Desalination plants no quick fix, experts warn

Experts have warned Western Cape authorities that it will take at least four years to build large-scale desalination plants and that they are not the answer to their prayers to avoid ‘Day Zero’. According to a Cape Argus report, the City of Cape Town, however, will continue with its plans to build desalination plants, which are expected to be completed in March. Dawid Bosman, senior manager at Trans-Caledon Tunnel Authority said desalination can change the industry and will secure the economic viability of the country. Bosman was speaking at a workshop presented by GIBB Engineering, which brought industry experts together to discuss solutions for the water crisis. Bosman said countries like Australia have built massive desalination plants. ‘The difference is that they knew what they wanted. The markets will punish you if they see that you are unsure of what type of plant it is that you want. The cheapest daily capital expenditure per cubic metre of desalinated water is about R2 823,’ he said. ‘A desalination plant cannot be a quick fix for a drought,’ he added. The city has budgeted just more than R3.3bn for their water projects, but the cost of a desalination plant could be much more depending on its size.

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Useful insights about the risks of building desalination plants were shared at an Umgeni Water annual performance briefing held last week. According to a report in The Mercury, owing to escalating electricity costs, power-heavy processes like desalination have been temporarily shelved, with water authorities investing in more conventional water storage methods, such as dams. General manager of engineering and scientific services at the body, Steve Gillham, said burgeoning costs helped to motivate the investment in an off-channel storage dam, the Lower uMkhomazi bulk water supply scheme, rather than a desalination plant. The scheme will serve parts of the eThekwini and Ugu District municipality and augment the coastal areas from eManzimtoti to Hibberdene via the South Coast pipeline. The project is expected to cost as much as R4bn and be operational by 2021. Gillham said the South Coast was constrained, which was a concern for them in terms of demand. Running a desalination plant could cost up to 35% more than other kinds of water schemes.

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