The problem is that ethanol’s benefits have been greatly exaggerated, leading to Congressional regulations that required ever-increasing amounts of ethanol in our gasoline supply. The government requirement goes back to 2005, when gas prices were much higher and the U.S. was in the midst of the Iraq war. Ethanol was supposed to be a clean way to reduce our dependence on foreign oil. The growing mandate for ethanol has instead created an enormous, artificial demand that has had unintended consequences, many of them bad.
Some background: Congress requires automakers to meet fuel economy (“CAFE”) standards for all their cars and light trucks. To encourage ever-greater use of ethanol, Congress modified the CAFE standards in 2005. As a result of that law, this year the EPA will require refiners to use 18.1 billion gallons of ethanol to fuel our cars.
Politicians still love ethanol. In the 2016 presidential campaign, several candidates came out in support of continuing the corn-based fuel program, hoping this position would win them votes in the Iowa caucuses. Iowa is a big corn state.
Unfortunately for the rest of us, mandating the use of ethanol is a terrible policy. Here are three reasons why.
1. Ethanol lowers your gas mileage–a lot. Ethanol only has about 2/3 the energy content of gasoline, meaning it simply cannot provide the same amount of power per gallon (or liter) as gas. E85 fuel, which uses 85% ethanol and 15% gasoline, is widely available, and some gas stations now offer no alternative. Consumer Reports put E85 to the test, and found that highway mileage decreased by 29% and city mileage by 22%. Car and Driver ran their own tests and found a 30% drop in mileage on E85. According to the Union of Concerned Scientists, nearly all gas sold in the US today has 10% ethanol–much less than in E85, but still providing lower fuel efficiency than straight gasoline.
Making things worse, ethanol attracts water and is more corrosive to some metals and rubber than gasoline. So it's bad for your car.
2. Using ethanol doesn’t reduce carbon emissions. The main argument for using ethanol is that because the carbon contained within it was recently put in the ground, burning ethanol (and releasing that carbon) is carbon neutral. Compared to extracting oil, which has lain in the ground for millions of years, growing corn and extracting ethanol puts far less carbon back in the atmosphere.
This argument makes sense, but only in a very narrow context. In an article published in Science in 2008, Timothy Searchinger and colleagues pointed out that previous analyses
“failed to count the carbon emissions that occur as farmers worldwide respond to higher prices and convert forest and grassland to new cropland to replace the grain (or cropland) diverted to biofuels.”When the scientists accounted for these land-use changes, they found that using corn to produce ethanol will double greenhouse emissions over a 30-year period. Switchgrass is only slightly better, increasing emissions by 50%. As the Union of Concern Scientists explains that “sustainable production is possible” only if we stop making ethanol from corn.
Admittedly this is a complex topic, but it seems that ethanol-from-corn simply doesn't reduce carbon emissions. Thus the entire justification for using ethanol to fuel our cars is unsound.
3. Increasing fuel efficiency means we’ll never be able to meet Congress’s mandated levels of ethanol usage, not unless we sacrifice even more gas mileage. Automakers have made great progress in producing more fuel-efficient cars, and the growing electric car market (Tesla!) mean that we’re using less and less fuel each year. This is terrific for reducing carbon emissions, but it means that Congress’s original mandate to use more ethanol becomes far harder to satisfy.
What happened was that back in 2005, Congress told us how to solve a problem (carbon emissions from our cars), instead of just encouraging us to solve it using innovative new ideas. Corn producers and their government representatives—governors, Senators, Representatives—all got behind the ethanol “solution” because they saw increased profits in it. Now we are stuck with a non-solution that, as the NY Times recently put it, is “a boon for Iowa and a boondoggle to the rest of the country.” It’s long past time to end the ethanol mandate.