The argument focuses on the energy consumed by the tractors and the farm equipment, the trucks that transport the ethanol to market, and the fertilizer that is made from fossil fuels, as well as the amount of energy required to extract the sugar from corn starch (or cellulosic biomass) and convert it to ethanol.
Bruce Dale, Professor of Chemical Engineering at Michigan State University (MSU) provides some very important information about “Net Energy.”
Professor Dale tells us: “Net energy analysis is fundamentally wrong: it assumes that all BTUs are equivalent. This is obviously untrue; otherwise, we would not pay over ten times as much for electrical energy derived from coal as we do for the energy in the coal itself. All energy conversion systems lose some quantity of energy in order to increase energy quality. Gasoline from petroleum actually has a poorer net energy than ethanol from corn. The MOST RELEVANT measure of energy efficiency for biofuels is the liquid fuel produced per unit of PETROLEUM CONSUMED.”
Do we have enough land?
Professor Dale gives us the answer: “The range of opinion on this subject varies enormously. A USDA-DOE study indicates that we can sustainably produce about 1.3 billion tons per year of cellulosic biomass, sufficient to produce at least 100 BILLION gallons/year of ethanol. I believe this estimate is conservative because: 1) we have at least 800 million acres suitable for energy crops, 2) we have devoted very little attention to increasing energy crop yields, 3) we have not explored the opportunities for integrating food/feed production with energy crops, and 4) biomass conversion technology is very far from mature. Given the proper emphasis on increasing energy crop yields, maturing biomass conversion technology, and integrating food/feed production with energy crops, it should be POSSIBLE TO PRODUCE SEVERAL HUNDRED BILLION GALLONS PER YEAR OF ETHANOL and other liquid fuels while simultaneously increasing food/feed supplies. We will not choose between food or fuel; we will produce food and fuel.”
Professor Dale responds: “The United States has a serious problem. Our national and state economies are absolutely dependent on liquid fuels. The United States currently uses more than 140 billion gallons of gasoline and almost 40 billion gallons of diesel fuel annually. More than 60 percent of the petroleum we use is imported, and the percentage is rising. At $20 per barrel, oil is still cheaper to refine than biofuels are,” Dale explained. “But when oil costs $40 a barrel, biofuels are very competitive. At current corn prices, corn ethanol is competitive with gasoline while petroleum is about $45/barrel.
When cellulosic biomass conversion technology is mature, we should be able to produce hundreds of billions of gallons of liquid biofuels at much less than $1 per gallon (energy equivalent basis) and be competitive with petroleum at about $25 per barrel. Hence it is critical that we do both the fundamental research and technology deployment at the scale required to rapidly develop mature biomass conversion technology.”
MIT ethanol analysis confirms the benefits of biofuels
Regardless of the energy balance, replacing gasoline with corn-based ethanol does significantly reduce oil consumption because the biomass production and conversion process requires little petroleum. And further MIT analyses show that making ethanol from cellulosic sources such as switchgrass has far greater potential to reduce fossil energy use and greenhouse gas emissions.
- Everything Biomass-Dale Research Group — The Biomass Conversion Research Laboratory at Michigan State University.
- Net Energy Basics: Rebutting Some Ethanol Myths — Debunking Pimentel and Patzek Studies
- Thinking Clearly about Biofuels: Ending the Irrelevant “Net Energy” Controversy — by Bruce E. Dale, Ph. D. Professor of Chemical Engineering, Michigan State University