(299a) Meeting U.S. Liquid Transport Fuel Needs with a Nuclear Hydrogen Biomass System

The two major energy challenges for the United States are (1) replacing crude oil with an alternative transport fuel and (2) eliminating greenhouse gas emissions. A system using hydrogen produced from nuclear plants and biomass could produce sufficient greenhouse-neutral liquid fuels to meet the total U.S. liquid transport fuel needs. A four-step strategy is described. The technology for the first three steps exists with the requirement to improve the economics.

Low-temperature nuclear heat plus corn yields fuel ethanol. The conversion of biomass to fuel ethanol requires large quantities of low-pressure steam that can be provided by existing nuclear reactors. The non-solar energy inputs to grow the corn and convert it to fuel ethanol are equal to 70% of the energy value of the fuel with half this energy in the form of steam. Nuclear steam can reduce both greenhouse gas emissions and reduce costs.

Low-temperature nuclear heat plus hydrogen plus cellulose yields fuel ethanol and hydrocarbon fuels. Work is underway to commercialize methods to convert cellulose (trees, grass, recycle paper, etc.) to ethanol with the goal to provide a third of the nation's liquid fuel demand by 2030. It is planned to burn the lignin in the cellulosic feedstock to produce the steam to operate these facilities. Lignin can not be converted to ethanol. Steam from nuclear plants can enable all the biomass to be converted into fuels--rather than burning some of the biomass to operate the biomass ethanol plants. For process heat from nuclear plants to replace lignin as the energy source to operate these plants, methods are required to convert lignin into liquid fuels. Hydrogen and lignin can be converted to liquid hydrocarbon fuels. Because fuel production is limited by biomass availability, there are strong incentives to maximize the liquid fuel production per unit of biomass.

Nuclear hydrogen plus biomass yields hydrocarbon fuel. The fundamental limit on liquid fuels from biomass is the availability of biomass. The estimates are that only a third of worlds liquid fuel demand could be met by biomass to ethanol. If one uses hydrogen plus biomass to produce gasoline, diesel, and jet fuel, the energy content of the liquid fuels per unit of biomass increases by a factor of 3 or 4 and there is sufficient biomass to meet the total U.S. need for liquid fuels.

Nuclear hydrogen as fuel. The direct use of hydrogen as a fuel is the long term vision; however, it depends upon the development of multiple new technologies. The large scale use of biomass fuels provides time to develop the technology and enable the continued use of liquid fuels for those applications where it is the most difficult to develop a hydrogen fuel technology.