Plug-In Hybrids Are Five Times Filthier Than You Think They Are, Says Study

[Sherminator98]

Article:
https://www.autoblog.com/news/plug-in-hybrids-five-times-dirtier-than-claimed-te-study

 

Direct link to study:

Smoke screen: the growing PHEV emissions scandal

 

Also looking like people aren't plugging in their PHEVs as often as they should, once again. 

[jpd80]

Same Euro report from early 2020s  that keeps going round and round, problem is European housing not able to do home charging due high percentage of on street parking …. All of this discussed in previous threads

Edited October 28, 2025 by jpd80

[Sherminator98]

19 minutes ago, jpd80 said:

Same Euro report from early 2020s  that keeps going round and round, problem is European housing not able to do home charging due high percentage of on street parking …. All of this discussed in previous threads

 

You sure? Its showing data from 2023...

[Texasota]

Quote

Even when driven in electric mode, PHEVs emit 68gCO₂/km as their electric motors have insufficient power and the combustion engine needs to kick in. The engine supplies power for almost one-third of the distance travelled in electric mode. This would mean an extra €250 in petrol costs every year, as drivers don't expect to pay for fuel when driving in electric mode.

I have never experienced this in my Escape PHEV. The electric motor provides more than enough power for my city and highway driving. It's nonsense.

 

The only entities that have factual data regarding EV vs ICE percentages in PHEVs is the OEMs. Unless the OEMs are now sharing that data with the media, then it is speculation, guesses and bias from the climate zealots.

[Sherminator98]

2 hours ago, Texasota said:

The only entities that have factual data regarding EV vs ICE percentages in PHEVs is the OEMs. Unless the OEMs are now sharing that data with the media, then it is speculation, guesses and bias from the climate zealots.

 

Quote

Because of this multi-mode functionality, the actual fuel consumption and resulting CO₂ emissions of PHEVs can vary significantly in real-world use. This variability is related to multiple factors, including how frequently the vehicle is charged and driving behaviour, particularly the share of kilometres driven in CD mode compared to CS mode. As a result of these real-world variabilities, estimating PHEV emissions using standardised test cycles such as the WLTP is often inaccurate. To address this, Article 12 of Regulation (EU) 2019/631 requires the European Commission (EC) to evaluate how well WLTP values reflect real-world driving, based on data collected from OBFCM devices.

OBFCM - On Board Fuel Consumption Monitoring

 

These where added in 2021, thus why the data doesn't go back that far 

Edited October 29, 2025 by Sherminator98

[jpd80]

11 hours ago, Sherminator98 said:

 

You sure? Its showing data from 2023...

Yeah, for the last two years it makes a frequent reappearance but this time also refers to the earlier 2021 survey.

its the same thing, PHEV owners in Europe can’t always home charge because a lot of places have no garage.

 

 

 

[akirby]

5 hours ago, jpd80 said:

Yeah, for the last two years it makes a frequent reappearance but this time also refers to the earlier 2021 survey.

its the same thing, PHEV owners in Europe can’t always home charge because a lot of places have no garage.

 

 

 

And they must use the ICE to charge the battery when driving from the suburbs to the city so they can use battery in the city.

[Sherminator98]

6 hours ago, jpd80 said:

Yeah, for the last two years it makes a frequent reappearance but this time also refers to the earlier 2021 survey.

its the same thing, PHEV owners in Europe can’t always home charge because a lot of places have no garage.

 

Well it hard to collect data when it wasn't collected prior to 2021 LOL

 

The data has been updated since then

[jpd80]

6 hours ago, Sherminator98 said:

 

Well it hard to collect data when it wasn't collected prior to 2021 LOL

 

The data has been updated since then

Originally I said it the same data from the early 2020s, I was only half right as you pointed out 

a second study released in 2023, still in the early 2020s. Now, two years later, they are still

going on about a study done in Europe two years ago.

[jpd80]

8 hours ago, akirby said:

And they must use the ICE to charge the battery when driving from the suburbs to the city so they can use battery in the city.

