Fact Sheet - Sustainable Production of Biofuels
A recent article by Searchinger et al, published February 7 in the on-line edition of the journal Science, concludes that biofuels production leads to land use changes whose greenhouse gas emissions outweigh the climate benefits of the fuels themselves. This study provides a useful contribution to the discussion of sustainable biofuels production. But a growing list of scientists and other experts has taken issue with the assumptions and methodology on which the authors based their conclusion.
BIO's member companies are committed to the sustainable production of biofuels. While we appreciate the authors' effort to further the discussion of this important topic, we share the concerns of the scientific community that the pessimistic conclusions of the Searchinger paper are not justified by the science.
Agricultural and industrial biotechnology are key enabling technologies that will allow the U.S. to sustainably reach the new national renewable fuels standard (RFS) established by the Energy Independence and Security Act of 2007. A critique of the paper, compiled from statements of the scientific community and others, follows.
- An Unrealistic Scenario - Searchinger assumed 30 billion gallons a year of corn ethanol by 2015. The 2007 Energy Bill established a corn ethanol cap of 15 billion gallons. Searchinger also assumed that 1 acre planted to an energy crop would result in 1 acre converted from an undomesticated state.
- Not a Life Cycle Analysis - As Dr. Bruce Dale of Michigan State University points out, "these analyses published in Science may not be termed life cycle analyses. Life cycle analysis (LCA) follows a specific set of rules, one of which is that the most recent and most appropriate data be used. LCA is data driven, but these two analyses are not driven by actual data at all."
Yield - Searchinger assumed constant corn yield in coming years, but:
- Per acre corn yield has increased 371% since 1944. Introduction of biotechnology varieties has helped increase U.S. corn yields 30% since 1996 alone. Based on a combination of genomics and biotechnology, leading corn seed companies Monsanto and Pioneer project accelerated yield increases over the next two decades, with current yield nearly doubling by 2030.
- McKinsey & Co in a December conference call with reporters estimated that if current corn yield improvements continue, the RFS would require little or no additional corn acres to meet projected food, feed and fuel needs.
- Yields in developing countries are considerably lower, leaving even greater room for improvement.
Cropping Practice (No-till) - The study fails to consider changes in cropping practices - such as no-till farming - that are reducing the GHG impacts of corn and other bioenergy crops:
- Biotech corn varieties and collection of agricultural residues both allow for greater adoption of no-till farming.
- No till corn farming results in carbon being stored in the plant's 'root ball', increasing sequestration 2-3 fold.
Improving GHG Profile- Searchinger used 2007 values for the GHG profile of ethanol production from corn and assumed no process improvements going forward. But ethanol production efficiency and environmental profile are improving rapidly:
- New fractionation and enzyme technologies are reducing energy inputs and delivering higher value co-products. New "no cook" enzymes substantially reduce biorefinery CO2 emissions because heat is no longer needed to disassociate the sugars from the starch.
- Biorefineries increasingly use renewable energy such as stover or manure to power their facilities, greatly reducing fossil fuel inputs.
Feed + Fuel (DDGs) - Searchinger assumes DDGs from corn ethanol pants would provide only 1/3 as much animal feed as would otherwise come from corn, but protein content is highly concentrated in DDGs.
- A forthcoming article suggests DDGs can replace 1/2 or more of re-directed grain, so Searchinger greatly overestimates land needed to replace lost feed.
- Yield - Searchinger assumed constant corn yield in coming years, but:
Dedicated Energy Crops - The study assumes that switchgrass and other dedicated energy crops will be planted on highly productive soils now used for corn:
- Switchgrass and other dedicated energy crops grow well in poorer soils, and can be planted on less productive land, building soil and sequestering carbon in the process.
- Dedicated perennial energy crops such as switchgrass and Miscanthus can be planted without tilling, and continuously sequester carbon even as above-ground biomass is harvested. These crops do not create a carbon debt - in fact, they can start reducing atmospheric CO2 right away.
- Dedicated energy crops often have multiple uses. Bioenergy crops can provide food/feed, fuels, and other high-value co-products from the same crop, making the highest possible use of the land.
- Dedicated bioenergy crops will provide a much higher biofuel yield per acre, since they use the entire plant, than first generation crops.
Indirect Land Use Impacts - Searchinger makes several unreasonable or false assumptions about indirect land use impacts of biofuels production:
- Searchinger assumes ethanol production will lead to dramatically reduced corn exports, driving greater cropland conversion oversees. But according to USDA, U.S. corn exports have not declined with increased ethanol production.
- Searchinger uses historical land use changes to predict future land use changes, but legislation and more effective land management has reduced deforestation rates in Brazil and elsewhere.
- Standard Life Cycle Analyses do not include "indirect" effects such as indirect land use impacts, since only very complex econometric models can even attempt to determine such indirect effects.
- Indirect land use changes are a function of land use policy. Sustainable biofuels production must go hand-in-hand with sustainable land use policy.
Other Facts on the Sustainability of Biofuels
- Climate Profile of Biofuels - Contrary to the findings of Searchinger et al., the vast majority of research from academia, NGOs, and federal labs suggests that biofuels have a positive and increasingly beneficial impact on climate. (See sample reference list below.)
- Renewable Fuels Standard (RFS) - All new biofuels production under the recently-passed RFS must meet stringent greenhouse gas reduction targets. BIO and its member companies supported these requirements because we share the goal of environmental organizations and others of sustainable production of biofuels.
- Feedstock Supply - The recent "Billion Ton Report" conducted by DOE and USDA found that the U.S. can displace over 30 percent of gasoline demand with biofuels without requiring any additional crop acreage. See: http://www1.eere.energy.gov/biomass/pdfs/final_billionton_vision_report2.pdf.
Sample Lifecycle Biofuels References