- Discussions held with WB, JICA, ADB
- Project aims to store 600 MW
- Expected to be completed by 2031
- Project design expected in 18 months
The Maha Oya Pumped Storage Hydropower Project, Sri Lanka’s first-ever ‘water battery,’ announced by the Ceylon Electricity Board (CEB) last week, is estimated to cost around $ 1 billion, with construction set to be completed by 2031 provided the CEB successfully completes the detailed design of the project within the next 18 months, The Sunday Morning learns.
According to the CEB, the feasibility study has already been conducted, but the detailed design of the project is yet to be completed. The initial cost estimate for the project alone was $ 450 million, but the total cost is now expected to range from $ 800 million to $ 1 billion.
Furthermore, it is also learnt that no international funding has been secured for the project yet.
The planned pumped storage is expected to store around 600 MW of energy. Located in Aranayake and Nawalapitiya, the project will store excess Renewable Energy (RE) from solar and wind sources.
It will feature two reservoirs connected by a 2.5 km tunnel and help stabilise the grid, while supporting the country’s goal of generating 70% of its electricity from renewables by 2030. The project aims to reduce fossil fuel dependency, lower carbon emissions, and provide grid support for RE absorption.
When contacted, CEB Spokesman Eng. Dhammike Wimalaratne said that the CEB was working to secure long-term funding from international agencies to minimise impacts on electricity tariffs.
“We had a meeting with international funding agencies, which was attended by the World Bank (WB), Asian Development Bank (ADB), and Japan International Cooperation Agency (JICA),” he said.
However, as learnt by The Sunday Morning, no funding agency has come forward to fund the project.
According to the Long-Term Generation Expansion Plan (LTGEP), pumped hydro storage accounts for nearly 97% of global storage applications in power systems. Used initially for peaking capacity, the technology has evolved to support flexible grid operation, especially with renewable energy integration.
The CEB, with technical assistance from JICA, conducted a study titled ‘Development Planning on Optimal Power Generation for Peak Power Demand in Sri Lanka’ in 2014. The study identified 11 potential sites for a 600 MW pumped storage power plant, evaluating them based on environmental, topographical, geological, and technical aspects.
After screening, three sites – Halgran Oya, Maha Oya, and Loggal Oya – were identified as the most suitable, with the Maha Oya site being concluded as the most promising for development.
The study determined that the plant’s optimum capacity should be 600 MW to meet peak demand beyond 2025, factoring in system limitations and turbine constraints.
Additionally, a new site in the Kandy District was proposed in the Electricity Sector Master Plan Study (2018), with a potential 1,400 MW capacity, utilising the Victoria Reservoir as the lower pond and a nearby irrigation pond in Wewathenna as the upper pond, with staged development.