For nearly 10 years, the U.S. Environmental Protection Agency (EPA) has required refiners to blend biofuels into gasoline and diesel sold in the U.S. The EPA recently finalized rules that effectively raise the ethanol portion of gasoline above the current 10 percent level. Such rules will likely create serious problems for motorists, fuel retailers and refiners, with no benefits for the environment.
The EPA’s biofuels regulations are part of a renewable fuel standard (RFS) first legislated by Congress in 2005 and amended in 2007. The RFS was primarily intended to improve energy security based on two key assumptions: that annual U.S. fuel consumption would continue rising indefinitely and that domestic oil supplies would be insufficient to meet that rising demand.
Both assumptions are false. Gasoline demand actually decreased since lawmakers enacted the legislation, driven by the 2007 recession and reduced consumption brought about by the replacement of older, less fuel-efficient vehicles with newer ones. In addition, domestic oil and gas production is up dramatically due to technological advances. The United States is now the world’s leading energy producer.
Nearly all gasoline sold today in this country contains up to 10 percent corn-based ethanol. This blend, known as E10, is not harmful to vehicle engines. However, that’s not true for higher-percentage blends. Ethanol is corrosive and attracts water. Testing such as that conducted by the Coordinated Research Council has shown that damage to engine seals, hoses, fuel systems and exhaust systems can occur when ethanol content in fuel rises above 10 percent. This applies to cars, trucks, motorcycles, boat engines, lawn mowers, snowmobiles and other gasoline-fueled engines.
“The majority of vehicles on the road today are designed and warranted for fuels up to E10,” says Elisabeth Vrahopoulou, senior fuels advisor for ExxonMobil Refining and Supply Company. “It is estimated that less than 15 percent of the cars and light-duty trucks are designed and warranted for blends containing more than 10 percent ethanol. In fact, auto manufacturers have unanimously advised consumers not to use higher ethanol blends like E15 in vehicles unless the owner’s manual specifies such fuels. The use of fuels with higher than 10 percent ethanol can void vehicle warranties.”
Over the years, some manufacturers have offered “flex fuel vehicles” (FFVs) that can safely use higher ethanol blends, including E85, which contains as much as 83 percent ethanol. But ethanol has lower energy density than gasoline and yields fewer miles per gallon. The market availability of E85 is limited because any retailer offering it must install expensive storage and handling systems to keep E85 separate from other fuels. According to the Petroleum Marketers Association of America, “… FFV owners are choosing to fill up with gasoline due to its 27 percent higher energy content and superior fuel economy. Given the slim margins on retail fuel sales, retailers are forced to convert slow-moving E85 tanks back to gasoline in order to increase volume and maintain profitability. Consumer choice is the real reason E85 pumps are on the decline.”
Given the trend of decreasing domestic gasoline demand, it follows that U.S. refiners won’t need more ethanol in the future to produce E10 fuels. Nevertheless, the EPA requires refiners to increase the amounts of ethanol they blend into their motor fuels each year. This not only increases the percentage of ethanol in motor fuel, but it ultimately exceeds the operational design standards of most automobiles.
While the EPA’s biofuels mandate for 2015 is about 17 billion gallons, that number more than doubles to 36 billion gallons by 2022. Non-food-based biofuels that could be used in place of higher ethanol blends – which
the RFS envisioned – are available commercially, but in very limited quantities due to significant technological and economic hurdles.
In short, the RFS requires fuels that are incompatible with today’s manufacturing technologies and vehicle fleet.
“The RFS should be scrapped, or at the very least reformed,” says Ken Cohen, Exxon Mobil Corporation Public and Government Affairs vice president. “The EPA should limit its ethanol mandates to no more than 9.7 percent of total U.S. gasoline demand. That would ensure that the gasoline sold at service stations across America does not pose any threat to the tens of millions of automobile engines not warranted by car manufacturers to handle gasoline with more than 10 percent ethanol.”
ExxonMobil clean fuels research
Our Corporate Strategic Research laboratory and ExxonMobil Research and Engineering Company conduct an array of programs designed to study future transportation fuels and engines. Biofuels research includes collaborating with Iowa State University on using heat to convert biomass into intermediates, which can then be upgraded into fuel, and research involving advanced biofuels from algae.
Other important programs include the study of advanced technologies for increasing fuel economy by separating fuel into high- and low-octane streams, which the engine can use to optimize fuel economy during driving.