Life Cycle Assessment And Environmental Benefits Analysis Of Electric Vehicles

As the requirements of the oil prices and low-carbon economy, environmentallyfriendly vehicles become an important direction of the development of automobile industy.The China State Council has approved the “Energy Saving and New Energy Vehicle IndustyDevelopment Plan” to achieve leapfrog development of China’s automobile industy. ThePlan states that Battery Electric Vehicle (BEV) will be the main strategic direction in China,while focusing on the development of plug-in hybrid vehicles (PHEV), and non-plug-inhybrid vehicles (HEV). Therefore, Electric Vehicles (EVs) will achieve a dominant positionin China’s automobile market. However, China’s electricity generation mix is domainated bycoal-fired power. The common interest of our government and people is whether electricvehicles can achieve real energy-saving and emission reduction benefits in China.In this thesis, three electric passenger cars with different electrification sysytems arestudied. They are non-plug-in hybrid electric vehicle (HEV), plug-in hybrid electric vehicle(PHEV), and battery electric vehicle (BEV). By the adopting of “Cradle-to-Grave” life cycleassessment (LCA) method, this study built the full electric vehicle life cycle model oncontext of China. The founctional unit is per vehicle travelled one kilometer. The HybridLife Cycle Assessment (HLCA) method which is the combination of Process based LifeCycle Assessment (PLCA) and Economic Input-Output based Life Cycle Assessment(EIOLCA) is adopted to acquire key input parameters of the LCA model. The primaryenergy use, green house gas (GHG) and regulated gas emissions of the full EVs life cycle arecalculated with the GREET software. In order to evaluate the environmental benefits of EVs,we compared the life cycle impacts of EVs with conventional Gasoline Internal CombustionEngine Vehicle (GICEV). The effects of environmental impacts on the natural world werealso studied. Finaly, the sensitivity analysis of the full EVs life cycle as well as the effect ofEVs promotion on China’s energy structure are performed, which provide the technical basisfor the healthy development and decision-making of China’s EVs industry.The main conclusions drawn by this research are as following:1、 Under current Chinese context, the full life cycle total primary energy use of HEV,PHEV and BEV are2.621MJ/vkm,2.617MJ/vkm and3.113MJ/vkm respectively. Compared with3.63MJ/vkm of GICEV, the life cycle total energy saving rates of HEV,PHEV and BEV are27.9%,28.0%and14.4%respectively. Among the total primaryenrgy use, the life cycle petroleum saving benefits for the three vehicles are32.7%、45.9%and95.0%respectively.2、 Using electricity entirely from clean energy such as hydro, wind, solar and geothermaletc., the whole automobile life cycle energy saving benefit improves as the theprowertrain electrification increases. In this case, the full life cycle energy savingbenefit of BEV is57.1%compared with the ICEV. Meanwhile, the full life cycle GHGreduction benefit of BEV is86.5%compared with the ICEV. The full life cycleemission reduction benefits of VOC, CO, NOx, PM10, PM2.5and SO2of BEV are55.3%,94.9%,82.0%,34.6%,42.0%and26.9%respectively compared with the ICEV.The environmental benefits of Health Toxic Potential (HTP), Global Warming Potential(GWP), Acid Potential (AP), Air Quality Potential (AQP) and Photochemical OzoneCreation Potential (POCP) of BEV are55.9%,86.5%,54.5%,34.6%and80.9%respectively, compared with ICEV.3、 Using entirely coal-based electricity, the environmental benefits of EVs are not obviousand even negative. In this case, the life cycle energy saving benefit of BEV is onlyabout4.1%compared with the ICEV. Meanwhile, the full life cycle GHG reductionbenefit of BEV is-15.5%compared with the ICEV. The full life cycle emissionreduction benefits of VOC, CO, NOx, PM10, PM2.5and SO2of BEV are47.3%,93.2%,-74.1%,-99.7%,-65.9%and-208.7%respectively compared with the ICEV. Theenvironmental benefits of HTP, GWP, AP, AQP and POCP of BEV are-138.0%,-15.5%,-143.0%,-99.7%and-43.8%respectively, compared with ICEV.4、 The higher of steel contained in vehicle by mass, the more sensitive to the usage ofrecycled steel. The full life cycle energy use of PHEV have the highest sensitivity to theusage of recycled steel, whicle is5.8%, followed by5.6%for HEV,4.5%for BEV, and3.8%for GICEV.5、 Under China’s current electricity mix, the amount of primary energy saving is1.99× 108GJ (equivalent to9.42million tons of standard coal) per year; and the amount ofpetroleum saving is1971.8tons per year.In summary, the full life cycle assessment of EVs shows that BEV has obviouslypotential for energy saving and emissions reduction, and can reduce the oil dependenc oftransportation sector. However, in order to truly realize energy saving and emissionreduction benefits of EVs, the development of clean electricity need to be encouraged andsupported by Chinese government.