Climate change

Report: Plug-in Hybrids Emit 5x More CO2 Than Lab Tests Show

Published OCT 17 2025

Story

Above: Electric car charging. Image credit: Unsplash

The Facts

According to a Transport and Environment analysis of data from onboard fuel consumption meters of 800,000 plug-in hybrid electric vehicles registered in Europe between 2021 and 2023, real-world carbon dioxide emissions were 4.9 times higher than official laboratory test results.
GB News
guardian
The study, published Thursday, revealed that plug-in hybrid vehicles emit only 19% less CO2 than petrol and diesel cars in real-world conditions, compared to the 75% reduction shown in official WLTP laboratory tests, which regulators consider to reflect normal driving patterns.
Express.co.uk
Businessgreen
Even when operating in electric mode, plug-in hybrids consume three liters of petrol per 100 kilometers on average, and emit 68 grams of CO2 per kilometer because electric motors lack sufficient power for higher speeds or steep inclines, requiring engine assistance.
Engadget
Fleetworld
The research found that drivers use electric mode for only 27% of their driving distance, significantly below the 84% assumed in official estimates, and that the gap between laboratory and real-world emissions increased from 3.5 times in 2021 to 4.9 times in 2023.
GB News
CleanTechnica
Mercedes-Benz showed the largest discrepancy between official and real-world emissions at 494% above claimed levels. The average selling price of plug-in hybrids in Germany, France and the U.K. is €55,700 as of 2025, exceeding that of battery electric cars by €15,200.
Independent
Fleetworld
Hidden fuel consumption costs reportedly add €500 to the annual costs for plug-in hybrid drivers on average — more than official estimates. European carmakers avoided over $5.8 billion in fines between 2021 and 2023 by underestimating emissions during laboratory testing.
Engadget
Pieter Cranenbroek on LinkedIn

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The Spin

Techno-optimist narrative

Plug-in hybrids still deliver meaningful environmental benefits by electrifying thousands of kilometers annually and reducing tailpipe emissions by 15-55% compared to conventional cars. PHEVs with longer electric ranges achieve 12,000-20,000 kilometers of annual electric driving, matching typical car usage patterns. Real-world performance varies significantly by market, with some regions achieving over 50% electric driving.

ICCT

Energy News

Bluesky Social

Techno-skeptic narrative

Plug-in hybrids are a costly environmental scam that emit nearly five times more CO2 than official tests claim while delivering only 19% emissions reduction over regular cars. These vehicles burn fuel even in electric mode and cost drivers an extra $500 annually in hidden fuel consumption. At an average price of $55,700, PHEVs cost $15,200 more than cleaner battery-electric alternatives.