Eco-Friendly Cars

Buying a car that's eco-friendly

With a population of just over 20 million, we Australians make up less than one third of one percent of the world's total numbers, yet we contribute more than 1.5% of the planet's carbon dioxide emissions. Per head of population, we are the biggest carbon criminals on Earth. It is probably time, therefore, to consider ways of cutting down on the noxious gases that are pumped into Australian skies.

The scientific consensus is that emissions of carbon dioxide gas (CO2) are the primary accelerant of the greenhouse effect and climate change. While nearly all cars produce a certain level of CO2 and a host of other unpleasant substances that are collectively referred to as greenhouse gases, the precise amount produced is determined first and foremost by the fuel the vehicle consumes, and the amount it requires.

The following are some of the chief considerations in searching for a more eco-friendly drive.

Start to finish

As well as looking at emissions produced while driving, in assessing a car's carbon footprint we must also consider the manufacturing process. Smaller vehicles demand less materials for construction and are typically made from lighter components, so shying away from great lumbering tanks is a good way to minimise your ecological impact right from the word go. It will often be the case that, in addition to demanding greater production parts, larger cars also require a greater number of disposable items when they come to be serviced. These throw-away goods are rarely made from recycled material, and nor can they be subsequently recycled themselves, something of a double whammy.

The government is here to help

We have regulations in place in this country that require all new cars, prior to being registered for the first time, to adhere to certain standards, environmental as well as safety, which are collectively known as the Australian Design Rules (ADR).

The Federal Government produces a document called the 'Green Vehicle Guide', which rates different vehicle models on a series of criteria relating to their environmental impact, allowing you to compare a full range of cars. A combination of two scores, a Greenhouse Rating that is based on CO2 emissions and an Air Pollution Rating based on emission standards, gives an overall rating out of five stars.

The 'Green Vehicle Guide' also contains information on each model's fuel consumption. The guide is designed to aid consumers in their quest for greener automobile options.

Cutting back on the juice

It's a pretty basic formula. If your car burns less fossil fuel, it will emit less CO2 . So heading up the list of ways to cut the carbon contribution of your car is fuel efficiency. The weight of the vehicle and the efficiency of its engine are the two major determinants of a car's consumption of fuel.

The more weight your car carries, the more fuel it will need to get between two points. A Morris Minor will consume less fuel than a Jeep Wrangler, in the same way that Rove McManus will burn fewer calories than your typical AFL footballer. While cars at the very lightest end of the market may not conform to your practical requirements, it is a good idea from an environmental (and financial) perspective to limit the weight of your next car to that which is strictly necessary.

Having said this, 'small is green' is not a golden rule. A thoroughly discerning environmentalist will look at engine efficiency as well as tonnage. And while the fuel one uses is the biggest single contributing factor to efficiency, there are a range of technical innovations that, when employed, will improve the performance of the most sluggish motor.

The contemporary range of model vehicles carry many of these features as standard. Common examples include turbo chargers, variable valve timing, hybrid engines, cylinder shut-off and direct fuel injection, and the list runs on.

Meanwhile, although we're still facing a bit of a wait until they are unleashed on the commercial market domestically, a range of innovative vehicles that run on alternative fuels are being lined up for release in the coming months. These cars all promise drastic reductions in greenhouse gas emissions while some promise to eliminate them entirely! While they will not come cheap, for those with deep pockets or healthy imaginations, take some time to daydream about cars like the BMW Hydrogen 7 or the Tesla Roadster. The only thing standing between you and one of these mean, green machines is a bit of a wait and several hundred thousand dollars.

For those with more grounded ambitions, or an appreciation of the joys of amateur customisation, have a look at the Blade Runner, which was devised and retrofitted here in Australia by mechanic Ross Blade, in partnership with CSIRO.

As futures analysts and climate scientists continue laying on the bad news, and predictions of fuel reaching the $8 per litre stratosphere sooner rather than later, the question ought not to be 'why burn less fuel?', but rather 'why on earth not?'

The importance of the right fuel

Of the three major fuels used in domestic road vehicles in Australia, diesel will cost the most per litre, with unleaded petrol next, and the cheapest being Liquid Petroleum Gas (LPG). The three fuels are as different in environmental impact as they are in price.

The last decade or so has seen a rapid development in the quality of diesel engines, with the result that they perform better and operate with less noise. While the per litre cost of diesel is greater than any of its alternatives, engines that run on it do tend to outperform petrol engines in the efficiency stakes, which translates to reduced emissions. Nonetheless, they burn less cleanly than those that run on petrol, and some manufacturers address this issue with a form of 'smog trap' to prevent the poisonous particles from dispersing through the exhaust into the atmosphere.

Petrol has long been the preferred fuel for those preoccupied with noise and overall performance, additional to the savings available at the pump. As mentioned, a petrol engine is the cleaner option but will, as a general rule, emit more CO2 than the diesel alternative since they are typically less efficient.

LPG enjoys a healthy popularity locally due to governments subsidies and incentives for converting diesel and petrol engines to the new fuel. But while this fuel does perform marginally better than petrol when it comes to overall emissions, it seems probable in the majority of cases that it is the lower prices at the pump tempting many of the converts.

Of late there has been a surge in the availability of a range of renewable fuels like ethanol, bio-diesel and hydrogen. Although supplies of these newcomers are relatively sparse in this country, they can still be purchased privately and at certain service stations.

Emissions comparison

Fuel type CO2 emissions Diesel 2.7 kg/L Petrol 2.3 kg/L LPG 1.6 kg/L

It looks, upon inspection of the table above, as if LPG is the comfortable winner in the carbon stakes, with petrol performing slightly better than diesel. It is worth bearing in mind, though, that cars that use LPG fuel need more fuel to travel the same distance than the alternatives.

Comparing the benefits of the three in the 'Green Vehicle Guide' suggests that the apparent advantages of LPG aren't so self-evident as might initially appear to be the case:

Vehicle Fuel type Fuel consumption CO2 emissions Holden VE Commodore sedan 3.6L 6cyl, 4 speed auto LPG 15.5 L/100km 252 g/km Holden VE Commodore sedan 3.6L 6cyl, 4 speed auto Petrol 10.8 L/100km 256 g/km

Going green for resale benefits

Who said altruism had to be entirely selfless (apart from the definition in the dictionary)? Vehicles that are recognised to be environmentally responsible can have enhanced value when it comes to selling them on. Most people these days recognise the pressing need to cut back on our greenhouse gas emissions, and even more Australians want to minimise fuel expenses.

It makes sense, then, that fuel efficient vehicles that run economically are going to be pretty popular as used cars. Those cars that have both eco-friendly cred and a solid reputation for reliability are prized possessions, and consequently maintain resale value well.