While most hybrids are said to use one to two litres of fuel per 100km, a study claims they need six litres on average
Plug-in hybrid electric cars (PHEVs) use much more fuel on the road than officially stated by their manufacturers, a large-scale analysis of about a million vehicles of this type has shown.
The Fraunhofer Institute carried out what is thought to be the most comprehensive study of its kind to date, using the data transmitted wirelessly by PHEVs from a variety of manufacturers while they were on the road.
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According to the study, the vehicles require on average six litres per 100km, or about 300%, more fuel to run than previously cited.
The scientists of the Fraunhofer Institute found that the main reason for the higher-than-stated fuel usage was due precisely to the fact that the PHEVs use two different modes, the electric engine and the combustion engine, switching between both. Until now it has been claimed by manufacturers that the vehicles used only a little or almost no fuel when in the electric mode. The studies showed that this was not in fact the case.
The article is horribly unclear: it seems to say that PHEVs are no good, but “the main reason for the higher-than-stated fuel usage was …that the PHEVs use two different modes, the electric engine and the combustion engine”. Well, so do non-plugin hybrids. I doubt they’re saying that plug-in hybrids are worse than non-plugin, but you might guess that from the title.
The article states that Porsche PHEVs used 7 liters per 100 miles (33.6mpg), but Kia/Toyota/Ford/Renault used “85% less” (1.05L/100k or 223mpg… I think we can agree this is not a serious number).
Porsche mentioned “different usage patterns”. I can buy that a typical Prius owner is plugging-in every night, filling low-rolling-resistance tires to 54psi and driving like grandma, and a typical Porsche owner… isn’t. If you want apples-to-apples, then compare a gas Corolla vs a Prius vs a Plug-in Prius, where the cars are from the same city/suburb, and similar owners (e.g.: no ubers, no regional sales reps).
This “study” is evaluating real-world use of one class of vehicles, and not other vehicle types; then using the dismal ways some people drive to imply that this particular class of vehicles is the problem.
I think the point is that PHEVs do not achieve the real world emissions promised by the manufacturers, which would call into doubt reliance on them to save the climate as well as tax reliefs. Particularly, company cars are historically subsidized too much, and they get even more subsidies if they are hybrids, only to then never charge them.