New car CO2 emissions in the UK fell by their fastest ever rate last year to an average of 158g/km, and it is fleets who are at the vanguard of the move.

Fleet and businesses buy more new cars every year than private buyers, and the availability of new low CO2 models is a key factor.

Recent figures from the BVRLA (Fleet News, May 28) back this up with average CO2 emissions of new leased cars in 2008 standing at 149.9g/km.

Many car manufacturers now offer their own sub-brands which promise low emissions and increased fuel economy.

The names can be confusing – Blue means green for Mercedes-Benz and Volkswagen, DRIVe signifies low emission Volvos while Ford, Seat and Vauxhall use the term ‘eco’ in the names of their brands.

But just because a car has eco branding on it, it doesn’t necessarily mean it is the best bet for a company car driver.

While CO2 emissions and fuel economy are always better than the standard models on which they are based, often these eco models have a higher front-end price.

To find out if an eco-brand is always best, we looked through the various models on offer to see how much they will cost a fleet to run, and a driver to tax.

While the majority of eco cars are cheaper, there are a few surprises along the way, so it is wise to not assume that because a car has green branding it is the best bet.

Case study: Avon

Cosmetics giant Avon runs an essential user fleet of 400 vehicles.

The cars are all Vauxhalls, either Agilas or Astras, and the 300 examples of the latter are 100% Ecoflex.

Fleet manager Gerard Finn (pictured) said: "Even though there is a price premium for the Astras, they are costing us £13 a month each less to run than a non-Ecoflex model, plus there is the benefit-in-kind saving for the drivers."

Finn manages the disposal of his cars at auction, and says the
decision to take on Ecoflex models was also swayed by concerns of what used car buyers will want.

What's behind the names?

BlueEfficiency

Mercedes-Benz’s low emission models offer lower weight, improved aerodynamics including smaller wing mirrors, low rolling resistance tyres, a gearshift indicator and enhanced engine management systems to lower economy.

The only manufacturer not to charge a price premium for its eco-brand.

* Models available A-Class, B-Class, C-Class
* Coming soon E-Class saloon and Coupé, S-Class

BlueMotion

Volkswagen's solution is centred on high-efficiency diesel engines allied to revised gearbox ratios and low rolling resistance tyres which make the car more fuel efficient when cruising, and also aerodynamic tweaks.

Future plans include even more optimised and smaller capacity TDI engines with stop-start and regenerative braking.

* Models available Jetta, Passat, Touran, Sharan
* Coming soon Polo, Golf, Golf Plus

Ecoflex

Vauxhall uses revised gearbox ratios, lower ride height and optimised airflow to cut emissions, plus fitting narrower wheels with low rolling resistance tyres.

* Models available Agila, Corsa, Astra, Zafira
* Coming soon Insignia

Ecomotive

Seat's green models feature software changes, particulate filters, revised gearbox ratios and special low rolling resistance tyres.

Future plans include adding stop-start and brake energy regeneration to lower emissions, with a Leon concept car fitted with these features promising CO2 emissions of 99g/km.

* Models available Ibiza, Leon, Alhambra
* Coming soon Version two models

Econetic

Ford uses a modified engine ECU, extra aerodynamic deflectors, revised gearbox, lowered suspension, low rolling resistance tyres and a gearshift indicator to improve economy.

* Models available Fiesta, Focus, Mondeo
* Coming soon FiestaVan, Transit

DRIVe

Volvo’s eco-brand majors on low-rolling resistance tyres, revised gearbox ratios, special engine and gearbox oil and a gearchange indicator light in the dashboard to improve economy.

Drive versions have a reduced ride height,underbody panels, covered radiator grill, spoilers and special flush wheels to improve airflow.

New models arrive soon with stop-start technology which reduces emissions even further.

* Models available C30, S40, V50
* Coming soon V70, S80, XC60


Savings to be made

Eco-branded models all carry a price premium at the front-end, expect for Mercedes-Benz which doesn't charge extra for its BlueEfficiency versions.

Premiums average around the £500-mark but increased fuel economy helps the eco models pull back this disadvantage and offer cheaper wholelife costs than the regular versions.

