One of the biggest controversies within the biofuels industry is whether first-generation biofuels have a more substantial carbon footprint than petroleum.
On the surface, this seems to be a no-brainer. According to the Department of Energy, a gallon of gasoline, diesel, and jet fuel emits between 18.4-21.1 pounds of C02 upon burning. Transportation sources accounted for 29% of total U.S. greenhouse gas (GHG) emissions in 2006 and are the fastest-growing source of GHGs in the U.S., accounting for 47% of the net increase in total U.S. emissions since 1990. These estimates of transportation GHGs do not include emissions from additional life-cycle processes, such as the extraction and refining of fuel, transporting the petroleum to and from the refinery, the manufacture of vehicles, and a whole slew of other variables that make petroleum production and consumption an environmental catastrophe.
Yet, creating biofuels like corn ethanol is an energy-intensive process. The steps involved with growing a feedstock like corn on an agro-industrial scale -- think farm equipment, fertilizer, harvesting, transporting the feedstock to the biorefinery, converting the feedstock into ethanol/biodiesel, and further transporting the biofuel to a petroleum refinery or service station -- require a tremendous amount of energy, especially when more than 10 billion gallons of biofuel are being produced in any given year in the United States (see Ethanol and the Looming Blend Wall). Similar to the need to view the carbon contained in the adjacent processes that facilitate petroleum production and distribution (and not just combustion), any authentic carbon audit of biofuels needs to examine the carbon contained in the materials and components embedded within the up-front fixed and operating costs.
While this might seem straightforward, simplistic models can break down as one attempts to determine the source of energy used in the process (i.e., coal vs. renewable), the distance between the field and the processing facility, the way that the feedstock and biofuel are transported (truck vs. barge vs. railroad), etc.
While the variables involved in calculating the true carbon footprint of biofuels are indeed complicated, the complexity is raised to an exponential power when the simultaneously abstract and tangible concept of "Indirect Land Use (ILUC)" is factored in.
The basic idea of ILUC is that as biofuels from crop plants proliferate, there is less cropland available to grow food for human and animal consumption. As a consequence, land, such as forests, becomes converted into crops. For example, the U.S. is the largest grower and exporter of corn in the world; it used 86.5 million acres to grow 13.2 billion bushels of corn in 2009. Approximately 30% of this crop is diverted to produce ethanol (note that some of this is then returned to the animal feed market in the form of distillers dried grains). The question is whether the carbon footprint associated with rainforests being cleared in Brazil (see Brazilian Ethanol Takes a Hit) and Southeast Asia to "replace" corn and oilseeds like soybeans that are no longer exported by the U.S. (due to ethanol and biodiesel production) ought to be counted when considering the GHGs of biofuels. If so, what methodology does one use?
In Europe, the controversy over ILUC was reignited this week when a British government report was leaked to the Times of London claiming that although the European Commission requires each liter of biofuel to reduce emissions by 35% compared to petroleum, biodiesel via palm oil actually increases emissions by 31% due to forests being converted into plantations.
Why are forests so significant?
Forests can be thought of as the lungs of the earth, serving a two-fold function in mitigating carbon. As deforestation occurs, sequestered carbon contained in the tree is released into the atmosphere; concurrently, those cut-down trees are no longer able to reabsorb C02 from the air.
More than one acre of forest is cleared every second on earth. This translates to 100,000 acres per day and more than 34 million acres per year -- a landmass the size of Greece. While this is partially mitigated by new growth, the net loss is equal to 18 million acres. Indonesia and Brazil are the third and fourth largest contributors to global warming. These two countries account for 60% of all deforestation in the world. Deforestation and land use changes are estimated to account for 12%-15% of global C02 emissions.
As such, when organizations like the pro-ethanol lobby group Renewable Fuels Association and Growth Energy publicly cast doubt on the existence of Indirect Land Use Changes and attempt to mobilize their friends in Congress to strip the EPA's authority (see COP15: EPA's Lisa Jackson Sings the Biofuel Blues) to include ILUC in the process of evaluating the carbon footprint of biofuels, it is clear that such groups are more interested in self-serving politics than environmental stewardship.
These groups' categorical dismissal of ILUC is reminiscent of the Gore-Bush debate in 2000, when Gore repeatedly cited economic data attacking the deficit consequences of Bush's prospective trillion dollar tax cut -- to which Bush responded again and again with charges of "fuzzy math."
Yes, calculating ILUC is messy. The California Air Resource Board (CARB) and EPA (see EPA Issues Renewable Fuel Standards) have vastly different conclusions about corn ethanol's carbon footprint when they factor in ILUC. And while it is easy to attack any environmental model -- because by nature, models are based on a series of assumptions, variables, and projections -- something as serious as climate change and creating policy that seeks to mitigate it should not be left to special-interest groups that are allowed to define science according to their own agenda. If science suggests that first-generation biofuels that come from feedstocks like corn, soybeans, palm oil, and rapeseed are found to have a higher per-unit carbon footprint than petroleum, we need to have the courage to be authentic about it and examine whether the billions of dollars of subsidies that we provide to these industries could better be deployed to those advanced biofuels -- such as algae -- that do not need scarce cropland or promote deforestation.