Biogas is a clean fuel, thus reducing the levels of indoor air pollution, a major cause of ill-health for those living in poverty. Lighting is a major social asset, and already there are estimated to be over 10 million households with lighting from biogas (Martinot, 2003). Improved lighting is associated with longer periods for
work or study. Where biogas is substituted for woodfuel, there are two benefits: a reduction in the pressures on the forest, and a time-saving for those who have to collect wood – usually women and children. If a biogas plant is linked to latrines in a sanitation programme, it is a positive way of reducing pathogens and converting the waste into safe fertilizer. Where biogas is linked with sales of the resultant fertilizer, it is an excellent source of additional income. Fertilizer can be used on crops to increase their yield. Biogas can be used to generate electricity, bringing with it the possibilities of improved communications, telephone, computer, radio and television for remote communities. Fuel produced locally is not as vulnerable to disruption as, for example, grid electricity or imported bottled gas (Bates, 2007).