The use of ethanol as an alternative fuel source

Bio-ethanol is manufactured from fermenting starch, wheat and sugar cane. Ethanol is also made from the hydration of ethylene from petroleum, though the majority of ethanol is produced by fermentation. It is considered an alternative fuel source as it is regarded to be renewable and more beneficial to the environment. As a car fuel ethanol is blended with petrol in different concentrations.

In cars, carbon monoxide is produced from the incomplete combustion of petroleum. By adding ethanol which has 35% oxygen the combustion is more complete and there for reducing the amount of carbon monoxide. Within Australia, studies have shown that the effects of 10% ethanol have decreased the amount of carbon monoxide emissions.

In Brazil 10% of the energy used is provided from ethanol. In car fuel the mix of ethanol and petrol is about 85% ethanol with only about 15% petrol but in Australia fuels that contain ethanol are mainly about 10% ethanol and 90% petrol. Though a 85% ethanol blend has started being used in Australia but is not available at all petrol stations. As a car fuel it is blended with petrol to decrease how fast petrol burns, extend petrol reserves and to reduce green house gas emissions. For Brazil the use of ethanol as a car fuel has been very successful as it has a very large starch industry. It is also beneficial to the country economically because the high concentration use of ethanol has replaced expensive oil imports with locally produced fuels.

Australia has previously avoided E10 as an alternative fuel. Many people choose to not use ethanol to avoid the possible damage it can do to engines not designed for it. That is; the deterioration of rubber and plastic components in the fuel system. Also redesigning car engines are expensive, however newer cars are E10 ready.

Since 2006 Australian car fuel E10, is being increasingly used in cars following government legislation allowing it. Since 1996, Ford has sold more than 1.6 million cars that can run of ethanol. This shows how car companies have realised the potential ethanol has as a car fuel. Many new cars can be converted to run on E85 and the number of petrol stations that provide E85 and E10 is slowing increasing.

Natural gas when used in vehicles creates less harmful emissions than petrol or diesel. Natural Gas needs to be stored at high pressure 3500 psi (compressed natural gas) and is only 30% as efficient as petrol. For this reason it is not suitable for normal cars, but is being trialled on busses and trucks as a diesel substitute. Electricity can be used as an alternative fuel for battery powered electric vehicles but at the moment batteries only give a limited range. Electric cars can be made into a very efficient Hybrid that increases range. The cost of electricity and the carbon cost to recharge batteries and replace used batteries makes this less attractive environmentally but it is a viable alternative from a fuel CO2 emissions point of view.

Biodiesel fuel uses vegetable oils or animal fats, even those recycled after restaurants have used them for cooking. Biodiesel has many environmental advantages to diesel such as lower emissions and its renewable, though it needs modifications to avoid fuel flow problems at cold temperatures. Diesel vehicles that are able to use biodiesel are increasing in numbers. Liquid Petroleum Gas is currently supplying to high mileage, light vehicles in many countries. Although around 80% of the energy efficiency of petrol, it is much less expensive and produces 30% less CO2 emissions. Stored at only 200 psi is efficient to carry and fill. It is a by product of oil, so is non renewable. It is currently supported as an alternative fuel by government conversion subsidies.

The advantage for ethanol is that it is offered as part of service station infrastructure and is used the same way as petrol. Service stations already have hoses and tanks available for conversion to E10. Biodiesel and LPG also use petrol stations, this assists in the take up of the alternative fuel techniques because it does not involve costumers having to change routine. This is an advantage over electric cars which reply on electrical boosting stations which don’t exist at the moment or on large household transformers. Compressed Natural Gas requires a total purpose built infrastructure and for the foreseeable future will only be used for long haul freight as there are not many places to fill up.

There are many factors that affect the consideration of ethanol as an alternative fuel source. When compared to more commonly used fuels ethanol has both positive and negative effects.

A main factor that contributes to its potential as an alternative fuel is that ethanol is a renewable source. Unlike petroleum which is derived from million year old fossils that cannot be replaced within a reasonable time period, ethanol is a renewable source of fuel as it can be produced from agricultural food crops. This means that it could be a readily available source of energy if there are sustainable amounts of crops.

It is also safer for the environment. Blending ethanol with petrol for fuel is seen as a way of reducing the amount of greenhouse gas emissions produced by cars. The higher the percentage of ethanol in fuel, the greater the reduction of gas emissions from cars. In cars, carbon monoxide, which has small amounts of oxygen, is produced from the incomplete combustion of petroleum. By adding ethanol which has 35% oxygen the combustion is more complete and there for reducing the amount of carbon monoxide.

For cars that are compatible with alcohol fuel, ethanol blend produces higher engine performance. By using E10 the octane rating will increase which means the rate at which petrol burns will be slower, engines will be cleaner as the ethanol burns more completely leaving less carbon deposits and as a result of more complete combustion will also work more smoothly.

Even though the use of ethanol as a fuel reduces the amount of greenhouse gases, its energy output is less than petrol. Ethanol produces about 34% less energy in cars meaning that for every kilometre travelled by a car using petrol it would consume 34% less fuel to yield the same amount of energy.

A down side to using ethanol as a fuel is that the amount of cars in Australia that can use it is limited. It has only been within the last 5 to 10 years that cars began to be manufactured with specially designed engines to cope with the use of alcohol fuels. In car engines not designed for alcohol fuels, ethanol can cause deterioration of the rubber and plastic parts of the fuel system meaning many cars are unable to safely use ethanol fuel.

The crops necessary for the production of ethanol raises ethical issues lowering its potential as an alternative fuel source. As the demand for ethanol increases, the land needed for growing suitable crops would also have to increase. This creates problems such as food crops being used for fuel instead of human and animal food consumption. About 3 billion people in the world are malnourished and every day the global population increases and more people will require food. As more land is used to produce ethanol the land used to produce food may decrease.

Although the use of ethanol as a fuel has been limited, it has the potential to decrease the demand for petroleum which will eventually run out. It is better for the environment as it reduces green house gases but at the moment the limited amount of potential users and the availability and stability of crops significantly impacts the effectiveness of using ethanol as a fuel along with the ethical issues that need to be considered.

Websites:

Microbiology. (2006). Mad Sci Network [Internet]. Available from: [Accessed on: 26 February, 2009].

Ethanol case studies (2009). Queensland Government [Internet]. Available from: [Accessed on: 26 February, 2009].

Books:Anderton J.D, Garnett P.J, Liddlelow W.K, Lowe R.K, and Manno I.J, (1996). Foundations of chemistry. Publisher: Longman. Printed by: Longman in Malaysia.