RAC Foundation report presents mixed picture on well-to-wheel emissions of different fuel technologies

Thu 19 May 2011 View all news

A new report by the RAC Foundation based on 51 vehicles taking part in the Foundation's 57-mile Brighton to London eco-rally found that well-to-wheel emissions were better for the only highly efficient petrol internal combustion engine vehicle in the rally than for electric, hybrid, hydrogen fuel cell or diesel cars also taking part. The report highlighs that the eco-credentials of electric cars depend on when they are charged.

The report also revealed a wide range of performance characteristics between and within the different vehicle technologies taking part in the rally.

Three groups of cars participated in the actual trial. 63 vehicles took part in the full event of which 51 completed the drive:

• Pure electric (battery);
• Hybrids (including plug-ins and hydrogen fuel cells);
• Internal combustion engines emitting no more than 110g CO2/km on the official New European Drive Cycle.

In terms of tank-to-wheel emissions, electric vehicles were the most efficient, registering 0.61 MJ/km while the only petrol vehicle consumed 0.91 MJ/km. Hybrids were the next most efficient category averaging 1.16 MJ/km while the only hydrogen fuel cell vehicle clocked 1.23 MJ/km. Diesels were the least efficient with 1.74MJ/km.

Driving style and vehicle and passenger weight had a considerable impact on fuel consumption. Where the same make and model of vehicles was entered more than once, consumptin ranged from 65 to 126mpg for one of the hybrid models and between 38 and 76mpg for one of the diesel vehicles.

On a well-to-wheel basis, the results were quite different. On average:

  • hybrids emitted 103g CO2/km
  • electric vehicles emitted 105g CO2/km
  • the diesels emitted 147g CO2/km
  • the only petrol ice engine emitted 81g CO2/km
  • the hydrogen fuel cell vehicle emitted 112g CO2/km

For further details about the report, please follow the associated links.

 


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