• Ben Parker
Director, Irin News
+254 20 762 2147 or +254 733 860 082
With the number of people in Africa’s urban centres expected to grow rapidly in the next few decades, municipal waste and its disposal could pose a variety of logistical and public health challenges.
Now, researchers at South Africa’s University of Cape Town are examining how to convert organic waste into biogas, which would alleviate disposal problems and help poor residents, particularly those in informal settlements, save on energy costs.
The number of people living in Cape Town is expected to grow almost 60% in the next three decades, according to a 2010 demographics projection (PDF, 733KB) by the city. Meanwhile, energy prices, including the cost of electricity, have gone up at least 50% in the last four years.
University of Cape Town (UCT) researcher Rethabile Melamu told Irin: “Up to 70% of organic municipal waste could be used to create biogas. We are going to set up a biogas project near an abattoir and use the leftover blood and animal waste to create fuel that can be used for cooking and heating water.”
The process of turning waste into gas involves the breakdown of organic waste in an oxygen-free environment called a biodigester – usually a large rubber bladder or a concrete structure, depending on the scale of the project – which operates like a human stomach.
This produces methane gas that can be siphoned off and used for cooking and to replace paraffin, an increasingly expensive fuel commonly used in informal settlements.
In June 2012, a grant of R2.5-million (US$305 000) was provided by the National Research Foundation to UCT for small biogas demonstration projects.
UCT partnered with the NGO Engineers Without Borders (EWB) and African Green Energy, a private company, to install a rubber bladder biodigester at the Siyazama Community Garden in the community of Khayelitsha near Cape Town, in 2011.
EWB volunteer Francois Petousis said it cost about R10 120 ($1 200) for the raw materials and labour to install the equipment, which has a 10-year lifespan. The community gardeners grow vegetables and use the organic waste to fuel the system.
Cynthia Nkqayi, a group leader at the garden that supplies vegetables to Abalimi, an urban agriculture association, believes the biodigester is a great addition to their operation because they use gas for cooking every day. It has also saved them money.
“We used to buy about R300 [$36] worth of gas every two months for cooking, so it is a big saving for us to have the biogas here, as it is free,” said Nkqayi.
There are similar pilot projects underway across the country.
Melamu, who has researched biogas since 2000, believes it is not a fuel that could replace traditional energy sources, but that it should be added to a mix of renewable energy sources like solar and wind power.
“Biogas system installations have creased steadily since 2000, and now there are thousands of systems … around the country,” she said.
The company Bio2Watt, for example, aims to build and operate commercially viable biogas plants throughout South Africa. These plants will use waste streams to produce green electricity.
South Africa slow to catch up
The government is now considering whether it should supply biogas to the poor.
David Mahuma of the South African National Energy Development Institute (Sanedi), which has been asked to examine the question, said, “Biogas becomes a good energy provider if you have the biomass resources to create it. But we are only beginning to assess its potential, and are still at the costing stage in terms of looking at its viability at a national level.”
Last year, the government announced that renewable energy should make up 42% of new capacity.
But despite the suitability of biogas as a fuel source for low-income families and agricultural businesses, South Africa has been slower than other African countries to embrace biogas.
The country’s energy infrastructure is more developed than those in Kenya and Ethiopia, where biogas production has secured a firm foothold.
Dutch development agency, SNV, which has been involved in setting up domestic biogas programmes in Nepal since 1989, has partnered with national bodies in nine African countries to roll out biogas initiatives under its ‘Africa Biogas Partnership Programme’ framework.
This market-orientated programme took off at the end of 2008, with Burkina Faso, Ethiopia, Kenya, Senegal, Tanzania and Uganda coming on board. It aims to reach 70 000 households via a variety of different biogas projects by 2013. Cameroon has been developing its own programme since 2009, and Benin since 2010.
UCT’s Melamu said the potential for biogas in South Africa’s urban areas is “huge when you see what has been achieved in countries like India, where biogas production is very well-developed. In India’s Pune City, municipal waste is turned into biogas and used to power the urban street lights. There really are numerous ways to use it,” she said.
Urban and rural energy needs
The dichotomous nature of South Africa’s economy – which has highly developed industries and living standards alongside widespread poverty – coupled with rising fuel and electricity costs mean there is a huge need for affordable energy sources both in urban and rural areas.
Government statistics show that 3.7-million people in South Africa, predominately in rural areas, currently do not have access to electricity, and many more still use traditional biomass for cooking.
The 2008 South Africa National Household Biogas Feasibility Study, produced by Agama Energy, an engineering consultancy, concluded that at the timethere were at least 310 000 households – 9.5% of South Africa’s rural households – showing technical viability for participation in a rural biogas programme.
For a household to be viable, it needs access to enough animal or plant waste to feed a biodigester.