A New Energy Cocktail for a New Age of Mobility
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World energy demand is expected to double by 2050. Transportation will play a large role in this. The world must change its approach towards motorized mobility and the design of road vehicles and the energies they use. What is not clear is which energies are the most promising for transport. Bus operations rely heavily on diesel. Encouraging the use of diesel for personal transport has been a cornerstone of European policy to reduce carbon dioxide. As a result, the market share of diesel in Europe has grown to nearly 70%, bringing about a surplus of gasoline in Europe and a deficit of diesel. Bioenergy and biofuels are of growing interest, but the widespread debase on biofuels is not sending reassuring messages to operators. Biofuels come from crops, and some of these feedstocks can be used either for food or fuel. Present first-generation biofuels (biodiesel and bioethanol) made from feedstocks such as rapeseed and sugarbeet cannot be viewed as affordable alternatives for transport use. In most cases, they are less energy efficient than fossil fuel and their full life cycle analysis shows a carbon dioxide net increase as quantities of fertilizers and water are needed. There is much potential for second-generation biofuels that use non-food feedstocks or waste products. Both switch grass and algae seem to have quite good potential and the process for producing biodiesel from straw can be considered to be proven. Getting them into the mainstream is going to be quite another thing. Biogas made from urban waste is a win-win situation, but requires other non-mobility actors to take the responsibility to produce the biogas from the waste, and expensive production infrastructure. Improvements in energy efficiency are certainly needed--what is also clear is the need to change from using one dominant fuel to a "cocktail" of different energies, suited to the local conditions.