09 August 2012

Buying a more efficient car

The impending arrival of a second child meant we needed to look at purchasing a different car - primarily because the Subaru Imprezza sports wagon we have had cannot fit two child seats with a pram in the back. Other than buying something we could afford, our two biggest considerations were (1) ensuring the new vehicle allowed us to offer lifts to people and (2) fuel efficiency. The first criterion put us in the market for a people mover; the second launched us into the world of European-manufactured diesel cars.

We are now the proud owners of a 2008 Citroen C4 Picasso people mover.


Why a people mover? Already I have had several people respond to our choice with 'how many kids are you planning to have?!'  For us it is about ensuring our vehicle allows us to live in line with our values around hospitality and generosity. If our car is only sufficient to meet the needs of our immediate family members, it is too limited. We were already at capacity once a week in our smaller car, as we regularly give a lift as a family to another adult. We want this new car to get us through at least the primary school years, for which it will need to be able to cart our kids plus their friends plus assorted junk treasures, and in the more immediate future we want to be able to take more than two adults in the car while it has two child seats.

Temporarily we are a two-car family again, but we intend to sell the Subaru just as soon as we get our heads above the water of a newborn in the household. I can't at this stage see how we could manage with no car at all, so researching and purchasing the most efficient model we could was the next best thing for us in retaining our commitment to sustainable living.

Totally gratuitous brag photos of our new little man and his super-proud big sister

Initial Time: As you would expect when taking on an expensive purchase, we spent a considerable amount of time researching before making this decision. Once we had identified the type of vehicle we wanted, the challenge was to find one - no easy search, as few Citroen C4 Picassos are sold in Australia and even less seem to come onto the second-hand market. A brand new Picasso could of course have been ordered, but that was beyond our budget.

We were assisted by Allpike Citroen in Osborne Park, who eventually located our car through a dealer in Sydney and arranged its transport to and re-registration in WA. From standing in the Citroen yard discussing options to driving the car home took about two months. Our Picasso arrived four days before our baby, which was perhaps cutting things just a little fine...

Initial Cost: Our drive-away cost was $24,000. This included all the running around to find the car and get it to us.

Ongoing time or cost commitment: Any car has ongoing costs! Modern diesel engines need servicing only about half as often as petrol engines and, we are led to believe, generally require less maintenance. We shall see. It is also possible that parts will be harder to obtain, and take longer to turn up, as there are not many Citroens on the road here. The cost of fuel, however, will be less (see below).

Trip computer showing distance travelled, fuel economy and average speed

Impact: Various car information sources suggest we have reduced our fuel consumption from around 10L/100km to something closer to 7.4L/100km (combined urban and open road economy).

In the 2011-12 financial year we filling our car with petrol 30 times. As we roughly fill it every 400km, I estimate we travelled about 12,000km in the year. Averaging 10L/100km, this means we burnt around 1200L of petrol in the year. Petrol produces 2.3kg of carbon dioxide for every litre used, resulting in the 2011-12 carbon dioxide contribution from our car being 2760kg.

Assuming our travel distance remains constant this year, our fuel use will be around 888L - a reduction of 420L. Diesel has a higher rate of CO2 emission than petrol, at 2.7kg/L, but we still come out well ahead as diesel engines are so much more efficient. Our 780L of diesel will produce around 2398kg of carbon dioxide - 362kg less.

In the 2011-12 financial year we spent $1847.64 on petrol for our previous car. Diesel is generally more expensive per litre than ordinary petrol, but on par with the high-octane petrol we tended to opt for, so we are likely to spend closer to $1370 on fuel this year, a saving of nearly $480. As fuel prices cannot but increase over coming years, and we hope to retain this car for at least a decade if not longer, the cost savings on fuel will only increase.

In the not-quite four weeks we have had the car, we have driven only within the metro area and are running at around 7.4L/100km as per the estimates (rather than the urban driving estimate above 8L/100km, probably because our urban driving includes regular runs on roads where we can cruise along at 70-80kph or more). I am enjoying monitoring how efficient my driving is with the real-time fuel efficiency read-out on the trip computer, which is helping me learn to drive more efficiently. Any car's fuel efficiency is only as good as the way it is driven. As I drive more gently, I immediately reduce our fuel consumption.

At this stage we are not exploring options for biodiesel, but it is a nice feeling to know that we have a vehicle that could go in that direction if (when? surely this must be 'when') technology catches up with making it readily available and issues of biofuel vs food crops are addressed (perhaps using Australian native microalgae?!). Many diesel products already on the market are blends that include biofuel.


The Australian government's Green Vehicle Guide gives all sorts of useful information and allows comparison of cars across 'green' criteria. It compares air pollution and greenhouse ratings as well as simple fuel consumption.

The government also provides an online calculator to determine the carbon emissions of your vehicle.

This article at a website about family cars has a useful fuel efficiency comparison table for people movers.

The online second-hand car sales website http://www.carsales.com.au was the main searching place once we knew what sort of car we were looking for, and also to do a little bit of comparing between some of the different makes and models that were competing for our attention. Information about listed cars includes 'green info', which for some cars only includes fuel consumption and for others has details such as CO2 emissions and a green rating. My guess is that if there's not much 'green info' included its because the report would not be very encouraging to a potential buyer.

Pretty much the day we signed a contract to purchase this car, this article about the cancer-causing properties of diesel fuel was in the news. While it is concerning that diesel has been linked to cancer by the WHO, our understanding is that these findings relate primarily to the 'particulate matter' (ie soot) in diesel exhaust. This has been dramatically reduced in recent years as cleaner diesel has been produced to meet the demand of pollution-conscious consumers and greenhouse legislation, especially in Europe.

For information about biodiesel: The Australian Government's site on biofuel quality standards; Biofuels Australia - industry peak body, with plenty of background information (although of course they are pro-biofuel so its all positive coverage!). For some discussion of other, less encouraging, aspects of the biofuel industry, have a look at these links.