To Diesel, or not to Diesel?

Diesel cars are finally available in Singapore! Before you exclaim "Cheaper fuel here I come!", allow us to show you why buying a diesel car may not be entirely beneficial for your wallet, despite the cheaper fuel cost...

OneShift Editorial Team

03 Nov 2008

All right, let’s get down to it. The Polo BlueMotion commands a $20,000 premium over the petrol version. Assuming that you’ll be driving the car for 10 years, this means you’re looking for $2,000 in fuel savings over the petrol counterpart in a year. However, you’re also paying an extra $1,790.40 a year in road tax. Therefore, you need to save more than the combined amount of $3,790.40 a year over the petrol Polo to enjoy any real savings.

Arithmetic time

But how far would you need to drive in a year to realize this cost saving? Let us find out with some simple use of algebra.

Let us call the minimum number of kilometers that you will have to drive, X.

We also need to find out how much it costs to drive the petrol and diesel variants per kilometer, respectively. So, we’ll take the price per litre of each, and divide them by their official fuel consumption figure.

So, the petrol Polo travels 14.5km per litre, which amounts to $0.12 per kilometer travelled. The diesel Polo travels 25.64 km per litre, which amounts to $0.06 per kilometer.

Recall that we need to save a minimum of $3,790.40 a year to make economical sense of buying a diesel. Hence, when the value of X is multiplied with the difference in cost per kilometer, you should get the saving amount $3,790.40. Therefore:

X multiply by (0.12 - 0.06) = 3790.40

With this equation (are you still with me?), you do a little re-arragement of the equation to get the following:

X = 3790.40 / (0.12 - 0.06)

X = 63173.33

Based on this formula, you would have to cover at least 63,173.33 km per year (or 5264 km per month) in order for the BlueMotion to make sense. Considering that the average driver in Singapore covers about 20,000 km per year, you’d have to drive 3.16 times further than the typical motorist.

So for now, it seems that diesel cars are a viable choice only to motorists who really clock up the mileage. If you don’t belong in that group, but want a diesel car anyway, what can we say? That’s one hell of an extravagant, environmentally friendly statement you’d be making, and we’d be the first to take our hats off to you!

What does this really mean?

Credits: Story by Jeremy Chua, pictures by Azfar Hashim