Sustainable Transportation Energy Pathways (STEPS)
Yang, Christopher and Sonia Yeh (2012) The Future of Low-Carbon Transportation Fuels. Physics and Society 41 (3), 10 - 13
According to the Energy Information Administration’s Annual Energy Outlook projection, petroleum fuel uses make up essentially all transportation fuel usage today and will continue to account for 95% of transportation fuel usage in 2035 if we continue on our current path. Biofuels are projected to make up the largest increase in the use of alternative fuels, to about 4% of fuel usage in 2035. As is well-known, fossil fuel use has many economic and environmental impacts, including reliance on imported energy sources that weakens our energy security, air pollution, and greenhouse gas emissions that contribute to climate changes.
In this article we qualitatively examine the possibilities for low-carbon transportation fuels. Specifically we consider biofuels, electricity and hydrogen as displacers of petroleum-based fuels. The discussion here focuses on fuels, though fuels such as electricity and hydrogen are intimately tied to the vehicle platform and their success will be influenced by the success of the other. We will emphasize fuels for light-duty vehicles (passenger cars and trucks), which make up around 55% of energy use in the transportation sector. We will discuss the transition challenges to alternative fuels, particularly the infrastructure challenges, and the issues of making a transition to sustainable transportation over the long run.