The quest for renewable and sustainable energy

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 R59-billion 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 carbon-based 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.

Is energy efficiency your first step to a sustainable energy journey?

With load shedding said to worsen by August this year, companies are scrambling to find alternative sources of electricity — and renewable energy is a viable but expensive alternative. Energy efficiency on the other hand could see savings immediately, not only saving companies on the bottom line, but also reducing the investment required in more expensive renewables.  

According to the International Renewable Energy Agency (Irena) and the Copenhagen Centre on Energy Efficiency (C2E2), implementing energy efficiency and then deploying renewable technologies could be a viable option for energy crises, not only in South Africa but the world. Energy efficiency could result in the reduction of the global energy demand by up to a quarter by 2030. Energy efficiency could also account for between 50% and 75% of the total energy savings, with renewable energy delivering the rest. 

In South Africa since 2011, the South African Industrial Energy Efficiency (IEE) Project has assisted 138 industrial companies to realise energy savings of 6.5 TWh, equivalent to five years of load shedding at the 2019 level of 1.352 TWh. This translates into cumulative cost savings of R5.3-billion for these companies.

The National Cleaner Production Centre South Africa (NCPC-SA) in fact won an international energy award for the impact of the IEE Project. The NCPC-SA has successfully implemented energy efficiency in companies of all sizes through optimising systems such as compressed air, motor, fans and industrial heat pump systems. It also introduces energy management to all areas of business, from installing efficient lighting and equipment and internal metering, to changing human behavior when it comes to switching lights and machinery on and off. 

The companies that embarked on an energy efficiency journey have also benefited from a reduction in greenhouse gas emissions, improved production quality and decreased water use. Economic benefits for these companies have been lower individual utility bills, job retention, and faster payback on capex expenditure.

“The success of the project proves that energy efficiency maximizes the use of existing power supplies and reduces the required generation capacity,” says NCPC-SA’s National Industrial Energy Efficiency Manager, Sashay Ramdharee. “It is important that companies do this before they invest in renewables, as their energy requirements could be significantly reduced.”

Energy management will often lead to the installation of renewable energy sources, and there are a number of viable options to choose from.  The NCPC-SA believes that Biogas (gaseous fuel produced by the fermentation of organic matter) is an energy source and technology well suited to the African and South African context that is often overlooked.

According to Ramdharee, not only does biogas offer a potentially endless energy supply, it also addresses some waste issues, and could support emerging businesses in the process.  In February 2021, the NCPC-SA launched a training course on small-scale agricultural and commercial biogas project development.

Potential biogas waste sources in South Africa include food waste, animal waste such as chicken manure and cow manure and numerous other agricultural waste streams. It is also clear that there is an opportunity here for landfill gas as well as municipal waste. The gas that is released from the decomposition is a blend of primarily methane and carbon dioxide.

The combination of energy efficiency and renewable energy is not only incumbent on companies, but also involves government, industry, selected regulatory bodies and education institutions. The NCPC-SA is a national support programme funded by the Department of Trade, Industry and Competition. It is hosted at the CSIR, and with the funding of the IEE Project through the United Nations Industrial Development Organization, its services and advice on energy are highly subsidised and are often supplied at no cost. 

Feel free to visit www.ncpc.co.za for guides, tools or more information.