- Joined
- 14 February 2005
- Posts
- 15,190
- Reactions
- 17,194
Re: Petrol - $1.40-1.50 / litre by year end?
10% ethanol blended with petrol is generally accepted in the oil industry as being acceptable for use in vehicles designed to run on unleaded petrol (ULP). This should cause no problems. This is known as E10.
Up to 23% may be used without major fuel system modifications. Using a higher concentration than this will require the replacement of rubber components etc.
100% ethanol is generally not considered to be acceptable for two reasons although it has been used. Firstly, people will drink the stuff. Seccondly, a fire in the open air during daylight hours is literally invisible. Ethanol burns with a pale blue flame. Since ethanol is highly flammable just like petrol, this is a significant safety issue especially at service stations etc. It's a bit hard to extinguish a fire that you can't see!
To overcome the problems with 100% ethanol, a blend of 85% ethanol / 15% petrol is used. This is known as E85. This deliveres most of the benefits of ethanol whilst preventing human consumption. E85 burns with a visible yellow flame just like petrol (but with less black smoke). This overcomes the fire safety issues.
Ethanol in various blends is used in many countries without undue problems. Media reports relating to the negatives of ethanol in Australia some years ago were ultimately a result of some independent fuel distributors suppying petrol blended with more than 23% ethanol, mostly in NSW. Other fuel blending incidents involved adding toluene to petrol. In both cases the motivation to do so is financial (in the case of toluene was purely tax avoidance). These practices will cause damage to vehicles and have unfortunately damaged the reputation of ethanol in general.
At the time of the public concern over ethanol, BP was selling E10 in Brisbane without problems. Demand slumped following the media publicity although the 10% blend that BP were selling appears to have caused no problems.
Ethanol blends CAN be used in two-stroke engines (lawn mowers, outboards etc.) although it is not an indeal situation. Use straight petrol for two-stroke engines wherever possible. (Better still, don't use two-stroke engines wherever possible, especially in urban areas, since they are incredibly polluting. That said, there's not much choice for chainsaws, brushcutters etc. but a four stroke mower will help air quality more than you might expect.)
Ethanol is an oxygenate and thus promotes more complete fuel combustion. To some extent this will offset the lower energy density of ethanol as compared to petrol such that overall volume fuel consumption changes are minimal. Overall energy consumption (no smart comments about energy not being "consumed" - you know what I mean
) would fall slightly due to the more complete combustion.
Various US states specify the use of reformulated gasoline (RFG) as a means of reducing vehicle exhaust emissions.. This must generally contain an oxygenate as a legal requirement. Whilst there are various oxygenates, MTBE (produced from methanol which is itself produced from natural gas) has historically dominated the market for financial reasons. Unfortunately, MTBE is particularly persistent as a ground water pollutant and most service station fuel tanks will at some stage leak (this is why you often see drilling rigs around old service station sites even in city areas. They are testing for (leaked) petrol and diesel). The MTBE ground water pollution problem has become serious and has resulted in the phasing out of MTBE as an oxygenate in the US.
MTBE also increases petrol MON and RON ("octane") thus permitting the purchase of lower grade petrol by wholesalers which can be sold as higher grade following the addition of MTBE. A well known Australian service station chain unsuccessfully applied to use MTBE in order to import low grade petrol and increase the octane via addition of MTBE.
Fortunately, ethanol is not only an oxygenate but is an octane booster as well. Ethanol is thus viewed as a replacement for MTBE although it is not the only option.
Point of use emissions will change with ethanol blends as compared to non-blended petrol. Exhaust hydrocarbon (HC) emissions in particular should be significantly reduced due to the more complete combustion. However, evaporative fuel losses during Summer in particular tend to increase. Depending on the location and the relevant standards, the meeting of reed vapour pressure (RVP) requirements is problematic with the use of ethanol blends.
The real environmental concern however relates to resource use and greenhouse emissions. The situation here is somewhat difficult to assess and is also controversial due to the vested interests involved in both sides of the debate.
Whilst the ethanol itself is exactly the same, the environmental and resource situation can be divided into two categories - ethanol produced from waste and ethanol produced from purpose grown crops.
In the case of using waste to produce ethanol, environmental impacts are limited to building the ethanol production plant, electricity to run it etc. They are minimal compared to the petrol consumption displaced such that there is little disagreement that the utilisation of waste in this manner constitutes an overall saving of resources and benefit to the environment.
