Biogas is generated through conversion of animal or human dung, within an air tight enclosure (digester or biogas plant) that does not let in oxygen, into combustible methane gas. This controlled degradation within a digester results in production of 60% methane gas and 40% carbon dioxide forming clean and renewable gas for household lighting and cooking.
A minimum of 20 kilograms of dung, produced by about two penned (zero grazed) cows or 7 pigs, is required to feed into the plant daily. Biogas is used for cooking and lighting using simple stoves and lighting lamps. Unlike liquefied petroleum gas (LPG), biogas is non-volatile and clean.
Production of biogas involves channeling the human or animal dung to a gas-tight digester for anaerobic digestion. There are several types of biogas digesters; Fixed dome, Earth pit, Ferrocement, Horizontal, Balloon, Floating, etc.
In Africa and Asia, the Fixed-Dome plants are the most popular due to their relatively low cost of construction, long life – about 20 years, space utilization since they are constructed underground, and their labor intensive nature leads to creation of employment.
Specially trained masons are responsible for plants construction, while the programme offers a one year guarantee against any construction errors.
Bio-slurry automatically discharged from the digesters into a compost pit or channel is used as organic fertilizer for agricultural production. Application of bio-slurry in agricultural fields results in increased yields and food sufficiency.
Installation of biogas plants under the ABPP can be done under different size categories ranging from 4m2, 6m2, 8m2, 10m2, and 12m2– depending on the needs, costs, space and capacity available. While the plants are constructed using the conventional building materials, research in more cost effective technology, like the interlocking stabilized soil blocks (ISSB), that reduces costs by up to 30%, is undergoing to minimize initial installation costs.
Also, production of locally assembled special biogas stoves and lighting lamps is being encouraged to further reduce costs of installation, and equally develop the local industry. Knowledge sharing between programme countries helps improve the technology, and tailor it to the local needs.
Partnerships with relevant research agencies and stakeholders to ensure construction standards and evaluation of biogas appliances are being created. On average, it takes about 10days to construct a biogas plant to operational status.
The benefits of biogas technology are enormous, both direct and indirect to the immediate end users, and the wider society. Clean and sustainable biogas energy is used for cooking and lighting thus saving users costs associated with other sources of energy, mostly fossil fuel energy.
The biogas programme ensures that countries, and societies benefiting from the programme, attain their MDGs. Access to clean and affordable energy goes a long way in ensuring environmental sustainability, reduction of child mortality through elimination of toxic inhalable gases that cause respiratory illnesses, promotion of sustainable development, eradication of extreme poverty through creation of employment opportunities, and uplifting of women as active economic actors through gender mainstreaming.
Reduction in carbon emissions is achieved through use of clean energy, and by using cow dung that produces methane, an ozone depleting gas when left in the open, the technology helps turn an otherwise destructive emission into an economically beneficial product, biogas. Equally, biogas energy negates the need for biomass fuel like firewood which results in time loss for women and children, environmental degradation and desertification.
As of 2010, over 3596 biogas plants have been constructed. About 1096 masons have been trained (in the six countries), with 3% of them women. Use of bio-slurry for agricultural purposes has seen tremendous increase in agricultural produce, and revenue generation from the sale of extra bio-slurry to other farmers.