Study On Carbon Emissions Of Water System In Zhengzhou Based On “water-Energy-Carbon” Nexus

The urban water system is one of the important sources of urban carbon emissions.Rapid urbanization process is accompanied by the intensive development and utilization of urban water resources,which leads to a sharp increase in the demand for water and energy resources in the urban water system.And the problem of carbon emissions in the operation of urban water system is increasingly prominent.The research on carbon emissions of urban water system from the perspective of“water-energy-carbon”nexus is helpful to reveal the internal relationship between water resource flow,energy consumption process and carbon emissions in the water system.The research helps to coordinate the sustainable utilization of urban water and energy resources,and provides theoretical and practical guidance for the low-carbon operation and management of urban water system.Based on“water-energy-carbon”nexus,this paper constructed a theoretical framework and method for studying the carbon emissions of urban water system,and used the energy consumption data of water intake,water supply,water use and wastewater treatment in Zhengzhou from2008 to 2017 to evaluate the carbon emissions in the whole operation process of urban water system.The study explored the factors affecting the carbon emissions of urban water system,and analyzed the carbon emission reduction potential of water system under different operation modes based on scenario analysis,and finally put forward policy suggestions for the low-carbon operation of urban water system.The research results show that:(1)During the study period,the carbon emissions of water system of Zhengzhou increased from 583.58×10~4t to 833.16×10~4 t,with an annual growth rate of 4.04%.This was because the continuous increase of water for household and public life.In the carbon emissions of water system of Zhengzhou,the carbon emissions of water use system played a dominant role(contribution rate of the carbon emissions was 91.31?92.65%),followed by the water intake system,water supply system,and wastewater treatment system.(2)Difference of energy intensity of different running part of water system in Zhengzhou was bigger,and among them,the highest energy intensity was household water use(17.931kWh/m~3),the lowest was Yellow River water supply(0.090kWh/m~3),the rest part of energy intensity from high to low in turn was the public water use,industrial water use,rainwater utilization,wastewater reuse,water production process,agricultural water,water distribution process,wastewater treatment,groundwater water supply,water storage project,surface water lifting,South-to-North Water Diversion Project.As the three links with the highest energy intensity belong to the water use system,this was the main reason that the carbon emissions of water use system accounted for more than 90%of the total carbon emissions of water system in Zhengzhou.(3)The carbon emissions of water system per unit of GDP in Zhengzhou showed a downward trend from 2008 to 2017,and carbon emissions decreased from 0.19t/10~4yuan to0.09t/10~4yuan.The change of per capita water system carbon emissions in Zhengzhou was relatively stable(0.74?0.86t/person),and its interannual trend was consistent with the change of water system carbon emissions.The contribution rate of water system carbon emissions to the energy consumption carbon emissions of whole society was 9.85?14.15%in Zhengzhou.(4)Based on“water-energy-carbon”nexus,this paper analyzed the influencing factors of carbon emissions of urban water system of Zhengzhou,which was essentially to explore the influencing factors that affected the change in“water”and“energy”.The factors that affected the carbon emissions of urban water system mainly including the types and conditions of water sources,water quality standards and water treatment technologies,types and energy efficiency levels of water equipment,social and economic development levels,human behavior and habits of water use,and planning policies related to energy and water resource utilization,and so on.(5)According to the carbon emissions of water system of Zhengzhou in 2030 based on different scenario predictions,the operation mode of urban water system in highly low-carbon scenario had the greatest carbon reduction potential,and it could reduce carbon emissions 629.91×10~4t compared with the baseline scenario.In addition,among the internal subsystems of the urban water system,water use system had the greatest carbon reduction potential.And the carbon reduction potential of household water sector was the most obvious in the water use system.Therefore,the carbon emission reduction of urban water system could focus on water-saving and energy-saving of daily water in the future.(6)Combined with the above study,the following strategies should be considered in the low-carbon operation of urban water system:(1)The low-carbon design of urban water system should be combined with the goal of energy saving and carbon reduction.(2)Improve the water-saving system and mechanism to guide the energy conservation and carbon reduction of water system.(3)Optimize the process of water-saving and energy-saving,and promote the low-carbon operation of water system.(4)Strengthen comprehensive management of resources,and promote coordinated optimization of water energy and carbon reduction.