After spending a decade covering the EV market, one stat in a new 61-page Fraunhofer Institute study stopped me cold: the average Porsche PHEV driver charged their battery to less than 50% capacity exactly once over two years. That’s 7 kilowatt-hours total. You’d use more electricity running a space heater for an afternoon.

The study, dated February 18, 2026, analyzed on-board fuel consumption data from 981,035 plug-in hybrid vehicles across Europe. The findings are damning for every automaker currently pivoting toward PHEVs as their electrification strategy.

The Fact: PHEVs consume an average of 6.12 liters per 100 km in the real world, compared to the 1.57 L/100 km claimed under WLTP testing. That’s nearly four times the fuel manufacturers say these vehicles burn.
The Delta: Even in electric-only mode, PHEVs burned 2.98 L/100 km of fuel, nearly double what testing protocols assume, because combustion engines kick in far more often than manufacturers admit.
The Buyer Impact: If you’re shopping for a PHEV expecting 150 MPGe, real-world performance is closer to 38 MPGe. That’s regular hybrid territory, not the efficiency breakthrough manufacturers are selling.

Nearly One-Third of German PHEV Owners Rarely or Never Plug In

The Fraunhofer Institute for Systems and Innovation Research used on-board fuel consumption monitoring (OBFCM) data, pulling numbers directly from vehicles’ computers rather than relying on manufacturer-submitted lab results. The full study, the largest real-world PHEV analysis ever conducted, exposes a systemic gap between what automakers promise and what buyers actually get.

Less than a third of the 1 million PHEVs studied in Germany plugged in either occasionally or never at all, according to TechCrunch’s Tim De Chant, who analyzed the findings. The brand-by-brand breakdown tells the real story. Toyota drivers used electricity for 44% of their driving energy, the best showing in the study. Cheaper PHEVs from Ford, Kia, and Renault with smaller engines also came closer to matching their claimed efficiency numbers.

German luxury brands were the worst offenders. Porsche drivers averaged just 0.8% electric energy use over two years. The company responded by saying it conducted efficiency tests according to legal requirements and blamed different usage patterns.

Patrick Plötz of the Fraunhofer Institute told German broadcaster SWR that researchers suspect combustion engines in PHEVs turn on far more frequently than previously thought. He urged regulators to use real-world emissions data instead of manufacturer-submitted figures.

The Company Car Loophole Explains Everything

A massive share of European PHEVs are company cars, a compensation perk where employers buy the vehicles to satisfy emissions regulations. The Fraunhofer data shows company car PHEVs charge far less than private ones. Industry analysts point to a simple incentive mismatch: in many European fleets, employers reimburse drivers for gasoline but not for electricity, removing any financial reason to plug in. The car checks a regulatory box on paper while running on gas in practice.

This matters for American buyers because Ford, Stellantis, and other U.S. automakers are now rushing to build PHEVs as their primary electrification strategy. Ford CEO Jim Farley said during a February 2026 earnings call that the company is “looking to make CO2 reductions across our lineup, but we’re doing it in a very efficient way.” That “efficient way” means hybrids.

Ford’s pivot to PHEVs didn’t happen in a vacuum. The company killed the next-generation F-150 Lightning in its all-electric form, took $19.5 billion in restructuring charges, and is converting BlueOval City from EV production to battery storage. Ford’s Model E division lost $5.1 billion in 2024. The company’s CFO announced a $2 billion shift from all-electric SUVs to hybrid models back in August 2024.

The Fraunhofer data suggests Ford is building its future around a powertrain category that produces 3.5 times more emissions than official ratings indicate.

Europe’s PHEV Boom Is a Regulatory Shell Game

The timing of this study is brutal for European automakers. PHEV registrations in the EU surged 43.2% year-over-year in October 2025, with plug-in hybrids outselling diesel vehicles for the first time in automotive history. We documented this shift extensively at EVXL: the September 2025 PHEV explosion showed automakers choosing profitable hybrids over money-losing pure electric vehicles to meet emissions targets.

Now Fraunhofer has proved what critics suspected. Those PHEVs checking regulatory boxes aren’t actually reducing emissions. They’re burning three times more fuel than the rules assume they are.

The EU already knows about the problem. A planned adjustment to the “utility factor,” the government estimate of how often PHEVs run on electric vs. fossil power, was supposed to take effect in 2025 emissions regulations. But automaker lobbying has targeted the changes. The German Association of the Automotive Industry (VDA) told Fraunhofer that it believes existing methods for determining fuel consumption and CO2 emissions are reliable.

That claim looks increasingly difficult to defend with nearly a million vehicles’ worth of real-world data saying otherwise.

EREVs Won’t Fix the Core Problem

Extended-range electric vehicles (EREVs) are the industry’s proposed fix. These vehicles run on battery power until depleted, then use a combustion engine as a generator to recharge the battery. In theory, this forces more electric driving. In practice, no EREV has ever required the owner to plug in. A driver could run the vehicle on gasoline for its entire lifespan.

Ford and Stellantis have both announced EREV pickup trucks, neither of which has gone on sale. BMW made an EREV version of the i3 for years before discontinuing it. The Fraunhofer study didn’t test EREVs, and their electric-first design may produce better results. But if PHEV owners won’t plug in when the car is designed for it, there’s a real risk EREV owners behave the same way when plugging in is entirely optional.

EVXL’s Take

I’ve been tracking legacy automakers’ PHEV pivot for over a year, and this Fraunhofer study confirms what the data has been whispering since European PHEV sales started surging in mid-2025: plug-in hybrids are a compliance strategy, not an emissions reduction strategy.

The pattern is clear. Ford lost $1.4 billion on EVs in Q3 2025 alone and pivots to hybrids. European automakers face billions in potential fines for missing CO2 targets and flood the market with PHEVs that look clean on paper. Meanwhile, the actual vehicles on actual roads burn three times more fuel than the regulations assume.

This is the Volkswagen diesel scandal’s slower, legal cousin. Nobody is cheating a software test this time. Instead, the regulations themselves are built on fiction. Laboratory cycles assume daily charging and short trips. Real owners use PHEVs as gasoline cars with extra weight and complexity. The outcome is the same: vehicles that appear clean on paper but pollute far more on the road. The Fraunhofer researchers are calling for urgent regulatory changes. I think they’ll get them, but not fast enough. European automakers have already placed their bets on PHEVs for the 2026-2028 product cycle, and those bets are locked in.

For American buyers watching Ford and GM pivot toward hybrids: this study is your warning. When EV manufacturing investments collapsed 30% in Q3 2025 while companies doubled down on hybrid production, we noted the disconnect. Fraunhofer just quantified it.

My prediction: by Q4 2026, at least one major European automaker will face a formal regulatory investigation into PHEV emissions claims. The gap between 1.57 L/100 km on paper and 6.12 L/100 km in practice is too large to survive political scrutiny, especially with this much public data backing it up. The diesel scandal started with smaller discrepancies.

Editorial Note: AI tools were used to assist with research and archive retrieval for this article. All reporting, analysis, and editorial perspectives are by Haye Kesteloo.