Household Biogas Utilization And Its Coenvironmental Benefits: Evidence From Enshi

Energy is an essential condition for the production and living of modern human beings and the important physical foundation for the social and economic development. The global energy consumption has been dramatically increased since the Industrial Revolution. Many fossil energy resources are facing the plight of exhaustion, shortage and tension in supply as fossil energy resources such as coal, petroleum and natural gas are rapidly consumed. China has become a big energy producer and consumer in the world. With constant socioeconomic development, China's energy demand, including demand of rural energy, will continue to rise. It is the nation's strategic mission that is practical, pressing and significant to increase energy supply for production and livelihood, safeguard energy security and protect the ecological environments of the country, especially the fragile one in the central and west regions.To protect eco-environments, renewable energy sources need to be developed. China's government has attached great importance to develop renewable energy sources including biogas. The government popularized energy saving and renewable energy source projects including coal and firewood saving ranges, household biogas, small hydropower stations, wind energy and solar energy for the purpose of alleviating rural poverty in supply of energy. These measures have effectively increased energy supply in rural areas, rural energy efficiency and energy using levels, promoted the economic development of the countryside and helped improve the living conditions of the farm households. With the rapid development of the rural economy in recent decades, problems such as weak agro-eco-environment, low efficiencies in biomass resources utilization and insecure agricultural products, have been increasingly highlighted. Under this background, the government chose biogas as a key popularizing project of rural energy source with the expectation of realizing a benign and interactive development between the countryside and the agriculture through the pattern of agricultural circular economy driven by rural biogas construction. Although the development of biogas for farm household use has been through quite long and different stages including pilot and launching, technical breakthrough and improvement of procedure and technologies, and rapid development, the construction, popularization and usage of biogas for farm household use are successful as a whole. A basic construction unit featuring "one pit (biogas generating pit) and reconstruction of three places (kitchen, toilet and pen)" has been formed. In addition, according to the natural and economic conditions in different regions and the practical need in adjusting the industrial structure of agriculture, ecological energy development modes of biogas for farm household use has been creatively developed with the southern "pig-biogas-fruit" (combination of pig raising with biogas and fruit trees planting) and the northern "four in one" (combination of pig raising with biogas, vegetable planting and sunlight greenhouse building) as typical models. At present, with the constant increase of government investment, the extensive central and west regions of China are making efforts to develop rural energy sources and ecological agriculture with biogas as the bond or leading source for further facilitating the construction of a new socialist countryside.While farm household biogas development is filled with opportunities, there are more challenges. To summarize, these challenges mainly cover the following aspects: (1) co-existence of low efficiencies and wastes in use; (2) dispersed supply and demand of energy resources, relatively high cost in construction, operation and management; (3) severe deficiency of capability of technical and service support; (4) great regional disparity and insufficient capacity of public financial support, which makes difficult a far and wide service of energy; (5) weak governmental support and backward institutional arrangements; (6) deviation of farm households' practical need due to intervention driven by government departmental self interests.Most of the current studies on usage of farm household biogas start from the perspective of government administration. It is rarely seen that studies set off from the actual situation of farm households with the views to further discover the causes for appearance of problems and challenges, find out ways out and proposing measures and coping strategies by taking into account farm households aspiration and actual use situation in promoting biogas development.This dissertation pays attention to investigate farm households' inclination in the process of building and using biogas from the perspective of analyzing farm household behaviors. It studies the input-output of the building and using biogas from the perspective of farm household's livelihood. In addition, it discusses the internal relationship among relevant factors. What's more, it assesses, by means of empirical analysis, the eco-environmental benefits brought about by farm household's biogas energy use and attempts to establish an assessment index framework system for the eco-environmental benefits.The various research and analytical approaches adopted involve literature review, fieldwork, case study, eco-environment assessment, econometric analysis, and system modeling. Large quantity of first-hand farm household data from Enshi, Hubei, is employed for the empirical analysis. Quantitative questionnaire survey and analysis are combined with qualitative analysis in an effort, and theoretical and empirical studies are jointly used together. Thereby, the relationship and rules of changes among each relevant factor or variable are discussed.The disertation is divided into seven chapters. The first chapter is an overview, which gives a general introduction of the research background, objectives, contents and approaches etc. The second chapter is an overview of the theories and empirical approaches. Its major objective is to introduce the basic concepts, theories and approaches pertinent to this study and the summary of the research status quo, which provides references for the empirical analysis of this study. The third chapter is a description of the background information of the study area. It mainly introduces the general situation of the biogas development in the study area and local background. The fourth chapter analyzes farm household behavior of adopting biogas. This is for the purpose of analyzing main factors affecting farm household behavior in choosing biogas technologies through modeling and discussing the relationship among relevant factors. The fifth chapter involves cost-benefit-analyzes of farm household biogas system and energy flow analysis, with a view of analyzing input-output benefit of biogas use and biogas ecological system from the perspective of engineering economics and ecological economics. The sixth chapter is an empirical study of the eco-environment benefit assessment of biogas development. It focuses on studying and discussing the establishment of a simple and feasible index system framework specially aimed at the eco-environment benefit assessment of biogas energy. It makes an attempt to help develop compensation on the eco-environment benefit of farm household biogas use and establish relevant compensation mechanisms. The seventh chapter is conclusions and suggestions. Besides, this dissertation tries to make a simulating prediction to the development trend of the overall benefit of the farm household biogas system in Enshi by means of system dynamics analysis.The study of this dissertation has been based on scientific knowledge already available both domestically and internationally. It based on plenty of first-hand data and information from the study area and the study farm households. The main innovative points may include the following aspects:(1) The new research perspective: It starts from the perspective of farm households to analyze the eco-environment assessment and multiple influential factors during the usage of biogas energy. Most of the current researches study the overall benefits produced from the perspective of government administration. It is rarely seen that a study that is developed on usage and benefits of farm household biogas utilization.(2) An index system for household biogas assessment: This dissertation comments and discusses the principal problems of the existing eco-environment benefit assessment and proposes an eco-environment benefit assessment index system which is based on farm household biogas useI and is simple and easy to use practically. This dissertation takes into account the fact that the generation of biogas eco-environmental benefit is directly related to the energy use structure of the farm households, their utilization degree of biogas and action of production, whereby an index system of two levels (ecological and environmental benefits) consisting of seven chosen indexes (supply of organic fertilizers for farm land, increase of disposal rate of organic sewage, increase of disposal rate of animal and human excreta, increase exhaust rate of SO₂, increase of damage rate of land ecology and increase of damage rate of forestry). The seven indexes can be calculated and converted through the first-hand data obtained from household questionnaire survey. A set of new eco-environment benefit assessment system of biogas energy for farm household use is thus provided.(3) Integration of research theories and approaches: This dissertation comprehensively applies diversified theories and approaches covering behavioral analysis, case studies, analysis of energy flow, system assessment, measurement of ecological benefit and system dynamics, to conduct qualitative and quantitative assessment and analysis on the eco-environment benefit assessment of biogas use at farm household level, behavioral characteristics of farm household's biogas use and the influential factors etc. It closely combines ecological economics, the science of eco-environment and the science of environmental system, and has certain points of innovation in terms of integrated application of theories and approaches.