The City of Cape Town’s ‘Building Hope’ budget for 2023/24 proposes continued investment in its Steenbras hydroelectric pumped storage scheme, laying the foundation for a potential estimated investment of about R1.2-billion over the next nine years on the maintenance and expansion of the plant.

City of Cape Town Energy MMC Councillor Beverley van Reenen says about R1-billion has been set aside for the refurbishment and extension of the 160 MW Steenbras scheme and about R200-million is earmarked for the maintenance of Steenbras.

The metropolitan municipality uses the Steenbras plant to shield Cape Town residents to a degree from loadshedding and to safeguard Cape Town’s electrical infrastructure.

Van Reenen adds that the investment in Steenbras and the maintenance programme is crucial to fulfilling the municipality’s commitment to protect customers from a stage or two of loadshedding, where possible, with plans to expand protection to up to four stages in the near future as part of the city’s loadshedding protection plan.

The city states that all due processes will be followed in terms of regulatory and legislative requirements and that the budget and execution of the professional services to maintain and expand Steenbras will determine the final budget and delivery programme.

“Importantly, all Capetonians benefit directly or indirectly from the city’s power generation management and loadshedding protection as it also protects critical city infrastructure used for service provision and protects the city’s electricity network,” says Van Reenen. 

The budget allocations enable the city to begin the process of delivering on Mayor Geordin Hill-Lewis’s energy priority programme to end loadshedding. This programme includes the investment of R220-million on embedded independent power purchases; R288-million on the Power Heroes programme, which entails voluntary power reduction in return for an incentive; and the R1-billion investment in Steenbras.

It also includes R640-million on solar photovoltaic (PV) infrastructure; R53-million for a cash-for-power programme, which involves selling excess power back to the city; R50-million in battery storage; and R32-million on waste-to-energy projects.

Further, Hill-Lewis on April 17 also announced plans for the city to design, build and operate a R1.2-billion 60 MW ground-mounted solar PV plant, with battery storage, near Somerset West. He said the PV plant would help the city avoid one stage of loadshedding.

The Steenbras hydroelectric power station comprises four turbines, through which water from the Upper Steenbras dam is passed to the Lower Steenbras dam, creating electricity during peak electricity demand periods.

When electricity demand is low, usually between 23:00 and 07:00, the turbines work in reverse to pump the water back to the Upper Steenbras dam to be re-used the next day.

In this way, the scheme operates like a battery, storing potential energy to be deployed through kinetic and mechanical energy, when required. The amount of electricity that it can generate in one day depends on the available capacity of the lower reservoir – Lower Steenbras dam.

Cape Town is the only metropolitan municipality in South Africa to own and operate a large pumped hydroelectric scheme.