Why the delay in harnessing SAï¿½s latent hydroelectricity?
June 11 2013
With the delays and costs of the coal-fired Medupi plant rising, and Eskom imploring us to turn off lights and geysers, South Africaï¿½s dire need for more electric power is impossible to ignore.
Perhaps it is time to investigate more options (excluding for the moment, nuclear power since, for illogical reasons, it seems to scare the pants off the public).
Environmentalists are not all loons. Those who have travelled down the ï¿½small is beautiful routeï¿½ and do not reject technology will embrace fuel cells and photovoltaics. Our government, on the other hand, while seeming to back the Green Agenda, appears to be slow in embracing the potential of water power hidden in the countryï¿½s urban and rural water supply systems and perennial rivers.
This potential hydropower was detailed during a technical workshop last year at Pretoria University and again during the Clean Energy conference this year in Cape Town. What the participants presented was very interesting indeed. These highly qualified engineers produced solid scientific evidence of South Africaï¿½s untapped hydro-power potential and offered practical ways of accessing it.
It seems there are no less than 30 sites in the Eastern Cape and KwaZulu-Natal with the potential for small-scale hydroelectric power. Many are in deep rural areas where the chances are slim of ever getting Eskom power and where lack of electricity makes life grim.
These are areas where children study by candlelight, with schools where teachers cannot use overhead projectors or operate television sets. These are places where vaccines grow stale and useless in the summer; places where clinics can offer only basic health care.
In these parts of South Africa, power tools are useless without expensive petroleum-fuelled generators. Water power could provide sustainable ï¿½ and in the long run ï¿½ cheap energy, allowing the growth of small-scale industry such as carpentry, welding, and so on.
All these 30 sites have perennial rivers, streams or springs, all with enough water to power Francis/Pelton or Kaplan-wheel generators; and able, in some cases, to provide electrical power to whole villages.
When the whole of South Africa is considered, the opportunities are even greater. New dams being built or planned could provide water power. Old dams could be adapted to do the same. All that is needed is the political will. We have the engineering skills required.
It is remarkable that this opportunity to provide power cheaply is not given top priority. After all, in similar circumstances elsewhere in the world, notably China and India, mini-hydropower and larger small-scale hydropower, are eagerly exploited whenever possible.
Our governmentï¿½s avowed target is to achieve 10 gigawatts from renewable energy sources. The plan expects a mere 10 megawatts to come from small-scale hydropower (driven by existing dams and dams yet to be built).
Then here is another potential source of hydroelectricity ï¿½ the pipes and storage facilities in our cities. If we harness these to a far greater degree, we could add another 250MW to the electricity available.
Despite the national target for hydropower we continue to build new dams with no hydroelectric capacity at all. This is in contrast to China where there are more than 45 000 small hydroelectric plants driven by dams, rivers and large streams. These generate 175 000 gigawatt-hours annually. They supply electrical power to 300 million people. Power output from such systems has doubled in the last 10 years.
By the end of 2011 those employed in China in the small hydro-electric sector numbered 658 000, of whom 150 000 were technical staff. Even scaling that number down for South Africa, there is no doubt job creation for a small-scale hydroelectric programme would be significant.
Water sources in China vary between 2m and 1 000m above the generator. A wide range of dam types are employed ï¿½ earth, stone masonry, concrete, rock-fill, concrete-face rock-fill, rock-core wall and even rubber.
The Chinese direct water to their small-scale hydroelectric generators in different ways as well ï¿½ by open channels, aqueducts, all kinds of pipes under various pressures or under no pressure at all, merely using gravity. There are 500 manufacturers of hydro generators in China. Some will even deliver a complete small-scale power station that fits neatly into a ship container, ready to be connected.
In South Africa, we know the potential of hydropower. We have identified new dams and old dams that could have hydroelectric plants attached to them ï¿½ at a fraction of the cost of coal burning plants and built in considerably less time.
We know that 1MW generated by hydropower will replace 300 tons of fossil fuel. It will also avoid the emission of 3 200 tons of carbon dioxide (a key factor if you believe carbon dioxide is a poison) and prevent 20 tons of sulphur dioxide (which is a poison) reaching the atmosphere. All that while supplying 1 000 urban households with electricity.
Despite this, we are now building four dams without hydroelectric generating capabilities. At the same time, Namibiaï¿½s planned Neckartal irrigation dam will generate 1MW.
What is even more difficult to understand is that in the Eastern Cape in particular, dams and weirs (some with hydropower generators, some which have the potential) are being allowed to silt up, making them useless.
Compared with mega coal-burning monsters like Medupi, small-scale hydroelectric systems are cheap ï¿½ between R10 million and R20m. They also feed power to the grid more quickly, in 18 months to three years. Micro hydropower systems come on stream even faster.
There are even ocean energy sites that are suitable for power generation and together they could add almost 7 250MW to the national grid within the next 10 years, postponing the need for nuclear energy for at least a generation.
Medupi (R33.6 billion) is going to generate 4 800MW, so thatï¿½s a potential quarter of what we theoretically could get for a whole lot less. What is holding us up? The usual things: bureaucracy in general. Departmental rivalries. Public objections.
Itï¿½s a great pity. As the Chinese experts say: ï¿½Small hydropower is the rural renewable energy with the most mature technology, the longest development history and the most rewarding benefits.ï¿½
Itï¿½s time we listened.
Keith Bryer is a retired communications consultant. He is indebted to Bo Barta of the Sustainable Energy Society for information pertaining to South Africa and Li Zhiwu of the Chinese National Research Institute for Rural Electrification.
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