The Japan International Cooperation Agency (Jica) has been assisting state-owned power utility Nepal Electricity Authority (NEA) and its subsidiary Tanahu Hydropower to carry out a preliminary feasibility study to build two pumped storage projects.

A 150 MW pumped storage project, which involves moving water from a lower reservoir to a higher reservoir where it is stored to generate power, is planned to be built on Rupa and Begnas lakes in Pokhara.

Similarly, a 104 MW pumped storage project has been planned to be built at the Lower Seti Hydropower Project, the cascade of the Tanahu Hydropower Project which is being developed by Tanahu Hydropower.

Jica has already sent consultants to the field and they are about to complete the study, according to the NEA.

“We will probably get a report from Jica by the first week of February,” said Pradeep Kumar Thike, managing director of Tanahu Hydropower who is working closely with the Japanese agency. “After we get the report, the installed capacity of the project will be finalized, and we will move forward with the preparation of a detailed project report (DPR).”

The current installed capacities for both projects were determined by a desk study, and they are likely to change after the field study report is completed. 

The Energy Ministry awarded the survey licence for the Begnas-Rupa Pumped Storage Project to the NEA in November. The Department of Electricity Development awarded the license for Lower Seti to Tanahu Hydropower in October.

The Lower Seti project will be built around 20 km downstream of the powerhouse of the Tanahu Hydropower Project and utilize the water from its tailrace. Similarly, the powerhouse of the proposed pumped storage project on Begnas and Rupa lakes will be built on Rupa Lake.

In a pumped storage project, the water stored in the higher reservoir is released to the lower reservoir to produce electricity during periods of high power demand. The power plant itself becomes an electricity consumer when pumping water, but it pays less because it does so during off-peak times. The plant produces energy using the stored water during peak times when it charges a higher rate.

As Begnas Lake is located at a higher altitude than Rupa Lake, hydroelectricity can be generated by channelling water from Begnas to Rupa where the powerhouse will be built. The NEA has said that the natural head of around 60 metres between the two lakes is sufficient to generate electricity. The project, according to the state-owned power utility, will be designed to generate power for 4 hours daily.

The NEA is also planning to seek the help of Jica to prepare the DPR of the pumped storage project as Japan has vast experience in developing such schemes.