Rain check for Cape Town desalination plant

Desalination, a long-term solution to Cape Town’s water problems, will not get off the ground anytime soon due to cost concerns, the city says.

The city has been exploring the possibility of constructing a multibillion-rand desalination plant on its northwestern coast to offset an expected shortage of potable water. However, the cost of maintaining such a plant would result in residents paying more for water.

Xanthea Limberg, the city’s mayoral committee member responsible for water and waste services, said: “It’s an option, but it just won’t happen tomorrow. We are looking at a number of other options [in the short to medium term] including water reclamation and the Table Mountain group aquifer.”

The city was looking at building the plant between 2025 and 2035. Desalination removes salt and other minerals from sea water, making it suitable for human consumption.

The technology is also being considered to make acid mine water usable. The government estimates that by 2030, desalination plants could provide up to 10% of SA’s urban water supply.

According to a summary of the Cape Town feasibility study, a 450-megalitre-a-day desalination plant would cost R16.5bn, excluding VAT, but including design and construction supervision costs. The estimated operating cost of the plant is R1.2bn a year, excluding VAT.

Limberg said another concern was that the plant could add pressure to SA’s already strained electricity grid. Energy is the largest expense for the plants, accounting for as much as half the operating costs.