Biogas the future for alternative energy in South Africa

Following China’s lead, plans to increase the use of biogas, or Anaerobic Digestion, in South Africa could help improve the country’s service delivery and serve as a local solution to the worldwide energy crisis caused by the depletion of fossil fuels.

Anaerobic Digestion or biogas is both a waste management system and a clean, efficient source of energy. The process involves the breakdown of organic waste in an oxygen-less environment. This produces methane gas which is an incredibly rich source of energy.

Furthermore, the natural by-product of an anaerobic digester is nutrient-rich slurry, a water-based fertiliser that, once re-introduced into the soil, helps to grow the very same food source that feeds an anaerobic digester. This slurry can also be further processed using algae tanks, simple reed bed filters or naturally occurring wetlands to reclaim the water used in the process. From this approach, South Africa can gain a waste management system that produces not only gas and valuable fertiliser but clean water too.

The process of anaerobic digestion is carried out in a sealed container that, fed with water and organic waste, consistently generates enough methane-rich biogas to power gas stoves, lights, generators and water geysers. The waste source fed into the container can be anything from food scraps to raw sewage to agricultural waste. In a developing country where so many people live below the poverty line without basic services, it is a way of creating efficient energy – and thus powering desperately needed basic services – from something that is otherwise unwanted and costs nothing.

Furthermore, biogas has the potential to de-centralise energy production and effect change in the areas that need it most. At present in South Africa, numerous large scale waste digesters are being commissioned and built by the Cape Town based energy company AGAMA in otherwise removed rural areas. The recently AGAMA installed Three Crowns School digester in the Eastern Cape, for example, has used sewage and garden waste from the school to power the school kitchens. The slurry is also filtered by algae ponds so that the water can be reused to water the school grounds and the algae itself to fertilise the school gardens.

As South Africa continues to develop, it is in the perfect position to reconsider its focus with regard to energy production. Fossil fuels are fading whilst other alternative technologies are less sustainable and involve inhibitive start-up costs and unjustifiable investments in infrastructure. Meanwhile, the basic needs of large parts of South Africa are not currently met by the electrical grid, resulting in excess use of kerosene, paraffin and wood-fire, all of which are in increasingly short supply and are harmful to the ozone layer. Biogas effectively fits the current needs of the country, revolutionsing pre-industrial natural cycles of waste and simultaneously producing valuable energy for the whole of South Africa.