrigation (MoWRI), the disaster caused damage worth NPR 2.45 billion and resulted in a temporary shutdown of around 1,100 MW of hydropower capacity, while also disrupting 15 ongoing projects. These disasters not only impact operations but also delay construction timelines and increase costs. Landslides and floods frequently damage road infrastructure, hampering the delivery of construction materials and slowing progress.

Floodwaters carrying sediment and debris also pose serious threats to hydropower infrastructure. Fine sediments and sand entering turbines and associated equipment can cause severe abrasion to runner blades, guide vanes, and wicket gates, leading to reduced efficiency, greater wear, and increased maintenance needs. Debris accumulation can block intakes, trash racks, and even turbine passages, reducing flow and power output. The 2014 Jure landslide blocked a river, submerging a 5 MW plant and disrupting connections to the 45 MW Bhotekoshi and 10 MW Sunkoshi plants, leading to a combined loss of 67 MW, or around 10% of the nation's hydropower capacity at the time. Super Madi Hydropower in Kaski suffered more than NPR 1 billion in damages from floods and landslides.

In June 2023, floods in eastern Nepal's Taplejung, Panchthar, Sankhuwasabha, and Bhojpur districts damaged 30 hydropower projects with a total capacity of 463 MW, resulting in losses exceeding NPR 8 billion. Thirteen operational plants (132 MW) sustained losses of approximately NPR 6 billion, while 17 under-construction projects (327 MW) faced over NPR 2 billion in damages. Tragically, 18 workers were swept away at the Super Hewa Khola project site, underscoring the human toll of climate-driven disasters. Additionally, there is a decline in winter precipitation, which already strained Nepal's hydropower generation during dry seasons, revealing the sector's vulnerability to climate change.

In summary, the disrupted precipitation pattern, natural disasters such as floods, landslides, GLOFs shows the vulnerability of hydropower sector to the climate change. Such recent disasters have not only caused immense human and economic losses but have also disrupted national energy production. To protect and sustain Nepal's hydropower sector, urgent climate-resilient planning and infrastructure are essential. This includes thorough environmental impact assessments, smarter site selection, and advanced sediment filtration systems to minimize debris-related damage. With proactive and sustainable approaches, Nepal can strengthen its energy security and ensure hydropower remains a reliable resource in an increasingly uncertain climate.