Oil: Fuelling the future

By Bob Guntrip 7 July 2009
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Oil reserves are dwindling and petrol prices rising, but few of us have any intention of abandoning our cars. What’s the solution?

If there is any consolation in the soaring price of oil it can only be because we’re thinking twice about using so much of the stuff. Indeed, Planet Earth would surely be a better place were we to leave the car in the garage altogether, though that’s hardly a practical plan for most of us. But we need to do something. Australians burn the world’s dwindling oil reserves at the rate of 320 million barrels per year (on 2004 figures) and our vehicles are generating some 80 million tonnes of greenhouse gases (GHG) in the process. And you’ve surely noticed petrol’s hovering around $1.60 per litre at metropolitan bowsers.

So what’s the solution? Right now, the holy grail of motive power is probably hydrogen. It’s the most abundant element in the known universe and making it react with oxygen, either in a fuel cell to produce electricity or in a hydrogen combustion engine, will yield energy in impressive quantities – with no waste beyond a steady trickle of water.

But there are problems. Storing hydrogen safely in the Earth’s oxygen-rich atmosphere is tricky enough, yet the real difficulty lies in collection/extraction. Hydrogen is at its most stable when combined with other elements. Separating it from these other elements to generate naked, unadorned molecular hydrogen to drive your car using any technology we have is extremely energy intensive – so much so that it’s uneconomic. But the work continues. In June, Honda released news of its latest fuel-cell project car, the FCX Clarity. So far, President George W. Bush’s US$1.2 billion National Hydrogen Initiative has produced a couple of hundred experimental vehicles, but on present estimates a practical hydrogen-fuelled car is decades distant. So we’re unlikely to be running the kids up to the Sunshine Coast this Christmas on a whiff of hydrogen, but there are real alternatives.

Part-exchanging the family petrol guzzler for a Hybrid Electric Vehicle (HEV) is proving popular. Australians are buying about 5000 Toyota Prius HEVs each year, and the Honda Civic HEV, a comparative newcomer, is likewise finding favour. The HEV benefits both the owner and the environment by using a battery-powered electric motor to provide motive power in stop-go traffic or light-acceleration driving, with a relatively small petrol/diesel engine to take on the heavy lifting. A clever bonus of many HEVs is their so-called “regenerative braking”, which converts the heat generated during braking to electrical power that recharges the batteries (usually nickel-metal hydride) used to drive the electric motor. It’s a tidy, durable and economical system that cuts fuel consumption and GHG emissions by up to 50 percent over a comparable petrol-only vehicle.

The HEV has its detractors, however. They point out that the electric motor can be run only for relatively short periods, and that the initial vehicle cost can be high: in July 2008, a Toyota Prius hybrid cost $37,400, $2500 more than the company’s prestige 3.5L Aurion.

Fortunately, an outlay of $30,000-plus isn’t a precondition for doing our bit to clean up the planet. In 2007, 100,000 of us handed over some $3000 each to convert our cars to run on Liquid Petroleum Gas (LPG), and this year’s total will run much, much higher. Several LPG installers report hefty spikes in enquiries on Thursdays and Fridays, when the price of petrol takes its weekly rise.

“In the early months of this year our installers were looking at empty vehicle bays,” says Steve Woodward, chief of LPG Australia, “though the current splurge seems like a sustained feature – and as demand grows installation times and costs will come down.”

But why the interest? LPG is, after all, a fossil fuel and must be pressurised to about six times atmospheric pressure and stored in a sizeable tank in a car’s boot. “LPG is a by-product of natural gas and oil refining,” says fuels expert Steve Atkinson, of Deakin University’s School of Life and Environmental Sciences. “But the collection and processing of LPG is much less energy intensive than that of petrol – a lot of it is separated at the wellhead itself.” And the savings pass through to the individual motorist. “I’m on my fourth LPG car,” says Steve. “On current calculations I’m saving $1500 a year on running costs.”

LPG doesn’t pack quite the punch of petrol. Industry critics cite power losses of up to 15 per cent, though users tell a different story. “You’d only notice any difference if you were racing at Bathurst,” says Steve. “You can still pick up speeding fines on LPG.” Drivers do, however, report LPG consumption figures around 30 per cent higher than petrol, but as it’s currently tracking at less than half the price of petrol, significant savings seem easy to come by. It’s easier on the environment too, generating some 15 per cent less GHG than petrol in a typical car. Perhaps its most serious problem stems from its growing popularity, with the rush to convert adding to waiting lists that now run to months.

