How much more pollution do PHEVs emit compared to lab tests?

According to the analysis, PHEVs emit 4.9 times more CO2 in real-world driving than in standardized lab tests.

How much do PHEVs actually reduce emissions compared to petrol and diesel cars?

The report found that PHEVs only reduce CO2 emissions by 19%, much less than the 75% reduction previously claimed in lab tests.

Why are PHEV emissions increasing?

The trend towards longer electric ranges in PHEVs is a key factor, as bigger batteries make the vehicles heavier and cause them to burn more fuel when operating in engine mode.

Home / Environment / Plug-In Hybrids Emit Nearly 5 Times More Pollution Than Lab Tests Suggest

Plug-In Hybrids Emit Nearly 5 Times More Pollution Than Lab Tests Suggest

16 Oct, 2025

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Summary

Plug-in hybrids emit 4.9 times more CO2 in real-world driving than in lab tests
Plug-in hybrids only reduce emissions by 19% compared to petrol and diesel cars
Plug-in hybrids are more expensive to drive and buy than clean alternatives

Plug-In Hybrids Emit Nearly 5 Times More Pollution Than Lab Tests Suggest

According to a recent analysis, plug-in hybrid vehicles (PHEVs) are failing to live up to their emissions-reducing claims. The non-profit group Transport and Environment examined data from 800,000 European cars between 2021 and 2023 and found that PHEVs emit nearly five times more "real-world" pollution than suggested by lab tests.

The report revealed that PHEVs only reduce CO2 emissions by 19% compared to traditional petrol and diesel cars, a far cry from the 75% reduction previously claimed in lab tests. This growing gap between official and actual emissions is a major concern, as PHEVs are now polluting almost as much as regular gasoline-powered vehicles.

The issue is exacerbated by the trend towards longer electric ranges in PHEVs. Bigger batteries make the vehicles heavier, causing them to burn more fuel when operating in engine mode. Even when driven in electric-only mode, the electric motors often lack the power to operate alone, requiring the combustion engine to kick in for nearly a third of the distance.