Net Energy Analysis Of Energy System In China And The Impacts Of Net Energy On Economic Development

Mainstream energy economics mostly studies the relationship between energy and economy from the aspects of energy price and consumption and ignore the changes of energy input and output in the process of energy production and their influences on economic development.At the same time,mainstream energy economics takes too much attention to cash flow mislead the true purpose of energy production,brings risks to the energy strategies and policies making.The net energy analysis pays attention to energy input and output of energy conversion chains,thus avoiding the above problems.Net energy is energy surplus after energy process(energy outputs minus energy inputs),which is the real energy supply for economic and end of use after excluding the energy input consumed in the process of energy production(direct and indirect).The complete net energy analysis including two aspects: on the one hand,the evaluation of energy investment on energy return(EROI),which considers the relative efficiency of net energy production;On the other hand,is the calculation of Net energy yield,which is the supply of net energy yields.There are several problems with the net energy analysis of the energy system,the first is that the net energy analysis of fossil fuels is focused on the energy extraction boundary;the second is the lack of a top-down methodology to study the energy system;the third,existing assessment model for renewable energy resources is too simplified and does not combine with net energy analysis;finally,the effect of net energy output on economic development is unclear.This paper summarized the existing net energy theories and takes these theories as the theoretical basis of this study.Then study on fossil fuels(represented by oil,coal and natural gas)and non-fossil energy(represented by wind,solar energy,and bioenergy).Finally,the top-down net energy analysis method is used to analyze the impact of the net energy production efficiency and output on the economic development of China’s energy industry from a macro perspective.According to the research results,in 1987,China’s energy system consumed 10,000 tons of standard coal energy input in 1987,which could supply 4.6 tons of standard coal net energy yield to the economic system.By 2015,1 ton of standard coal energy input could only supply 1.24 tons of standard coal net energy yield.The premise for maintaining the growth rate of China’s economy above 5% before 2030 is that the energy expenditure on the energy system cannot be higher than the 58.2% critical value,that is,the EROIpou of China’s energy industry should be higher than 1.72:1.This means that if China’s economy is to grow by more than 5% in 2030,it will need at least 3.96 billion tons of net energy yield of coal equivalent to support economic and social development.In 2015,the EROI values of coal,oil and natural gas in China were 6.6:1,3.9:1 and 4.3:1 respectively.It is predicted that the EROI values will decrease to about 1.7:1,1.3:1 and 2.1:1 respectively in 2030.At that time,the net energy yield of fossil energy will total 1.67 billion standard coal,which cannot meet the demand for net energy yield in 2030.According to the results of the renewable energy resource potential assessment model,the average EROI of wind energy,solar energy,and bioenergy energy is 34.4:1,18.1:1 and 7.6:1,respectively.The net energy potential of wind energy,solar energy and biomass energy in mainland China is 8667TWh/ year,42389TWh/ year and 20016TWh/ year,respectively.That would make up for the net energy yield demand from the EROI decline in fossil fuels.