However, the gaps are very tight, and in some cases down to just 0.2 pence per mile advantage.

Ford Mondeo
P11D price: £19,015 (1.8TDCi Edge)/ £19,470 (1.8TDCi Econetic)
CO2 (g/km): 149/139
BIK band: 20%/18%
Annual BIK bill (20%): £760/£700
VED: £125/£120
Combined mpg: 50.4/53.3
Running cost: 36.72/36.12

Mercedes-Benz A170
P11D price: £17,675 (Avantgarde SE Edge)/£17,675 (Avantgarde SE BlueEfficiency)
CO2 (g/km): 159/146
BIK band: 19%/17%
Annual BIK bill (20%): £671/£600
VED: £150/£125
Combined mpg: 42.8/46.3
Running cost: 34.06/33.14

Seat Leon
P11D price: £14,265 (1.9 TDI Reference)/£14,700 (1.9TDI Ecomotive)
CO2 (g/km): 135/119
BIK band: 18%/13%
Annual BIK bill (20%): £513/£382
VED: £120/£35
Combined mpg: 56.5/62.8
Running cost: 27.95/27.11

Skoda Superb
P11D price: £16,160 (1.9 TDI S)/£16,945 (1.9 TDI Greenline)
CO2 (g/km): 151/136
BIK band: 21%/18%
Annual BIK bill (20%): £678/£610
VED: £150/£120
Combined mpg: 49.6/55.4
Running cost: 30.35/30.15

Vauxhall Astra
P11D price: £17,190 (1.7 CDTi Life)/£17,610 (1.7 CDTi Ecoflex)
CO2 (g/km): 135/119
BIK band: 18%/13%
Annual BIK bill (20%): £618/£457
VED: £120/£35
Combined mpg: 56.5/62.8
Running cost: 33.58/33.21

Volkswagen Passat estate
P11D price: £18,541 (2.0 TDI S)/£19,091 (2.0 TDI Bluemotion2)
CO2 (g/km): 146/129
BIK band: 20%/18%
Annual BIK bill (20%): £741/£687
VED: £125/£120
Combined mpg: 50.4/57.6
Running cost: 34.58/33.59

Volvo S40
P11D price: £16,560 (1.6D S)/£16,905 (1.6 DRIVe S)
CO2 (g/km): 129/118
BIK band: 18%/13%
Annual BIK bill (20%): £596/£439
VED: £120/£35
Combined mpg: 57.6/62.8
Running cost: 31.74/31.50

Three to watch out for

Ford Focus

A £1,750 premium for the Econetic over a Studio model with the same engine output makes the green model look expensive. Driver BIK tax and wholelife costs favour the non-eco branded model.

P11D price: £15,955 (1.6 TDCi Studio)/£17,705 (1.6 TDCi Econetic)
CO2 (g/km): 118/114
BIK band: 13%/13%
Annual BIK bill (20%): £414/£460
VED: £35/£0
Combined mpg: 62.7/65.6

Seat Ibiza

Both fall into the 13% BIK band despite the Ecomotive's sub-100g/km emissions. Base 1.4 TDI S model will cost a driver less in tax, although Ecomotive has slightly lower running costs and no road tax.

P11D price: £11,305 (1.4 TDI S)/£11,940 (1.4 TDI Ecomotive)
CO2 (g/km): 114/98
BIK band: 13%/13%
Annual BIK bill (20%): £293/£310
VED: £35/£0
Combined mpg: 65.7/76.3
Running cost: 21.30/ 20.92

Skoda Fabia

As both models fall into the lowest 13% diesel BIK tax braket, the Greenline’s £355 price premium means it will cost a driver more in company car tax. Running costs dip in favour of the eco model, though.

P11D price: £11,695 (1.4 TDI 80 2)/£12,050 (1.4 TDI 80 Greenline)
CO2 (g/km): 120/109
BIK band: 13%/13%
Annual BIK bill (20%): £304/£313
VED: £35/£35
Combined mpg: 61.4/68.9
Running cost: 23.75/23.06

 Average new car CO2 emissions