PHEV's - Poor CO2 Emissions?

I think the 15-ish-year newer and .5 liter smaller ICE than my 2001 CR-V combined with 4-5 times the average MPG (108 on the Clarity so far, vs 24 average over 17 years on the CR-V) and solar panels say this "study" was funded by we all know who.
 
Summary so you don't have to click through all these links:
The UK is considering banning the sale of all new cars with ICE by 2035/2040; auto manufacturers said that since PHEVs are almost EVs, they should be exempted. This was refuted by another group that published data showing that with infrequent charging and the various on/off ICE cycles of the engines even in EV mode, the real-world emissions of a PHEV were only about 30% less than a regular non-hybrid ICE vehicle and about 20% less than a conventional hybrid. They accused manufacturers of lying about the actual emissions of PHEVs, compared it to dieselgate and said that PHEVs should be banned in the UK as well.

I think very few people on this particular message board care about absolute gCO2/km emissions over EVs though - we wanted to have that ICE safety net while being mostly earth-friendly in day-to-day EV mode, even if the Clarity gets considerably worse EV performance than other vehicles.
 
I’m sure there’s no possibility of agenda driven, biased, cherry picked analysis from EFTE and Greenpeace.
 
MrFixit said:
Don't shoot the messenger...

An article from the UK makes this claim.
https://www.bbc.com/news/science-environment-54170207

As a footnote, they do mention the significance of 'Driver Behavior' - ie: operating on electric is good...
This seems like a no-brainer to most of us who are able to maximize electric usage.
Click to expand...
There is insufficient information in the article, and there are so many variables I don't see how they could come to this conclusion.

The first thing I would note is the much shorter EV range of non Clarity PHEVs certainly will cause the ICE to run more often which could contribute to increased emissions. Second it seems to me that having an ICE shut down, then come back to life once in a while would cause more emissions than if the ICE ran continuously. But our personal experience with the Clarity is much different and I believe much cleaner.

Our annual use consists of daily driving our son to school which is 25 miles round trip so 50 miles each day. Couple that with stops at the gym, church, and some shopping and we often reach 60-70 miles. However we charge at home about twice per day so ALL of that daily driving is done in EV mode and the ICE doesn't come on until we take longer trips.

Our longer trips consist of 350 mile round trips about every six weeks, which are done all in a single day. That averages out to about 9 trips per year. Then there is our annual 1,100 mile vacation which is a 7 day period. For these long trips we are in HV mode on the highway and, when possible, EV mode around the destination. So the total use of the ICE in our Clarity is 9+7=16 days out of 365. Truthfully there are also a few times when we unintentionally cause the ICE to run for a few minutes, or take a few short trips where we let the battery run low and the ICE kicks in but those don't amount to more than about a few hours per year. to top it off we charge only at home using our roof solar.

So each use case is different. I do believe the world-wide average for PHEV cars may be less clean than we would hope for. The solution is longer EV range, for our family 50 miles of EV range in the winter would be ideal.
 
MrFixit said:
Don't shoot the messenger...

An article from the UK makes this claim.
https://www.bbc.com/news/science-environment-54170207

As a footnote, they do mention the significance of 'Driver Behavior' - ie: operating on electric is good...
This seems like a no-brainer to most of us who are able to maximize electric usage.
Click to expand...

Obviously if you don’t charge the car frequently a PHEV makes no sense. So it is a great option for people who have access to overnight or workplace charging. In European cities many people don’t have this option, so a long range EV is a better option for those people. In US many people can charge overnight, combined with our more rural road network and long distances it makes PHEVs a great option for most US households.


Sent from my iPhone using Tapatalk
 
Transport and Environment's analysis says a key problem with plug-in hybrids is that so many owners rarely actually charge their cars, meaning they rely on the petrol or diesel engine.
Click to expand...
I would like to see their survey results. This wording is extremely vague and uninformative.
 
Maybe they can provide a list of all those diesel PHEV’s as well.

Mercedes offers one. Are there any others?
 
Pooky said:
I would like to see their survey results. This wording is extremely vague and uninformative.
Click to expand...
The report and source data is linked in the original article for people that care to know what they are actually commenting on.

https://www.transportenvironment.or...tions/2020_09_New_evidence_PHEV_emissions.pdf

There seems to be a strong inclination to say the report can't be right, because my Clarity does ...., I drive like ... and get ....

This is actual data collected from multiple studies of real world usage of PHEV's available in Europe (the Clarity is not). Almost all (all?) PHEV's (except the Clarity and i3) don't have a true "EV" mode the user can select and keep the engine from firing in normal driving conditions.

