Environmental and energy implications of coal-based alternative vehicle fuel pathway from the life cycle perspective

Coal-based fuels are effective alternative vehicle fuels in coal-rich countries, but whether it is beneficial to the environment and carbon neutrality has always been a concern. This study evaluates the energy efficiency, greenhouse gas (GHG) emissions, water footprint (WF), and environmental impact of coal-based diesel, coal-based synthetic natural gas, coal-based hydrogen, and coal-based electricity pathways from the life cycle perspective. Furthermore, scenario analysis predicts the impact of coal-rich countries on energy and emissions by adjusting vehicle fuel ratio. The results show that the coal-based diesel fuel pathway has lower energy efficiency and emits more GHGs. And GHGs are concentrated in fuel production stage. In terms of WF, the coal-based electricity pathway has the greatest benefits, which gray WF is dominant. From environmental impact perspective, a single vehicle fuel pathway cannot satisfy all impact categories. But the coal-based electricity pathway has the lowest value for the end-point environmental impact categories. Scenario analysis shows that the USA, India, and the European Union can significantly save energy and water resources and reduce GHG emissions with the increase in the proportion of alternative fuel vehicle in 2030. However, even a complete ban on the use of conventional gasoline vehicle in Norway will not reduce water consumption.