Fleet decision-makers are beginning to turn away from diesel power in favour of lean-burn petrol engines, hybrids and electric vehicles, says fleet management specialist CLM.

Analysis shows that although diesel is still by far the most popular means of propulsion among its fleet customers by an overwhelming margin, diesel’s dominance is beginning to show signs of being eroded in favour of the new generation of petrol-engined models and alternative-powered vehicles now available.

CLM looked back over months of new vehicle registrations to identify a series of clear trends developing among its fleet buyers.

The first trend was a move away from diesel to other forms of propulsion. At the end of quarter four in 2014, diesel models accounted for 90.4% of all new models ordered on the CLM fleet. However, by the end of quarter one of this year that rate had fallen by 4.8% to 85.6% of all new orders.

At the same time, the percentage of petrol models being ordered increased from 4.5% at the end of 2014 to 9.6% by the end of the first quarter of 2015 – the highest level for a number of years.

Meanwhile, hybrids and electric vehicles are beginning to increase their toe-hold on the CLM-managed fleet of 14,000 vehicles.

Although the starting point is still from a very low base, the number of hybrids and plug-in hybrids now being ordered by CLM has increased to 4.9% of the fleet mix.

Pure-electric vehicles, meanwhile, continue to struggle to make an impression on the order statistics, accounting for just 0.2% of the fleet mix at the end of 2014, but enquiry levels are rising.

CLM has regularly been advising fleet clients of the importance of encouraging the take-up of low-carbon cars among company car drivers to cut tax bills, reduce the corporate carbon footprint and slash fuel costs.

Clients have been clearly heeding the advice as the average CO2 emissions across the CLM fleet have declined by 5g/km year-on-year from an average of 125g/km to 120g/km at the end of last year.

Simon Cotton, CLM general manager, said: “One of the reasons for the move away from diesel could be the introduction of stricter new Euro 6 emissions standards which apply to all new vehicle registrations from September 1 this year.

“The new systems required to meet these standards seem certain to come at an increased cost, some of which may be borne by the vehicle manufacturers, but some of which may have to be passed on to the buyer.

“At the same time, health concerns about the safety of diesel emissions, particularly nitrous oxides, have been increasingly publicised both here and in Europe. Many major cities are considering additional congestion and parking charges for diesel vehicles which do not meet the Euro 6 regulations.

“However, the latest generation lean-burn petrol models face no such problems and their upkeep and maintenance, compared to future diesel models, could be viewed as less complicated and more straightforward, with lower front end costs, improved economy and better carbon emissions,” he said.

CLM’s current advice to its clients on the best mix of vehicles for their fleets is based on the most common type of driving that they do.

Cotton said: “For fleets with a large percentage of high-mileage journeys, typically on motorways, then we advise that diesel vehicles remain the most cost advantageous option due to their lower fuel consumption.

“For fleets with mainly low mileage needs, petrol-engined models usually present the best option because of their improved running costs and lower capital outlay compared to diesel equivalents, which have a front-end price premium.

“And for fleets that operate in a largely urban environment with a lot of stop-start driving, the best options can be hybrids, range extenders and pure EVs.

"The final choice comes down to the flexibility requirements of the fleet and overnight parking and recharging arrangements."