JUST HOW ENVIRONMENTALLY
FRIENDLY IS ETHANOL?
Fuel ethanol has received wide-spread support from many sources because of its benefits to the environment. These benefits have come under increasing scrutiny by sceptics.
How does fuel ethanol stack up, environmentally? Is this truly "green fuel"?
What are the facts?
A key issue is energy efficiency? Former Ontario agriculture minister, Elmer Buchanan said, soon after his election, that he'd support fuel ethanol if he could be sure it contained more fuel energy than was needed for its production. As a result, the Ontario government funded a major study, called the "Cemcorp" study. Cemcorp examined a number of questions about ethanol, including energy efficiency. The conclusion? Ethanol contains at least twice the amount of energy (sunshine energy not included) as is needed for its production, including the production of corn used as a feedstock. This includes all inputs used to grow corn. Further, the energy efficiency is expected to increase substantially in the coming decade according to Cemcorp analysts. These findings are consistent with those of several U.S. studies, including one done by the U.S. Department of Energy.
High levels of carbon monoxide in automobile exhaust are a health hazard. Carbon monoxide emissions are greatest with cold engines and cold outside temperatures. This is why the use of "oxygenated" gasolines (eg., ethanol-blended gasoline) is mandated in many U.S. cities during winter months, and why several auto manufacturers, including GM, recommend its usage. If Canada used the same air quality standards as the U.S., the use of oxygenated gasolines would be mandatory in many Canadian cities as well. Research data show up to 30% reduction in carbon monoxide emissions when ethanol-blended gasoline is used.
Carbon monoxide emissions are lower with fuel injected engines, than with carburetted engines, but this is only after the engines are fully warmed up. In many cities, in winter, this may rarely occur with commuter cars. Stop-and-go traffic heightens carbon monoxide emissions. And recent data show significant reductions in carbon monoxide emissions even from warmed-up fuel-injected engines, when ethanol-blended gasoline is used.
Ground-level ozone is a summer-time air pollution problem with automobiles. Many exhaust compounds such as nitrogen oxides and unburned hydrocarbons, and evaporative emissions from gasoline (eg., vapours released during refilling) are ozone "precursors" (they cause ozone formation in the presence of sunlight). Carbon monoxide is also an ozone precursor. U.S. studies have found that ethanol-blended gasoline, on balance, is mildly beneficial with respect to its contribution to ozone formation, compared to gasoline.
But U.S. ethanol-blended gasoline is different than in Canada. U.S. ethanol-blended gasoline is granted a "waiver" which allows it to be more volatile (up to 1 psi in Reid Vapour Pressure to be specific) than regular gasoline. This increases evaporative emissions and the potential for ozone formation. In most of Canada, including Ontario, ethanol-blended gasoline must meet all federal gasoline standards, including that for volatility. There is no Canadian waiver. Because of this, the use of Canadian ethanol-blended gasoline means decreases in ground-level ozone formation as compared to regular gasoline.
A major environmental problem with gasoline involves compounds added to raise its octane level. Lead was used until recently. Now MMT, a manganese-containing compound, is widely used for this purpose in Canada. MMT is rarely used in the U.S. for environmental reasons. The use of MMT is opposed by Canadian automobile manufacturers because it messes up pollution control equipment on modern cars. Another octane "biggie" is benzene and other benzene-like compounds. These are high in octane, but benzene is a powerful liver carcinogen. In general, the higher the octane level, the more benzene found in Canadian gasoline. Because of this heath hazard, authorities are moving to limit benzene levels in U.S. gasoline - but not in Canada. Pity! Farmers who have safety masks for use when applying pesticides should use them when filling their cars at self-service stations, especially with high-test gasolines which don't contain ethanol.
Ethanol is a high-octane alternative to MMT, benzene, and a number of other hazardous compounds. Ethanol can be hazardous to liver health, as well, but only if imbibed regularly, in large quantities. Fuel ethanol is intended for use in cars, not for drinking - indeed, it's "denatured," usually by blending in about 5% gasoline, so that it's impossible to drink.
The potential for ethanol made from corn and other biological materials to reduce net carbon dioxide emissions to the atmosphere is a major environmental strengths.
Environment Canada estimated, in the late 1980s, that the replacement of a litre of gasoline by a litre of ethanol means a 40% reduction in net carbon dioxide emissions (including emissions associated with the growing of corn, and the manufacture and transport of all inputs). This is similar to the results of U.S. government studies.
A more recent analysis by Natural Resources Canada has found the actual ratio to be up to 100%, using corn and ethanol production technology appropriate to Ontario.
Some recent media articles have cited a 1993 analysis done for the Paris-based OECD purporting to state that ethanol-blended gasoline represents no benefit over regular gasoline, in net carbon dioxide emissions, when the ethanol is made from "maize." But most of these critics and journalists have not actually read the OECD report (over 200 pages) which shows, in fact, that the calculated ratio of net greenhouse emissions with ethanol- made-from-corn to those associated with gasoline usage ranges from 30 to 170% - depending upon assumptions made about corn production and co-product usage. Much higher greenhouse gas emissions can be expected in western Europe because of the much more energy-intensive nature of corn production technology used there, as compared to Ontario.
Future usage of fuel which is higher in ethanol - for example, "E85" containing 85% ethanol, now being introduced in the U.S. - will mean far greater reductions in the net amount of carbon dioxide released as a result of automobile travel.
Oxygenated gasolines, including those containing ethanol, form more aldehydes during engine combustion than do non-oxygenated gasolines. Some of these aldehydes can be health hazards. However, the Royal Society of Canada studied this risk as part of mid- 1980s research which led to the banning of lead-containing gasoline in Canada. The Royal Society of Canada concluded (1986) that, with respect to the use of ethanol-blended gasoline, "the amounts [of aldehyde emissions] involved are extremely small and they are quite efficiently removed by the [exhaust system] catalysts, so that the possibility of negative health effects appears to be remote."
What is it worth to have a renewable, home-grown supply of transportation fuel instead of increasing dependence on imports of off-shore light crude oil (projected by the Energy Board of Canada to exceed 500,000 barrels per day by the late 1990s, and this is after Hibernia comes on stream.) What is it worth to reduce the risk of tanker wreckage off Canada's coasts?
These must also be considerations in any analysis of the overall environmental benefits of fuel ethanol.