Fleet operator consultancy finds plug-in hybrid vehicles are not efficient for all types of operation

A new report from The Miles Consultancy (TMC), which provides advice to fleet operators, found that real-world driving data for a small sample of plug-in hybrid vehicles (PHEVs) was, on average, about 45mpg; lower than some conventionally-fuelled alternatives. The study showed that PHEVs are not well-suited to certain types of operation - particularly where a lot of motorway or long-distance driving is involved. 

 

Car registration figures for August showed a 47% rise in hybrid car sales compared with last year, and some leasing companies report a 300% increase in orders for plug-in hybrids.

 

TMC’s real-world driving analysis found that the average CO2 output for a sample of 7 PHEVs was 168g/km in day-to-day use. The study analysed fuel consumption data for 14 models of hybrid and 7 models of PHEV. All the cars in the sample, representing 12 different manufacturers, are in regular fleet use. The data for the analysis came from TMC’s Mileage Capture and Audit system, which holds detailed records of fuel transactions and total mileage for each vehicle.

 

The PHEVs in the sample achieved an average of 45 miles per gallon compared with what TMC says is their 'average advertised consumption' of 130 mpg. This average fuel use is equivalent to actual CO2 emissions of 168 grams per kilometre (g/km). That compares with the cars’ advertised emissions (which determine the drivers’ benefit-in-kind tax rates), which averaged 55g/km.

 

Paul Hollick, Managing Director of TMC, said: "Deploying PHEVs is not at all a straightforward decision for fleets. Managers need to allow for the fact that their fuel cost per mile can increase substantially on longer journeys.

 

"PHEVs can be a cost-effective choice where drivers cover only moderate mileages; but only if the cars’ batteries are recharged daily.

 

"On the evidence of our sample, one has to question whether some PHEVs ever see a charging cable.  In a lot of cases, we see PHEVs never being charged, doing longer drives and this is not a good fit for a lot of business car users. A robust PHEV deployment policy is essential."