While most hybrids are said to use one to two litres of fuel per 100km, a study claims they need six litres on average
Plug-in hybrid electric cars (PHEVs) use much more fuel on the road than officially stated by their manufacturers, a large-scale analysis of about a million vehicles of this type has shown.
The Fraunhofer Institute carried out what is thought to be the most comprehensive study of its kind to date, using the data transmitted wirelessly by PHEVs from a variety of manufacturers while they were on the road.
. . .
According to the study, the vehicles require on average six litres per 100km, or about 300%, more fuel to run than previously cited.
The scientists of the Fraunhofer Institute found that the main reason for the higher-than-stated fuel usage was due precisely to the fact that the PHEVs use two different modes, the electric engine and the combustion engine, switching between both. Until now it has been claimed by manufacturers that the vehicles used only a little or almost no fuel when in the electric mode. The studies showed that this was not in fact the case.
How is it misleading?
Manufacturers make claims about fuel consumption. Based on studying real-world data, fuel consumption is significantly worse than claimed. The study authors say that internal combustion engines are active much more frequently than claimed. They propose that manufacturers and regulators use real-world data because it’s more accurate. Is that such a bad idea?
Because the stupidity of consumers is hard to under estimate by engineers.
The problem is not the car designs, it’s that idiots don’t plug in, plug in hybrids, they run them only on gas. They should be charging them overnight. Regardless, they still use significantly less fuel than just ICE designs.
Its misleading because they’re pushing this like it’s Dieselgate when in reality it’s just that the “MPGe” rating (and metric equivalent) is just a dumb fucking estimation. Porsche states that you get 29 miles electric range at most and then everything else is 22-29 MPG. That’s how PHEVs should be quantified.
Imagine a Porsche owner driving 20 miles to work, charging, and then driving 20 miles back home. How much fuel was used?
Now imagine another Porsche owner driving the same 40 miles but in one trip. How much fuel was used?
How about a third Porsche owner driving 20 miles but flooring it after every stop light in cold weather, not charging, and then driving 20 miles back home. How much fuel there?
These would all give wildly different results which is why any combined estimation will be wrong regardless of the method. Same goes for ICE vehicles but to a lesser extent since they’re always burning fuel. Combined city/highway is going to be different if that ratio is 90/10 versus 10/90. Its going to be different based on weather, driving style, number of passengers, etc. The whole point of this is to simply compare vehicle efficiencies in an apples to apples way not perfectly predict what you’ll actually experience driving the car.
There’s no scandal here just sensationalism.
Why are people so bizarrely defensive about this?
This isn’t sensationalism. It’s a scientific study of actual real-world fuel use based on data from thousands of vehicles (at least ten thousand, I assume, based on earlier studies). If, as the study author says, internal combustion engines are being used more frequently than estimated, should it not be addressed? Should we not be aiming for higher efficiency in these vehicles? If tests aren’t accurately predicting usage, should we not develop more accurate tests?
This is about owner behavior, not the design of the vehicle. If I had a PHEV, for my commute, I would use no fuel if I charged overnight.
Idiots are paying extra for PHEVs, then not plugging in. What is the point.
Likely these owners actually have no idea how their cars work.
On the assumption phevs have the combustion engine off unless they are in hybrid or performance mode:
I think it’s decisive because the article’s focus is fuel consumption but fuel consumption in phevs is actually just a proxy for driver behaviour. (Once you factor out differences between models)
So while the study does show that phevs technically have worse fuel economy in real world usage, it doesn’t show they use more fuel in either electric mode or in hybrid mode than previously believed.
The conclusion is useful for understanding the overall impact of phevs on petroleum consumption, air quality and global warming, but it’s misleading when evaluating what kind of car you should buy.
Since you know how you drive, learning new information about average driver behaviour doesn’t factor into your decision on what kind of car you buy.
The environmentally conscious answer is still no car if possible, electric if you need a car but most journeys fall within the range limit and phev if you need a car for frequent long range usage.
Tldr; it’s contentious because the article reports information useful for policy decisions to a general public who are making individual consumer decisions where the information is misleading.
Its not defensiveness it’s just recognizing the issue for what it really is. You can change the estimation calculation all you want, but it will always be wrong because the variables being used don’t blend together well. You can make gas engines that get 100MPG or even 1000MPG but it won’t make for an accurate estimation when averaged out with ∞MPG or 0GPM.
That’s a problem with the estimation not with the manufacturers. The manufacturers tell you exactly what the electric range is and also what the ICE fuel economy is. It’s trivial to apply these values to your driving habits to get an estimation for your use case.
As an example, I’ve been eyeballing the Prius PHEV with its 44 mile range (and 47MPG hwy). My commute is about 45 miles each way and I have access to chargers at work, so my daily fuel consumption would either be 0.04 gallons (charge at home and work) or 1 gallon (charge at home only) giving a 2400% variation in fuel economy for the exact same trip based solely off my actions alone, having absolutely nothing to do with the car itself.