The situation is very different where crops are grown specifically to produce ethanol. Agriculture is incredibly petroleum dependent. Nitrogen fertilizers are produced directly from natural gas. Most chemicals are produced from oil or gas. Farm machinery runs on oil. Then you have the non-fuel issues such as water, land degradation etc. And then there's moral issues about using land to grow automotive fuel whilst millions overseas are undernourished.
Various studies have been done into the issue. As a rough guide, it has been found that around two thirds of the energy content of the ethanol is used to produce it where crops are purpose grown. So, if you produce enough ethanol to displace 30 litres of petrol at the point of use (car) then it has taken the equivalent of 20 litres of oil (partly in the form of natural gas for fertilizer) to produce it. The environmental economics (as opposed to financial economics) of growing crops to produce ethanol are thus somewhat marginal once land use, runoff, chemicals etc. issues are included.
It has been suggested that the use of wood as an ethanol feedstock would deliver environmental benefits as compared to fast growing crops. I am unable to confirm this since it is fundamentally a debate about forestry versus broadacre farming.
Forestry is a contentious issue although I must point out that most farms are land that was once forested. Regardless of what crop is now grown, in most cases trees were cleared to enable it. Simply growing more trees and then cutting them down again is thus not that different to growing any other crop when viewed this way.
It would seem logical to use forest WASTES to produce ethanol rather than simply burning it in the open as is presently done. This would not affect the number of trees cut in any way but would produce significant volumes of ethanol from an otherwise wasted resource.
Whilst some have suggested using this wood to generate electricity it must be considered that electricity can be produced from numerous resources (coal, nuclear, hydro, solar, wind, geothermal, wave, tidal etc. and of course oil) whereas liquid fuels supply is becomming a far greater problem with most OECD countries (including Australia) affected by faltering domestic oil production and rising imports.
My personal view is that we should use the available agricultural and forest WASTES to produce ethanol as a matter of urgency. This would lead to a relatively low concentration of ethanol being added to petrol which should not cause problems. Benefits to regional Australia would occur due to the ethanol production plants being most economically situated near the source of feedstock. The option of growing crops specifically for ethanol production needs detailed study to increase certainty about the the benefits / disadvantages from a resource and environmental perspective. Such detailed studies should be undertaken as a priority matter IMO.
10% ethanol blended with petrol is generally accepted in the oil industry as being acceptable for use in vehicles designed to run on unleaded petrol (ULP). This should cause no problems. This is known as E10.
Up to 23% may be used without major fuel system modifications. Using a higher concentration than this will require the replacement of rubber components etc.
100% ethanol is generally not considered to be acceptable for two reasons although it has been used. Firstly, people will drink the stuff. Seccondly, a fire in the open air during daylight hours is literally invisible. Ethanol burns with a pale blue flame. Since ethanol is highly flammable just like petrol, this is a significant safety issue especially at service stations etc. It's a bit hard to extinguish a fire that you can't see!
To overcome the problems with 100% ethanol, a blend of 85% ethanol / 15% petrol is used. This is known as E85. This deliveres most of the benefits of ethanol whilst preventing human consumption. E85 burns with a visible yellow flame just like petrol (but with less black smoke). This overcomes the fire safety issues.
Ethanol in various blends is used in many countries without undue problems. Media reports relating to the negatives of ethanol in Australia some years ago were ultimately a result of some independent fuel distributors suppying petrol blended with more than 23% ethanol, mostly in NSW. Other fuel blending incidents involved adding toluene to petrol. In both cases the motivation to do so is financial (in the case of toluene was purely tax avoidance). These practices will cause damage to vehicles and have unfortunately damaged the reputation of ethanol in general.
At the time of the public concern over ethanol, BP was selling E10 in Brisbane without problems. Demand slumped following the media publicity although the 10% blend that BP were selling appears to have caused no problems.
Ethanol blends CAN be used in two-stroke engines (lawn mowers, outboards etc.) although it is not an indeal situation. Use straight petrol for two-stroke engines wherever possible. (Better still, don't use two-stroke engines wherever possible, especially in urban areas, since they are incredibly polluting. That said, there's not much choice for chainsaws, brushcutters etc. but a four stroke mower will help air quality more than you might expect.)
