Policymakers should carefully consider the potential impact of policies on the environment, energy security, and consumers. Unfortunately, well-intentioned regulations or legislation, especially involving energy and environmental policies, can and have had unintended negative consequences. An example of such consequences can be seen with biofuels mandates that are being rethought across the globe amid serious economic and environmental concerns.
Biofuels must be sustainable. As the use of biofuels has increased dramatically, so have concerns about the potential consequences of increased biofuel use.
Ethanol and biodiesel are hydrocarbons – they are not carbon-free. Biofuels are often perceived as carbon-neutral because the carbon released when combusted is recycled as the biomass feedstock is grown for later use in the production of the crop-based biofuel. However, many scientists are concerned that the greenhouse gas (GHG) emissions resulting from biofuel production and associated agricultural practices could effectively negate or even reverse any reduction in emissions that could be achieved by significantly expanding the use of ethanol as a transportation fuel. Nobel Prize winner Paul Crutzen concluded that increased biofuels production is accompanied with a dramatic increase of N2O emissions, which has nearly 300 times greater warming potential than CO2. This would offset all GHG emissions reductions from the displaced petroleum fuels and actually result in a net increase in total GHGs. In fact, the European Union passed a law that may essentially ban certain biofuels due to environmental impacts.
A large increase in the production of biofuels could lead to further deforestation and release of soil carbon. Clearing land to grow crops as a feedstock for biofuels can increase GHG emissions. Carbon in the soil and plants is released when land use is changed and can be higher than the reduction in carbon releases by replacing fossil fuel combustion with biofuel combustion. It would take many years for the increased GHG emissions from land use change to be offset by the decreased GHG emissions from the replacement of fossil fuel with biofuel combustion – a biofuel carbon debt. This biofuel carbon debt is substantial and is projected to take decades or centuries from which to recover.
Several analyses outline the land-use impacts from biofuels production. The following are excerpts from two studies published in 2008:
Ethanol from corn produced on newly converted U.S. central grasslands results in a biofuel carbon debt repayment time of ~93 years. . . . At least for current or developing biofuel technologies, any strategy to reduce GHG emissions that causes land conversion from native ecosystems to cropland is likely to be counterproductive. . . . Our results demonstrate that the net effect of biofuel production via clearing of carbon rich habitats is to increase CO2 emissions for decades or centuries relative to the emissions caused by fossil fuel use.
We calculated that GHG savings from corn ethanol would equalize and therefore “pay back” carbon emissions from land-use change in 167 years, meaning GHGs increase until the end of that period. Over a 30-year period, counting land-use change, GHG emissions from corn ethanol nearly double those from gasoline for each km driven. . . . As part of our sensitivity analysis, we found that, even if corn ethanol caused no emissions except those from land-use change, overall GHGs would still increase over a 30-year period.
In addition, a University of California, Berkeley memo to the California Air Resource Board affirms these earlier studies. This memo states that estimates of greenhouse gas emissions from direct land use changes are very large and are much larger than the emissions associated with the fuel itself because there are large amounts of carbon stored in ecosystems of all sorts.
This was recently emphasized by the Environmental Working Group: “The researchers estimated that converting the land also released climate-warming carbon emissions equivalent of 34 coal-fired power plants operating for one year or 28 million more cars on the road.”
In addition, there have been recent carbon debt discussions:
As Oregon and Washington work to develop new energy markets for pellets and wood chips, some scientists have pushed back and raised concerns that replacing fossil fuels like diesel and coal with forest biomass may actually increase greenhouse gas emissions in the near term. After all, wood, like fossil fuels, emits carbon dioxide when it burns…. [Oregon State U. professor Beverly] Law says that often, it takes decades or longer for new forest growth to recapture the burst of carbon that’s released when pellets or wood chips burn. Meaning it takes years before the use of woody biomass for energy actually decreases carbon emissions, even if it takes the place of a fossil fuel. Law contends that if policymakers want to cut carbon emissions as quickly as possible to limit the impact of climate change, burning biomass isn’t an effective strategy.
This concern was recently affirmed by the World Resources Institute. “Large estimates of GHG emissions reductions from bioenergy are based on a misplaced belief that biomass is inherently a carbon-free source of energy.” Recommendations are offered, including:
• “Governments should fix flaws [i.e., double-counting the benefits] in the accounting of the carbon dioxide consequences of bioenergy…
• “Governments should phase out the varied subsidies and regulatory requirements for transportation biofuels made from crops or from sources that make dedicated use of land.
• “Governments should make ineligible from low-carbon fuel standards biofuels made from crops or from the dedicated use of land….
• “Governments should maintain current limits on the share of ethanol in gasoline blends.”
“Much of the case for bioenergy is grounded in technological optimism.” Bioenergy optimism should not be the basis for a regulatory program.
The Environmental Working Group has used this new WRI study in its advocacy to repeal the corn ethanol mandate part of the federal Renewable Fuel Standard:
Growing corn to make fuel for your car just doesn’t work. And reversing government policies that require it would ease a world of problems.
