According to a recent study, most plug-in hybrid models aren’t more environmentally friendly than their regular combustion engine counterparts due to their limited all-electric range, and their CO2 emissions can actually be worse than those of a conventional gasoline or diesel model.
Researchers at the Fraunhofer ISI institute and the International Council on Clean Transportation (ICCT) examined usage data found that, at best, a plug-in hybrid car produces average CO2 emissions that are twice as high as what carmakers claim regardless of test cycle.
A big reason for this is the fact that PHEVs are also used as company cars, which in turn are usually driven distances that exceed their relatively limited full-electric range. Furthermore, company car drivers are in most cases incentivized to fill up with gas seen as how their employers pay for the fuel.
Read the article at Carscoops.