The UK’s ten top selling PHEVs all behave in a similar way. This includes cold external
temperatures triggering the engine to switch on in the Volvo’s XC90 SUV, the Mercedes-Benz E
Class executive car, as well as the Kia Niro. The Mitsubishi Outlander SUV has an “EV” button but
the engine switches on with the adaptive cruise control or with high or low external
temperatures. Jaguar Land Rover’s Range Rover and Range Rover Sport plug-ins will start their
internal combustion engines if more power is required than the electric engine can provide alone,
as will Porsche’s Cayenne. The Mini Countryman switches on the engine if you drive faster than
the electric mode allows as do BMW’s PHEVs.​

One PHEV, the Kia Nero plug-In hybrid that claims to operate with a ‘battery only, zero emission
mode’ switches on the engine (in this mode) when the windscreen demister is turned on.​

This report never states that PHEV's are not capable of getting lower emissions than they do, only that when driven in a "normal" fashion, they achieve nowhere near the CO2 reduction claimed by the manufacturers. Not that hard to design a vehicle to optimize results on a known test (even without a dieselgate type software cheat), with little regard for whether it achieves the same results in daily driving.

Is is possible for PHEV's to be designed to be primarily battery driven? Absolutely, but that is not what is commony on the market and the reductions in CO2 from their use are nowhere near what is claimed by manufacturers. Are PHEV's an improvement over both ICE and traditional hybrids? Once again the answer is yea and the report confirms that with real world results.

Real world PHEV data
Source and Gap between test and real world emissions CO2
  • Netherlands Travel Card data 2017 in ICCT Lab to Road report 242%
  • Netherlands Cleaner Car Contracts data 2017 in ICCT Lab to Road report 270%
  • Spritmonitor data - Germany 256%
  • Miles Consultancy data - UK 281%
  • Fisches-Auto France - France 294%
  • Netherlands Travel Card data 2018 in ICCT Lab to Road Report 256%
  • AutoCentrum - Poland 306%
  • Netherlands Travel Card data 2019 in ICCT Lab to Road Report 221%
  • Automotor and Sport (Sweden) in ICCT Lab to Road Report 255%
Average 265%

As to the politics of whether PHEVs should be added to the sales ban in the UK of pure ICE vehicles as the report is promoting, I don't have a dog in that fight.
Landshark said:
I’m sure there’s no possibility of agenda driven, biased, cherry picked analysis from EFTE and Greenpeace.
Click to expand...
Also no possibility of slamming anything critical of a PHEV without any actual reading or research
 
DucRider said:
The report and source data is linked in the original article for people that care to know what they are actually commenting on.
Click to expand...
Thank you for your response, but it does not actually answer my question. I did check the Transport & Environment PDF but I can't find any information in the report about how many people, whether a number or percentage, "so many owners" is supposed to represent.

This is because the cars are frequently not charged by their owner or the car does not drive using only the battery and electric motor even when in the supposed zero emission mode.
Click to expand...
They are attributing the poor emissions due to driver negligence in regards to not plugging in their cars, but the PDF does not state what percentage or number of drivers surveyed that represents.

DucRider said:
There seems to be a strong inclination to say the report can't be right, because my Clarity does ...., I drive like ... and get ....
Click to expand...
I am not claiming that it is false, I simply would like to know from what source are they drawing this conclusion.

Cheers
 
Last edited:
Pooky said:
Thank you for your response, but it does not actually answer my question. I did check the Transport & Environment PDF but I can't find any information in the report about how many people, whether a number or percentage, "so many owners" is supposed to represent.


They are attributing the poor emissions due to driver negligence in regards to not plugging in their cars, but the PDF does not state what percentage or number of drivers surveyed that represents.


I am not claiming that it is false, I simply would like to know from what source are they drawing this conclusion.

Cheers
Click to expand...
I listed the 9 different studies and the links to those individual studies are available in the actual report I linked above. The "Annex" on page 6 has those links

And they are attributing the difference between the CO2 emissions data from the NEDC test cycle and real world driving to several things, primarily being the design of the PHEVs that prevents the user from driving in "pure EV" mode. Not plugging in their cars and other factors are secondary to the ICE being used even in "EV mode".

While critical of PHEVs as "clean", the real gist of the report is that the NEDC test cycle used by manufacturers indicates far less CO2 emissions than are achieved in actual use.
 
DucRider said:
I listed the 9 different studies and the links to those individual studies are available in the actual report I linked above. The "Annex" on page 6 has those links
Click to expand...
The only mention in any studies of the lack of charging was a link to this BBC article on this page in reference to 1,500 fleet cars. See, the reason I even mention this in the first place is because I am curious as to how much of the low MPG can be attributed to negligence, how much can be attributed to significantly exceeding the battery capacity (even if fully charged every morning), and how much is attributed to the lack of true EV modes. As we know, being able to commute exclusive in EV mode is the primary draw of a PHEV, and this is why the misleading EV modes (or lack thereof) are concerning.

Clearly European automakers have an issue to deal with, specifically fulfilling the EV in PHEV.
 
A few comments, though to be honest I haven't read through it - just skimmed through it and the references.

