Mail & Guardian

The quest for renewable and sustainabl­e energy

South Africa already has several biomass production plants, and is investing in more solar and wind farms

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Sporadic scheduled power cuts have been sprung on South Africans for over a decade and serve as a reminder that energy sources are finite, but they have helped the country to re-think its energy options. Scheduled power cuts, termed “load shedding” by energy utility Eskom, come at great economic cost. In 2019 load shedding is estimated to have cost the South African economy between R59billion and R118-billion, according to the Council for Scientific and Industrial Research.

South Africa’s per capita emission of greenhouse gas is higher than the global average, but with plenty of sunlight and wind in some parts of the country, which provide alternativ­es to the burning of fossil fuels, this problem could be addressed while South Africa’s growing energy needs are met.

Tobias Bischof-niemz, engineer and author of the book South Africa’s Energy Transition, told a Sanedi panel discussion on the sidelines of the Mining Indaba in 2019 that South Africa has a competitiv­e advantage in renewable energy.

This is because South Africa has superb wind and solar resources and enough land on which to construct plants to harvest them. “These three things give South Africa a huge competitiv­e advantage, which can never be taken away,” he said.

Solar and wind power costs have declined and, although initial costs are higher than for convention­al energy sources, in the long run it has become the cheapest option for many countries in terms of new generation. It’s believed that most of the world’s energy will come from solar and wind by 2050. By that time only two coal power stations — Medupi and Kusile — are likely to still be operationa­l in South Africa. This reality is also recognised in the Integrated Resource Plan (IRP) for South Africa’s future energy mix.

There is, however, an impression that wind and solar energy is unreliable, but Bischof-niemz said it is more correct to use the term “variable”. He said: “Wind and solar power is not intermitte­nt. It is variable, it changes over time, and these changes are predictabl­e.”

Energy operators keep an eye on weather forecasts and bring in a flexible power supply such as gas during the times when the other resources are low.

These are the options for renewable energy sources:

Solar

This holds the most potential of all South Africa’s renewable energy sources, as the country receives a lot of sun. It is so rich in solar energy, that compared to countries in Europe, the same plant in South Africa can produce up to 20% more electricit­y for the same capital investment. This is according to a 2015 paper entitled Renewable Energy Gathers Steam in South Africa by Richard Walwyn and Alan Colin Brent, from Pretoria and Stellenbos­ch universiti­es respective­ly.

How it works is that light and heat radiated from the sun is transforme­d into electricit­y through photovolta­ics, or concentrat­ed solar power.

A solar park has already been built near Kimberley in the Northern Cape, which is set to deliver 180 000 megawatts of solar power every year — enough to power up to 80 000 households.

Wind

This is also a potential major source of energy, especially in Cape Town, which has already built a number of wind farms due to the high wind velocity on the coast. South Africa ranks as having fair to reasonable wind resources on the internatio­nal scale.

Wind power uses wind turbines which convert the wind into kinetic energy and mechanical power. The turbines have 50-metre-long blades attached to 80 metre-high shafts, on wind turbine farms.

The wind needs to be between 13-90 km/h for the turbines to produce power. These turbines can be offshore or on land, although offshore has stronger winds.

South Africa has 10 major wind power farms and 19 wind energy developmen­ts, with more than 600 wind turbines. One of the first farms was near Darling in the Western Cape, which has since 1997 been developed as a national demonstrat­ion project.

Hydroelect­ric power

Hydropower needs flowing water to be turned into energy, and most commonly hydroelect­ric dams are used for this. Water is then released from the dam, or the reservoir, and that generates electricit­y.

South Africa has seven hydroelect­ric power stations but due to a low annual rainfall rate of 500mm, the country’s hydroelect­ric potential is limited. The Eastern Cape is currently the best region for hydroelect­ric power.

The dams aren’t only used to generate power, but could also be put to use for irrigation and flood control, which helps to develop the economies around the dam.

This form of power isn’t as environmen­tally friendly as solar and wind power, especially when done on a large scale, as the large amounts of flowing water can damage the river ecology, and also take up a lot of land space.

South Africa is hoping that the Grand Inga Project in the Democratic Republic of Congo will help supply some of its energy needs, and this is also provided for in the Integrated Resource Plan.

When completed, the Grand Inga will be the largest hydro-electric power generating facility in the world, and will provide energy for much of the region. It will generate more than double the power of the current world record holder, the Three Gorges facility on the Yangtze River in China.

Inga would be a “run-of-the-river” hydroelect­ric project, which means it needs only a relatively small reservoir to back up the power of the river’s flow.

Even though some environmen­tal pressure groups have cautioned that the project costs will be unaffordab­le and that other power options should be considered instead, DRC President Felix-antoine Tshisekedi Tshilombo has vowed to push the project forward while he is chair of the African Union.

Biomass

This is the largest renewable energy contributo­r in South Africa with 9-14% of the energy mix; there are already several biodiesel production facilities. According to the Department of Environmen­t, Forestry and Fisheries the concept of converting biomass to energy “is still at its infancy in South Africa” but holds promise for future sustainabl­e developmen­t.

With 42-million hectares of natural woodlands and 1.35-million hectares of plantation there is a large potential for biomass production.

Biomass is generally regarded as any carbonbase­d material that comes from materials derived from plants and has the capacity to produce electricit­y, heat or liquid fuels.

It can be used as a direct energy source, such as for heat or cooking fuel, or it can be burned to generate electricit­y. It can also be used indirectly to produce ethanol, methanol and fuel that can be used for transport and cooking. Most biomass fuel is derived from wood, including tree stumps, forest residue, dead trees and wood chips, but animal and plant matter such as algae can also be used, and so can human and industrial waste.

Producing biofuel from waste could also help municipali­ties solve the problem of lack of suitable land for new landfills.

Geothermal energy

This is produced by using the heat from the Earth’s crust and converting it into energy. This heat comes from the original formation of the planet and from the radioactiv­e decay of material. South Africa currently has no geothermal energy plants, but there are plans to implement projects. Research has shown that there is high geothermal potential in the country, and the relevant temperatur­es rank from medium to high on the global scale.

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 ??  ?? South Africa has ample sun, wind and land upon which to build solar plants and wind farms
South Africa has ample sun, wind and land upon which to build solar plants and wind farms

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