Here you’re conflating two separate issues and highlighting exactly why people are calling this misleading. You can change the calculation all you want but that isn’t changing the efficiency of these vehicles and this study doesn’t demonstrate that these vehicles are inefficient. All it shows is “your MPGe or l/100km is greatly effected by how often you stay on electric power” and that factor is solely dependent on the driver and ranges from near zero to infinity regardless of the vehicle chosen.
It doesn’t get more accurate. We should just scrap the combined “MPGe” (and EU equivalent) and stick with “electric range” and “MPG”. Both of those can be fairly accurately predicted as separate values. How they combine is entirely up to the individual.
I agree with everything you’re saying, but this part. As you stated before, those are intended to allow for an apples to apples comparison and make it easier for the consumer to judge a car’s funel economy, without having to do their own math (which - lets face it - most people suck at).
If the underlying usage pattern doesn’t reflect a typical average use, that’s an issue, that can be adressed. And when studies show that they don’t why not take that as a call to improve upon the methodolooy?
There’s always going to be the caveat that one’s one usage pattern might deviate greatly from the standard, and absolutely it’s a must, that the individual values are indicated, so people CAN do their own math. But having a standard combined measure is still a useful tool.
Addendum. I have to admit to really only having read the article just now.
This is the real underlying issue here. It’s the EUs regulation on CO2 emissions reduction, that car manufacturers are abusing here. They are designing their car in such a way, that they look good on paper and can pass the requirements of the regulation, while their real-world emissions are much higher. (And in that regard, it’s not too unlike Dieselgate. Minus the intentional technical manipulation ofc.)
While your claim, that it’s the individuals responsibilty how they use their car is obviously true for an individual car’s fuel consumption, that realization is also utterly useless as a basis for effective policy. There needs to be a standard, and that standard better reflect an empirical assessement of reality.
The issue isn’t really that the estimate is wrong, it’s that it’s wrong by an enormous amount – and one that’s been increasing every year. I don’t think that the study is trying to say that these vehicles are inefficient as some kind of absolute judgment, but that they’re less efficient than estimated (although there are big differences based on vehicle make and model).
I don’t think the problem really lies with manufacturers, it’s that the current tests aren’t accurate enough to predict real-world usage closely enough. Although, driver input is mediated by computer systems and if on-board systems are being too aggressive in switching over to ICE, I suppose that’s a manufacturers problem.
Really, they’ve been doing these very large studies for a long time. The sample size is large enough to capture the full diversity of driving styles and it cannot be a few outliers skewing results. Since 2012, the disparity between estimated and observed fuel usage has grown every year. Why? Why is it changing and why is it always changing in the same direction?
It getting worse over time I would think is partially a function of customer mix changing.
You start with early adopters who are more eco conscious and then now entering mainstream, and also people choosing plug-ins for performance purposes.
plug in hybrids are impossible to properly quantity fuel usage. because unlike normal cars where you estimate highway/urban use, now you have to also consider EV/ICE use.
if you rarely use the engine, then your fuel usage is negligible. while if you mostly drive it like s hybrid and never charge it, it’ll be just as good as a comparable hybrid.
Statistics exist, taking a sample of thousands of PHEV drivers and examining fuel consumption is exactly what we can do to quantify fuel usage. And the reality is that, on average, they use up more fuel than my 2006 diesel I got for 2000€. For the vast majority of people, PHEV are just a scam
Do you know why diesels are no longer made? It’s not just about fuel consumption. They are filthy oil burners sold illegally on faked data and you are wearing it like a badge of honor. Read.
Not a badge of honor, I’ve participated in climate research in my career, I’m fully aware of the pollution issues of Diesel cars regarding particulate matter and nitrous oxides. What do I do about it: I don’t drive it in cities. I only use my car for trips that take me between towns that have no solid public transit communication (which is unfortunately the case for many towns near Madrid among each other). The nitrous oxide impact is mostly local and, if you look at NO2 pollution maps, the problem is pretty contained within cities, so driving it far from urban centres has a lot less of an impact. As for climate change effect, it has a similar effect to the average contemporary hybrid cars per the study, and the fact that I bought it used means I’m not stimulating the production of new cars, which produces a ton of emissions, instead I’m spending my money locally fixing the car, which is arguably more sustainable than buying new ones with similar fuel consumption.
acreage is meant to give you an estimate of how much is it going to cost you, if it is off by 20% based on you doing now highway than the average, that’s fine.
but if it’s off by 100%? that’s useless.
also, averages only works if the data falls under a normal distribution. if you have people charging their cars at night, and others who don’t, that is not a normal distribution amd averages are useless
Averages don’t only work if data falls under a normal distribution. I can have two very non-Gaussian distributions for fuel usage of two vehicle types but one of them has much lower fuel consumption than the other, I can vouch for the lower one using the average alone.
for plug in hybrids, they should give you average fuel consumption for hybrid use only AND EV range. Trying to get a total average use is useless and removes all the important information.
I had a plugin hybrid once, rarely used it for trips that needed fuel. if your daily driving fits in the EV range, then you don’t really care about fuel consumption.
This article is less important for individual consumers (whose fuel usage varies wildly depending on their needs and their routines) but it’s extremely important for policy: PHEVs have a very similar climate change result on average than my 2006 diesel car.
