Common Urban Myths About Transport

The road lobby itself never denies that cars do a lot of damage to the environment through the pollution and carbon dioxide they generate. But they tell us not to worry, because we are only a few years away from technological solutions that will make cars truly environmentally friendly. Next to the usual fairy tales about improving fuel efficiency, their favourite argument is that new 'green' fuels, already under development, will replace petrol and render pollution and greenhouse emissions a thing of the past.

A Fuel's Paradise

The quixotic quest for the new miracle fuel that will surpass petrol, and be cheap and plentiful to boot, has been with us for at least half a century. In the 1950s, cars powered by personal nuclear reactors capable of travelling thousands of kilometres on a handful of uranium were supposed to be on the verge of becoming a reality. In the 1970s solar cars were just around the corner, and in the 1990s the next big thing was running cars on used cooking oil - assuming you could get it in the quantity required. Still no challenger has risen with serious prospects of toppling the dominance of petrol and diesel.

On the margins, LPG conversions are becoming popular as a way to avoid high petrol prices (and have now got a boost courtesy of the Howard Government), but the efficiency benefits should not be overstated: as the following table shows, the average LPG-fuelled car has only about 3 per cent less CO₂ emissions than the average petrol-fuelled car, and is slightly less energy efficient.

Source: Australian Greenhouse Office. Australian Methodology for the Estimation of Greenhouse Emissions and Sinks 2002. Fuel consumption figures are based on fleet averages. Emissions from the fuel supply chain are excluded.

But even if the new miracle fuel became available tomorrow, along with cars capable of running on it, it would still take many years before most vehicles on the road used the new fuel. This was seen with the introduction of unleaded petrol in 1986; after 15 years there were still many pre-1986 vehicles on the road, hence the need to distribute 'lead replacement' petrol extensively when leaded petrol was finally phased out. And this was a relatively minor technology shift, so the technology could be made available in all new vehicles from 1986 onward for very little additional cost. Changing to an entirely new fuel source is a much larger technological leap, so even when new fuel technology becomes commercially viable it will take some time before it accounts for even a significant minority of new vehicle sales. (Thus, while cars with hybrid petrol/electric engines have been on the market now for some years, their higher price tag and doubts about their performance have kept their market share low.)

Substituting One Problem For Another

The real difficulty with alternative fuels is, however, the same as with any attempt to treat the symptoms instead of the cause of a problem: the fundamental problem doesn't go away but instead lingers to cause more difficulties later on. Any hydrocarbon fuel when burnt in air, whether it be petrol, diesel, biodiesel, LPG or ethanol, produces both carbon dioxide and noxious byproducts such as nitrogen oxides and ozone. Of course they differ in degree: diesel and biodiesel produce lower sulphur emissions than petrol, but produce more particulate matter (soot) which is associated with higher rates of lung disease; ethanol may or may not reduce net carbon dioxide emissions (depending on where it comes from) but increases emissions of formaldehyde, a highly toxic organic solvent. Even the lowest-emission fuels, LPG and natural gas, can often produce as much or more carbon monoxide and nitrogen oxides than petrol (and are also much more limited in supply). And just as with the claim that free-flowing traffic cuts pollution, any overall reduction in pollutants is soon cancelled out by the sheer growth in car and truck trips.

The only 'fuels' that do not produce local pollution are electricity and hydrogen. But these are not fuels so much as energy carriers; they do not occur naturally but instead must be generated from some other, naturally-occurring energy source. In practice electricity in Australia will continue to be sourced mainly from coal for a while yet, while hydrogen is today most commonly produced by 'steam reforming' of hydrocarbons, which generates carbon dioxide as a byproduct. As a result, use of electric or hydrogen-powered cars will not reduce greenhouse emissions, and may even increase them. While it is possible to imagine that at some time in the future we may be able to use electricity or hydrogen piped from massive solar collectors in the desert, it is unlikely to be either as cheap as petrol per kilometre driven, or to be available in such large quantities.

These same caveats apply also to more exotic, enthusiastically promoted alternatives such as compressed air, flywheels and hydraulic fluid. The energy always has to come from somewhere, and the available sources are either expensive, scarce or environmentally damaging. It also has to be remembered that even pollution-free cars and trucks would still crash just as often, take up just as much land for roads, and generate the same equity problems as they do today. There truly is no 'free lunch' when it comes to solving the problems with car transport.

Petrol From Coal?

One of the scarier suggestions to emerge from the fuel price hikes of 2005 is that we hasten climate change by using liquefied coal as a replacement for petrol and diesel. Although this is feasible with current technology (indeed, the Germans did it during both World Wars), it is still too inefficient and expensive to be commercially attractive. And because to liquefy coal one essentially has to remove the 'excess' carbon from it, thereby generating carbon dioxide, we would actually wind up generating CO₂ even faster than we currently do by pumping oil and burning it in car engines.

