Farm fields landscape

The Net Energy of Ethanol Debate Must End

David Morris
Institute for Local Self-Reliance, Sept 12, 2005

A new report from the Institute for Local Self-Reliance offers a scathing critique of a 2005 study by biofuels critics, Professors David Pimentel and Tad Patzek. David Morris, ILSR's vice president and author of the study, "The Carbohydrate Economy, Biofuels and the Net Energy Debate," stresses that "A carefully designed biofuels strategy may be the answer not only to our energy problems but to another global dilemma as well: the plight of agriculture." [Emphasis added]

Morris notes, "It often seems every public discussion about our most used and visible biofuel, ethanol, starts, and sometimes ends, with the question, 'Doesn't it take more energy to make ethanol than is contained in the ethanol?'" In 1980, the short and empirical answer to this question was yes. In 1990, because of improved efficiencies by both farmer and ethanol manufacturer, the answer was, probably not. In 2005 the answer is clearly no.

The new report focuses on the energy balance of biofuels production. In doing so, it inevitably focuses largely on the studies of David Pimentel, who has been ethanol's most visible critic. Reporters and interested parties who want to examine the numbers and report on or participate in the debate might take into account six key points.

  • David Pimentel's pessimism about biofuels derives from a methodological approach that leads him to a far more sweeping and highly controversial conclusion: the world's population has vastly exceeded its biological carrying capacity.
  • Policymakers should base their decision on whether to aggressively expand biofuels on the latest production technologies and techniques that show farmers are far more energy and resource efficient than they were 20 years ago.
  • Although an enormous amount of attention has been focused on the debate about the energetics of corn to ethanol, the differences actually have narrowed to the point that they are relatively modest. On the other hand, Pimentel and Patzek's new estimates of the energy balance of making ethanol from cellulose and biodiesel from oil seeds diverge dramatically from those of other studies.
  • All other studies done after 1992, except for Pimentel and Patzek's have found a positive energy balance of corn to ethanol. Of the sources Pimentel and Patzek cite in support of their conclusion, only one was an actual scientific study.
  • Biofuels displace large quantities of imported oil, regardless of the net energy findings, because their production relies on non-petroleum fuels.
  • Energy balance analyses should take into account the quality of the energy produced.

Those who do take the time to review the various reports will discover that only a handful of factors account for over 80 percent of the variations among net energy studies of ethanol. "Many of us believe that biological sources can play an important, perhaps even a crucial role in our future economies. But moving in this direction will require tackling fundamental questions, such as the ownership structure of the agricultural industry and world trade negotiations," said Morris. "We can't tackle these fundamental questions if we continue to spend an inordinate amount of time and intellectual resources poring over net energy studies," he added.


David Morris is co-founder of the Institute for Local Self-Reliance and directs its initiative on The Public Good. He is the author of New City States and four other non-fiction books. His essays on public policy are regularly published by On the Commons, Alternet, Common Dreams and the Huffington Post.