LPG’s keenest competitor for the mobility dollar may be its related product, natural gas. It’s predominantly methane, burns very cleanly, is even more abundant than LPG and can be run in conventional engines. The two fuels are vying for supremacy among Australia’s commercial vehicle fleets, and compressed natural gas (CNG) is attracting plenty of enquiries from the private motorist.

“We run a Ford Territory on CNG,” says Sean Blythe, CEO of Advanced Fuels Technology, one of the prime movers of CNG in Australia. “It doesn’t quite have the get-up-and-go of a petrol engine but by sacrificing perhaps 5 per cent of power output I’m doing the environment a lot of good.”

CNG’s emission performance is better than that of petrol in carbon monoxide, smog-forming nitrogen oxides and heavier materials – encouragement enough for Mercedes-Benz to build a CNG-burning version of its B170 hatchback. Running the car on petrol and CNG, Mercedes reports a 17 per cent drop in emissions and, on gas alone, a 50 per cent saving on fuel costs.

But if the benefits of CNG have been established, the infrastructure necessary to make it a viable fuel in Australia has not. LPG is available at about half of the country’s 6000-plus service stations; CNG users must top up at dedicated filling stations where specially designed fast-fill pumps deliver the gas into high-tech, high-pressure tanks.

“At present there are just three stations, in Liverpool, Goulburn [both in NSW] and Canberra,” says Sean. “The alternative is a home refuelling station that can use your domestic gas supply. They’re slow-fill devices that’ll refuel your car in four to eight hours, depending on your gas supply. I use one – it sits in my garage.”

Take the home refueller option and you’ll be adding some $6000 to the $4000 cost of having your car modified to burn CNG. And unlike LPG, there is no government subsidy for switching to gas. At first glance the numbers are unappealing, but with CNG costing 55–65 cents per cubic metre (roughly equivalent to a litre of liquid fuel) “it’s easy to amortise the cost of the hardware,” Sean says.

Ethanol, at least in the E10 blend found at main-street service stations around the country, requires no special hardware, costs about the same as petrol and offers a 10 per cent reduction in GHG emissions simply by stopping your car alongside a different pump at the servo. The point is that alcohol can be ‘carbon neutral’ – that is, the GHG generated by burning it in your car is cancelled out by the carbon dioxide absorbed by the plants – feedstocks – from which it’s distilled. But those feedstocks are proving a problem.

Traditional raw materials include maize, sorghum and sugar cane, which need valuable agricultural land to grow, and so ethanol manufacture competes with food production. Ethanol production from native grasses that lack value as grazing feed is being researched, but the large-scale harvesting needed could pose environmental problems of its own.

There’s more. “Alcohol is corrosive, and leakage from service-station pumps poses a contamination threat to the water table,” says Dr Robert Niven, of the University of New South Wales School of Aerospace, Civil and Environmental Engineering.

As with alcohol in petrol, adding small quantities of biodiesel to standard diesel yields an immediate reduction in polluting emissions, without the need for special hardware. Diesel is typically a cleaner burning fuel than petrol but generates more “particulate” emissions – the clouds of sooty black stuff you complain about when you’re behind a truck at the lights. Biodiesel use is in its infancy in Australia. Some biodiesel is refined from recycled cooking oil or waste animal fat; but more, globally, is made from agricultural products including canola and palm oil. As with ethanol, there are concerns about the swathes of land being cleared in developing countries for growing biodiesel feedstocks.

Australia’s leading biodiesel producer and retailer is Gull Petroleum. “We sell a 20 per cent blend of biodiesel [B20] at most of our 130 outlets around WA,” says Gull’s Darryl Copestoke. “We try to keep the price 2 to 4 cents per litre below mineral diesel, as an incentive for our buyers – we like to be known as a ‘green’ supplier. Our materials all come from waste material, mostly tallow, and not plants.”

There are short-term solutions to the growing poser of getting from A to B responsibly, even allowing for the lack of an adequate CNG supply network and the question marks over some sources of ethanol and biodiesel. “We have to be intelligent about informing consumers about options,” says Steve Woodward. “There’s no one-size-fits-all solution.”

But the meter is running, and we’ll ultimately need to turn to hydrogen or one of the outer-edge technologies. What’s certain is that cheap, plentiful petrol is a thing of the past. Now we must deal with its legacy.

Source: Australian Geographic Oct – Dec 2008