It’s misleading because it is reporting a very generalized average fuel consumption (actual usage) of all PHEVs while manufacturer claims are based on individual vehicle potential.
Manufacturers cannot control how people use their cars, they can only assure that the cars operate the way they claim when used the way they suggest.
But isn’t that like Apple saying “you’re holding it wrong”?
I don’t think it’s being portrayed as a manufacturer conspiracy. When Porsche says their tests are “based on the legally prescribed EU measurement procedures,” I’m sure they’re not lying. But these data say pretty clearly that those tests don’t predict observed reality. If they don’t, what good are they really? Shouldn’t we use testing that better reflect observed fuel usage?
No. It’s like blaming ladder companies because people fall off ladders while drunk.
If a person designs to bash in their face with a hammer, government should not ban hammers.
Americans love to sit idling their V8 trucks.
The way I read it is:
Sadly, it sounds like Porsche drivers may fall into the first category and Toyota drivers in the second. And there are enough Porches to skew the MPG of the whole PHEV class.
(it’s also possible that Porsche/VW/Audi just make PHEVs that score well on gov’t tests but poorly in the real world, though I’d lean towards the drivers. But the article title really implies that all PHEVs get shockingly bad mileage)
The article is designed to support the anti green agenda now popular. Like that Volvo white paper that claims EVs take more resources to make, but no one read that paper. They compared ICE to EV, but excluded the engine and transmission metals from ICE. I guess those grow on trees.
The media constantly quotes this paper and no one actually read it.
I think it’s more like Apple saying you get 24 hours of battery life on an iPhone, but in reality, if you use it frequently or play games, the battery underperforms to the stated life. If these vehicles are driven aggressively or not recharged at mfg expected intervals, like fleet utilization, that would skew the general mpg for the population. I’m not saying that’s what happening, but it’s a possible explanation.
People are buying PHEVs and not plugging them in. Ever. Service centers can see how often the batteries are charged and it is common to see people who never charge their PHEV.
Part of the problem is auto consumers are idiots, and years ago at car shows, these cars were being marketed as “self charging”.
This is not new. When VW first sold the Beetle to America, they advertised it as maintenance free because it was air cooled. People never changed the oil.
The level of STEM ignorance has never been this bad. People have no idea how anything works, and don’t care.
I guess it’s just that 300% on average seems like a lot, y’know? Like, if the average iPhone user was getting just 8 hours of an advertised 24, people would be pretty pissed. They’d probably ask for testing that better reflects real-world usage ;)
But if 50% of iPhone users are professional mobile gamers, their utilization is an outlier skewing the sample. I’d like to see the population in the sample for this study. For the average PHEV driver, they probably get close to the mfg estimate when driven as expected but the generalized data encompasses non standard users.
ICE vehicle manufacturers don’t give MPG estimates based on burning out at every stop light, driving with various octane fuels, or many other factors that can effect fuel economy. They give estimates based on a certain usage. I have a Subaru WRX and average 2-3 more mpg than mfg estimates on hwy usage. That difference is in my favor, but it still shows that estimates are just estimates based on a baseline use.
If Apple were dismissing half their users as outliers, I still think people would be pretty pissed…
Based on what though? Is this just an assumption?
Unfortunately (and annoyingly), the Guardian doesn’t link to the study. I took a quick look and found a similar study from 2022 (PDF) but nothing recent. Their conclusions are similar and they do differentiate between private and fleet vehicles.
Yea. All of my theories on this are just based on assumption. Everything I mentioned is probable and at some degree does play a part in the numbers. Some people drive crazy, some don’t charge, etc. There are some other anecdotes in this thread that support some of my claims. One comment mentioned a PHEV driver thought the battery recharged while driving, not knowing it needs to be plugged in. That’s certainly a more extreme case, but I would imagine there a lots of users that drive too long between charges. IF that is happening widespread, then people are using the vehicles outside of mfg specs. We don’t know the exact reason and probably never will get that sort of detail, but it’s a possibility, and if it’s true, that would take the liability off of the mfg imo. All speculation though.
Well, I think we both effectively said our bits. Fun disagreeing with you. Cheers 🍻
Outrage seems to be inversely proportional to experienced convenience, not necessarily performance disparity.
Car manufacturers have always overstated mileage ratings because their tests are done in very controlled environs under ideal conditions.
They cannot control how you use their vehicle, but they can baseline it. That’s what those ratings have always reflected, and why. “Here is the way this car performs under ideal circumstances. YMMV”
There’s a guy at my gym who leaves his lifted brodozer idling for his entire workout.
Because the outcome of that “statistic” highlights phev as a bad purchase. It took far more scandal and coverup exposing to reveal more egregious figures from ice cars, for example the Volkswagen testing thing.
If fuel economy can be tempered with real-world use effects for ice cars, the bigger picture is warranted for this study as well.
Because they are more energy efficient…
Because when in pure electric mode they do use little or no fuel (different cars have different architectures but this is generally so)
But, yes there is a good point buried in there. Europe needs to update rules on efficiency claims. l/100km in gas mode, and electric range gets you pretty far.
I see both of those listed pretty much everywhere when it comes to plug in hybrids.