“The U.S. transportation sector is almost entirely dependent on oil… Biofuels, such as ethanol has the potential to displace oil use in transportation fuel.”
—The U.S. Government Accountability Office (GAO)
Fuel economy estimates for all cars and trucks in the USA, including flex-fuel vehicles, are given in miles per liquid gallon (MPG). If the USA is serious about reducing gasoline consumption and ending foreign oil dependence, then the important measure should be miles per gallon of gasoline (MPGG).
MPG vs. MPGG
Ford’s F150 flex-fuel pickup is designed to run on either gasoline or a blend of 85% ethanol and 15% gasoline (E85).
The 2010 Ford F150 flex-fuel Pickup, is estimated to get 14 miles per gallon in city traffic and 20 miles per gallon on the open road.
20 MPG vs. 130 MPG
E85 contains only 15% gasoline per gallon of liquid fuel. Therefore, a flex-fuel vehicle, using E85, will burn one gallon of gasoline for every 6 and 2/3 gallons of E85 consumed. At 20 miles per gallon on the open road, the 2010 Ford F150 flex-fuel pickup, running on E85, will travel over 130 miles before it burns a gallon of gasoline.
Engines can be optimized for ethanol—Alcohol fuels (ethanol or methanol) can tolerate compression ratios up to 15:1 or higher (like diesel which generally uses compression ratios of around 13:1 and gets higher mileage as a result). Gasoline is restricted to compression ratios below 10:1.
Gasoline engines throw off most of their power in heat losses. Ethanol’s higher octane offers engine manufacturers an opportunity to significantly improve engine efficiency with higher compression ratios that will convert more of the fuel’s energy into a force that can turn the wheels, and reduce the heat losses.
A typical gasoline-powered automobile is only about 25% efficient. In other words, out of the 100% thermal energy potential of a gallon of gasoline, only about 25% of the energy is converted to real mechanical work that turns the wheels of the car — the other 75% is lost in the form of wasted heat and friction.
Ethanol and Net Energy
There is much discussion, or argument, about Ethanol: Does it take more energy to make it than you can get back from it?
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.
Some people say ethanol is a net energy loser—don’t believe it, but even if it was, so what? Popcorn sold in theaters is a net energy loser!
In the past, nobody really cared about “net energy” because there was plenty of oil and gasoline was cheap. People just wanted to fill their tank up and drive, kind of like eating popcorn at a theater without being concerned about how much “energy” was spent cooking the popcorn. Today, we can’t just worry about how much fuel costs, now we are expected to also worry about how much energy is spent making it.
So, how much energy is “spent” making ethanol, and why should we care?
It takes a lot of thermal energy to make ethanol from corn. In general, about 35,000 Btu of heat energy is required to produce a gallon of ethanol. For comparison, the energy content of ethanol is about 75,000 Btu per gallon.
People who want to discredit and discourage the use of ethanol in America often employ deceptive arguments about net energy by claiming that ethanol production consumes more “fossil fuels” than can be replaced by ethanol. (The original arguments against ethanol also included the solar energy “consumed” by the corn plant during the growing season.)
All attempts to discredit ethanol with the fossil fuel argument are deceptive because the argument is based on a false premise: it assumes that fossil fuel always means oil. Yes, petroleum is a fossil fuel, but not all fossil fuels are petroleum. The fossil fuel most often used for ethanol production is natural gas.
About 85% of the ethanol plants in the U.S. use natural gas as a source of thermal energy. The remainder uses propane, fuel oil, or coal. Newer plants are developing renewal sources of thermal energy, such as methane from cow manure produced at nearby dairy farms or from landfill methane. Geothermal energy is also being developed.
Geothermal Energy Utilization in Ethanol Production size: 212 Kb – 4 pages
Professor Dale tells us: “Net energy analysis is fundamentally wrong: it assumes that all BTU is 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 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.”
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 require 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.
The amount of petroleum consumed in the process of making ethanol is less than 10% of the total energy within a gallon of ethanol — this covers every stage related to ethanol production, including planting, growing, and harvesting the corn as well as transporting the ethanol to where consumers buy their fuel and fill their gas tanks.
Diesel fuel made from petroleum is consumed by the tractors and other farm equipment as well as the trucks that transport the ethanol to market. If the corn fertilizer was produced by petroleum refineries, then that too contributes a portion of the overall percentage of petroleum used to make a gallon of ethanol.
A joint study by the Department of Energy (DOE), Argonne National Laboratory, and General Motors found a 10 to 1 net energy gain—Ten gallons of ethanol for every gallon of petroleum consumed.
Some people believe that more fossil energy is required to produce ethanol than it provides as fuel. But in fact, a study by DOE’s Argonne National Laboratory and General Motors Corp. concluded that today’s corn growers and ethanol plants consume only about 7 British thermal units (Btu) of fossil-fuel energy for every 10 Btu of fuel they produce. In other words, it takes less energy to produce ethanol than is supplied by ethanol fuel, so the fuel provides a net energy benefit.
The benefits are even greater in terms of replacing petroleum. Because most of the fossil fuel energy is supplied by coal and natural gas, only about 1 Btu of petroleum is consumed for every 10 Btu of ethanol fuel produced. That means that every gallon of ethanol fuel produced significantly reduces our use of petroleum.
