| The interdependence between energy and environment is growing significant accompany with the increasing demand on power energy in China.It is crucial to evaluate,quantify and compare the environmental effects of different power energy in order to achivie sustainable transformation of the power sector.In this study,from the perspective of environmental foorprints,we tried to inversitage the environmental effects of power energy,including thermal,hydro-,nuclear,wind,and solar power for improving effective of power sector management and policy making.Firstly,a Mixed-Unit Input-Output(MUIO)table in 2012 was complied,and the waterfootprints of fossil and non-fossil energy power were calculated based on the electricity generation and production.Then,the interprovincial virtual water and scarity virtual water emboied in electricity transmission were analysed.As the results shown,the virtual water via hydropower would change the transmission mode besides the virtual water via thermal power.The contributions of virtual water via hydro-and thermal power account for 71.02%and 28.87%,respectively.Using the water stess index(WSI),the proportion of scarce virtual water via hydropower decreases to 52.1%,while that in thermal power increases to 47.4%.The transfer of virtual water from the central region(such as Sichuan and Hubei)to the eastern region(such as Shanghai)has shifted from the northeastern region(such as Inner Mongolia)to the north region(such as Hebei).Then,the nitrogen oxides(NO_X)footprint(NF)which is defined as the NO_Xgeneration per k Wh,is decomposed temporally and spatially based on the temporal and spatial LMDI(Logarithmic Mean Divisia index)methods.The NF dropped significantly from 2.90 g NO_X/k Wh to 2.15 g NO_X/k Wh from 2000 to 2016.The temporal and spatial decomposition results showed that the major driving forces were the ratio of non-fossil energy power and thermal power generation efficiency,which decreased NF by 10.5%and 7.74%during the study period,respectively.Thirdly,an accounting method of environmental footprints was built based on life cycle famework,and the envrinomental footprints of hydro-,nuclear and wind power were evulated and compared.The results show that wind power technology has the most significant environmental impacts amongst these three non-fossil energy power,followed by nuclear power and hydropower.In addition,this study revealed that the the manufacturing stage is the largest contributor of environmental impacts for wind and hydropower.By contrast,the decommissioning stage is most significant for nuclear power in terms of environmental impacts.In conclusion,non-fossil energy power is conducive to the emission reduction of pollutants in the power sector.The long-distance power transmission will continue to expand the scale of virtual water outflows in the western region,except for the water scarcity in the northwestern region caused by thermal power,and the southwestern region with abundant hydropower.Thus,this energy policy imposes pressure on available freshwater resources and increases water scarcity.It is foressable that the development of non-fossil energy should be actively promoted,and the development layout of different types of non-fossil energy power should be optimized and adjusted. |