Ethanol is an oxygenate and thus promotes more complete fuel combustion. To some extent this will offset the lower energy density of ethanol as compared to petrol such that overall volume fuel consumption changes are minimal. Overall energy consumption (no smart comments about energy not being "consumed" - you know what I mean
) would fall slightly due to the more complete combustion.Various US states specify the use of reformulated gasoline (RFG) as a means of reducing vehicle exhaust emissions.. This must generally contain an oxygenate as a legal requirement. Whilst there are various oxygenates, MTBE (produced from methanol which is itself produced from natural gas) has historically dominated the market for financial reasons. Unfortunately, MTBE is particularly persistent as a ground water pollutant and most service station fuel tanks will at some stage leak (this is why you often see drilling rigs around old service station sites even in city areas. They are testing for (leaked) petrol and diesel). The MTBE ground water pollution problem has become serious and has resulted in the phasing out of MTBE as an oxygenate in the US.
MTBE also increases petrol MON and RON ("octane") thus permitting the purchase of lower grade petrol by wholesalers which can be sold as higher grade following the addition of MTBE. A well known Australian service station chain unsuccessfully applied to use MTBE in order to import low grade petrol and increase the octane via addition of MTBE.
Fortunately, ethanol is not only an oxygenate but is an octane booster as well. Ethanol is thus viewed as a replacement for MTBE although it is not the only option.
Point of use emissions will change with ethanol blends as compared to non-blended petrol. Exhaust hydrocarbon (HC) emissions in particular should be significantly reduced due to the more complete combustion. However, evaporative fuel losses during Summer in particular tend to increase. Depending on the location and the relevant standards, the meeting of reed vapour pressure (RVP) requirements is problematic with the use of ethanol blends.
The real environmental concern however relates to resource use and greenhouse emissions. The situation here is somewhat difficult to assess and is also controversial due to the vested interests involved in both sides of the debate.
Whilst the ethanol itself is exactly the same, the environmental and resource situation can be divided into two categories - ethanol produced from waste and ethanol produced from purpose grown crops.
In the case of using waste to produce ethanol, environmental impacts are limited to building the ethanol production plant, electricity to run it etc. They are minimal compared to the petrol consumption displaced such that there is little disagreement that the utilisation of waste in this manner constitutes an overall saving of resources and benefit to the environment.
The situation is very different where crops are grown specifically to produce ethanol. Agriculture is incredibly petroleum dependent. Nitrogen fertilizers are produced directly from natural gas. Most chemicals are produced from oil or gas. Farm machinery runs on oil. Then you have the non-fuel issues such as water, land degradation etc. And then there's moral issues about using land to grow automotive fuel whilst millions overseas are undernourished.
Various studies have been done into the issue. As a rough guide, it has been found that around two thirds of the energy content of the ethanol is used to produce it where crops are purpose grown. So, if you produce enough ethanol to displace 30 litres of petrol at the point of use (car) then it has taken the equivalent of 20 litres of oil (partly in the form of natural gas for fertilizer) to produce it. The environmental economics (as opposed to financial economics) of growing crops to produce ethanol are thus somewhat marginal once land use, runoff, chemicals etc. issues are included.
It has been suggested that the use of wood as an ethanol feedstock would deliver environmental benefits as compared to fast growing crops. I am unable to confirm this since it is fundamentally a debate about forestry versus broadacre farming.
Forestry is a contentious issue although I must point out that most farms are land that was once forested. Regardless of what crop is now grown, in most cases trees were cleared to enable it. Simply growing more trees and then cutting them down again is thus not that different to growing any other crop when viewed this way.
It would seem logical to use forest WASTES to produce ethanol rather than simply burning it in the open as is presently done. This would not affect the number of trees cut in any way but would produce significant volumes of ethanol from an otherwise wasted resource.
Whilst some have suggested using this wood to generate electricity it must be considered that electricity can be produced from numerous resources (coal, nuclear, hydro, solar, wind, geothermal, wave, tidal etc. and of course oil) whereas liquid fuels supply is becomming a far greater problem with most OECD countries (including Australia) affected by faltering domestic oil production and rising imports.
My personal view is that we should use the available agricultural and forest WASTES to produce ethanol as a matter of urgency. This would lead to a relatively low concentration of ethanol being added to petrol which should not cause problems. Benefits to regional Australia would occur due to the ethanol production plants being most economically situated near the source of feedstock. The option of growing crops specifically for ethanol production needs detailed study to increase certainty about the the benefits / disadvantages from a resource and environmental perspective. Such detailed studies should be undertaken as a priority matter IMO.
