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 for decades they’ve told us not to worry, because we were always only a few years away from technological solutions making cars truly environmentally friendly. Next to the usual fairy tales about improving fuel efficiency, their favourite argument has been that new ‘green’ fuels would soon 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 would surpass petrol and be cheap and plentiful to boot, existed for over half a century before the advent of mass-market electric vehicles. 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. Then there was Europe’s experiment with so-called ‘clean diesel’ in the 2000s which famously ended in tears, but only after poisoning the air in Europe’s cities.

In the face of petrol price hikes preceding the Global Financial Crisis in the 2000s, LPG conversions had a wave of popularity amid touted efficiency benefits. These benefits were arguably exaggerated: 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.

Electricity is simply the latest, albeit the most promising, challenger seeking to topple the dominance of petrol and diesel where all others have failed.

Yet the full realisation of electricity’s potential is still many years into the future. The biggest issue is the size of Australia’s car fleet and the many years required to transition, even were the best of incentives to be introduced tomorrow. 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, where the technology could be made available in all new vehicles, for little additional cost, starting right from 1986.

Switching to electricity is a much larger technological leap, so even in those countries with more enthusiastic take-up than in Australia, it is seen to be taking some time to account for the majority of new vehicle sales. This was already seen with hybrid petrol/electric technology; despite being on the market for many years now, their (smaller) price premium and other factors have kept them from conquering the market.

[Industry analyst Felix Kuhnert] said attempts by car makers to persuade people to buy more environmentally friendly cars were failing in the showroom, where financial considerations always beat environmental ones. He said 31% of drivers surveyed said they would consider purchasing a hybrid car as their next vehicle, but that figure dropped by two-thirds if the purchase price was higher. “Only 6% of those questioned would consider purchasing a hybrid car if the price premium was more than 2000 euros [about $A3000].”

—Money rules the road to a green car, The Age, 6 March 2008

Talk to high emitters in the transport industry and they say, “We need 25 years to turn the issue around”. We don’t have that time…. The question is what path do we take to that. Our thinking is not too clear about that – 25 years are needed for breakthrough technologies such as telephones and computers.

—Ben Wheaton, PriceWaterhouseCoopers, May 2008

Many Australian motorists think hybrid cars are too expensive, don’t suit their needs and wouldn’t even consider buying one, a survey reveals…. The top two reasons cited for not considering the greener option were the cost (41 per cent) and that hybrids did not offer what they were looking for (28 per cent).

—Aussies unconvinced by hybrid cars: poll, The Age, 5 June 2008

In Australia it is not uncommon for households to hold onto the same vehicle for 10 years or more. If they have sunk their finances into a new petrol car in the past five years, it may be five years more before they will contemplate trading in for an electric vehicle, regardless of what incentives may be on offer. Yet a member of that same household could make a decision tomorrow to leave the car at home and catch the local bus, if only that alternative were made convenient for them.

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.

For many years the proponents of alternative fuels focussed on the marginal benefits of various hydrocarbon alternatives to petrol and diesel. But 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. 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 ozone and of formaldehyde, a 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 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.

Electricity and hydrogen again stand out as the only ‘fuels’ not to produce polluting tailpipe emissions. 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. Even under the most optimistic ‘step change’ scenarios the majority of Australia’s electricity this decade is likely to be sourced from coal and gas; meanwhile most hydrogen today is ‘grey’ hydrogen produced from hydrocarbons, with the unavoidable waste carbon dioxide vented to the atmosphere. As a result, while use of electric or hydrogen-powered cars is unlikely to increase greenhouse emissions, it can’t be counted on to reduce them substantially in the short term unless all users have access to a dedicated source of renewable electricity or ‘green’ hydrogen.

This dedicated energy source will need to be substantial in size—rivalling that required to power a small household. State-of-the-art electric vehicles, such as the much-vaunted Tesla Model S, achieve an efficiency of 110–150 watt-hours per kilometre: a figure that’s unlikely to be improved upon with anything that looks like a motor car, since electric technology is now quite mature and the motors in these cars already achieve up to 95% efficiency. But a car in Australia is driven on average around 35km every day (12,600km a year) which means the electric car requires 4 to 5kWh of electricity per day to run with typical usage patterns—equivalent to two hours a day of full duty for a 2400W air conditioner. (And this is for the best case: conventional sedans like the Nissan Leaf or electric SUVs like the Volkswagen ID.4 under similar assumptions run the ‘virtual air conditioner’ for 6 hours or more each day, summer or winter!)

