BEST cars are in operation among all BEST partners. Some are used as pool cars, i.e. shared by many employees in one company or administration. Others have only one user.
Flexifuel cars are tested in a variety of conditions, e.g. by the police in Somerset, home services and fire services in Stockholm, taxi in BioFuel Region, the mayor in La Spezia, the alderman in Rotterdam and the municipal waste company in Madrid.
The possibility to fuel E85 varies between the participating cities and regions. This also affects the proportion of E85 used in the cars. In some sites, like La Spezia, it wasn’t possible to fuel E85 until spring 2008, and therefore the first flexifuel cars operated on 100 percent petrol in the beginning.
The tendency to fuel the cars with E85 also varies between drivers and between different cars in the same site. Gareth Brown at Imperial College is involved in collecting and analysing data from FFV cars used at the BEST sites:
– In BEST we have monitored in detail fuel consumption in 83 flexifuel cars – 76 Ford Focus and 7 Saab Biopower. On an aggregated level we monitor 167 cars.
Even though Gareth Brown has not evaluated all the data he does have some preliminary results based on calculations from 30 of the cars:
– The log shows no extra unscheduled maintenance related to the fact that these cars are FFV cars as compared to normal cars. The evaluation shows that when fuelled with E85, the Ford Focus cars consume between 9.3 and 14.4 litres of fuel per 100 km, with an average consumption of 10.6 l E85/100 km.
The big variations in fuel consumption can be explained by how the car is used (city traffic or long distance) and driver behaviour (aggressive or ecodriving).
When fuelled with petrol, the Ford Focus cars show a consumption of between 6.8 and 10.2 litres of fuel per 100 km, with an average consumption of 8.8 l petrol/100 km. The Saab 9-5s consumed between 12.5 and 16 litres of fuel per 100 km when running on E85, with an average consumption of 13.9 l E85/100 km.
The monitored Saab FFVs have not been continuously fuelled with petrol for any significant period, so we have not calculated real-world petrol consumption averages for these cars. Instead, we have measured fuel consumption of a Saab 9-3 2.0t Biopower in an emissions laboratory, with the results given below.
Gareth concludes that the Ford Focus consumes approximately 1.2 times as much E85 as petrol/km. In the dynamometer tests, the Saab Biopower consumed 1.3 times as much E85 as petrol/km.
–This is, however, preliminary data. In summer 2009 a much more detailed data analysis will be performed, he says.