Biofuels - The Oxford Topic of Food, Politics, and Society - page 183

to climate change, “peak oil” doesn't seem to have been paid any lip service. Both climate
change and “peak oil” are based on observations and data. The increased production of
natural gas through fracking technology is lowering the price of natural gas relative to
coal and older coal-fired power plants that cannot meet new, more stringent EPA stan-
dards for carbon dioxide and other toxic emissions. These plants are being replaced by
power plants using natural gas (Leek 2012; Lydersen 2012; New York Times 2012).
Biomass Resources
The previous section concludes that fossil fuels cannot be assumed to be readily available
forever, even if changes in technology such as hydraulic fracturing create short-term
disturbances of the trend line. Given these forecasts, attention turns to biomass as an
alternative energy source. Our analysis now has to consider how much biomass—of
what kinds, and used in what ways—might address the interdependent needs of energy
and agriculture.
Of particular significance is the fact that fuels from biomass are liquid fuels, either
ethanol or biodiesel. Why liquid fuels? Other than some trains and the occasional elec-
tric car, the industrialized world's transport systems run on liquid fuels, and virtually
all motorized or jet-propelled vehicles are powered by liquid fuels. Alternative power
sources other than biomass produce electricity, not a liquid fuel. Clearly, the decision
has been made by the political and corporate systems in the developed world that rather
than retooling and adapting the transport system, attempts should be made to exploit
biomass as a possible new source of liquid fuels.
One of the first questions asked should be how much cellulosic biomass resource is
available for energy production? The two rough estimates of how much cellulosic bio-
mass should be used to produce ethanol are from a study by Perlack et al. (2005), which
reported that 1.3 billion tons of biomass could be collected in the United States to pro-
duce 30 billion gallons (11 kg of biomass per liter) of ethanol per year, and by President
George W. Bush, who in 2007 estimated there was about 1.6 billion tons of biomass
available, and that by 2020 the United States could be producing 36 billion gallons of
ethanol per year. Neither Perlack et al. nor President Bush reported on the total biomass
produced in the United States annually, nor what proportion could be harvested each
year as biofuel.1 The amount of biomass produced annually in the United States, includ-
ing all agricultural crops, all forests, and all grasses, is about 1.8 billion tons, according to
the best data available (Pimentel et al. 2010), and the same value as calculated by Perlack
et al., but the data for the different sources are quite different. Note that this net annual
primary productivity of about 1.8 billion tons per year for the United States includes all
the human food consumed each year. The total food consumed annually in the United
States is about 400 million tons (USDA 2008). This means that the net primary produc-
tivity minus food is only 1.4 billion tons of cellulosic biomass per year. After harvest of
the food crops and nonfood crops, about 500 million tons of crop residues remain on