This is a point unfortunately overlooked in articles like this one from The Age in 2021 comparing various ways of reducing carbon emissions from large household appliances such as cars, air conditioners, heaters and hot water units. On the one hand, it cites Grattan Institute findings that in Victoria—which still relies on brown coal for the majority of its electricity generation—the benefits of switching from gas to electric household appliances are, for the time being, marginal. Yet it fails to point out that in this respect, electric cars are no different.

There is little doubt electric vehicles will play a key role in the future of motoring. But the point emphasised by their promoters—that the vehicle produces zero emissions if it runs on renewable electricity—is equally true of air conditioners, halogen lamps, plasma TVs or any other energy-hogging appliance. If a carbon-constrained world requires us to moderate our use of halogen downlights, it likewise requires us to moderate our car travel. The problem with presuming everything can be run on renewable electricity is the burden it places on the (already challenging) renewable energy transition itself. Notwithstanding what has been achieved to date, it is far from certain that—without more effort to shift travel to public and active transport—the deployment of renewables can be made cheap, plentiful and fast enough to sustain the status quo in road transport as well as our existing demand for electricity.

There’s every reason to be excited about the proliferation of electric cars heralding the long-delayed extinction of the internal combustion engine. But there’s not enough lithium—or car parking—for everyone to own a two-tonne electric SUV, even if we wanted to deploy enough photovoltaic solar energy to power them. Older disciplines of public transport, compact, transit-oriented urban design and truly accessible cities can help to inform out decisions if we broaden our horizons.

—Scott Ludlam, Getting to Zero: Correspondence, Quarterly Essay 82, 2021

Hydrogen faces a similar problem. The only carbon-free way to produce hydrogen yet demonstrated at scale is as ‘green’ hydrogen from renewable electricity. Technology based on fuel cells supplied by green hydrogen is not going to be significantly more efficient than if it uses the original electricity to begin with; it comes down to comparing the losses in a hydrogen supply chain with those in electricity transmission, which are about the same in any case. And if the electricity isn’t renewable, then neither is the hydrogen.

The next day, I got a look at the Hydrogen 7…. The car is very nice. But does it make environmental sense? The simple answer is no. In the context of the overall energy economy, a car like the Hydrogen 7 would probably produce far more carbon dioxide emissions than gasoline-powered cars available today. And changing this calculation would take multiple breakthroughs–which study after study has predicted will take decades, if they arrive at all. In fact, the Hydrogen 7 and its hydrogen-fuel-cell cousins are, in many ways, simply flashy distractions produced by automakers who should be taking stronger immediate action to reduce the greenhouse-gas emissions of their cars.

—David Talbot, Hell and Hydrogen, Technology Review, March/April 2007

Hydrogen was 40 years away 40 years ago. It’s still 40 years away.

—David Lamb, CSIRO Low Emissions Transport Group

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. For example, though compressed air is commonly regarded as a ‘free’ energy source (it’s just air!), most air compressors are only 10 to 20 per cent efficient, losing the bulk of their energy input as heat or through leakage. So every unit of energy stored in compressed air has required another 4 to 5 units just to produce.

Of course, a lot of the appeal of electric and other ‘alternative-fuelled’ cars is not due to environmental benefits as much as simple cost savings—being able to swap a $100 petrol bill for $30 or less worth of electric power to travel the same distance. Unfortunately, the likely effect of this is the same as that of a cut in petrol prices or an increase in fuel efficiency: people will take advantage of the cost reduction to travel more often and to travel further. This has in fact already been observed among electric car users in Europe and the United States: industry figures show that Nissan Leaf owners drive 50% more than owners of equivalent petrol and diesel vehicles.

In 2008 when electric vehicles were still a ‘fringe’ technology, commentator Alex Steffen wrote an extended essay outlining the problem with trying to reduce the environmental impact of car use simply by tinkering with the way we use cars rather than the amount of car travel we feel compelled to do. As new vehicle technologies move into the mainstream, his essay is still widely cited as highly relevant.

[T]he answer to the problem of the American car is not under the hood, and we’re not going to find a bright green future by looking there…
there is a direct relationship between the kinds of places we live, the transportation choices we have, and how much we drive. The best car-related innovation we have is not to improve the car, but eliminate the need to drive it everywhere we go.

