Opinion: Plug-in hybrids under fire - with old arguments

Contents

Wow, that was almost unexpected: "Plug-in hybrids consume drastically more in practice than in WLTP!" Scandal! Fraunhofer ISI has come to this not exactly groundbreaking conclusion after an extensive analysis of plug-in hybrids sold between 2021 and 2023. SWR and dpa are spreading the non-sensation across the media landscape, along with the expected commentary from various directions. However, only those who have so far paid little attention to the topic and the development of standard consumption figures can be surprised. Yet the plug-in hybrid drive offers so many starting points for criticism, including consumption, that this old chestnut was really not needed.

What happened?

For the umpteenth time, someone has suddenly noticed that plug-in hybrids consume more in practice than in WLTP. While such a consumption difference exists for almost all powertrains, it is particularly pronounced with PHEVs. However, the supposed bombshell fizzled out the first time, as it requires a very pronounced naivety to seriously assume that an adult SUV can be moved 100 km with less than 2 liters without very special consumption calculations. As with no other type of drive, the user has control over how much fuel flows through the injectors. If they charge diligently, it will be little, possibly even less than suggested in WLTP. If they don't charge at all, fuel consumption will be drastically higher.

Fraunhofer ISI has now found: While the average standard consumption is around 1.4 to 1.6 liters per 100 km, according to real data, depending on the calculation method, it is between 5.8 and 6.1 liters per 100 km. To be precise, the data only reveals that the external charging option was used only sparingly. This can and should undoubtedly be criticized and has two main reasons. Firstly, for models from the production years examined, there were numerous models that could only be charged at a maximum of 3.7 kW. On average, a full charge for the traction batteries common at the time with an energy content between about 10 and 14 kWh took a good four hours.

High Consumption

Unless it was deep frost, a cautious driver could manage something between around 35 and 50 km purely electrically. This also outlines the second sticking point: The electricity consumption is usually significantly higher than that of a battery-electric car. Some drivers ignore this in their calculations. But at the latest when such a model has to be charged publicly, the consumption is also no longer negligible in monetary terms. We have tested numerous models that, on average over the year, with an average driving profile and a driver who is not aiming for particularly economical driving, consume well over 30 kWh per electric drive.

It was a shock for the scientists involved that the cars consumed an average of about 3 liters per 100 kilometers in everyday use, even in the predominantly electric discharge mode, quotes study leader Patrick Plötz from Fraunhofer ISI to SWR. Because this is much more than previously thought. This statement, without any information on how high the electric mileage share was, is worth very little or says a lot about the participants' engagement with the topic.

PHEV without E-Support? Nonsense

Many plug-in hybrids, the dpa quotes the report, were charged little or not at all. This would also have contributed to higher fuel consumption because the "power then has to come entirely from the internal combustion engine." Technically, this is nonsense, of course, because the traction battery can also absorb energy through recuperation. Depending on the profile, quite a bit can be accumulated. A long downhill drive can thus easily enable a few kilometers of purely electric driving – without any external charging. In a Ford Kuga PHEV, I was able to read about 50 percent electric mileage on a commute once – after starting with zero kilometers of purely electric range. The idea that a PHEV is just an internal combustion engine with an empty battery is fundamentally wrong. Because the battery is never completely discharged, even if the indicated e-range is zero. It then acts as an oversized buffer and can, under certain circumstances, even help reduce fuel consumption.

How often external charging was done varies by manufacturer, the study says. Little surprising, because manufacturers also make it more or less difficult for users to use the e-mode. Whoever has to wait four hours to then drive 40 km electrically – for exorbitant costs – will use it less often than the owner of a model that picks up 90 km of e-range while doing the weekly shopping.

Appetite Suppressors

Plug-in hybrids were and still are called bridging technology. However, anyone who wants to help the internal combustion engine extend its life through this detour should clearly state that the total energy requirement, even with frequent use of the electric component, is significantly higher than that of an e-car. It may be possible to actually drive a PHEV SUV on two liters, but then correspondingly more electricity must be recharged. Although a plug-in hybrid can be really helpful: Those who have discovered electric driving for themselves usually want "more of it" – and consequently opt for an e-car.

However, an efficient overall system practically never arises from this, and therefore no one needs to hold vigils for it at the political level either. Rather, it would also be economically sensible to clearly communicate the direction the powertrain is heading. The time of interim solutions should finally be over in 2026. Because the path towards e-mobility has long been set. On the one hand, many models are convincing in everyday use, and on the other hand, due to the tightening of fleet consumption, manufacturers have no other choice but to sell more electric cars. The European automotive industry is not helped if doubts are constantly cast on this. It is quite possible that the change in driving energy can be postponed somewhat. But not canceled. Trying to help the plug-in hybrid with old findings on consumption does little to serve the cause.

(mfz)