NAS study falls short on biofuels
In this photo, biomass is being harvested as a feedstock for cellulosic ethanol production.
One conclusion from an October National Academy of Sciences (NAS) report seems indisputable—the Renewable Fuels Standard (RFS) has not and might not spark a commercial cellulosic ethanol industry.
A NAS report says cellulosic biofuels do little to reduce greenhouse gas emissions. The report is criticized by several scientists. Another NAS conclusion is debatable—cellulosic biofuels may do little to reduce greenhouse gas emissions compared to fossil fuels.
NAS reports often are considered credible voices on controversial scientific issues, but the latest report on the biofuels industry has raised concerns from the industry and scientists alike.
The RFS requires gasoline blenders to use 36 billion gallons of ethanol and other biofuels by 2022, including 16 billion gallons of cellulosic ethanol. The policy has been viewed as a market driver for biofuels and in expanding cellulosic feedstock markets for farmers.
“Renewable Fuel Standard -- Potential Economic and Environmental Effects of U.S. Biofuel Policy,” looks at available data on everything from indirect land-use changes, biofuels’ effect on food and feed prices, to the effects of expanded biofuels production on the federal budget.
National biofuels associations have written off the 423-page study. Some scientists are concerned about how data was used, about some of the report’s conclusions, and how the report did not live up to expectations of a NAS study.
Wallace E. Tyner, James and Lois Ackerman professor in the department of agricultural economics at Purdue University and cochairman of the study committee, said he believes the study reflects the current state of biofuels and the committee acknowledges the report’s shortfalls.
“If you read the preface prepared by myself and Indy Burke, the other co-chair, we point out the large uncertainties and some of the major areas of uncertainty,” he said. That includes future oil prices, feedstock costs and availability, technological advances in conversion efficiencies, land-use change and other issues.”
In the past 30 years, the U.S. ethanol industry has built more than 200 plants with more than 14 billion gallons of production capacity. Near the end of 2011, cellulosic ethanol is not produced commercially.
Tyner said the technology is “uncertain,” feedstock costs are high and there are only 11 years to reach the 16 billion-gallon target. “It would take a build rate two to three times corn ethanol to reach the cellulosic ethanol RFS target,” he said. “It is simply not likely to happen.”
Robert Brown, professor of mechanical engineering at Iowa State University (ISU), said the study used different assumptions when looking at an ISU economic analysis on advanced biofuels.
In particular, NAS conclusions that advanced biofuels likely will not meet RFS2 standards are based almost entirely on ISU research— and the data was discounted by a consultant, he said. Some of that research examined the state of pyrolysis biofuels.
Pyrolysis produces oil using heat and pressure to break down a feedstock. The oil can be used to produce other biofuels. ISU researchers estimated that pyrolysisbased biofuels are close to being cost-competitive with gasoline.
“But I discovered that the petroleum industry consultant engaged by the panel to prepare the economic analysis for the report did not like our analysis for pyrolysisbased biofuels,” Brown said.
The consultant, he said, decided ISU’s capital costs were too low and “raised them sufficiently” to make the advanced biofuel economically unattractive in the near-term.
“We discovered that he employed unpublished data that only he had access to, which is not stated in the report,” he said. “In the research community, such inaccessible data would never be allowed in a peer-reviewed publication, but its use in the National Academy report gives it the stamp of credibility that it does not deserve.
“I am disappointed that two years of analysis by researchers from academia, the national labs, and a petroleum company using detailed process models and vetted by three separate groups of reviewers can be dismissed by one person who extrapolated one unpublished data point.”
NAS re-analyzed existing data in a way “that allowed the study to make broad generalizations about advanced biofuels, which are not supported by the published literature,” Brown said.
Although academia is split on the merits of indirect land-use change, Brown said the NAS report doesn’t reflect the divide.
The theory is that feedstocks produced in response to expanded biofuels production in the U.S. lead to changes in acres planted in other countries. This places the blame on U.S. ethanol producers for land-use changes in other countries.
“The academic community is sharply divided on this issue, but the National Academy report appears to come down on the side of those that want to charge the sins of the developing world to American farmers,” he said.
One of the findings from the NAS report is that RFS2 may be ineffective at reducing global greenhouse gas emissions (GHG) because the effect of biofuels on GHG emissions depends on how biofuels are produced and “what land-use or land-cover
changes occur in the process,” the report said.
Virginia H. Dale, Oak Ridge National Laboratory corporate fellow in the landscape ecology and regional analysis group for environmental sciences division, and a member of the NAS committee, said readers should read the report with caution.
“I find parts of the report to be misleading if the assumptions of the analysis are not considered,” she said.
Dale describes the NAS report as a “compromise” among the academic committee members and is based on research published in the literature—not necessarily based in science.
“It is difficult to conduct a scientific process when the data are inadequate, models are applied at scales inappropriate to the situation, or key processes are not included in the theories,” she said. “All of these limitations are applicable to current analyses of effects of biofuels.”
Dale said the report’s conclusions on land-use change are based on model projections and not on site-specific details such as water, climate, soils, local governance, economic conditions, policies, socioeconomic forces or environmental conditions.
Uncertainties are compounded because NAS did not use current information, she said. Instead, “outdated estimates” of biomass production were used and the report does not include current information from bioenergy technology industries or ongoing government research, Dale said.
The NAS report issued several other findings:
• Key barriers to achieving RFS2 are the high production cost of cellulosic biofuels compared to petroleum and uncertainties in future biofuel markets.
• Biofuels would be costcompetitive with petroleum only in an economic environment characterized by high oil prices, technological breakthroughs, and a high implicit or actual carbon price.
• Additional cropland will be required for cellulosic feedstock production without “major increases” in agricultural yields and improvement in the efficiency of converting biomass to fuels. This would create competition among land uses, raise cropland prices and increase production costs for food and feed.
• Food-based biofuels have contributed to upward price pressure on agricultural commodities, food and livestock feed since 2007.
• Achieving RFS2 would increase federal budget outlays mostly as a result of increased spending on payments, grants, loans, and loan guarantees to support
the development of cellulosic biofuels, and forgone revenue from biofuel tax credits.
• The environmental effects of increasing biofuels production depend on feedstock type, site-specific factors, management practices used in feedstock production, land condition prior to feedstock production and conversion yield.
Ethanol industry groups doubt the NAS study will be taken seriously by lawmakers when looking at biofuels policies.
“Ultimately, this NAS study needs to be rewritten, with better attention paid to the science,” said Chris Thorne, director of public affairs for ethanol interest group Growth Energy. “It hasn’t settled anything, and only served to raise more questions.”
Matt Hartwig, director of public affairs for the Renewable Fuels Association, said members of Congress have not taken the report seriously.
“What members of Congress choose to consider valid science too often depends upon their predetermined point of view,” he said.
“No doubt those predisposed to disliking renewable fuels will try to use this as evidence to support their bias. That said, we have not seen this study get much traction.” — Todd Neeley, DTN