State utility Dubai Electricity & Water Authority (Dewa) has extended the bid submission deadline for the planned Hatta pumped storage project to 13 January 2019.

The client has extended the deadline from 18 November to give bidders more time to work on proposals, according to sources close to the project. The pumped storage project is planned to have a generation capacity of 250MW.

In June last year, Dewa awarded a AED58m ($15.8m) contract to France’s EDF to provide consultancy services for the pumped-storage project. The state utility announced this week that EDF had completed engineering studies for the proposed project, including design, geological, hydro-geological, environmental, geotechnical and deep excavation studies.

The hydro project will use water stored in the Hatta Dam, near the Oman border. The existing Hatta Dam can store up to 1,716 million gallons of water. The project will involve the construction of an upper reservoir, which will be able to hold up to 880 million gallons. The upper reservoir will be located 300 metres above the dam level.

During off-peak hours, turbines will use solar energy to pump water from the dam to the upper reservoir. The project will support the AED1.3bn ($354m) Hatta development plan, which was announced last November.

The appeal of pumped storage is that it can be integrated with different renewable energy sources like wind and solar power – power supply options that are intermittently affected by wind patterns and cloud cover. Pumped storage is an important source for energy storage as water is stockpiled when excess energy is produced. This can then be used to provide electricity when energy demand is highest during peak hours.