Energy Consumption Analysis Of Hydropower Projects Based On Carbon Footprint Theory

With the rapid development of social economy, worldwide environmentalproblems are becoming more serious, therefore saving energy and reducingconsumption from all fields is a matter of great urgency. The targets for reducing theenergy consumption intensity and carbon dioxide emissions intensity, which is that theenergy consumption per unit of GDP should decrease16%and CO2emissions per unitof GDP should decrease17%, were set forth in the12th Five-Year plan. Hydropoweris a renewable green energy, so giving priority to hydropower development is aninevitable choice to realize the global energy policies. However, no power developmentis without significant environmental costs. Economic, technological and environmentalconditions are comprehensively assessed to make a hydropower project investmentdecision. Nevertheless, carbon emissions intensity index of hydropower has beenneglected in the environmental assessment.To respond to the goals of China’s12th Five-Year Plan for reducing carbonemissions, and in order to strictly control the environmental impacts of hydropowerbased on more comprehensive indexes to achieve sustainable development, the theoryof energy consumption analysis, the analytical methods of energy consumption, theapplications of the analytical methods of energy consumption in hydropower projects,the synthetic environmental evaluation method of hydropower considering CO2emissions, and energy consumption analysis system are studied in detail for the firsttime in this paper. Based on the carbon footprint theory and methods, a few questionswere answered, including that how many greenhouse gases will be emitted and howmany standard coals will be consumed by a large hydropower project in the whole lifecycle? How does the result of the comparison of environmental impacts between rock-filled dams and concrete dams? What is the proportion of greenhouse gases emissionand energy consumption in every life cycle stage? What influence emissions andenergy consumption most and how to tap the potential for energy saving of hydropowerproject? What is the proportion of greenhouse gases emission in the wholeenvironmental impacts of hydropower? And how to obtain the carbon footprint andenergy consumption of large hydropower quickly and exactly? The aim of this paper isto provide a theoretical foundation and an application platform for the energy consumption analysis work of hydropower projects systematically andcomprehensively. Main contents and results are as follows:(1) The carbon footprint theory of hydropower projects was discussed, andhybrid life cycle assessment (hybrid-LCA) method was studied to analyze thecarbon footprint of large hydropower projects. The purpose and position of energyconsumption analysis of hydropower were figured out, the concept of the carbonfootprint of hydropower was proposed, the conversion relationship between carbonfootprint and energy consumption was studied, the system boundary was defined, andthe standards of carbon footprint analysis were discussed. In view of the long time andcomplex processes of hydropower projects, the evaluation of the carbon footprintconsidered the emissions from material production, transportation, construction, andoperation and maintenance phases and included all relevant materials and energyconsumption. The hybrid life cycle assessment (LCA) method combining thecompleteness of economic input-output LCA (EIO-LCA) and the specificity ofprocess-based LCA (PA-LCA) was applied to quantify the carbon footprint over thewhole life cycle of the hydropower system. The ideas and methods of carbon footprintanalysis were proposed, and the used carbon emission data were collected, contrastedand selected to provide the data foundation for energy consumption analysis in thehydropower industry.(2) Take the example of Nuozhadu hydropower station, the carbon footprintsof two types of Nuozhadu hydropower schemes with the same scale, earth-coredrockfill dam (ECRD) and concrete gravity dam (CGD) were studied andcompared. There are significant differences in the layout, cross section, materials, andconstruction technologies between ECRD and CGD. The results indicate that ECRD ismore environmentally responsible throughout the life cycle, and could help decisionmakers to choose the appropriate type of hydropower system in the design phase. Itwas found that ECRD reduced CO2emissions by approximately31.84%comparedwith CGD. The total carbon footprint of CGD is903.19×104t CO2e, which is equivalentto3.47million tons of standard coal. The total carbon footprint of ECRD is615.57×104tCO2e, which is equivalent to2.37million tons of standard coal. With respect to eachlife cycle stage, the production was the greatest contributor to CO2emissions, followedby operational maintenance, construction and transportation stages. The largest sourcesof CO2eemissions in the material production stage are the cement production processand steel production process, during which large amounts of CO2eemissions are generated. Excavation and filling are the main sources of CO2eemissions in theconstruction stage. CO2eemissions in the transportation stage are related to the amountof materials. Thus, reducing the amount of cement and steel and improving theconstruction technology of excavation and filling may be effective measures todecrease the emissions.(3) The ecological effects assessment method of dams considering the carbonfootprint was studied. Carbon footprint was introduced into the emergy analysismethod to analyze the impact on the whole ecological effects quantitatively, andevaluate the ecological effects of hydropower more comprehensively. Take theexample of Nuozhadu hydropower station, the proportion of carbon footprint in theecological effects is1%. The emergy loading ratio (ELR) is only0.35, which indicatesthat the interference of a hydropower project with the environment is very little.Sustainable development index of Nuozhadu hydropower station is32.2, indicating thehigh ability of sustainable development. Carbon emergy yield ratio is814.75,illustrating that the rate of resource utilization efficiency is very high.(4) The carbon footprint analysis and ecological effects assessment system wasdeveloped. The computational processes of carbon footprint and assessment processesof ecological effects are realized in this system developed with object-orientedprogramming language C#with the help of database management techniques on.NETplatform. This system can provide people, who have been engaged on the hydropowerenergy consumption work, a more convenient, useful, and efficient operationalplatform.