In addition, 78 scientists signed a letter (dated February 9, 2015) to Gina McCarthy, Administrator of the U.S. Environmental Protection Agency (“EPA”), objecting to a new EPA policy because wood energy is not a GHG emissions reduction solution due to carbon debt. They request that EPA “employ a scientifically valid system for counting the global warming effects of biomass.” This concern was also expressed by The Washington Post in a recent editorial:
Giving biomass too much credit would encourage a lot of wood burning. This is counterproductive, since live trees pull carbon dioxide out of the atmosphere…. The scientists pointed out that Europe’s biomass industry has ramped up because of poor carbon accounting, with European power companies establishing wood pellet plants in the southeast United States and shipping the product across the Atlantic to be burned for electricity. The EPA, they said, is on the verge of making the same mistake. If the West settles on faulty accounting, other nations will burn their forests for electricity and claim credit for carbon dioxide cuts, too.
Timothy Searchinger (Princeton U.) recently explained issues with bioenergy accounting. Biomass should not be treated as carbon-free or low carbon. In addition, “… harvest of trees for biomass will result in increased emissions because the avoided fossil fuel emissions will be far less than the lost carbon stocks… if we harvest more trees for biomass, we will report net increases in emissions in the years harvested.”
The Natural Resources Defense Council released this warning:
Biomass is often described as a clean, renewable fuel and a greener alternative to coal and other fossil fuels for producing electricity. But recent science shows that many forms of biomass—especially from forests—produce higher carbon emissions compared to fossil fuels. In particular, a growing body of peer-reviewed, scientific studies shows that burning wood from whole trees in power plants to produce electricity can increase carbon emissions relative to fossil fuels for many decades—anywhere from 35 to 100 years. This time period is significant: climate policy imperatives require dramatic short-term reductions in greenhouse gases, and these emissions will persist in the atmosphere well past the time when significant reductions are needed.
Biofuel feedstocks include many crops that would otherwise be used for human consumption directly, or indirectly as animal feed. Diverting these crops to biofuels may lead to more land area devoted to agriculture, increased use of polluting inputs, and higher food prices. Cellulosic feedstocks can also compete for resources (land, water, fertilizer, etc.) that could otherwise be devoted to food production. As a result, some research suggests that biofuel production may give rise to several undesirable developments.
Changes in land use patterns may increase GHG emissions by releasing terrestrial carbon stocks to the atmosphere (Searchinger et al. 2008). Biofuel feedstocks grown on land cleared from tropical forests, such as soybeans in the Amazon and oil palm in Southeast Asia, generate particularly high GHG emissions (Fargione et al. 2008). Even use of cellulosic feedstocks can spur higher crop prices that encourage the expansion of agriculture into undeveloped land, leading to GHG emissions and biodiversity losses (Melillo et al. 2009).
Biofuel production and processing practices can also release GHGs. Fertilizer application releases nitrous oxide, a potent greenhouse gas. Most biorefineries operate using fossil fuels. Some research suggests that GHG emissions resulting from biofuel production and use, including those from indirect land use change, may be higher than those generated by fossil fuels, depending on the time horizon of the analysis (Melillo et al. 2009, Mosnier et al. 2013).
Regarding non-GHG environmental impacts, research suggests that production of biofuel feedstocks, particularly food crops like corn and soy, could increase water pollution from nutrients, pesticides, and sediment (NRC 2011). Increases in irrigation and ethanol refining could deplete aquifers (NRC 2011). Air quality could also decline in some regions if the impact of biofuels on tailpipe emissions plus the additional emissions generated at biorefineries increases net conventional air pollution (NRC 2011).
Economic models show that biofuel use can result in higher crop prices, though the range of estimates in the literature is wide. For example, a 2013 study found projections for the effect of biofuels on corn prices in 2015 ranging from a 5 to a 53 percent increase (Zhang et al. 2013). The National Research Council’s (2011) report on the RFS included several studies finding a 20 to 40 percent increase in corn prices from biofuels during 2007 to 2009. An NCEE working paper found a 2 to 3 percent increase in long-run corn prices for each billion gallon increase in corn ethanol production on average across 19 studies (Condon et al. 2013). Higher crop prices lead to higher food prices, though impacts on retail food in the US are expected to be small (NRC 2011). Higher crop prices may lead to higher rates of malnutrition in developing countries (Rosegrant et al. 2008, Fischer et al. 2009).
On June 23, 2015, OMB issued a Statement of Policy on H.R. 2822. OMB recommended that the President veto this legislation if it is passed. The Administration objects to the legislation’s classification of forest biomass fuels as carbon neutral:
This language conflicts with existing EPA policies on biogenic CO2 and interferes with the position of States that do not apply the same policies to forest biomass as other renewable fuels like solar or wind. This language stands in contradiction to a wide-ranging consensus on policies and best available science from EPA’s own independent Science Advisory Board, numerous technical studies, many States, and various other stakeholders.
These concerns refute the perception that biofuels are part of the solution to quickly reduce lifecycle GHG emissions. Current mandates and targets for liquid biofuels should be reconsidered in light of the potential adverse environmental consequences and difficulty of meeting goals without large-scale land conversion and without carbon debt.