Plug-in hybrids emit almost as much pollution as gas cars, report finds

The difference in emissions between plug-in hybrid electric vehicles^[1] (PHEVs) and gas cars is merely 19 percent and not 75 percent as lab tests show, according to a report^[2] by a group of European transport and environment NGOs. They analyzed data transmitted by the onboard fuel consumption meters of 800,000 plug-in hybrids registered in the continent between 2021 and 2023. What they found was that the real-world carbon dioxide emissions of PHEVs were 4.9 times higher than what they’re supposed to emit on paper, mostly because of manufacturers’ and testers’ flawed assumption on the share of the vehicles’ electric driving mode.

Specifically, the official estimates for the share of electric driving mode are 84 percent, but the share is only as little as 27 percent in the real world. That means most of the driving done on PHEVs uses gas. In addition, even when PHEVs are in electric driving mode, they’re still emitting considerable pollution. Apparently, their electric motors don’t have sufficient power to operate on their own, and their combustion engines have to supply power for almost a third of the distance driven. The lack of fast charging in PHEVs also makes it less convenient to charge, leading people to just fill their tanks with gas. All these factors don’t only translate to pollution, but also to additional gas expenses. The report says drivers end up paying $582 more than official estimates for fuel costs.

As The Guardian^[3] notes, carmakers have been pushing for the adoption of PHEVs in Europe as a low-emissions alternative that won’t give owners range anxiety, with Volkswagen, Mercedes-Benz and BMW accounting for most of the sales over the past years. The researchers have noted that four major carmaker groups have avoided over $5.8 billion in fines between 2021 and 2023 due to the underestimation of PHEV emissions in the lab. These official emission numbers allowed companies to comply with the required carbon dioxide emission targets for their fleets. Based on real-world data, however, the vehicles they sold emitted 52 million tons more carbon dioxide than they were supposed to.