—Alex Steffen, My Other Car Is a Bright Green City, Worldchanging.com, January 2008

It has to be remembered—but alas, frequently is not—that even zero-carbon cars and trucks will crash just as often, take up just as much land for roads, and generate the same equity problems as they do today. They will also continue to pollute, since much local pollution from cars (including ultrafine PM2.5 particulate matter) arises from tyre, brake and road dust rather than tailpipe emissions. And these pollution factors also scale up with the weight of the vehicle, meaning that an electric car (due to the substantial weight of the batteries) may actually produce more of some kinds of pollutants than a petrol car of the same power.

There truly is no ‘free lunch’ when it comes to solving the problems with car transport; instead there is an unavoidable imperative to use cars less and travel more by public transport, by bike or on foot.

The Happy Motoring era is over. No combination of “alt” fuels – solar, wind, nuclear, tar sands, oil-shale, offshore drilling, used French-fry oil – will allow us to keep running the interstate highway system, Wal-Marts, and Walt Disney World. The automobile will be a diminishing presence in our lives, whether we like it or not.

—US commentator James Kunstler, Freakonomics blog

Petrol From Coal?

One of the scarier suggestions to emerge from the fuel price hikes of 2005-08, and still defended by politicans and technologists today, was 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 former Brumby Government—one of many that refused to spend money on new rail extensions—helped back a $5 billion project to convert coal into transport fuel. The success of the project relied 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

Alas for all that misplaced government investment, the Monash Energy project was shelved in December 2008, less than two years after commencing.

Monash Energy, the company jointly owned by Shell and Anglo American, said market conditions made it unfeasible to move ahead with the project…. “At this stage, critical requirements for this project are not yet in place. The reasons for this include higher capital cost estimates and escalated construction costs” [said project director Roger Bounds]

—“Fuel clean-up put aside as too costly”, The Age, 3 December 2008

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 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.
4. London analyst David Jackson calculated in 2007 that blending just 5% biofuel into all the world’s cars would require an additional 100 million hectares of farmland. This is about equal to the remaining land available for farming on Earth, much of which is uneconomic to develop.

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

Meanwhile there are increasing doubts whether the production and use of biofuels really has a net positive greenhouse impact at all. Although it seems obvious that biofuel crops should soak up roughly the same amount of carbon dioxide when growing that they give off when burned, there are other factors that intrude on the process. The biggest of these is that the crops rely on fertilisers that produce significant emissions of nitrous oxide (N₂O), a greenhouse gas 300 times as potent as carbon dioxide. A 2007 paper by Nobel laureate Paul Crutzen concludes that biofuel crops can cause as much global warming via N₂O as they save in CO₂ from displaced fossil fuels.

For rapeseed biodiesel, which accounts for about 80 per cent of the biofuel production in Europe, the relative warming due to N2O (nitrous oxide) emissions is estimated at 1 to 1.7 times larger than the quasi-cooling effect due to saved fossil CO2 emissions. For corn bioethanol, dominant in the US, the figure is 0.9 to 1.5.

—Paul Crutzen, statement to International Policy Network, 2010

Then, there is the tendency for biofuel crops to be grown on cleared peatland or rainforest land in countries like Indonesia or Brazil. Clearing a rainforest removes a carbon sink more significant than a biofuel crop, while draining a peatland releases enormous quantities of stored CO₂. Together, all these effects wipe out the emission savings from use of the harvested biofuel.

According to two studies independently published in the journal Science in February 2008, and a third study in October 2009, almost all current biofuel production is causing more greenhouse emissions than conventional fuel use. A related article points out that the failure to account for this kind of land use change counts as a critical error in carbon accounting under the Kyoto Protocol (which also formed the basis for Europe’s emissions trading scheme).

Biofuels also suffer from other more practical problems. One such problem is their limited shelf life – as short as two weeks in ethanol’s case, or around three months for biodiesel. While ordinary petrol or diesel can sit unused in a fuel tank for long periods, current biofuels will degrade, and this can result in engine damage. For this reason, owners of recreational boats (which are used only seasonally) are advised against using biofuels or biofuel blends. The same advice might apply to car owners who use their cars rarely.

Last but not least there is 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 (much of them on cleared Amazon rainforest), 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.

Corn has about doubled in price during the last few months, thanks to an increasing demand for ethanol…. [t]he higher corn prices…. mean that [dairy farmer David] Kyle has to pay almost double this year for the corn feed he gives his cows. Kyle says he may well have to reduce his herd, which means there’ll be less milk produced because of the price of corn. That’s the bottom line.….

