Life cycle study of coal-based dimethyl ether as vehicle fuel for urban bus in China

With life cycle assessment (LCA) methodology, a life cycle model of coal-based dimethyl ether (CBDME) as a vehicle fuel is established for China. Its life cycle from well to wheel are divided into three phases. They are feedstock extraction, fuel production and fuel consumption in vehicle. The primary energy consumption (PEC) and global warming potential (GWP) of CBDME pathway are analyzed and compared with coal-based diesel (CBD) as a latent rival to replace conventional petroleum-based diesel (CPBD). This study demonstrates that the LCA methodology is very suitable and effective for the choice of vehicle fuels. One result is that the greenhouse gases (GHGs) emission of coal-based vehicle fuel pathways is usually concentrated on fuel production stage. The percentages of CBDME and CBD pathways both exceed 60%. The application of carbon capture and storage (CCS) is helpful for coal-based vehicle fuel pathways to improve their global warming effect dramatically. Compared with CBD pathway, CBDME pathway consumes less PEC and emits less GHGs emission as well. Even though the CCS and CH4-fired generation are used, the advantages of CBDME are still kept. For saving petroleum energy and reducing global warming effect, CBDME has greater potential than CBD to substitute CPBD under current fuel synthesis technologies. If the hurdles such as the maturity of engine and vehicle technologies, corresponding regulations and standards and infrastructures are reliably solved, CBDME will have better prospect in China.