| With the sustained and steady economy growth in China,energy shortage is increasingly turning for the worse. Developing energy with great efforts has long been the dire need for economic development. Whereas the economy and energy develop,the environmental problems emerge inevitably. At present,in the primary energy mix of China,coal takes up to 75%,much higher than the world average level (27%). Coal constitutes the major part of fuels for thermal power generation in China. In 2000,coal-fired power accounted for 77.18%,oil 3.78%,hydropower 17.77% and nuclear power 1.22%. Such ratio of power source mix has been improved better than the situation in the end of 80's and the beginning of 90's of 20 century,coal-fired power 90%.Energy consumption is the main sources accounting for the increase of global greenhouse gases. 55% contributing factors of the global greenhouse effect arise from the greenhouse gases generated during energy consumption. In this sense,greenhouse gases emission is an important aspect of energy source and environmental problem. In the structure of energy consumption,if the proportion of clean energy increases while the outrageous proportion of coal consumption lowers down,and the availability of energy utilization raises,then the environmental quality can be improved in the premise of keeping the total demand of energy source. To further promote the scientific and technological progress of energy and environment,argue for the practical problems of harmonious development of energy and environment,and provide scientific and precise gist as basis for the government to make decisions in adjusting energy mix,it is of great importance to carry out studies on energy and environment,especially the studies on greenhouse gases emission during energy production. It has become one of the great concerns attracting global attentions.Quantitative evaluation and prediction for the environmental consequence resulting from energy consumption are called for by the sustainable development strategy of China,and have great value as reference to the rational allocation of energysources,decision-making for the energy system,and establishment of the comprehensive plan for energy,environment and economic development in China.Being dead against the characteristics of the energy mix in China,the task aims to discuss the contribution of greenhouse gases by thermal power,nuclear power and hydropower system and the greenhouse gas discharging law resulting from water body fluctuations by comparing the greenhouse gases emitted by the above-mentioned energy sources. And referential proposals are put forward for future energy mix adjustment.The article includes seven chapters,which mainly covers five parts. The first part expounds the analytical method for life cycle assessment (LCA),introduces the history of the analytical method and the specific principles.In recent years,life cycle analysis method is introduced in the assessment for some other production activities. Namely,not only the direct environmental problems caused by a certain activity or facility are evaluated,but also the environmental burden relevant to these activities or facilities,influential to the evaluated contents,and generated together with effects and all materials input during production are taken into consideration. The greenhouse gases emission factors of energy system in China is calculated as detail as possible in this paper by using the LCA method and the definition of full energy chain.The second part makes a full comprehensive analysis for the chain of coal power generation and the nuclear power plant by using the life cycle analytical method. Based on looking up a lot of conferences and according to existing circumstances and data of thermal power generation in China,in-depth exploration is carried out for the greenhouse gases emission factors concerning thermal power generation. The emission factors of each link in the chain of coal power generation and the general emission factor are given out. The greenhouse gases emissi... |
