Politicians need to think like Engineers to combat water and electricity crisis
6 December 2017
What the electricity crisis and the current water crisis tell us is that we have fallen into the way of short-term thinking and it is the fault of our politicians.
Politicians are mainly interested in the here and now with their attention focused on their chances in the next election. They know they won’t be around in 20 years to be held responsible for the things they neglected to do. The result is that they are unprepared for a crisis and when it comes we see them scurrying around doing little things to stave off the evil day.
Civil engineers, on the other hand, think differently. They design dams and bridges to last centuries and they think in terms of 100-year flood plains. This is the kind of long-term thinking that seems to be beyond most politicians.
Think of the Government and Eskom. The old engineers at Eskom warned the government in the previous century that demand for electricity was growing and it was time to build a new power station. The Government, focused on the here and now and the next election, rejected the Eskom plan. When load-shedding became a fact of life, we saw them scurrying around with lots of little plans to swop incandescent globes for compact fluorescent lights and an ill-conceived subsidy for solar water heaters.
Common sense disappeared completely. Most of the subsidies were used for imported solar geysers when the money should have gone into local industry to manufacture local solar water heaters and create new jobs at the same time. Then we had the gas turbines that burned billions of rands of imported diesel and finally the decision to build giant new power stations that are supplying more electricity than we can use.
Now we have a water crisis in Cape Town and the mayor is rushing around telling people to store five-litre bottles of water for emergency use and looking for more places to sink boreholes.
A previous administration was even more obtuse. It asked the civil engineer in charge of Cape Town’s water supply to reapply for his job. He was not successful. Instead the job of looking after the dams, the pipelines, the filtrations plants, reservoirs, pumping stations and hundreds of miles of underground pipes was given to a micro biologist.
The crisis is of our own making and is the product of short-term thinking. Cape Town recycled only six percent of its water and that was mainly for golf courses and parks. Increasing this percentage to supply industry with recycled water should have been a no-brainer, but why do it when industry was prepared to pay higher prices for sweet damn water? Think of the Athlone treatment plant. It is ideally situated to supply recycled water to the surrounding industrial areas and the airport where all the hired cars are washed and many thousands of loos are flushed by departing and arriving passengers. Ten million of them over the course of a year.
And then there is the question of desalination. The Chamber has suggested it many times but the idea is simply brushed off as too expensive. It is not too expensive if you do it on a large scale as the City of Perth in Western Australia has proved. Seventeen percent of Perth’s water is desalinated sea water and the energy for the process is supplied by a wind farm. When the reservoirs are full and the wind is still blowing the surplus electricity is fed into the grid.
Most of the Middle East lives on desalinated sea water. Most islands desalinate water hand have been doing so for a long time. Malta, for instance, built its first desalination plant in 1881. There is nothing mysterious about the process. The technologies are well understood. The first is to use waste heat from power stations to boil water in low-pressure chambers to produce steam in a process known as flash distillation, but the main focus now is on reverse osmosis. It is more efficient and it is getting cheaper all the time as one can use renewable energy to power the plants.
The problem with reverse osmosis desalination is that plants generally deliver about 60% pure water and one is left with roughly 40% in the form of a very salty brine and discharging this back into the ocean is difficult and must be done with great care.
Fortunately, thanks to some pioneering work done in the Department of Chemical Engineering at UCT, there will soon be another option and it will be a world-class breakthrough.
The idea is to freeze the brine. As the temperature goes down the dissolved salts crystallise and settle on the bottom while the ice, which is pure water, floats to the surface where it can be raked off and added to the fresh water supply. The residual salts have commercial value. The technique, has been developed by a team lead by Professor Alison Lewis. At present it is being used to treat mining water.
This new technique means we can have a two stage desalination plant in which the reverse osmosis plant delivers 60% of the fresh water and freezing delivers even more. It will also be a way of “mining” the sea for valuable minerals.
This is the way of the future and if there was long-term thinking in the Civic Centre, the water crisis could become a huge opportunity for Cape Town to lead the world into a new era.
So what should Cape Town do? The answer is simple. Follow the example of the Department of Energy and issue a tender for the supply of a fixed quantity of water every year for the next 20 years. The private sector will be happy to finance and build desalination plants, small emergency ones at first and then a large plant on the scale of the one in Perth. We could even see major new investments in the country just as we saw with the renewable energy projects.
At no cost to the City, it can gain both the technology and the expertise to run a giant plant and receive a guaranteed supply of water for a generation or longer. The water would be paid for as it is used over the life of the desalination plant. If the plant supplies, say, 20 percent of the city’s water needs, the higher cost will be blended with the other 80 percent of the supply. Consumers will hardly notice it. Then, as recycled water costs about half as much as fresh water, we can make a project of recycling more and the City will actually be able to reduce the cost of water it supplies to industry.
It’s not rocket science. Consumers will pay slightly more over the next 20 years as they use the water, but they will have a guaranteed supply. There will be no need for special drought charges and the kind of emergency measures we are now seeing.
Two further advantages flow from this approach. Firstly, desalination should free up more water for the labour-intensive agricultural industry and it will reduce dependence on the dysfunctional national Department of Water and Sanitation.
Issued by Dean Le Grange, Media and Digital Co-ordinator, Cape Chamber of Commerce and Industry, 6 December 2017