Correct, the zero emission zones in euro cities means that PHEVs have to run in charge sustain

or worse, try to recharge on the run so they can operate in electric mode within the zero emission zones.

 

All of that tied with infrequent home charging means much higher emission than the official figures.

Edited October 29, 2025 by jpd80

[Biker16]

#RealEVs4EVA

[Rick73]

Did not read entire study but data suggest that PHEV emissions are being analyzed based on tailpipe basis, not actually overall, otherwise how could they have even started with a number as low as 35 grams CO2 per kilometer?  Unless CO2 from electricity generation is ignored, how is that possible?  And if recent “real world” data shows PHEVs so much higher due to engine emissions, then adding more for electric power plants emissions makes it even worse than being reported.  The whole thing is crazy.

 

 

 

 

Apparently EREVs are a target along with PHEVs.

 

[akirby]

The PHEV data was based on computer downloads from cars in for service.  

[Texasota]

19 minutes ago, akirby said:

The PHEV data was based on computer downloads from cars in for service.  

It would be interesting to know how my data is interpreted when I do a long road trip (e.g. traveling to our snowbird location in Florida).  I suspect it categorizes me as an owner that rarely plugs in my PHEV.

[Rick73]

1 hour ago, Texasota said:

It would be interesting to know how my data is interpreted when I do a long road trip (e.g. traveling to our snowbird location in Florida).  I suspect it categorizes me as an owner that rarely plugs in my PHEV.

Regardless of how it’s classified, isn’t what is important the end result?  If an owner took 100 trips to local destinations averaging 10 miles round trip each, and then takes 1 round trip of 3,000 miles, how much CO2 savings does PHEV or EREV actually accomplish?

 

I’ve seen reports that focus more on number of trips to represent usage patterns rather than driven miles, which is a closer indicator of how much gas is burned.  Your point that one long trip skews data is valid.  Obviously analyzing actual cumulative fuel consumption data yields much better and useful information.

 

Even that doesn’t address that when operating in EV mode the vehicle still produces significant amounts of CO2, just not at tailpipe, but rather at electricity generation power plant.  The corrected numbers would be much worse because very few BEVs or PHEVs are charged with zero emissions electricity.

[Sherminator98]

4 minutes ago, Rick73 said:

Even that doesn’t address that when operating in EV mode the vehicle still produces significant amounts of CO2, just not at tailpipe, but rather at electricity generation power plant.  The corrected numbers would be much worse because very few BEVs or PHEVs are charged with zero emissions electricity.

 

If you get bored, the calculations are here:

https://www.epa.gov/energy/greenhouse-gas-equivalencies-calculator-calculations-and-references

8.89 × 10^-3 metric tons CO₂/gallon gasoline × 10,917 VMT _{car/truck average} × 1/22.8 miles per gallon _{car/truck average} × 1 CO₂, CH₄, and N₂O/0.994 CO₂ = 4.29 metric tons CO₂e/vehicle /year

 

The other way to look at it is that for every kwH being produced by a power plant, its going to multiple things not just powering a car...then multiple the number above for every single vehicle being operated at that time, which adds up very quicky

 

TLDR-Powerplants overall produce less CO2 then thousands/millions of cars operating at the same time. 

 

 

[Rick73]

3 hours ago, Sherminator98 said:

If you get bored, the calculations are here:

Thanks, but no need.  I can still do it from memory.  All I need is a calculator and to remember EPA estimates that burning one gallon of gasoline produces 8,887 grams of CO2.  Helps to remember basic conversions as well.

 

For example, in above data I posted previously, simple math shows ICE and HEV fuel economy dropped from approximately 40 rated MPG to 33 actual real-world MPG.  That seems reasonable to me.  However, the 35 grams per kilometer rating for PHEV is completely unrealistic unless the vehicle operated mostly in EV mode and electricity was generated carbon free, which on average it is not.

 

 

[akirby]

5 hours ago, Rick73 said:

Regardless of how it’s classified, isn’t what is important the end result?

