| The energy transition oriented by carbon emission peak and carbon neutrality is to gradually build a clean,low-carbon,safe and efficient energy system,and China will further promote the development and exploitation of PV power generation in the future.Comprehensive evaluation of the environmental impacts and energy efficiency of PV systems and rational planning of large-scale application of PV systems can provide important decisionmaking basis for energy transition practice.Therefore,this dissertation studied the environmental impacts,energy efficiency and urban deployment planning of PV systems in different application forms from a life-cycle perspective.A complete PV system life cycle inventory was established.By method of midpoint CML and endpoint ReCiPe,the environmental impact analysis was carried out for PV systems,different PV system components and each PV system life cycle stage.The results show that the overall environmental impact of centralized ground-mounted copper indium gallium selenide(CIGS)system is the greatest,and that of distributed slanted-roof integrated cadmium telluride(CdTe)system is the least.The overall environmental impact of the centralized system is greater than that of the distributed system,the retrofitted system is greater than the integrated system,the slanted-roof system is greater than the facade system,and the flat-roof system is the least.Among them,centralized ground-mounted systems and distributed rooftop CdTe systems have the main environmental impact from balance-of-system,rather than the PV modules themselves.PV modules and balance-of-system both mainly produce human health impact,with Marine Aquatic Toxic Potential the most significant.Among all life cycle stages,the system manufacturing stage has the greatest environmental impact,and no system recovery stage has achieved net zero environmental load.For PV module manufacturing,the production of singlecrystalline silicon module has the greatest environmental impact and the production of CdTe module has the least.For decommissioned module recycling and processing,the environmental impact of decommissioned module full recovery technology is mainly from polyvinyl fluoride treatment,decommissioned module mobile recovery technology is mainly from the transportation process,double green recovery technology is mainly from sewage sludge treatment,and FS CdTe module recovery technology is mainly from power consumption.A method of life cycle energy effciency analysis was put forward,based on the technical framework of life cycle assessment,combined with net energy analysis method,introducing cumulative energy demand and cumulative exergy consumption,to study life cycle energy efficiency and exergy efficiency indices,providing a more comprehensive and long-term method for energy efficiency evaluation of energy systems.The life cycle energy efficiency of PV system was analyzed,and the cumulative energy consumption of different PV system components and each PV system life cycle stage was analyzed.The results show that the energy efficiency of slanted-roof integrated CdTe system is the highest,and flat-roof retrofitted CIGS system is the lowest.The energy efficiency of the integrated system is higher than retrofitted system,the fa?ade system is higher than the slanted-roof system and the flat-roof system is the lowest.Among them,the main energy demand of all PV systems comes from PV modules;54%of all PV systems’ main exergic consumption comes from balance-of-system.In each life cycle stage,the energy consumption mainly came from the system’ manufacturing stage,followed by the recovery stage,but the crystalline silicon system based on the complete recovery technology of decommissioned modules achieved a net output of energy and exergy in the recovery stage.For PV module manufacturing,the cumulative energy consumption for the production of singlecrystalline silicon modules is the largest,and the production of CdTe modules is the smallest.In the process of crystalline silicon module production,solar grade silicon production has the greatest energy saving potential.To study the application of PV system at city level,the 4E+R(Environment,Emission,Energy,Economy and Resilience)urban deployment planning model of PV system was constructed,with the environmental impact,carbon emission,energy efficiency,cost and economic benefit of PV system as optimization objectives,and policy planning and natural resources as constraints.NSGA-Ⅱ algorithm was used to optimize the urban deployment planning scheme of PV system by multi-objective optimization.An urban energy system resilience assessment method was proposed to quantify energy security.Taking Jinan City of Shandong Province as an example,this dissertation solved the planning scheme of the installed capacity of various PV systems in Jinan from 2021 to 2030.The results show that the installed capacity of distributed rooftop PV system accounts for more than 80%each year.The maximum installed capacity is expected to be 10.45 GW.It can focus on the development of flat-roof and facade retrofitted crystalline silicon systems.Among the different PV system application forms,the multicrystalline silicon system based on the full recovery technology of decommissioned modules is the preferred option for the retrofitted installation scenario,and CdTe system is the preferred option for the integrated installation scenario.Furthermore,the energy system resilience of 309 Chinese cities in 2020 was assessed.The resilience analysis of Jinan PV system deployment scheme shows that the development of PV power generation project is conducive to improving the urban energy system resilience. |
