PULP? Diesel? LPG? The choices can be confusing. NRMA's senior environmental advisor, Jack Haley, surveys the options and explores recent developments in car and fuel technology.
It used to be simple. If the car was low on petrol, you'd pull in to the closest servo and fill up the tank with petrol - leaded petrol. Times have changed and we are all more aware of the damaging environmental effects of what is emitted from our cars' exhaust pipes. Leaded petrol has been phased out and car manufacturers are slowly migrating to alternative energy and fuel-efficient cars. To help you next time you are looking to buy a car or need to fill up, here is a rundown of what is currently available, what has changed and what you can expect in the future.
There will be progressive environmentally-friendly changes to the specifications of standard unleaded petrol (ULP) over the next decade. The sulphur content of premium unleaded petrol (PULP) is 150 ppm (parts per million) now and all petrol, including standard ULP, must be at that level from 2005. In addition, the benzene content of petrol must be less than one per cent from 2006.
Some oil companies offer high octane (ultra-premium) unleaded petrol of 98 octane, compared with standard unleaded at 91 octane and premium unleaded at 96. There is no advantage in using high octane fuel unless your vehicle's engine management system is designed to adjust to take advantage of the higher octane. If in doubt, check your vehicle handbook.
Even if the engine does adjust for the higher octane, the maximum advantage is generally around one per cent increase in engine power (or reduction in fuel consumption) per octane number. Unless the price of the higher octane fuel is less in cents per litre than the difference between the fuels in octane numbers, it is probably not economically worth your while using the higher octane.
Leaded petrol was phased out in 2000 and replaced by Lead Replacement Petrol (LRP). LRP is essentially premium unleaded petrol (PULP) with an additive to protect engine valve seats and valve faces, which on older vehicles can erode without some protection.
The number of older vehicles that need LRP is decreasing, and it is probable that the oil industry will withdraw LRP. Motorists would then fill their vehicles with either premium or standard unleaded petrol, depending on the octane requirement for their vehicle, and buy a valve protection additive, available in concentrated form, over the counter.
The sulphur levels in standard diesel fuel will be reduced over coming years to enable vehicle manufacturers to introduce more advanced engine technology, and to reduce smoke emissions. When sulphur in the fuel is burned, it contributes a significant proportion of the harmful particulates (soot) from diesel exhaust.
Australian diesel in the past has been allowed to contain up to 5,000 ppm (0.5%) of sulphur compounds. Sulphur is present in crude oil and has to be removed in the refinery during the production of diesel.
From the beginning of this year, the maximum allowable sulphur content in diesel is 500 ppm and from 2006 it will be 50 ppm. Some States (WA and Qld) have introduced 500 ppm sulphur diesel ahead of legislation. It is likely that 50 ppm diesel will also be introduced ahead of the legislated date in most States.
Liquefied Petroleum Gas (LPG) is a valuable indigenous source of transport fuel. LPG is a mixture of propane and butane. Availability of LPG varies from State to State, so some States import LPG to satisfy demand while others export it.
LPG produces about 30 per cent less Greenhouse gas, but it contains less energy than petrol, so more LPG is burned for each kilometre driven. Depending on the efficiency of the petrol engine conversion, the Greenhouse benefit can vary from relatively marginal up to 20 per cent, with the accepted industry average being 10 per cent.
Dedicated LPG is the most effective system because engine operation can be optimised for LPG without compromising the engine settings to accommodate petrol. Bi-fuel (petrol and LPG in the same vehicle) systems cannot take advantage of LPG's high octane, as operating on petrol has to be incorporated into the engine design.
The price of LPG is linked to the international price, so although LPG is exempt from excise charges, the price has increased over the last year in line with overseas pricing. LPG is a comparatively small-volume product for service station operators, so there is little incentive for them to discount LPG, in comparison to unleaded petrol.