According to industry figures obtained by the University of Technology, Sydney, the use of liquid fuel derived from Victorian brown coal would generate more than double the greenhouse emissions of ordinary petrol (182g CO₂/MJ compared with 84g CO₂/MJ). The liquefication plant alone would have eight times the emissions of a conventional oil refinery. This would be a huge backward step in the search for sustainable energy.

Nonetheless, the very same Victorian Government that refuses to spend money on new rail extensions is now backing a $5 billion project to convert coal into transport fuel. The success of the project relies on being able to pump the excess CO₂ underground, an unproven technique that so far no-one has got to work reliably despite all the breathless PR that has been devoted to it:

VICTORIA could lead the world in turning coal into transport fuel after multinationals Royal Dutch Shell and Anglo American made Melbourne-based joint venture Monash Energy their top global research priority.... New Victorian Energy Minister Peter Batchelor has met Monash Energy executives twice this week to discuss the coal-to-liquids project....
The project is expected to cost $5 billion and Monash Energy plans to produce commercial quantities of diesel fuel by 2016. As part of its geosequestration plan, the Victorian Government plans to build a pipeline from the Latrobe Valley to a carbon dioxide storage facility. Access to this pipeline, which the Government has dubbed a "CO2 hub", would be open to energy producers and industry to dispose of carbon dioxide emissions.
---Batchelor meets Anglo on coal venture, The Age, 9 February 2007

The Biofuel Red Herring

Finally there are the now vigorously-promoted schemes to actually 'grow' the fuel for our cars by planting crops, digesting the crops to produce biofuel, running cars with the biofuel and using the carbon dioxide emissions to grow a new crop. While superficially attractive, these schemes suffer from the same problem as schemes to plant trees to soak up carbon emissions: the sheer scale of our driving habits makes them unviable. Converting the entire Australian wheat crop to ethanol production would, for example, only substitute for around 15% of Australia's oil consumption. There are many similar findings:

1. CSIRO scientist Barney Foran estimated in 2000 that fuelling the Australian vehicle fleet with methanol derived from trees (the most dense bio-energy source available) would require 30 million hectares of plantation. But as we explain on the page linked just above, there are at most about 9.6 million hectares available in all of Australia for plantation farming (and even this assumes an over tenfold increase in the use of land for plantations).
2. In 2003, Jeff Dukes of the University of Utah estimated that the world each year burns up fossil-fuel energy equivalent to 400 years of global plant growth.
3. According to a statement by the US Department of Energy in 2006, to replace just 30% of US petrol supplies with ethanol would require 60 billion gallons of ethanol a year, while all the corn currently grown by US farmers could make just 18 billion gallons a year.

Biofuel schemes, then, can only possibly work in conjunction with policies to substitute environmentally friendly transport for car and truck trips.

There is also the rather nasty side-effect, that using 'energy crops' for fuel competes directly with food supplies. The Earth Policy Institute in the US estimates that the grain required to fill one 25 gallon (95 litre) fuel tank would feed one person for a year. The US already uses nearly one-sixth of its grain crop (and over half of all its corn) to produce ethanol for cars, and while this represents only 3% of all fuel sold, it is starting to affect the global prices of wheat and corn, which feed into other food prices. (The price of one corn variety increased 45% in 2006 alone.) Brazil meanwhile uses its extensive sugar cane crops to make ethanol, and this has been a factor in the world price of sugar trebling between 2004 and 2006. According to a paper in the Proceedings of the National Academy of Sciences in the USA, it would be impossible for ethanol to significantly replace petroleum without a serious impact on food supplies.

In the 1850s, the great Irish Potato Famine resulted when wealthy consumers bid up the price of scarce potatoes, so that poor people could no longer afford to eat. A similar threat exists to those in developing countries today if ethanol and biodiesel become significant fuel sources for affluent motorists.

Conclusion

In its investigation of all the options, the British Royal Commission on Environmental Pollution concluded that

there would not be any environmental advantage in widespread use of alternative fuels in the UK.

There is certainly a limited role for some alternative fuels in particular contexts; Paul Mees notes in A Very Public Solution that use of compressed natural gas instead of diesel in vehicles that stop frequently in urban areas, such as buses and garbage trucks, would help put these essential services on a more sustainable footing. (Though even here caution is required: the spark-ignition engines that burn gaseous fuels are less efficient than diesel engines.) In the final analysis, the use of alternative fuels will have at best a marginal benefit, and will have no benefit at all unless accompanied by a substantial switch from car trips to public transport, walking and cycling.

ptua.org.au