Green Machines - What Makes an Eco-friendly Car?

Eco Friendly Cars

Australia produces around 1.5% of the world's carbon dioxide emissions from only 0.003% of its population.

Most cars produce greenhouse gases, primarily CO2. CO2 emissions are the largest contributor to global warming and climate change. The amount of CO2 a car produces is largely a function of the amount and type of fuel consumed.

What should you consider in the search for a greener car?

From go to whoa

Before a car drives a single kilometre it already has a carbon footprint.

Selecting smaller vehicles with lighter parts and less materials is a great start if you're looking for a green car. In addition, larger more complex cars often require many more consumable items at service time.

Many of these are neither manufactured from recycled material, nor recyclable.

The Green Vehicle Guide

In Australia, before a car can be registered for the first time it must meet specific safety and environmental standards known as the Australian Design Rules (ADRs).

The government's Green Vehicle Guide provides ratings that can help you define a vehicle's impact on the environment - right down to the difference between models. The overall star rating is comprised of a Greenhouse Rating (based on CO2 emissions) and an Air Pollution Rating (based primarily on emission standards). Fuel Consumption (in L/100km) is also listed.

Use the Green Vehicle Guide to help you find a high-rating green vehicle that meets your needs. You can also request a free Green Vehicle Guide Kit including a poster and bumper stickers!

Reducing fuel consumption

Less fossil fuel consumption means less greenhouse gas. Simple. When it comes to reducing the environmental impact of our cars, reducing our consumption of fuel is at the top of the list.

There are two major factors that contribute to a vehicle's fuel consumption: engine efficiency and weight.

The weight of your car directly affects the amount of fuel it needs to get from A to B. Lighter cars on the whole consume less fuel than their supersized counterparts. Practically, a light car may not meet your needs, but you can make sure that your next vehicle is no heavier than what you absolutely require.

All cars of the same size are not created equal. For true green cred, consider not only weight but engine efficiency. Engine efficiency is partly a product of the fuel used (see The right juice, below), but can also be improved by any number of technical developments.

Many of these features are standard in current model vehicles. Cylinder shutoff, engine shutoff-at-stop, direct injection, petrol-electric hybrid engines, smart engine control computers, variable valve timing, and turbo (or super) chargers are just some examples, and are all relatively common.

Although not available in Australia currently, there are a number of exciting alternative-fuel vehicles waiting in the wings, that promise significant cuts in (or the elimination of) fossil fuel consumption and/or Greenhouse Gas emissions. If money is no object take a look at the electric-powered Tesla Roadster or the BMW Hydrogen 7. We're talking six-figure price tags and significant waiting periods, but just imagine!

Tip: For tips on saving even more fuel see 10 Ways To Save Fuel.

The right juice

Not all fuels are equal. In Australia there are three main fuels used in household vehicles - unleaded petrol, diesel and Liquid Petroleum Gas (LPG). Of these, diesel is the most expensive per litre, followed by unleaded petrol and, the least expensive, LPG.

Diesel engines have changed dramatically in the last few years, becoming quieter and offering better performance. Although the fuel is more expensive per litre, diesel engines are generally more economical than petrol engines, thus producing less CO2 emissions. They do, however, burn less cleanly than petrol engines. This is addressed in some vehicles with a "smog trap" or "soot trap" to catch particles before they exit via the exhaust.

Petrol, as well as being somewhat cheaper per litre than diesel, has also been the fuel of choice for quieter running and better overall performance. Petrol engines burn cleaner, but do generally produce more CO2 emissions than their diesel counterparts due to lower efficiency.

LPG has experienced relative popularity in Australia, in part due to government subsidised fuel prices and incentives offered for engine conversion. Although LPG has some minor emissions advantages over petrol, it is most likely the attractive price that has induced many drivers to make the change.

There are also a range of renewable alternative fuels available, such as bio-diesel, ethanol and hydrogen. Currently these fuels are not widely available in Australia, although ethanol blended petrol - often known as E10 - can be found at some service stations.

CO2 emissions by fuel type:

Fuel typeCO2 emissions
Petrol 2.3 kg/L
LPG 1.6 kg/L
Diesel 2.7 kg/L

From the table above LPG appears to be the clear leader when it comes to CO2 emissions.

However, vehicles running on LPG require more litres of fuel per km than their petrol equivalents. Using the Green Vehicle Guide's comparison tool it becomes clear that from a greenhouse gas perspective, the advantages of LPG aren't quite so clear-cut.

Comparison of CO2 emissions from petrol and LPG:

VehicleFuel TypeFuel Consumption
(combined cycle)
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
(91 RON)
10.8 L/100km 256 g/km

Green Finance

Although car finance is not usually thought of as an environmental decision, green car finance does exist. Green Finance, an initiative of stratton, is a no-cost, environmentally friendly, carbon-neutral finance program for cars and light commercial vehicles.

For every car that is financed through Green Finance, the program will plant enough native trees to offset that vehicle's CO2 emissions for one year. All cars and light commercial vehicles financed through Green Finance are automatically enrolled - and there are no additional costs.

Head to for more information.

Resale reputation

It's not strictly an environmental concern, but for most people resale is an important consideration.

Recognised green cars, and other efficient and economical vehicles, are attractive resale propositions. Most of us are aware of fuel prices, and many of us are aware of our responsibility to reduce our emissions.

Whether the environment is top of mind, efficient and economical vehicles have wide appeal. Green cars with a solid reputation hold their value well. Go to to check prices on your next vehicle, or read more about protecting your car's resale value now.

For more information on Green Finance for your next vehicle, visit, call us on 1300 STRATTON (1300 787 288) or contact your finance consultant directly.