Study Of The Benefits To Energy, Economic And Environment Of Household Biogas Digesters In Rural Areas

It is very important for resolving our country energy problem in rural areas that promoting the household biogas digesters. For example, by the end of 2005, there are more than 18 million household biogas digesters in the rural areas, with an annual output of about 70 billion cubic meters of biogas. Then 50 million rural residents who are in short of energy improved their living conditions fundamentally by means of using the clean energy of biogas. From the years of 2003 to 2005, after survey among households in Jiangsu Lianshui and Anhui Guichi was carried out, this paper mainly discusses the difference of two aspects between these places: household energy consumption and the biogas' impaction on the consumption, then the benefits on economic, environment and social from biogas digesters were assessed quantitatively or qualitatively.Investigation results showed that there is a very huge gap between these two places about both energy consumption situation and the biogas' impaction on the consumption. In Lianshui with household net income in the lower level, there is strong correlation between family energy consumption and other factors, such as: the family sizes and straw harvest, and the biogas digesters greatly effect on both per capita household effective energy and commercial energy proportion in effective energy. But in Guichi, with relatively high household net income, the family the energy consumption is effected by income, so only in the year of 2004 with lowest income did biogas digester impress the family energy consumption.After analyzing on benefits and costs of biogas digesters and quantifying them by the various of the methods of environmental economics, the digesters' financial and economical evaluation including sensitive analysis are completed from personal and social perspective respectively. The evaluations reveal that the benefits were greater than the costs for either the farmers' individuals or society as a whole, and economical benefits far outweighed the financial benefits. The sensitivity analysis shows that building household biogas digester has a strong capability to resist risks.The indicator weights of evaluation of impaction on environment were determined by the method of AHP analysis, the indicators were transformed though methods of Environmental Economics, and the evaluation criteria were confirmed by the means of accessing the information, then the environmental impact assessment was carried out through the weighted summation after data conversion. Evaluation results show that the household biogas digester construction in the two cities have great environmental benefit.