A team of researchers from the Fraunhofer Institute has found that plug-in hybrid vehicles consume three times more fuel on average than manufacturers claim.
The study encompassed around a million plug-in hybrid (PHEV) vehicles made in the EU in 2021–2023. The collected telemetry data revealed that the average fuel consumption was close to 6 liters per 100 km traveled, or 39.2 MPG for our U.S.-based readers. The manufacturer-rated fuel economy numbers came closest to just 2 liters per 100 km (117.6 MPG).
Porsche was found the single biggest offender with 7 liters per 100 km (33.6 MPG) being the average. The company has already issued an official comment to The Guardian, basically blaming driver habits and external factors for the discrepancy.
Apparently not satisfied with this explanation, the research team now intends to petition the EU authorities to revise the testing protocols used. Simply put, everyone would benefit if OEM-rated fuel economy numbers coincided more closely with the actual experience of the average consumer.
In related news, a non-commercial organization called Transport & Environment conducted similar research in Europe last fall. It found that hybrid vehicles tend to produce nearly five times as much polluting emissions as their makers claim. Once again, inadequate tests are likely to blame for this.
