Recently Executive director of Nepal Electricity Authority (NEA) Hitendra Dev Shakya has mentioned that the utility institution is planning to construct pump storage hydropower plants to manage the peak hour demand of electricity in the dry season also manage other demand systems. For the advancement, a prefeasibility study for a 594 MW project had been carried out. So as NEA has prepared prefeasibility proposals for the 100 MW Kulekhani – Sisneri and the 494 MW Hulingtar – Dumkim projects. Moreover, it is remarked that NEA) has decided to prioritise the construction of pump storage hydropower projects to meet the daily fluctuations in electricity demand and the country’s energy security.
Shakya stated that the NEA has approached the Ministry of Energy for studies on two pump storage facilities. Reviewing his first 100 days in office, he said prioritising pump storage has been a key achievement.
Pumped storage hydropower (PSH) is a form of clean energy storage that is ideal for electricity grid reliability and stability. PSH complements wind and solar by storing the excess electricity they create and providing the backup for when the wind isn’t blowing, and the sun isn’t shining.
PSH absorbs surplus energy at times of low demand and releases it when demand is high.
When the grid has surplus power – like on a sunny or windy day—the water is pumped up to the higher reservoir (charging the battery). Later, when demand increases and the supply decreases, such as during the evening when people are cooking and the sun has gone down, the water is released to generate power (discharging the battery).
There are also seasonal variations. In winter when the days are shorter and the electricity demand is higher, PSH can again contribute to the rescue.
The amount of energy a PSH project can store depends on the size and height difference of the two reservoirs it is made up of, while the amount of electricity it can produce at once depends on the size of the turbines.
Pumped storage hydropower (PSH) is a type of hydroelectric energy storage. It is a configuration of two water reservoirs at different elevations that can generate power as water moves down from one to the other (discharge), passing through a turbine. The system also requires power as it pumps water back into the upper reservoir (recharge). PSH acts similarly to a giant battery, because it can store power and then release it when needed.
The first known use cases of PSH were found in Italy and Switzerland in the 1890s, and PSH was first used in the United States in 1930. Now, PSH facilities have been constructed in a number of countries.
The Project Development Department under the Authority had identified 156 pump storage projects across the country.
Out of these, 33 projects of 42,000 MW are under screening and ranking.
A feasibility study is being conducted after obtaining a survey license for a 332 MW pump storage project in Syarpu Lake located in Rukum (West), according to the NEA.
Similarly, the 670 MW Dudhkoshi Reservoir Hydropower Project is also being studied for the construction of 200 MW pump storage project.
The pumped storage projects are considered important for electricity system stability, peak demand and management of surplus energy and energy security.
Through the utilisation of pumped and stored water during off-peak periods, electricity can be generated during peak periods and consumed internally, and the surplus energy can be sold to India at a higher price during peak demand time.