1) Most of the papers cite the divergence from approval CO2 as their key metric, and when you have a lower set point then since it goes in the denominator it will make the same level of increase dramatically worse. So the numbers are real and probably correct, but they are reported in a way that is set up to make the vehicles with lower anticipated CO2 look worse when they exceed those.

2) In the UK I understand they employ a [1 - 25/(25+(EV range in km))] as the formula for estimating the amount of EV usage in a PHEV, in order to calculate the grams of CO2/km in order to scale the taxes appropriately. Car makers may overstate range which would push the CO2 numbers down, and actual usage CO2 can go up during winter months and in hot summers where AC is used.

3) The largest dataset in the study is from self-reported data collected from here: https://www.spritmonitor.de/en/over...ehicletype=1&activity=730&powerunit=2 ; nothing wrong with that, but such reporting can be skewed.

4) Many other of the datasets are from car fleets where employers pay for fuel and there is no incentive (or probably infrastructure) to plug in the company cars overnight. Also, company cars for sales or service folks probably log many more miles per day, and thus are prone to be only on ICE power, due to the limited EV range on most PHEVs.

5) There are a couple of small datasets from car reviewers who review the cars by doing long-range driving tests. Thus it is likely heavily weighted on ICE usage.

More caveats - it is very tricky to make conclusions about PHEV CO2 generation across the board when there are variables that have a big impact. Others have cited that many in Europe have limited access to overnight charging at home. Perhaps. Also, comparing CO2 generated during electricity production varies widely across Europe (France very small, Germany very large, UK used to be large and is dropping rapidly, etc.), and this has a big impact on the g of CO2/km for BEVs and PHEVs in EV mode.

By the way, my rough back of the envelope calcs on CO2 for the Clarity (just for amusement, since there is probably not an equivalent kind of PHEV car in Europe):
g of CO2 / km:
Clarity in EV mode from grid in France: ~11g
Clarity in EV mode from grid in UK: ~47g
Clarity in EV mode from grid in Germany: ~104g
Clarity using ICE @ 45 mpg: ~120 g

Again, I see the point they are making but the conclusion is to throw the baby out with the bathwater. The story is a little more nuanced.
 
Last edited:
In Alabama, our power is a mixture of natural gas, nuclear, coal, hydro, and some renewable. A company named fleetcarma works with the utility to provide a device called smartcharge that plugs into the data port. It measures charging energy, gasoline burned, miles traveled etc and reports it back to fleetcarma and they share the data with Alabama Power. They pay you about $5-10 per month and a sign up bonus of $25 to be able to get your data, but they share their information including some interesting emission and efficiency information. Anyway, for the 2019 Volt (this device isn't yet available for the Honda Clarity), they are estimating the GHG (CO2) emissions at 156.7g/mi on average for a couple of months of testing since I put the device on. That's 97.4 g/km. It's higher than the 44 quoted in the article due to percentage natural gas and coal that is burned by the electric utility. That value should decline over time due to more and more renewables being added to the electric grid. It's still 3/4 of what the article claims (120 g/km) and about 25% of what the average ICE passenger vehicle produces (From EPA.gov: The average passenger vehicle emits about 411 grams of CO2 per mile). I'd say that this is an improvement, not a "sheep in wolf's clothing." Since we rarely burn gasoline in the Volt, the 97 g/km is pretty much the same rate an all electric Vehicle would get here, unless it is more efficient than the Volt in kWh/mi.
 
Last edited:
One other note; the (https://www.spritmonitor.de/en/over...ehicletype=1&activity=730&powerunit=2) database filled with user data mileage is not a reliable / clean dataset. I was fairly certain that Honda had no plug-in hybrids in Europe, yet a search of Honda PHEVs finds CRVs, Jazz's, Insights, CR-Zs, etc. If you search Toyotas the first few that looked odd to me were also mis-categorized as PHEVs when they are either plain hybrids or regular ICE vehicles. So one would have to go through all 3622 to weed out the ones that aren't really PHEVs. This is likely another source of the oddly high fuel usage figures for PHEVs.
 
I went poking around a little deeper and several that were real PHEVs had really crazy numbers reported. On one A3 etron the user's distance reported was way off the odometer readings (e.g. 61 km change on odometer, 378 km travel reported, on 8 kWh charge...). Overall they were reporting 3 kWh/100 km.

So if they didn't clean up the dataset and took it at face value, I could see how "reported actual mileage" data for PHEVs as a class could wildly exceed the manufacturer estimates of actual PHEVs.
 
DucRider said:
Also no possibility of slamming anything critical of a PHEV without any actual reading or research
Click to expand...

Once again, you’ve demonstrated a remarkable ability to misinterpret written words.

I question the study and the results.

It’s garbage in, garbage out.

Now, why don’t you go ahead and comment on some of the other posts that have been critical of the report?
 
You must log in or register to reply here.
Back
Top