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Nepal Electricity Authority (NEA) is preparing to generate an additional 100 megawatts of electricity using water from the Kulekhani reservoir in Makwanpur. The authority is moving ahead with the construction of the Kulekhani–Sisneri pumped storage hydropower project in Indrasarowar Rural Municipality. This will be Nepal’s first pumped storage hydropower project.

With the implementation of this project, NEA claims it will reduce electricity imports from India during the winter season. The project proposes generating electricity by using water from the Kulekhani reservoir in Indrasarowar and then pumping the same water back into the reservoir. As part of the Environmental Impact Assessment (EIA) process, NEA has invited public suggestions for determining the scope of the study.

The authority has also collected feedback and conducted consultations in the affected wards of the local municipality. Wards 1, 2, and 3 of Indrasarowar Rural Municipality are expected to be affected. According to Ward Chair Devkrishna Pudasaini, interaction programs were held in these areas regarding the proposed project.

“Discussions were held on the possible impacts on human settlements, physical infrastructure, economic, social, natural, and environmental aspects, and suggestions were collected to address potential problems,” he said.

NEA project manager Suryanath Bhurtel said the project aims to generate electricity for 6 to 10 hours daily during peak demand periods by using water stored in the Indrasarowar reservoir and releasing it into the Kulekhani River.

“We are currently conducting EIA-related field visits and collecting suggestions to move forward with the Detailed Project Report (DPR),” he said.

Under the proposed plan, the existing Indrasarowar reservoir will be used as the upper reservoir. A new 36-meter-high dam will be built about 3 km downstream at Ranche in Ward 2 of Indrasarowar to create a lower reservoir with a storage capacity of 1.54 million cubic meters.

Water from Indrasarowar will be taken through an intake structure near Kalki in Ward 2 and sent via a 1.9 km tunnel to the power house at Lippane on the left bank of the Kulekhani River. After electricity generation, the water will flow into the lower reservoir.

During periods of low electricity demand, water stored in the lower reservoir will be pumped back through the same tunnel into the upper reservoir at Indrasarowar. This system is known as a pumped storage hydropower project, where water is cycled between reservoirs to generate electricity.

NEA states that the storage capacity of the existing Indrasarowar reservoir will not be changed. When operated at full capacity, the water level in Indrasarowar may fluctuate by up to 20 meters daily, while the lower reservoir may see fluctuations of up to 23.5 meters.

The project will install two turbines, each with a capacity of 50 megawatts, in the power house. The design flow rate is 68.12 cubic meters per second, and the estimated cost of the project is around NPR 15 billion.

NEA has stated that it is currently carrying out DPR studies and collecting feedback from affected communities as part of the EIA scope determination process. It has requested written suggestions from schools, hospitals, health posts, local bodies, and stakeholders regarding impacts on natural, physical, biological, social, cultural, and economic systems.

The Kulekhani Hydropower Project currently generates 106 megawatts in total: 60 MW from Kulekhani I, 32 MW from Kulekhani II, and 14 MW from Kulekhani III.

Over the years, sedimentation from rivers carrying stones, soil, sand, and debris into the reservoir has reduced its storage capacity. Initially, the reservoir could store 85.3 million cubic meters of water, but this has now decreased to 59.99 million cubic meters - a reduction of about 30%.

Sediment accumulation has also caused a 30% decline in electricity generation. Due to reduced storage capacity, NEA is reportedly facing annual losses of over NPR 31 crore compared to the initial operating conditions.

When Kulekhani I began operation in 1982, about 57 meters of water depth was usable for power generation. After floods in 1993, this reduced to 50 meters, and now only about 46 meters of water depth is usable.

Sedimentation continues to accumulate, reducing the usable water level each year. In 1993 alone, floods raised the reservoir bed by about 6 meters. It is estimated that around 170,000 cubic meters of debris (sand, soil, leaves, and stones) have accumulated in the reservoir.

According to an engineer from Kulekhani I, if this debris is not removed, the efficiency of Kulekhani I, II, and the under-construction III project will continue to decline. Removing the sediment would require completely draining the reservoir.

The Kulekhani reservoir was originally built at a cost of 12 million US dollars.

Kantipur