Improvements in automobile fuel economy would unambiguously improve the chances of an easier and better-managed introduction of biomass-based fuel alcohols: doubling the mileage achieved by gasoline-fueled vehicles in the United States would, for exam­ple, reduce the demand for ethanol by 45% or more at ethanol/gasoline blends of 10% or higher (figure 5.12). Mandatory fuel economy standards and voluntary agreements with automobile manufacturers in OECD and other countries aim at varying degrees of improved mileage in passenger cars and light commercial vehicles (table 5.20).

This (relative) parsimony harmonizes well with three of the principles stated by the National Research Council (NRC) in its report on the future for biobased indus­trial products:107

• Reducing the potential for war or economic disruption due to oil supply interruptions

[55] Reducing the buildup of atmospheric carbon dioxide

[56] A much less widely quoted prediction by Hubbert concerned nuclear energy, that is, that recoverable uranium in the United States amounted to an energy potential several hundred times that of all the fos­sil fuels combined and that the world stood on the threshold of an era of far greater energy consump­tion than that made possible by fossil fuels.

[57] These have little effect on greenhouse gas emissions because of fuel substitution (oil or gas to coal).114

until 2025.114 In that context, the supporting case for bioethanol and other biofuels is, therefore, threefold:

1. They are derived from biomass feedstocks that can, with careful manage­ment (“husbandry”), be accessible when fossil fuels have become depleted — possibly, within the next four decades.

2. Their use at least partially mitigates greenhouse gas emission, far more so if nonfossil fuel energy sources contribute to their production energy inputs.

3. They can, in crude production cost terms, be competitive with conventional fuels.

Arguments in favor of lignocellulosic ethanol have been almost invariably defensive, guarding against the charge of consumer costs far in excess of what an open market

[58] The extraction, processing, and use as an automobile fuel of oil shale hydrocarbons would also increase net CO2 emissions above those of, for example, the use of natural gas.113

[59] Hawaii had two sites but Alaska had none.

[60] Lime application was a major agricultural input in the 2005 study but may have been overestimated by a factor of 5, that is, the application rate should have been spread over five years rather than every season; making this change reduces the energy required to only 77% of the biodiesel energy content.

• In the National Renewable Energy Laboratory study, the energy input to pro­duce soybeans and then extract the oil was divided 18:82 in favor of soybean meal, that is, after the weight split of oil and residual material; allocating only 18% of the input energy to soybean oil changes the energy balance dra­matically to 5.3 times more biodiesel energy than fossil energy input.

[61] Ethanol is another candidate H2 producer, but the reaction must be performed at higher temperatures and undesirable by-products are formed.95

[62] As a (possible) harbinger of the future, the most significant plant oil in the literature of science fiction was that elaborated by the triffids, a species whose true biological and predatory capabilities were not adequately understood before disaster struck (John Wyndham, Day of the Triffids, Michael Joseph, London, 1951).

[63] Heterotrophic cultivation was mentioned in descriptions of experiments in the 1998 review, but no data for production systems using this approach were included.2

[64] In July 2007, Honda unveiled its FCX Concept hydrogen fuel cell car capable of 100 mph and with a range of 350 miles.

[65] Green chemistry was coined in the mid-1990s by the U. S. Environmental Protection Agency; of the twelve principles of green chemistry, the ninth is that raw materials should be renewable; inorganic materials appear difficult to fit into this vision but could be accessed by recycling.6

[66] With this motivation, simply burning biomass to produce energy and replace coal (the highest specific CO2 generator) would be the strategic option of choice for Europe, if not elsewhere.

[67] The example quoted was for a site in northwestern Europe (the Netherlands).

[68] Economic and commercial outlook for advanced biofuels — see chapter 6 (after section 6.1)

• Developing butanol as a transportation fuel — see chapter 6, section 6.3.3

• Commercialization of second-generation biofuels — see chapters 6 and 8

• The role of the federal government in supporting cellulosic ethanol devel­opment — see chapter 5, in particular, sections 5.2.2 and 5.2.7

• California’s commitment to advanced biofuels — see chapter 1, section 1.6.2

• Design and engineering challenges for cellulosic ethanol plants — see chapter 4