Biofuels - The Oxford Topic of Food, Politics, and Society - page 186

visible light is captured by photosynthesis. Over the course of a year (except in tropical
regions), this percentage is actually under 1%. Plants are relatively inefficient in convert-
ing solar energy. Photovoltaic cells, even inefficient cells, can capture 10% or more of vis-
ible light and convert this light into electricity for a full year whenever there is sunlight,
regardless of the growing season (Patzek 2012).
The subsidies for corn ethanol totaled more than $12 billion per year in 2008 (Koplow
and Steenblik 2008). This means that the subsidies per liter of ethanol are 60 times
greater than the subsidies per liter of gasoline. In 2006, nearly 19 billion liters of ethanol
were produced on 20% of US corn acreage (USCB 2008). This 19 billion liters represents
only 1% of total US petroleum use (USCB 2008). However, 45% more fossil energy is
required to produce a liter of ethanol than the energy yield of that liter of ethanol. Only
subsidies from the political system sustained so inefficient a process. However, the $6
billion per year federal tax credit which is equivalent to an outright subsidy (Friedman
2011) for corn ethanol was allowed to expire by Congress after three decades in 2011 but
replaced by the Renewable Fuel Standard mandate enacted in 2005 which for 2011-2012
mandated that at least 37% of the US corn crop be converted to ethanol. A Congressional
Budget Office report states, “In the future, the scheduled increase in mandated volumes
[of corn ethanol] would require biofuels to be produced in amounts that are probably
beyond what the market would produce if the effects of the tax credits were included”
(Pear 2012; Drum 2012; Congressional Budget Office 2010, p. 16).
However, even if we completely ignore corn ethanol's negative energy balance and
high economic cost, we still find that it is absolutely not feasible to use ethanol to replace
US oil. Indeed, virtually wherever ethanol is used as a fuel, it supplements and does not
replace fossil liquid fuel, even in Brazil. Sugarcane ethanol has been referred to as a “tran-
sitional fuel” by one researcher (Claudinei Andreoli, personal communication, 2010) and
has a positive energy return on energy invested when the effects on agricultural land and
non-agricultural land and water and wildlife are discounted. If all 341 billion kg of corn
produced in the United States (USDA 2007) were converted into ethanol at the current
rate of 2.69 kg corn per liter of ethanol, then 129 billion liters of ethanol could be produced,
replacing only 7% of total oil consumption in the United States. Of course, in this situation
there would be no corn available for livestock feed, human food, and other needs.
In addition, the environmental impacts of corn ethanol are enormous:
1. Corn production causes more soil erosion than any other crop grown (NAS 2003).
2. Corn production uses more nitrogen fertilizer than any other crop grown, and
the runoff from the Corn Belt is the prime cause of the “dead zone” in the Gulf of
Mexico (NAS 2003). In 2006, approximately 4.7 million tons of nitrogen was used
in US corn production (USDA 2007). Natural gas is required to produce nitrogen
fertilizer, and the United States imports more than half (54%) of its nitrogen fertil-
izer (Huang 2004; USDA, Economic Research Service 2013). However, the greater
availability of cheap natural gas due to fracking technology may extend the avail-
ability of relatively cheap nitrogen fertilizer. In addition, about 1.7 million tons of
phosphorus was used in the United States (USDA 2007).