The two major energy challenges for the United States are to replace crude oil in our transportation system and reduce greenhouse gas emissions. A multilayer strategy to replace oil using nuclear energy and various carbon sources (fossil fuels, biomass, or air) is described that (a) allows the continued use of liquid fuels (ethanol, gasoline, diesel, and jet fuel) in the transport sector, (b) does not require major changes in lifestyle by the consumer, and (c) ultimately eliminates carbon dioxide emissions from the transport sector. Nuclear energy is used to provide electricity, heat, and ultimately hydrogen, with the hydrogen produced by either electrolysis or more advanced thermochemical production methods.
In the near term, nuclear energy can provide low-temperature heat (steam) for ethanol production and electricity for transportation. Midterm options include low-temperature heat and limited quantities of hydrogen for processing cellulosic biomass into liquid fuels (ethanol and lignin-derived hydrocarbons) and providing high-temperature heat for (a) traditional refining and (b) underground oil production and refining. In the longer term, biomass becomes the feedstock for liquid-fuels production, with nuclear energy providing heat and large quantities of hydrogen for complete biomass conversion to hydrocarbon fuels. Nuclear energy could be used to provide over half the total energy required by the transportation system, and the use of oil in the transport sector could potentially be eliminated within several decades.