Natural gas is about 95 per cent methane, which is the fuel we cook on at home. It produces about half the carbon dioxide of black coal when used in power stations and up to 30 per cent fewer Greenhouse emissions when used in vehicles. It can also produce substantially lower tailpipe emissions, compared with petrol. However, this advantage is being eroded as petrol vehicles become cleaner in response to tougher emission standards.
There are large reserves of natural gas in Australia. There is, therefore, considerable scope for substituting natural gas for both power generation and transport fuels, leading to environmental and economic benefits.
There are two forms in which natural gas is used in vehicles: Compressed Natural Gas (CNG) and Liquefied Natural Gas (LNG). There is very little use of LNG in vehicles presently.
Natural gas is safer than LPG as it is lighter than air, so any leaking gas will float up, normally escaping harmlessly into the atmosphere. LPG is heavier than air and can 'puddle' on the ground or floor, possibly increasing the risk of an explosion.
Several Sydney councils have replaced a proportion or all of their fleet vehicles with natural gas-powered vehicles to provide benefits of lower noise and improved air quality to their local communities. There is currently only a limited range of light and heavy vehicles available with natural gas fuelling systems but this is expected to increase.
What else is happening?
A potentially Greenhouse-neutral fuel, biodiesel can be produced from a range of crops. Biodiesel is typically produced from canola in Australia. Another option is recycled vegetable oil if it is carefully filtered, treated and quality checked. The same qualifications on Greenhouse-neutrality apply as for ethanol.
Several trials have been run in Australia on heavy vehicles using biodiesel, either 100 per cent or blended at around the 10 per cent level. While there were no deleterious effects at the time of writing, a longer period of testing is required, given that these types of vehicles are typically expected to travel 500,000 km without a major overhaul. Some heavy vehicle manufacturers advise component changes if their engines are to be run on biodiesel.
Ethanol is attractive environmentally because it can be substituted for petroleum-based fuels. Research by NRMA and others has shown there are no technical combustion problems in using a 10 per cent ethanol-in-petrol blend in internal combustion-engined vehicles. However, some vehicle manufacturers have stated they will not maintain vehicle warranty coverage at ethanol content above 10 per cent.
Ethanol can be Greenhouse-neutral (that is, the carbon dioxide emitted when it is burned as a fuel is reabsorbed by a crop, which is then used to produce ethanol again, recycling the carbon) and some reduction in tailpipe emissions can be achieved. However, higher levels of aldehydes, which are highly reactive and toxic to humans, can be produced.
The Greenhouse costs of producing ethanol come from: burning the diesel fuel used for sowing, ploughing and harvesting; fossil fuels used for heating to encourage fermentation; and fertilisers used on the crop. The production cost for ethanol in Australia is up to 70 cents/litre. This compares with the ex-refinery cost of petrol and diesel of about 30 cents/litre. More efficient production technologies are needed before ethanol can compete with crude oil products without subsidies.
Methanol is another alcohol, currently used in the US primarily to obtain air quality management credits and to meet air pollution goals, rather than for Greenhouse or oil import reduction reasons. Methanol can reduce tailpipe emissions, but can increase aldehydes, and it is corrosive to some conventional vehicle fuel system components. It also burns with an invisible flame, so there are safety concerns. It can be produced from agricultural products or from natural gas. With current technology, there are significant energy losses when natural gas is used as the source.
The main interest in methanol now is as a possible fuel for fuel cell vehicles. Methanol could be distributed through the current petrol and diesel network. It could be re-formed on-board vehicles relatively easily to provide the hydrogen needed to power the fuel cell, with fewer difficulties than using petrol. However, the extra re-forming equipment on-board would increase the cost and complexity of the vehicle.
There are two areas of interest for solar power applications in transport: charging of electric vehicles and
the non-Greenhouse production of hydrogen.
A Sydney University study has shown that a significant proportion of the total energy requirement for a modern electric vehicle could be supplied by solar cells mounted on carports or garage roofs. These would augment mains charging, thus helping to reduce the carbon dioxide produced by power stations.
