Ethanol is ethyl alcohol, sometimes called “grain alcohol.” It’s made by fermenting the sugar and starch in the corn into alcohol, which is then separated from the water by distillation.
In the United States, most ethanol is produced from corn. You’re likely to encounter ethanol as a fuel additive or as E10 (10 percent ethanol, 90 percent gasoline), on which any modern vehicle with a gas engine can run. Full-fledged ethanol fuel — E85 (85 percent ethanol, 15 percent gasoline) — has limited, although increasing, availability and requires a car with a “flex-fuel” engine. Unlike gasoline, ethanol is renewable, and it causes less tailpipe emissions.
Why isn’t corn ethanol the answer?
As gas prices and concerns about global warming skyrocket, demand for ethanol continues to grow. But increased use of corn and other grains to produce ethanol is one of several factors pushing up the price of food made from these crops (including meat from animals fed with grains).
Lester Brown, president of the Earth Policy Institute, who has studied these issues for decades, describes this as the beginning of a great tragedy. “The United States, in a misguided effort to reduce its oil insecurity by converting grain into fuel for cars, is generating global food insecurity on a scale never seen before,” he says.
Other issues relative to corn ethanol include:
- In current engines, E85 provides about 30 percent less fuel economy than gasoline.
- Ethanol cannot be transported through existing pipelines because it is corrosive and easily absorbs water. It must be delivered by trucks, barges and rail cars, which produces more pollution.
- Converting remaining prairie, forests and rainforests into cropland will release CO2 and add to the problems of global warming. (Experts debate the extent of this concern.)
- Even if all current U.S. corn production went to biofuels, we could offset just 12 percent of our current gasoline use, according to a 2006 study from the University of Minnesota.
- Expanding ethanol production could diminish and pollute local water supplies.
- The numbers are debated among scientists, but it appears that, at best, the energy produced by corn ethanol is only slightly more than the energy required to make it.
Can we get ethanol from other sources?
Cellulosic ethanol has huge potential to be a part of the solution to declining gasoline supplies. It can be made from non-food sources such as switchgrass and wood chips, and can be produced on marginal (non-food crops) land. Cellulosic ethanol is the subject of extensive and rapidly evolving research, as its energy bang for the buck is much greater than that for corn ethanol — with anywhere from twice to four or five times the energy output versus the input (depending on the source and production technique). Significant hurdles remain before it can become a widely available fuel, but recent legislation (see On the Road to Energy Independence) will encourage its development.
So what’s the verdict?
Ethanol alone won’t become America’s replacement for gasoline. Given the increasing human population, using grain for fuel rather than food promises to be highly problematic. There is reason to be optimistic about cellulosic ethanol, but even with technological breakthroughs it’s unlikely to be a wholesale remedy. Instead, we’ll need advanced biofuels among a variety of solutions, including increased fuel efficiency; lower speed limits and less driving; advanced public transportation; electric and hybrid-electric vehicles; and more.