Unconventional power for an unconventional country

Life in rural Africa has never been easy. Living “out in the sticks” (as we comfortable city dwellers fondly call it) is hard work. There is no water on tap; there is no lighting or electricity available at the flick of the switch. It is hard to comprehend a life without these simple amenities… and it is hard, manual labour to provide for a family without them.

Imagine having a rooster as a substitute for your beside alarm cum clock/radio. Imagine collecting water and firewood for your daily consumption, and spending the evening chatting – or studying – by candlelight. Imagine not watching television, chatting on the telephone, or turning on the hot tap to run a nice warm bath.

This is life for residents of Maphephetheni, who live in the remote but beautiful gorges overlooking Inanda Dam. But, in a groundbreaking pilot scheme that has been established to convert dung and human effluent into biogas, life is slowly changing; and horizons are broadening.

Two 20 000 litre biogas digesters, funded jointly by the Department of Mineral and Energy Affairs and Winrock International (a US-based NGO), were installed at the Meyka High School in Maphephetheni. This has provided the school with methane gas that is piped to a diesel generator to create electricity – sufficient electricity to run home economics and computer classes on a regular basis. An achievement that school principal, Melusi Zwane, is particularly proud of.

“Because I wanted my pupils to be computer literate, we couldn’t run with solar power,” explained Zwane. Now the school not only has affordable power, but is also able to run 20 computers off its biogas system. The installation for the R250 000 test project was undertaken by Solar Engineering Systems, and the project also created the opportunity to teach the pupils about related aspects of environmental studies, mechanics, organic chemistry, science and mathematics – in addition to imparting an understanding of how the two biogas digesters convert cow dung and human waste into biogas, providing a cost-effective means of power for heating, cooking, refrigeration and lighting.
Biogas power from the school project will also be used to run the canteen, and excess power is made available to community members for domestic purposes.

The first phase of the project was the installation of flush toilets at the school to provide ‘food’ for the digesters. An additional inlet was added for accepting cow dung into the digesters, and then the biogas digesters themselves were installed.

Human effluent from the flush toilets is piped into the dome-shaped underground biogas digesters where bacteria transforms the waste, by means of anaerobic digestion, into biogas – a mixture of (predominantly) methane and carbon dioxide. The methane gas rises into the gas holder where it is contained by a water seal. The gas is then piped via the outlet point on a pressure-fed system to the school generator, to be available on demand.

The two digesters are ‘fed’ during term time by the 860 scholars and 24 teachers, with waste entering each digester via eight inlet pipes from flush toilets, and one cow dung receptor inlet. During the holiday period, the digesters are regularly filled with dung to keep it functioning.

Biogas is a cheap source of energy used widely in developing countries, like China, Nepal and India – India alone has 3,4 million biogas digesters. With the abundance of this natural waste resource in South Africa, Biogas usage should be commonplace; but, according to Will Cawood, director of Solar Engineering Services: “Biogas is a totally under-utilised resource in South Africa.”

Although solar panels also offer another alternative power option for rural residents, Cawood explained that a biogas digester was a more effective energy source, and that it was more reliable and not prone to theft – solar panels are subject to a high incidence of theft for their resale value.
In another pilot project in the area, a biogas digester was installed at domestic household level. “This project has changed the life of my family,” enthused Jerome Gwala. “Particularly that of my children – because they no longer have to collect firewood for cooking after school. Now, instead, they are able to just concentrate on their schoolwork. What is also good about this energy source is that it is free and runs itself.”

The residents of Maphephetheni who benefit from this alternative source of power are delighted. The biogas digester (apart from initial installation) costs them nothing but the effort to maintain. It saves them money in terms of gas, paraffin and candle purchases and provides them with free time; because the time spent collecting firewood for fuel, which previously could take up to two days within any week, is now free for other potentially more productive uses.

The advantages of using a biogas digester to convert human waste and cow dung into an easily accessible alternative energy source do not stop at cheaper power and free time. As a by-product of the energy generation process (using heat, waste and water) the biogas digester produces enriched liquid manure that flows out of the slurry outlet pipe. This is an effective fertiliser for both home and commercial vegetable gardens, and in turn, can increase income savings in reduced food bills and increase income generation from the sale of home-grown produce.

In addition, there are added health benefits to the use of the biogas digester. The first is sanitation. The digester provides a safe means of disposal of human faeces, which translates into reduced groundwater pollution and reduced incidences of water borne diseases such as cholera and other diseases related to poor sanitation. The second is that biogas provides a clean, smoke free form of energy – reducing the negative effects of smoke inhalation and pollution. It also provides light to study by, reducing the use of candles for reading and schoolwork – and resultant eyestrain.

Biogas as a cost effective, environmentally friendly alternative energy source, explained Cawood. A domestic biogas digester unit capable of producing energy for an entire family’s cooking needs can be installed for between R5 000 and R8 000. Based on the current price of liquid petroleum gas, the unit would pay for itself within two to three years, thereafter providing free fuel; a saving, in today’s terms, of approximately R200 a month – before one considers the environmental, health and time saving factors. For the residents of Maphephetheni, human effluent and cow dung are no longer waste, but are valued as a useful natural resource that brings light and power to their community.