“Almost everything in our refrigerator contains corn,” says Lester Brown of the Earth Policy Institute. “Whether it’s milk or eggs or chicken, pork, beef, ice cream, yogurt – these are all corn products.” And consider this: The price of wheat, soybeans and other crops will go up because farmers will be planting less of each.

—“As Cars Go Green, Food Prices Will Jump”, ABC News (USA), 9 April 2007

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. This is not just alarmist speculation: in all but one year between 2000 and 2010 the world’s consumption of wheat exceeded production, and in 2007 global wheat stocks were at their lowest level since 1972. According to New Scientist in April 2007, industry insiders are concerned about the recent emergence of new resistant varieties of old crop diseases like black stem rust; meanwhile, Australia’s own wheat production is regularly threatened by drought. We cannot be complacent any longer about the world’s capacity to produce staple crops.

What we’re beginning to see is a sort of epic competition emerging in the world between the 800 million people who own automobiles and the 2 billion poorest people in the world who are now beginning to compete for the same grain supplies. We’ve never faced a situation like this before.

—Lester Brown, Earth Policy Institute, April 2007

Further confirmation has come from the OECD (hardly the world’s most ardent greenies) who in 2007 weighed in with its own assessment, stating in its own way the same conclusions drawn by others.

The OECD considers the bioenergy industry to become a key factor in the functioning of agricultural markets. Food prices are expected to rise between 20% and 50% over the next decade…. consistent with the development of food prices in recent years that have gone up sharply in reaction to increased biofuel production in Brazil…., China, the EU and the United States….

The assumption [has been made]…. that competition between food and biofuels can be avoided. In reality, energy cropping on dedicated land is in competition with food production as of day one….

The current push to expand the use of biofuels is creating unsustainable tensions that will disrupt markets without generating significant environmental benefits…. Governments should cease creating new mandates for biofuels and investigate ways to phase them out.

—Organisation for Economic Co-operation and Development.
Biofuels: Is the Cure Worse Than the Disease?, September 2007.

Most recently, a study by the World Bank reported in the Guardian on 4 July 2008 confirmed that biofuels were responsible for 75% out of the 140% rise in global food prices since 2002, and that these price rises have pushed 100 million people below the poverty line in that time.

The Celsias Blog has compiled a useful round-up of the evidence on unintended consequences of biofuel promotion.

Conclusion

In its investigation of all the options back in the 1990s, 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.

And nearly two decades later, the same conclusion was reached by technology experts at MIT, in an assessment of emerging technologies.

Alternative fuels that replace petroleum fuels are unlikely to change GHG emissions significantly…. No single technology development or alternative fuel can solve the problems of growing transportation fuel use and GHG emissions. Progress must come from a comprehensive, coordinated effort to develop and market more efficient vehicles and benign fuels, and to find more sustainable ways to satisfy transportation demands.

—MIT Laboratory for Energy and the Environment.
On The Road In 2035: Reducing Transportation’s Petroleum Consumption and GHG Emissions, July 2008

Notwithstanding the explosion of electric cars into the mainstream, the substance of this conclusion is unaltered. Even the economically-dry OECD recognises the importance of reducing demand for fuel, as a necessary complement to the massive effort to convert the world’s vehicle fleets to run on renewable energy sources.

The demand side of the transport fuel problem should receive proportionally more attention than the supply side. A litre of gasoline or diesel conserved because a person walks, rides a bicycle, carpools or tunes up his or her vehicle’s engine more often is a full litre of gasoline or diesel saved at a much lower cost to the economy than subsidising inefficient new sources of supply.

—OECD, Biofuels: Is the Cure Worse Than the Disease?

And electricity aside, there is certainly a limited role for some alternative fuels in particular contexts. Paul Mees noted 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. That was in 2000: in the 2020s, the same recommendation might be made for green hydrogen.

But public transport already has the advantage here: even run using partly-coal-fired electricity and diesel fuel as at present, well-run and well-used public transport has energy use and emissions per passenger that are a fraction of those from present-day cars, and less even than those from the most efficient electric cars now available if charged from the grid. In the final analysis, the use of electricity and other alternative fuels will only deal with some kinds of pollution and other negative effects of cars, and then only if accompanied by a substantial switch from car trips to public transport, walking and cycling.

No matter what powers a car, there’s still too many cars on the road. Bit of a guilt trip for me, sitting in static traffic. Ho hum.

—Robert Llewelyn, Red Dwarf actor, while driving a Honda Insight hybrid

Last modified: 21 October 2021