A national biogas feasibility study, which was com- pleted in November last year, will be used by the Department of Minerals and Energy (DME) to undertake planning for a national biogas programme, Agama Energy director Greg Austin tells Engineering News.

Biogas, a type of biofuel that is a product of the anaerobic digestion, or fermentation of biodegradable materials, such as manure or sewage, municipal waste and energy crops, can be used for electricity production, water and process heating.

Austin comments that biogas is a frequently overlooked source of fuel in spite of the excitement surrounding the use of biofuels as an alternative source of energy.

“This is very surprising given that it is the most sustainable of all the biofuels, being derived essentially from waste materials,” says Austin. While energy crops can be grown for biogasification, outside of that context, all resources used in anaerobic digesters are derived from biodegradable wastes.

In the ‘South African National Rural Domestic Biogas Feasibility Assessment’ report, Austin and Jabenzi director James Blignaut comment that rural areas involved in the study demonstrated a great reliance on renewable sources of biomass in the form of fuel wood. This reliance, however, results in environmental degradation in the form of deforestation and soil erosion.

The existing unsustainable consumption of fuel wood represents about 8% of the total primary energy supply in South Africa, most of which is consumed as a household thermal fuel in rural areas.

The study also shows that provinces with the best technical potential for implementation of biogas and high demand for the fuel are the Eastern Cape, KwaZulu-Natal, and Limpopo provinces.

Although there is no policy specifically relating to rural energisation using biogas, the DME’s white paper on energy policy suggests biogas as a means to achieve rural energisation.

Blignaut says that the country has good supporting infrastructure to carry out the biogas programme, in the form of government and financial services, skills, and the assurance of microfinance, although mechanisms for making credit available remain to be established.

The study has found that there are about 310 000 households that have the technical ability to participate in a rural biogas programme. The programme would have 15% and 67% financial and economic internal rates of return (IRR) respectively, based on the installation of 6-m3 fixed dome biogas digesters. The highest rates of return attained from such a programme were in the Eastern Cape, which has a 26% financial IRR, and a 77% economic IRR.

The first phase of the national biogas programme will install biogas digesters in 20 000 households over a five-year period. The implementation of 20 000 biogas digesters will cost R238-million over five years.