South Africa has a power deficit of about 21 000 megawatts (MW) because demand exceeds supply. This gap continues to widen and the Council for Scientific and Industrial Research estimated that the economic costs of electricity disruption in 2019 were at least R59-billion.
The generation of energy from waste could address both the waste and energy crises.
Waste to energy (WtE) refers to various treatment technologies that convert waste to electricity, heat, fuel or other usable forms of energy.
According to the World Bank, the world’s cities generated 2.01 billion tonnes of solid waste in 2016 and this is expected to grow by 70% to 3.4 billion by 2050 on the back of rising population numbers.
There are more than 860 landfills in the country, according to the South African Waste Information Centre. In 2020, these landfills had 48.5 million tonnes of waste (64% hazardous waste and 36% general waste), of which 34% was recycled. These landfills pose a risk through the emission of greenhouse gases that cause climate change as well as respiratory diseases. They also contaminate the soil near the dump sites. Based on this, thermal WtE may reduce the volume of waste entering landfills by 75% to 90%, while also helping to address South Africa’s power deficit.
South Africa has only one large-scale waste to energy plant, the New Horizons Waste to Energy in Athlone in the Western Cape. It processes between 500 and 600 tonnes of general waste a day. The plant was launched in 2017 and cost R400-million.
Other emerging market economies are intensifying their waste to energy initiatives. The government in Malaysia commissioned the country’s first WtE plant in 2009 and is looking to build six new plants near major cities by the end of 2021. Malaysia’s Kajang Waste to Energy Plant is about 20km from the capital Kuala Lumpur and has the capacity to process about 1 100 tonnes of municipal solid waste (MSW) a day, generating about 8MW of electricity daily. Eight megawatts of electricity can supply about 5 200 average households. The electricity that is produced powers the WtE facility, and the remainder is sold to the national power grid through net metering.
Local authorities in the Kajang municipality contracted to deliver 700 tonnes of unsegregated MSW daily and are charged a tipping fee per tonne. The waste is first pre-processed to recover recyclables such as plastics and metals and to separate out the wet waste to enhance power generation, thus maximising the extraction of energy from the waste and contributing to a circular economy.
Embarking on this journey requires concrete steps be taken today. First, South Africa must understand the nature and type of waste that is being disposed of. According to the United Nations, organic waste makes about 53% to 56% of municipal solid waste in low- and medium-income countries. This suggests the quality of waste in South Africa is likely to be low (from an energy generation potential perspective) because of the higher moisture content than the intensity of the flames required in the incineration.
The type of waste will influence the viability and effectiveness of the WtE as an alternative source of power. Lessons can be learnt from countries such as Brazil, which produces 51% of organic waste. In 2018, a biomethanisation unit was set up in Rio de Janeiro to turn organic matter from municipal solid waste into biogas, to generate energy and biofuel. The organic waste is also changed into organic compost and used as fertiliser. The plant processes between 35 and 50 tonnes of waste a day, creating energy to power plant operations and the company’s fleet of 19 electric vehicles.
Second, a legislative framework that includes strategies for maintenance, monitoring and evaluation of the WtE facilities must be created. This can include guidelines on safe disposal of toxic by-products because thermal WtE can be a dangerous source of emissions when mismanaged. Legislation should be in line with internationally recognised emission standards, monitoring and enforcements to avoid contradictory laws. As an example, the Philippines lifted the thermal WtE ban in 2016 but it contradicts the country’s Clean Air Act.Finally, discussions must be had with respect to investment requirements, finance sources and those with good operating models. This is important given the country’s current debt levels and competing priorities.