Hemp Ethanol vs Petrol

May 8, 2008

Hemp Ethanol vs Petrol:

Net Reduction in Ground-level Ozone Forming Emissions: Ground-level ozone causes human respiratory problems and damages many plants but does nothing to increase ozone concentration in the stratosphere that protects the earth from the sun’s ultraviolet radiation. There are many compounds that react with sunlight to form ground-level ozone, which, in combination with moisture and particulate matter, creates ‘smog’, the most visible form of air pollution. These compounds include carbon monoxide, unburned hydrocarbons, benzene, and nitrogen oxides (nitrous oxide and nitric oxide).

In an effort to reduce automobile emissions that contribute to the formation of ground-level ozone, the highly populated state of California has legislated stringent automobile emissions standards. Several Canadian urban centers record similar hazardous exposures to carbon monoxide, especially during late fall and winter, and would be out of compliance if Canada implemented air quality legislation equivalent to the U.S. Clean Air Act. In Canada, southern Ontario, southern British Columbia, and parts of Nova Scotia and New Brunswick are prone to smog. Using oxygenated fuels, such as ethanol, is one way of addressing the issue of air pollution.

The net effect of ethanol use results in an overall decrease in ozone formation. The emissions produced by burning ethanol are less reactive with sunlight than those produced by burning gasoline, resulting in a lower potential for forming the damaging ozone. In Canada, where the volatility of ethanol blends must match normal gasoline, the ozone forming potential of ethanol blends is even lower than in the U.S., where ethanol blends are allowed to have increased volatility.

Reduction in Harmful Greenhouse Gases: The ‘Greenhouse Effect’ refers to the Earth’s atmosphere trapping the sun’s radiation. It is a term often used synonymously with ‘Global Warming’, which refers to the increasing average global temperature, arising from an increase in greenhouse gases from industrial activity and population growth. Greenhouse gases contributing to the Greenhouse Effect include carbon dioxide, methane, and nitrogen oxide.

The term ‘Climate Change’ refers to a wide range of changes in weather patterns that result from global warming. A substantial increase in the Earth’s average temperature could result in a change in agricultural patterns and melting of polar ice caps, raising sea levels and causing flooding of low-lying coastal areas.

The use of ethanol-blended fuels such 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%. By the year 2010, the reductions for E85 and E10 are projected to be 44.5% and 4.6%, respectively. This represents only a small percentage of the total greenhouse gas reduction required from the Kyoto Protocol. It is expected that once ethanol is made from cellulose, the greenhouse gas emissions reductions will further improve. Hemp produces four times as much cellulose per acre than trees.

Emissions Reductions from Using Ethanol-Blended Fuels:

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.

Sulphur Dioxide (SO2) and Particulates: 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.

References: Environmental Benefits of Ethanol


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