Major Study Questions Both Corn & Cellulosic Biofuels' Impact

Apr 2: An international team of scientists released what they say is the first critical science-based consensus assessment of biofuels’ impact on the global environment. The assessment says that synthetic nitrogen fertilizer used in corn-ethanol production will increase emissions of nitrous oxide (N2O), a greenhouse gas 300 times more potent than carbon dioxide in its ability to warm the planet. The report predicts that nitrous oxide emissions may be four times greater than estimates made in 2007 by the Intergovernmental Panel on Climate Change (IPCC).

The Scientific Committee on Problems of the Environment (SCOPE) Biofuels Project Chair Robert Howarth, professor of ecology and environmental biology at Cornell University said, “The policy of using ethanol to reduce reliance on the fossil fuels that cause global warming is self-defeating because ethanol production actually increases net greenhouse gas emissions.” The report indicates that biofuels production will also worsen water quality,. As conservation lands are increasingly converted to corn production for ethanol, more runoff from chemical fertilizer is ending up in U.S. lakes, streams and marine environments, robbing them of the oxygen they need to survive. Howarth said, “That risks expanding these so-called ‘dead zones, particularly in the Gulf of Mexico and the Chesapeake Bay."

Additionally, the report indicates that biofuels may also increase water scarcity at a time of increasing drought. Roughly 45 billion cubic meters of irrigation water were used for biofuel production in 2007, or some six times more water than people drink globally.

According to a release, many of the assessment participants are concerned about U.S. policies pushing ethanol, not only from corn, but from cellulose as well. Several previous reports have exposed the consequences of making ethanol from corn, which now dominates production in the U.S., but have held out hope that ethanol from cellulosic materials such as wood and grasses would be more environmentally friendly. Howarth said, “The SCOPE report agrees the cellulosic ethanol is better, but not better enough. The efficiency of making the ethanol is simply too low, requiring too much land and too much input of material.” The report suggests that biomass that does not compete with food production can be used much more efficiently (and therefore with less environmental impact) through direct combustion to generate electricity and heat, rather than being converted to liquid fuels such as ethanol.

The assessment reflects the work of the Scientific Committee on Problems of the Environment (SCOPE) of the International Council for Science (ICSU). More than 75 scientists from 21 countries and diverse disciplines have taken part in the SCOPE Biofuels Project’s “rapid assessment” of the effects of biofuels on the environment.

The Environmental Working Group (EWG) Midwest Vice President Craig Cox issued a commentary on the report saying, ". . .the report raises serious questions about how important a role liquid biofuels -- either current or next-generation -- can realistically play in the renewable energy economy that is vital to our prosperity and our environment. This timely report challenges the conventional wisdom that too often dominates the debate over biofuels policy in the United States and across the globe. Policymakers should pay close attention to the report as they move forward with climate change and energy legislation."

EWG summarized the key highlights of the report as follows: (2) Economic pressures on corn prices will likely limit corn-ethanol production to 15 billion gallons a year ¾ at best enough ethanol to replace 7 percent of the gasoline each year in the United States. (2) In 2007, the United States used 24 percent of its corn crop to produce ethanol, which supplied only 1.3 percent of U.S. liquid fuel. (3) New liquid hydrocarbon fuels produced from cellulosic biomass seem likely to offer several advantages, including more efficient yields and less environmental impact, over ethanol produced from cellulose. (4) Opportunities for biofuel production that maximize social benefits while minimizing environmental impacts are few, and those that exist are unlikely to make a significant contribution to society’s energy budget.

(5) Burning biomass itself as fuel to generate electricity and heat is likely a more efficient way to produce renewable energy than converting biomass to liquid fuel such as ethanol. (6) Current mandates and targets for liquid biofuels should be reconsidered in light of the potential environmental damage and impact on food prices. (7) A truly sustainable energy policy should first aim to reduce demand for energy through conservation and improved efficiency.

On April 1, the U.S. Senate Environment and Pubic Works Committee, Subcommittee on Clean Air and Nuclear Safety, Chaired by Senator Tom Carper (DE) held an oversight hearing on U.S. EPA's Renewable Fuel Standard (RFS). The bipartisan energy bill in 2007 amended the Clean Air Act to greatly enhance the RFS by requiring 9 billion gallons of renewable fuels be blended into our gasoline starting in 2008, and ramping up to 36 billion gallons by 2022. The hearing raised serious questions about the viability of the RFS.

Access a release from SCOPE (click here). Access the report preface, and links to an executive summary, and individual chapters of the report (click here). Access the statement from EWG (click here). Access the Senate hearing website for links to opening statements, all testimony and a webcast (click here).