Using existing data on refuse and urban population growth, the researchers measured the total energy potential of all Africa’s urban solid waste from both incineration and methane produced from landfill sites.
Their study was published last month in the journal Renewable and Sustainable Energy Reviews.
“Our analysis shows that waste, and in particular municipal solid waste, is a renewable energy resource that could provide a meaningful share of both gross energy consumption and electricity on the African continent,” says study author Fabio Monforti-Ferrario, from the European Commission’s in-house science service the Joint Research Centre.
The study reveals that Africa’s urban rubbish could have generated 62.5 terawatt-hours (TWh) of electricity in 2012 if it had been used in waste-powered plants, for example those that incinerate rubbish or use methane from decaying waste matter to generate electricity. This could increase to 122.2 TWh in 2025 as such plants become more efficient and widespread, the paper says. By comparison, Africa’s overall energy consumption in 2010 was 661.5 TWh.
But the researchers found a vast difference in waste production and management from country to country. Some data points to a drop in the production of suitable waste over the coming decade (see chart). Yet even if this happens, municipal waste could still produce energy for 27 million families in 2025, based on the average African electricity consumption in 2010, the researchers say. The World Bank predicts Africa’s population will expand to 2.8 billion people by 2060. This growth will bring greater demands on already struggling waste management systems, according to Mark Borchers, technical director at not-for-profit company Sustainable Energy Africa.
“Waste in African cities is often not effectively collected and, when it is, the landfill sites are often not managed in a way that will enable technologies, such as methane capture for energy purposes,” he says.
Financing is also a concern. Bettina Kamuk, chairwoman of the International Solid Waste Association’s working group on energy recovery, says it can be hard to find the money to build electricity plants that burn waste. “In the short term, treatment of waste by incineration is more expensive than landfilling or dumping,” she says.
Logan Moodley, manager of the Engineering, Cleansing and Solid Waste Unit of Durban, South Africa, adds that political support for renewable technologies is lacking.
“There is a need for legislation and incentives to support development,” he says. “For waste-to-energy to be a feasible way forward, political buy-in is needed on all levels.”