Sunday, June 26, 2011
The following was written by Forrest Jehlik, a researcher at the U.S. Department of Energy’s Argonne National Laboratory. In writing this post, Jehlik was not paid by, nor did he benefit from, the ethanol industry or its lobby. His research is energy-neutral and his paycheck remains the same regardless of his findings.
We must develop a multitude of alternatives to address our future energy needs. One such alternative is ethanol, which is domestically generated and sustainable. However, there are many myths surrounding ethanol, and I’ve come across a lot of them in my work at Argonne National Laboratory. I’m a mechanical engineer in the lab’s Transportation Technology R&D Center, so I’ve spent a lot of time researching ethanol.
Here are counterpoints to five prevalent myths about ethanol.
Myth No. 1: Ethanol requires more energy to make than it yields.
False. Argonne National Laboratory research has shown that corn ethanol delivers a positive energy balance of 8.8 megajoules per liter. The energy balance from second-generation biofuels using cellulosic sources is up to six times better, according to a study published in Biomass and Bioenergy Journal.
There are two key reasons ethanol is no longer net energy negative.
First, corn production efficiency has increased dramatically: Producers now grow 160 bushels per acre today versus the 95 grown in 1980, and corn yield continues to increase.
Second, ethanol production has become more energy-efficient. Today, more than 90 percent of corn used in ethanol production goes through a dry milling process that uses far less energy than the wet milling process used before. The combination of more corn per acre, coupled with a reduction of energy input to process ethanol, has resulted in a favorable energy output. The gallons of ethanol yielded per bushel of corn has also increased by about 50 percent.
Myth No. 2: Ethanol production reduces our food supply.
False. Only 1 percent of all corn grown in this country is eaten by humans. The rest is No. 2 yellow field corn, which is indigestible to humans and used in animal feed, food supplements and ethanol.
Specifically, a bushel of corn used for ethanol produces 1.5 pounds of corn oil, 17.5 pounds of high-protein feed called DDGS, 2.6 pounds of corn meal and 31.5 pounds of starch. The starch can be converted to sweeteners or used to produce 2.8 gallons of ethanol. DDGS displaces whole corn and some soybeans traditionally used in animal feed. The United States is a large exporter of DDGS to China and other countries.
Additionally, the food-versus-fuel debate has spurred significant research and development of second-generation biofuels like cellulosic ethanol that do not use food crops. Cellulosic ethanol is made from the “woody” structural material in plants that is unusable by humans. Unlike food crops, ethanol crops and cellulosic ethanol crops can grow in any soil that will sustain grass.
Researchers, including Argonne, are investigating using marginal land to grow ethanol crops. Studies from the U.S. Department of Energy suggest the United States has enough non-edible biomass to produce approximately 30 percent of our total transportation fuel requirements by 2030. That could go a long way toward easing our reliance on imported petroleum.
Taken together, the increase in crop yield and the use of marginal lands can enable us to produce food and fuels.
Myth No. 3: Ethanol crops and production emit more greenhouse gases than gasoline.
False. A 1996 EPA study analyzing sources of air pollution confirmed that gasoline vehicles and non-road equipment are the largest contributors to vehicular gaseous hazardous air pollutants. However, another study showed ethanol reduces tailpipe carbon monoxide as much as 30 percent and tailpipe particulate matter emissions by 50 percent (.pdf). And blending ethanol with gasoline dramatically reduces carbon monoxide tailpipe emissions and tailpipe emissions of volatile organic compounds that form ozone.
Finally, a life cycle analysis of ethanol found “at present and in the near future, using corn ethanol reduces greenhouse gas emission by more than 20 percent, relative to those of petroleum gasoline.” Blending cellulosic ethanol with gasoline to make E85 brings the reduction to 63 percent. Some purpose-grown woody crops for next-generation fuels actually increase soil carbon enough to yield over a 100 percent reduction in GHG emissions.
Myth No. 4: Ethanol requires too much water to produce.
False. The amount of water used to make ethanol has declined dramatically. Today, producing one gallon of ethanol requires about 3.5 gallons of water. That’s a little more than it takes to process a gallon of gasoline. Much of the criticism about ethanol’s water requirements stem from the need to irrigate feedstock crops in drier climates. But most ethanol is produced from rain-fed crops grown in the Midwest.
In addition, ethanol is not carcinogenic and doesn’t poison groundwater or the ocean. Ethanol rapidly biodegrades. Concerns over ethanol spills are muted by ethanol’s low toxicity. In fact, you’ll find ethanol in beer, bourbon and other happy-hour beverages you’ve probably consumed.
Myth No. 5: Cars get lower gas mileage with ethanol.
OK, this one’s true. If you completely burn a gallon of gasoline and a gallon of E85, you’ll get 25 percent less energy from the E85. Flex-fuel cars that run on gasoline and ethanol see 25 percent less mileage with ethanol. However, a gallon of ethanol costs approximately 17 percent less than that of a gallon of gasoline. In some, but not all, regions, the fuel-economy deficit is recovered by cheaper fuel costs. As the market grows and matures, production optimization would further drive down ethanol costs.
Research currently underway takes advantage of ethanol’s characteristics in a fully optimized engine that could greatly reduce the energy deficit. Last year, for example, Delphi cut the fuel economy penalty by one-third — while simultaneously increasing power. Downsizing the engine, combined with cheaper E85, would result in cost savings to the consumer, potentially making E85 more favorable than gasoline. On the plus side, ethanol has a higher octane rating than gasoline so it can improve performance.
On a final note, it’s important to take a step back and really look at our nation’s energy position. Currently, the United States consumes 20 million barrels of oil per day, approximately a quarter of the world’s total. Seventy percent of that petroleum is used for transportation.
To meet that demand, we import 65 percent of what we consume. Yet, there are a number of hidden costs associated with the use of petroleum. A study conducted in 2003 showed that the true cost of a gallon of gasoline (including all indirect costs) was $5.28 per gallon. Yet in 2003, the average pump price for a gallon of gasoline was only $1.50. One can imagine what the actual cost is today by factoring in such indirect costs.
We produce about 900,000 barrels of ethanol per day in the United States. That surpasses the volume of petroleum we import from Nigeria and is within striking distance of the amount that we import from Venezuela or Saudi Arabia. Ethanol is making a real contribution to our energy needs and reducing our dependence on imported petroleum.