Abstract:
The fast depleting supply of fossil fuels and growing global environmental degradation by potent greenhouse gases has pushed the World’s economies towards the usage of alternate energy sources. Biogas energy accounts for a major chunk of the different alternate energies used globally. Pakistan being an agricultural economy and livestock being a major contributor has a great potential of biogas energy. This study evaluates the socioeconomic, environmental and health impacts of biogas technology in two villages, one in Narowal and one in Sahiwal district. All the biogas users from both the villages were given questionnaires during field survey and ten non-users were interviewed informally. It was found that all the plants in the villages were well functioning except for one digester. Each plant was 6m3 in size and required 45 kg – 50 kg of dung daily to produce enough gas to fulfill the cooking needs of the household. However, during the months of January and December due to low ambient temperature the gas produced is not sufficient and dung cakes and firewood are used to meet the daily cooking needs. The users’ expenditure on chemical fertilizers decreased, 55% of respondents agreed that the bio-slurry completely fulfilled their fertilizer requirement. The consumption of dried dung cakes for cooking declined from 5,760 kg dung before biogas to 1,200 kg dung after the usage. The wood consumption in these villages after the biogas plant installation decreased from 28,080 kg to 2,520 kg annually. Wood was used during winters for heating purposes, also during the months of December and January fuel wood and dung cakes were used to fulfill cooking requirements as the gas produced was not sufficient to meet the requirements of the households. Biogas usage completely substituted the Liquefied petroleum gas (LPG) requirement of the respondents as the consumption and expenditure of LPG after biogas was nil. Women experienced time saving of two and half to three hours per day by using biogas stoves for cooking. It was estimated that nineteen functional plants altogether were saving nearly 125 ton of carbon dioxide per year. It can be concluded that many direct and indirect impacts of biogas on health and environment cannot be quantified. A greater public involvement is necessary for the large scale dissemination of the biogas technology throughout the country as an alternate energy source.