No because the conclusion is that people are not plugging in their PHEVs.  Has nothing to do with how effective it is at saving gasoline.

 

If all it measures is percentage of time in EV vs ICE then it’s not accurate.  If I drive 20 miles per day and charge every night I’m 100% EV so I must be plugging in.  If Texasota drives 200 miles per day and charges every night he’s only 10% EV.  But he’s still plugging in.

 

There isn’t enough data to prove whether people are or are not plugging in nightly.

[Sherminator98]

9 minutes ago, akirby said:

No because the conclusion is that people are not plugging in their PHEVs.  Has nothing to do with how effective it is at saving gasoline.

 

If all it measures is percentage of time in EV vs ICE then it’s not accurate.  If I drive 20 miles per day and charge every night I’m 100% EV so I must be plugging in.  If Texasota drives 200 miles per day and charges every night he’s only 10% EV.  But he’s still plugging in.

 

There isn’t enough data to prove whether people are or are not plugging in nightly.

 

Quote

OBFCM stands for On Board Fuel Consumption Monitoring and provides information about the amount of fuel or energy used by the vehicle.

 

Quote

From when do I need to read out OBFCM data in my workshop?

Workshops must provide the relevant OBFCM data from 20/05/2023.

 

So as time goes on, more data will be available 

[Sherminator98]

As for how it collect data:

https://theicct.org/wp-content/uploads/2022/02/fs-obfcm-accuracy-verification-feb22.pdf

 

 

[akirby]

2 hours ago, Sherminator98 said:

OBFCM stands for On Board Fuel Consumption Monitoring and provides information about the amount of fuel or energy used by the vehicle.

So that’s even less data.

[Rick73]

There is no easy way for me to know if this study is accurate or not.  Assuming it is fairly unbiased, and that data is based on 800,000 cars, a number large enough to provide good enough information on typical use, their conclusion that UF (utility factor) is much lower than previously thought is the main issue to accept or question.  If I’m reading this correctly EV versus gas mode went from anticipated 84% electric / 16% gas to a real-world 27% electric / 73% gas.

 

 

 

I would still like to know how they estimated original PHEV at an extremely low 35 grams CO2 per kilometer because their assumptions most likely also affect the revised CO2 estimates.  I’m sure this information is available but would likely require significant effort to find.

[rmc523]

Me figuring out all this talk.....

 

 

[Sherminator98]

58 minutes ago, Rick73 said:

There is no easy way for me to know if this study is accurate or not.  Assuming it is fairly unbiased, and that data is based on 800,000 cars, a number large enough to provide good enough information on typical use, their conclusion that UF (utility factor) is much lower than previously thought is the main issue to accept or question.  If I’m reading this correctly EV versus gas mode went from anticipated 84% electric / 16% gas to a real-world 27% electric / 73% gas.

 

 

 

I would still like to know how they estimated original PHEV at an extremely low 35 grams CO2 per kilometer because their assumptions most likely also affect the revised CO2 estimates.  I’m sure this information is available but would likely require significant effort to find.

 

It is simple-they assumed that people would always plug in their vehicles and use EV mode, but what is actually happening is people aren't charging the vehicles either due to laziness or because they can't. They went with the best case instead of worst case when making estimates, because they forgot to factor in human nature. 

[Rick73]

47 minutes ago, rmc523 said:

Me figuring out all this talk.....

 

 

 

It’s not that complicated if we focus on basics.  In 2023 average USA electricity generated a reported 0.81 pounds CO2 per kWh.  It’s improving gradually every year but let’s use that for now.

 

When we adjust for typical electricity transmission inefficiency and also vehicle charger inefficiency, we end up with approximately 450 grams of CO2 per kWh of electricity that ends up stored in vehicle battery.

 

Since many BEV or PHEV (in EV mode) SUVs perform in the range of 3 miles per kWh, it follows they generate around 150 grams per mile.  Large pickups as example can be much worse than that.  Europe may have cleaner electricity generation and they generally also drive smaller vehicles, but 35 grams per km (56 grams/mile) seems way too optimistic in the first place.