Under current conditions, use of ethanol-blended fuels as E85 (85% ethanol
and 15% gasoline) can reduce the net emissions of greenhouse gases by as much as 37.1%. Ethanol-blended fuel as
E10 (10% ethanol and 90% gasoline) reduces greenhouse gases by up to 3.9%. These blends are available at 1,000
retail stations across Canada. By the year 2010, the reductions for E85 and E10 are projected to be 44.5% and 4.6%,
respectively. This represents about 1% of the total greenhouse gas reduction required to meet Canada's commitment
to the Kyoto Protocol (Levelton Engineering Ltd. and (S&T)2 Consulting Inc., 1999). It is expected that once ethanol is made from cellulose,
the greenhouse gas emissions reductions will further improve.
Emissions Reductions from Using Ethanol-Blended Fuels
30% Reduction in Carbon Monoxide (CO) Emissions
Use of a 10% ethanol blend results in a 25-30% reduction in carbon monoxide emissions by promoting a more complete combustion of the fuel.
6-10% Reduction in Net Carbon Dioxide (CO2) Emissions
Use of 10% ethanol-blended fuels results in a 6-10% net reduction of CO2. The carbon dioxide released from ethanol production and use is less than that absorbed by the plants and soil organic matter used to produce ethanol. The carbon dioxide produced during ethanol production and gasoline combustion is extracted from the atmosphere by plants for starch and sugar formation during photosynthesis. It is assimilated by the crop in its roots, stalks and leaves, which usually return to the soil to maintain organic matter, or in the grain, the portion currently used to produce ethanol. Over time, the organic matter breaks down to CO2, but with the implementation of conservation measures, such as reduced tillage, the soil organic matter will build up. Therefore, by increasing its organic matter content, the soil acts as a significant sink for carbon dioxide.
Volatile Organic Compounds (VOC's)
Volatile organic compounds are highly reactive in the atmosphere, and are significant sources of ground-level ozone formation. Because ethanol oxygenates the fuel, there is approximately a 7% overall decrease in exhaust VOC's emitted from low-level ethanol-blended fuels relative to conventional fossil fuels. In high level blends, the potential for exhaust VOC reduction is 30% or more.
There is insufficient Canadian data on the emissions of evaporative VOCs. In Canada, where the volatility of ethanol blends must match normal gasoline, the VOCs emitted should be less than in the U.S., where ethanol blends are allowed to have increased volatility. Due to these Canadian regulations, the evaporative emissions of VOC's from ethanol blends are approximately equal to those from conventional gasoline. Although there is no existing Canadian data, it is highly likely that in high-level ethanol blends, due to a lower vapour pressure, there is a reduction in evaporative VOC emissions.
Sulphur Dioxide (SO2) and Particulates
Neither sulphur dioxide nor particulate matter emissions are considered of significance in gasoline-powered engines. Nevertheless, Environment Canada is encouraging lower sulphur levels in gasoline, since sulphur can adversely affect the performance of emission-reducing catalytic converters. As ethanol contains no sulphur, and because it promotes more complete fuel combustion, blending gasoline with ethanol would reduce any potential for these emissions and the adverse effects of sulphur. In diesel engines, where SO2 and particulates are of concern, the use of ethanol-blended diesel or neat ethanol shows a significant reduction in these emissions.
What are the environmental implications of feedstock production associated with the production of ethanol for fuel?
Fuel ethanol is produced from biologically renewable sources, such as grain or wood products.
With the development of sustainable and environmentally sensitive production methods in the agricultural sector, the impact of farming practices is very minimal. The demand for grain to produce fuel ethanol has not resulted in an increased corn or wheat acreage in Canada.
Ethanol contains about 22,400 (high heating value) BTUs per litre. The energy content, however, may not be as important as the energy replaced. Due to the higher combustion efficiency of ethanol and its octane credit at the refinery, for example, ethanol can replace 26,575 BTU of gasoline (Levelton Engineering Ltd. and (S&T)2 Consulting Inc.).
Using the displacement value for calculating the energy content of co-products, there is a further 3,720 BTU/litre of energy in ethanol represented by the co-products. The total energy represented b a litre of ethanol is therefore 30,290 BTU.
It takes about 4,700 BTU of energy to grow the corn required for one litre of ethanol. This is about 15.5% of the energy in the ethanol and the co-product. It takes a further 13,300 BTU (43.9%) of the energy in the ethanol) to process the corn to ethanol using current technology and practices. It is expected that fully optimized plants will be able to lower this to 10,600 BTU (35.0%) in the near future.
If corn farmers use state-of-the-art, energy efficient and sustainable farming techniques and ethanol plants integrate state-of-the-art production processes, the amount of energy contained in the ethanol and its co-products can be more than twice the energy used to grow the corn and convert it into ethanol.
The environmentally beneficial attributes of ethanol-blended gasoline have resulted in its designation as an "Environmental ChoiceTM" product by the Canadian General Standards Board, and it is therefore eligible to have the "EcoLogoTM" displayed at licensed retail outlets.
Greening the Fleet
'FleetWise' is a federal initiative to address the pollution caused by vehicle emissions and its effect on climate change. It involves a gradual phased-in increase in use of alternative fuels, such as ethanol. The Government of Canada has committed to integrating environmental considerations and sound management practices in the operation of its motor vehicles. This includes a phased-in acquisition of alternative fuel vehicles by the year 2005.
Where to Get More Information
Canadian Renewable Fuels Association
90 Woodlawn Rd. W.
Guelph, Ontario N1H 1B2