3.4 Ethanol

Ethanol has been used as a vehicle fuel since the early part of the 20^th century when Henry Ford converted a 1908 Model T to run on alcohol. Ethanol is flammable, colourless, volatile liquid possessing a strong odour. Hydrogen bonding causes pure ethanol to be hygroscopic, readily absorbing moisture from the air. Ethanol is produced both as a petrochemical, through the hydration of ethylene, and biologically, by fermenting sugars with yeast.

Ethanol can be produced from any feedstock containing plentiful natural sugars or starch that can be readily converted to sugar. Popular feedstocks include sugar cane (Brazil), sugar beets (Europe), wheat and corn (US and Canada). In North America, corn or wheat grain is processed to sugar in wet and dry mills. The sugar is fermented and the resulting mix is distilled and purified to obtain anhydrous ethanol. Major by-products from the ethanol production process include dried distillers’ grains and solubles, which are suitable for animal feed.

Cellulosic ethanol is produced from lignocellulose, a structural material that comprises much of the mass of plants. It is composed mainly of cellulose, hemicellulose and lignin. Corn stover, switchgrass, miscanthus and woodchips are some of the more popular cellulosic materials for ethanol production. Cellulosic ethanol is chemically identical to ethanol from other sources, such as corn starch or sugar, but has the advantage that the lignocellulose raw material is highly abundant and diverse. It does, however, require a greater amount of processing to make the sugar monomers available to the microorganisms that are typically used to produce ethanol by fermentation.

The Canadian firm, Iogen, brought the first pilot scale cellulose-based ethanol plant on-stream in 2004. This technology could turn a number of cellulosecontaining agricultural by-products, such as corncobs, straw, and sawdust, into renewable energy resources. To date, high capital costs have prevented the development of any commercial cellulosic ethanol plants in the United States or Canada. The Canadian Government has invested heavily in the commercialization of cellulosic ethanol and a production scale pilot plant is planned for Ontario.

Nearly all Canadian ethanol production is blended into gasoline at up to 10% by volume, to produce a fuel called E10. All cars and light-duty gasoline-powered trucks built for the North American market since the late 1970’s can run with a gasoline/ethanol blend of up to 10%.

Automakers (primarily Ford, GM and Chrysler) produce a number of Flexible Fuel Vehicles (FFV’s) for the North American market that can run on any blend of gasoline and ethanol up to 85% ethanol by volume (E85). More than 5 million FFV’s were produced for the US market from 1992 through 2005, because auto manufacturers were able to use FFV sales to offset US corporate average fuel economy (CAFE) requirements to avoid significant penalties.³ The FFV offering continues to be expanded in the US and Canada with additional FFV models becoming available in 2006 and 2007. Gasoline vehicles require minimal modifications at the OEM level to operate on E85. One or more sensors automatically detect the fuel mixture and the engine control unit tunes the timing of spark plugs and fuel-injectors so that the fuel will burn properly in the vehicle’s engine. As E85 is more corrosive, special fuel system materials are also required. Typically an OEM FFV does not command a premium price at the retail level.

Ethanol, and ethanol-blended gasoline, because of its ability to pick up water, cannot be transported by pipeline. Ethanol can be shipped by railcar or truck but must be blended at the terminal for those locations supplied by marine or pipeline. Dedicated tanks are required to store the ethanol and the gasolineblending component with which it will be mixed. The handling of ethanolblended fuels also requires modifications to the other aspects of the fuel distribution system, including trucks, retail storage tanks, and service station pumps.

³ Energy Information Administration – Biofuels in the US Transportation Sector – Originally published in the Annual Energy Outlook 2007, February 2007, Washington, DC.