An analysis by the European Federation for Transport and Environment of data on real-world emissions from plug-in hybrid electric vehicles (PHEVs) has shown that they generate up to 2.5 times more CO2 than their manufacturers claim.
On the basis of laboratory tests, automakers claim that PEVs emit less than 50g of CO2 per kilometer, however, this figure is in fact far higher in real-world conditions. A compilation of several European studies has shown that on average, PHEVs emit around 117g of CO2 per kilometer, which, at the end of the day, is just a little less than the 135g per kilometer generated by a conventional hybrid like the Toyota Prius.
Over its lifetime, a PHEV will therefore generate 28 tonnes of CO2, which is not that far removed from the figure of 33 tonnes for a conventional hybrid. By way of comparison, gasoline and diesel-powered automobiles respectively emit 39 and 41 tonnes of CO2 over their lifetimes. It goes without saying that emissions on this scale bear no relation to those for fully electric automobiles, which will use the equivalent of 3.8 tonnes of CO2 in electricity in the course of their usage.