South Africa definitely has exploitable bioenergy potential,” stated Council for Scientific and Industrial Research principal engineer Crescent Mushwana at the recent launch of the South Africa Bioenergy Atlas in Pretoria. “Bioenergy from organic waste, residues from forestry and agriculture [lignocellulose], and eradication of alien invasive plants is feasible.” These all amount to ‘low-hanging fruits’. “The economic viability of biofuels from purposely cultivated crops is currently negatively affected by the low price of oil.”
However, most agricultural residues are already allocated to other uses, he cautioned, such as soil and nutrient regeneration. On the other hand, there is a lot that can be done in urban areas. “Biomass potential is always closely correlated with population density,” he highlighted. And areas of dense population tend to have good infrastructure, making it easier and cheaper to deploy biomass as an energy source. “Organic waste is largely concentrated in big urban areas.”
Organic wastes are turned into biogas using simple devices called digesters. Basically, these are airtight containers in which a biological process called anaerobic digestion takes place. Ideally, the temperature has to be controlled for optimal efficiency. The result is a mixture of methane (the major part) and carbon dioxide gas. The methane can be used as fuel to generate electricity. The residues can be used as fertiliser. “Organic waste looks like a [low-cost] winner in all cases.
“Lignocellulose is a very important factor we should look at,” he pointed out. “In the short term, there is potential for what can be done with existing operations.” This could include co-located electricity generation at sawmills and sugar mills.
“[T]he bioenergy potential in the country can be exploited currently with available technology,” summed up Mushwana. “Bio-energy from organic waste and lignocellulose is cost competitive currently. Bioenergy has the potential of 3 500 MW for electricity generation and a total of 487 pJ/a (equalling 135 TWh) total energy contribution in all sectors. Bioenergy has the potential to contribute sustainably to the energy mix of the country. All the tools are here – all the resources are here.”
The goal of the atlas is to act as a “decision support tool” to help government in planning, investment and deployment decisions regarding bioenergy technologies for heating and transport fuels, as “This . . . is a product we’re really proud of,” affirmed Department of Science and Technology (DST) deputy director-general: technology innovation Mmboneni Muofhe at the launch. He assured that the South African view on bioenergy was that it must not put food security at risk by using food crops.
“The DST has developed a tool which we can use … increasing the participation of bioenergy in our programme,” stated Independent Power Producer Office head Karen Breytenbach. “The Bioenergy Atlas closes the gaps in the data and information necessary for planning and decision-making,” pointed out Department of Energy renewable-energy initiatives coordinator Noma Qase. “For example, it confirms the potential of the resource for consideration in the energy mix.”
South African Independent Power Producers Association chairperson Thomas Garner highlighted that the DST is playing a key role in developing renewable energy, addressing energy scarcity and inclusive development, and assured that bioenergy would be a part of the country’s future energy mix. “It sets the stage for South Africa’s transformation into a low-carbon energy future . . . We look forward to a low-carbon energy future.”