GREEN DRIVING: Lean, green machines
12 December 2013
Author: Jack Carfrae
Which of the alternative fuel drivetrains on the market today delivers the best results and make the best case for operators? Jack Carfrae pooled four of the most efficient cars for a real-world test in, and out, of the city.
Range extender vs. Diesel Hybrid vs. Diesel
There are plenty of economical vehicles on the market. You don't have to look far to find something that will emit less than 100g/km, promise in excess of 70mpg and meet all the demands that a fleet operator and a company car driver will require.
That same market has also been bombarded with alternative-fuel vehicles, which, if you're not used to the concept, can be a bit scary. Seemingly ludicrous mpg claims, worryingly sophisticated drivetrains and high price tags are enough to deter many. There's no guarantee that your drivers are going to get anywhere near those lofty claims either, so why bother?
BusinessCar has the answers.
We've pooled together four exceptionally clean and economical cars on sale today - all of which are powered in different and innovative ways and are vying for the attention of corporate customers - and pitted them against each other in a real-world driving experiment to establish how green and economical they really are.
The contenders are made up of:
- the Vauxhall Ampera, (right) a revolutionary plug-in hybrid model promising an official 235.4mpg with electric and petrol power combined and a range of up to 50 miles on electricity alone;
- the Peugeot 508 RXH, (below) one of the few diesel hybrid cars on the market, with a claimed 68.9mpg and exemption from the 3% diesel benefit-in-kind levy;
- the Volvo V60 plug-in hybrid, (left) with both diesel and electric power, claimed fuel consumption of 155.2mpg and a mammoth 304hp on tap;
- the BMW 320d Efficient Dynamics - (middle) the least inventive of the four on the technology front but still a very clean premium upper medium model at 109g/km, widely recognised as the car to beat in its segment and hugely popular with fleets.
The difference in technologies means that the cars are not directly comparable, so we didn't expect them all to chart similar mpg figures. What we did want to establish was which returned the best results in realistic driving conditions, and weigh that up against the price and compatibility of all four competitors.
Our test for each car consisted of a lap of the North and South Circular ring roads around London, followed by a steady motorway run along the M20 to the South-East coast and back to the BusinessCar offices. Each car was brimmed with fuel and, where appropriate, fully charged with electricity before its respective run.
We're not going to pretend that this test is at the pinnacle of scientific economy investigation, and though the routes were the same, slight differences in results are inevitable when you're travelling on busy roads within the capital and the South East's motorway network.
Also inevitable, specifically on the North and South Circular, is the reality of London driving. As much as we'd love to wax lyrical about the benefits of leaving plenty of distance, anticipating the road as far ahead as you can and maintaining momentum, the harsh reality is that such a driving style isn't always practical on the capital's roads.
Other road users do tailgate and cut you up, and lanes merge into one more quickly than you'd expect, so the occasional dab of brakes or squirt of acceleration is necessary if you want to get where you're going.
We're aware that those admissions might risk us falling out of favour with road safety and economy driving specialists, but we didn't set out to achieve the safest and most frugal drives ever recorded.
That's not to say that we drove like hooligans, but our aim was to approach the two routes in as realistic an environment as possible and one that was most likely to reflect the challenges those driving for work face every day.