Plug-in hybrid electric vehicles (PHEVs) emit almost as much carbon dioxide as conventional petrol cars, according to a new analysis by Transport and Environment. The study of 800,000 cars in Europe found that real-world CO2 emissions from PHEVs were nearly five times higher than official lab tests suggest.
While laboratory tests assumed PHEVs produce 75% less CO2 than petrol or diesel cars, the analysis shows they emit only 19% less in real-world driving. The gap between official and actual emissions has widened from 3.5 times in 2021 to 4.9 times in 2023.
The researchers attribute the discrepancy to overestimates of how much driving is done in electric mode. Official estimates assumed 84% of miles were electric, but the data showed only 27%. Even when in electric mode, the cars' engines often burned fossil fuels because the electric motors were not powerful enough to operate alone.
The analysis also found that four major carmaker groups avoided over €5bn in fines between 2021 and 2023 due to the underestimation of PHEV emissions. Drivers of PHEVs are paying about €500 more per year in running costs than lab tests suggest.
Colin Walker of the Energy and Climate Intelligence Unit said: 'Consumers are being duped into believing that in buying a PHEV, they are helping the environment and saving money. In reality, PHEVs are little better than regular petrol and diesel cars.'