Hydrogen for fuel cells can be produced from the electrolysis of water, but unless the electricity to do so is supplied from a non-Greenhouse source, environmental effectiveness is going to be reduced.
Solar cells provide a reliable source of non-Greenhouse electricity once the environmental cost of manufacturing the cells themselves has been amortised.
Hydrogen has value as a fuel for both transport and power generation, but the technology and cost for fuel production and storage have not yet been scaled up to industrial levels.
Several vehicle manufacturers have demonstrated hydrogen-fuelled cars, both internal combustion-engined and fuel cell, with practical on-road performance for many years. Volume and cost are still being addressed.
While hydrogen is expensive to produce, it is a non-Greenhouse gas and an essentially inexhaustible fuel. Therefore, it is the only fuel with the potential to be genuinely ecologically sustainable if it is produced from renewable energy sources.
There are two hybrid vehicles available in Australia: the Toyota Prius and the Honda Insight. A hybrid version of the Honda Civic is already available in major world markets and should be available in Australia about the middle of the year.
'Hybrid' means the vehicle has both a petrol engine, smaller than would be normal for a vehicle of that size and therefore more economical, and an electric motor, driving the wheels, as usual, through a transmission. The engine also drives a generator to charge a battery pack. When the vehicle stops, the engine stops, and restarts automatically when the accelerator or gear shift is operated. In high load conditions, the engine and the electric motor operate together. At low speeds, the vehicle runs off the battery pack and the engine is switched off by the on-board computer.
The vehicles have clever features, such as regenerative braking, so when you put the brakes on, power is fed back to the battery pack instead of all being converted into heat, and low-rolling resistance tyres that reduce friction losses.
Hybrid systems can achieve equivalent performance to current vehicles, while also having very low emissions and fuel consumption.
The advanced technology in these vehicles and the fact that they sell in small volumes means that currently they are more expensive than conventional vehicles. The NRMA supports the establishment of financial incentives by both Federal and State governments to encourage the greater adoption of this technology by vehicle buyers.
Electric vehicles use energy very efficiently, due to high-efficiency propulsion systems. However, our current dependence on coal-generated electricity with high carbon dioxide emissions limits their effectiveness for addressing Greenhouse impacts. Supplying electrical power from renewable resources would make electric vehicles very environmentally advantageous.
At current technology levels, electric vehicles are not as flexible as fossil fuel-powered vehicles. However, there are specific applications for which they are suitable, such as short distance commuting, or as a second car for local shopping and social trips.
A hybrid version of the Honda Civic (pictured) is due here by the middle of the year. Two hybrid cars are currently available: the Toyota Prius and Honda Insight. For more on hybrids, see p 30.
Hybrid engines, like the one in the Civic pictured left, combine a small petrol engine with an electric motor and a battery pack.
The Toyota Prius contains advanced computer technology (pictured above) that controls when the car runs on petrol and when it uses stored energy from a battery.
Chrysler's stunning left-hand-drive Charger R/T Concept Car (above left) runs on compressed natural gas (CNG); Chisholm Institute's experimental ZOOM Eagle (right) runs on electricity.
Occasionally, there are allegations, sometimes proved by analysis, of petrol and diesel fuel adulterated with other compounds being sold at the bowser.
Additives commonly include toluene in petrol and heating oil in diesel. These additives can substantially change the fuel quality and lead to poor vehicle operation or, in the worst cases, engine damage.
The advantage to the unscrupulous fuel retailer is that they can buy the additive free of excise, as it is not normally a component of fuel, and sell it with excise added, profiting by 38 cents per litre.
If you experience unfamiliar problems with your vehicle, such as hard starting or misfiring, take your vehicle back to the last place you obtained fuel and discuss the problem with the retailer. If you get no satisfaction and the station is branded by a major oil company, contact that company, as all the major companies guarantee the fuel they sell.
If you are still not satisfied, contact the NSW Department of Fair Trading. If you suspect that adulterated fuel is the cause of your problems, you should also contact the Federal Department of Customs, with details of the station at which you purchased the fuel.
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