Costly sea change for coastal cities
Slow work on water department projects is blamed for ‘last resort’ desalination plants
Richards Bay is joining other coastal cities and building a desalination plant to survive the crippling drought. By converting sea water into fresh, the plant will allow the town to tap into what engineers refer to as an “almost infinite” water resource.
But department of water and sanitation officials say the option is one of last resort because it is expensive as it uses so much electricity. The decision to build the plant, despite electricity costs, was taken because the department did not meet its water infrastructure development targets.
The Water Research Commission breaks these costs down: the City of Cape Town can produce water for R1.25 a kilolitre using a mix of water sources, and Rand Water in Gauteng can produce water for R2.50 a kilolitre. But a large plant along the coast produces water for anywhere between R5.80 and R8.30 a kilolitre.
A conventional water treatment plant uses 0.3 kilowatt-hours of electricity to treat a cubic metre of water, and a desalination plant, such as the one being built in Lamberts Bay in the Western Cape, uses up to eight kilowatt-hours of electricity.
In its desalination strategy, the water department notes that, although the process “could provide an unlimited resource of freshwater”, it would only be considered after all other options because the cost of electricity is escalating and there is no local desalination-plant industry and expertise.
An official in the department, who is involved in water planning but is not authorised to speak to the media, said desalination was at the back of the queue because: “We need to wait for the technology to mature so we don’t have to pay the R&D [research and development] costs and run plants that suck up critical electricity. But we should have had that breathing space.”
Other options would include, for instance, treating sewage water to make it potable, a much cheaper process in terms of electricity and cost. An attempt to do this in Durban was rejected by residents, who refused to drink the water on religious grounds.
There is also the option of fixing old infrastructure in municipalities, where up to a quarter of the water used is lost through leaks.
But the decision to desalinate seems to be the result of delays to other infrastructure projects. An official at the Trans-Caledon Tunnel Authority says desalination “was always going to be the technology of choice, in the future”.
The statement is based on the government’s 2012 National Water Resource Strategy. This master plan looked at how much water each town and city needed, and how much the water department could supply up to 2035.
For most cities, water use was projected to outstrip supply before that date. In Johannesburg and Cape Town, that crunch would come before the end of this decade. For Durban and areas such as Richards Bay, people and industry were already using more water than was available by 2005.
Solving the problem is the job of the water department, through agencies such as the Trans-Caledon Tunnel Authority.
Regular droughts mean the country does not have enough water for its needs for two to three years in a 10- to 20-year cycle. Big dams have been built to store water for the dry years, but the Tunnel Authority official says this breathing space has been whittled away by delays: “The delays in all sorts of bulk water schemes mean we need to turn to emergency options like desalination.”
Mega-projects, including the second phase of the Lesotho Highlands Water Project, fall under the department’s purview. This crucial scheme is five years behind schedule.
Although there are 4400 registered dams, the country’s water security relies on fewer than 50.
Upgrades to these dams, such as those planned for the Tzaneen Dam in Limpopo, have been delayed by years or indefinitely postponed. Upgrades to Hazelmere Dam, which supplies Durban and the North Coast, were delayed by six months
“Delays in all sorts of bulk water schemes mean we need to turn to emergency options like desalination”