The energy balance is even better for the production of cellulosic ethanol. Because the process residues will be used to produce heat and power for the conversion facility, biomass will provide 95% of the energy needed to make the fuel, with the remaining energy coming from petroleum. Because the process is only about 45% efficient, the net result is the same as that for corn ethanol: 1 Btu of petroleum is burned for every 10 Btu of ethanol fuel produced. However, the process uses less fossil fuel overall and thus produces fewer greenhouse gas emissions. Gains in processing efficiencies and economies of scale should boost the petroleum replacement and greenhouse gas benefits of cellulosic ethanol significantly.
From Biomass to Biofuels — National Renewable Energy Laboratory (NREL)
Net Energy Basics: Rebutting Some Ethanol Myths —Debunking Pimentel and Patzek Studies size: 200 Kb – 10 pages
Thinking Clearly about Biofuels: Ending the Irrelevant “Net Energy” Controversy
— By Bruce E. Dale, Ph. D. Professor of Chemical Engineering, Michigan State University
size: 19 Kb – 2 pages
With Cellulosic Ethanol, There is No Food vs. Fuel Debate
Ethanol made from cellulosic materials, rather than corn grain, renders the food vs. fuel debate moot, according to research by Michigan State University ethanol expert.
As more and more corn grain is diverted to make ethanol, some groups have become concerned about food shortages. Dr. Bruce Dale, Michigan Agricultural Experiment Station (MAES) chemical engineering and materials science researcher, has used life cycle analysis tools, which include agricultural data and computer modeling, to study the sustainability of producing biofuels — fuels such as ethanol and biodiesel that are made from renewable resources.
“We grow animal feed, not human food in the United States,” Dale said. “We could feed the country’s population with 25 million acres of cropland, and we currently have 500 million acres. Most of our agricultural land is being used to grow animal feed. It’s a lot simpler to integrate animal feed production into cellulosic ethanol production than it is to integrate human food production. With cellulosic ethanol, the ‘food vs. fuel’ debate goes away.”
Dale, who also serves as associate director of the MSU Office of Biobased Technologies, presented his findings on March 27, 2007, at the American Chemical Society annual meeting in Chicago
Cellulosic ethanol is made from the stems, leaves, stalks, and trunks of plants, none of which is used for human food production. Dale, who has studied ethanol for more than 30 years, said that as the country moves toward large-scale cellulosic ethanol production, the yield of so-called energy crops—grasses and woody materials grown for their energy content—also will dramatically increase.
“This will reduce pressure on our land resources,” Dale said. “We’ll be able to get more raw material out of one acre of land.”
Dale also pointed out that many of these energy crops will be grown on land that isn’t prime agricultural acreage, but rather on marginal land that isn’t growing a commercial crop right now.
“The evidence indicates that large-scale biofuel production will increase, not decrease, world food supplies by making animal feed production much more efficient,” Dale said.
Sustainability Analyses of the Biobased Economy — The biobased economy will grow rapidly during the 21st century. A combination of low-cost plant raw materials and gradually improving biorefinery process technologies for converting these raw materials into a variety of fuels, chemicals, materials, foods, and feeds will drive the adoption of the biobased economy. The biological sciences will have a particularly powerful impact on both the raw materials and the processing technologies underlying the biobased economy… Our sustainability analysis efforts are intended to outline how this new industry can achieve both environmental and economic sustainability. For perhaps the first time, humanity can design and develop a new industry, the biorefining industry, to achieve both economic and environmental goals.
— Bruce E. Dale
Relief from soaring prices at the gas pump could come in the form of corncobs, corn stalks, switchgrass, and other types of biomass, according to a joint feasibility study for the departments of Agriculture and Energy.
The recently completed Oak Ridge National Laboratory report outlines a national strategy in which 1 billion dry tons of biomass – any organic matter that is available on a renewable or recurring basis – would displace 30 percent of the nation’s petroleum consumption for transportation.
“One of the main points of the report is that the United States can produce nearly 1 billion dry tons of biomass annually from agricultural lands and still continue to meet food, feed, and export demands,” said Robin Graham, leader for Ecosystem and Plant Sciences in ORNL’s Environmental Sciences Division.—Growth in biomass could put the U.S. on road to energy independence
Facts on increases in fuel and food prices
- Corn accounts for less than 5% of the price of a box of corn flakes.
- The cost of marketing food is responsible for 80% of the retail cost of food. Marketing costs are the difference between the farm value and consumer spending for food at grocery stores and restaurants. Marketing costs include the increased price of diesel fuel paid by trucking companies.
- The price of rice has nearly doubled. Rice is not used in the production of biofuels. Corn for ethanol cannot be grown in rice paddies.
- In 2007, the same year the U.S. produced a record amount of ethanol from corn, the U.S. increased its surplus of corn to more than 1.4 billion bushels. In a record ethanol year, the U.S. actually fed more of the world by increasing its exports of corn by 6%.
- As a whole, fish prices are up. Fuel prices account for approximately 60%-70% of operating costs of fishermen. Fish are not used in the production of biofuels.
- An increasing amount of biofuels are produced from nontraditional feedstocks such as waste products from the beverage, food, and forestry industries. In the very near future, biofuels will be produced from agricultural residues such as grain straw, sugarcane bagasse, corn stover, municipal solid waste, and energy crops such as switchgrass and algae.
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 per 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 proper emphasis to 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 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 when 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.”
Everything Biomass-Dale Research Group —The Biomass Conversion Research Laboratory at Michigan State University.