EVs and Particulate Emissions 3

[TugboatEng]

I would have posted to the old thread but it's closed.

Original thread:

https://www.eng-tips.com/viewthread.cfm?qid=493416

Here is some affirmation of my previous suspicion about EVs and it's worse than I thought. 1850x the particulate emissions from all EVs vs all combustion powered vehicles.

https://nypost.com/2024/03/05/busin...missions-are-worse-for-the-environment-study/

Of course, the methodology needs to be examined. Secondly, article mentions tires and brakes as the source of PM. Is road wear not included?

Note that particulate emissions from all properly running on-road diesel engines post 2008 is 0pmm so 1850x may still not be a very large number.

 

[TugboatEng]

Exactly, the emissions control systems on road vehicles work VERY well to the point that the vehicle emissions are essentially zero. This makes all other sources of emissions very significant. The side note is that the power plants that charge MOST electric vehicles are not necessarily as clean.

 

[BrianPetersen]

hmm.

https://www.canada.ca/content/dam/e...a/CEPA-Guidelines-CombustionTurbines-2-en.pdf

All remaining significant fossil-fuel electricity generation in this province is from gas-turbine combined-cycle plants which are only used during high-demand periods. There are no remaining coal-fired generating stations.

PM emissions from natural-gas-fired gas turbines ought to be near zero.

https://www3.epa.gov/ttnchie1/ap42/ch03/final/c03s01.pdf

NOx emission limits (one would hope that actual operation is below these limits ...) are given as 140 g/GJ for the bigger units. 1 GJ = 277.8 kWh so this is 0.5 g/kWh.

If we take EV consumption to be 20 kWh/100 km then this is 10 g NOx / 100 km if the electricity source is 100% from the natural-gas-fired power plant. It's actually in this province about 10% from that source, the other 90% being from non-fossil-fuel sources, so that's (in my case, for my local grid sources) 1 g / 100 km.

US standards appear to be 0.07 g NOx per mile for the federal test procedure. That's about 5 g / 100 km, so it's right in the middle of the same order of magnitude. Interesting.

 

[BridgeSmith]

So ... how does a +30% increase in vehicle mass (+500 kg) result in a +90% increase in tire wear?

The same way one tractor-trailer rig does as much damage to the road as 200 passenger vehicles, even though it only weighs 20 times as much. The relationship between contact pressure and wear is typically not linear.

 

[swimfar]

Using tailpipe emissions and ignoring tire and brake contributions of an IC vehicle compared to tire and brake contributions of an EV vehicle is not oranges to apples. It is a peanuts to elephants comparison.

It's not an unreasonable comparison if the point is to show that EVs do not produce significantly lower particulate emissions than ICEs. If they just compared the total emissions for both vehicles and said they're the same then people would either 1. Not believe it, or 2. Ask how that could be the case. By showing that particulate emissions from the exhaust are overshadowed by other emissions, it's more clear why this is the case. Alternatively, they could have talked about what percentage of particulate emissions from ICEs are due to the exhaust vs other, and used that to show that changing the engine type to electric can only reduce your emissions by 0.1%. But then you aren't taking into account the reduced brake pad particulate and (possibly) increased tire particulate.

Based on the discussion here, they probably could have done a better job articulating their point, if it's not clear from reading the article (which I didn't).

 

[BrianPetersen]

Based on the discussion here, they probably could have done a better job articulating their point, if it's not clear from reading the article (which I didn't).

As is far too often the case, the title of the article was clickbait to their target audience. "EVs bad."

 

[hokie66]

Pothole Pete is trying to defend the Government's inept policy of providing 500,000 federally provided charging stations by 2030. In the first two years, they have built EIGHT. Does that indicate government is incompetent, or alternately that EV's are just a fad like 'pet rocks'?

https://www.cbsnews.com/news/pete-b...retary-face-the-nation-transcript-05-26-2024/

 

[BrianPetersen]

It probably indicates that the NEVI funding has too many strings attached and/or too much red tape. Tesla doesn't want to build credit card readers into their Supercharger stations. In a way, I understand their point, payment issues are big part of charging station reliability issues. I'm not sure forcing use of smartphone apps (not everyone has one and they don't always work) or Tesla style "plug and charge" (not all vehicles are compatible) is going to work. Just accept payment cards ...

There are other charging networks in the works. Rivian is opening theirs up. GM Ultium is putting in a bunch at Flying J filling stations. Then there's this

http://www.ionna.com

(cousin of European Ionity network)

Despite recent FUD and negative propaganda, EV sales worldwide are continuing to increase.

Chevrolet Equinox EV is arriving at North American dealers now.

 

[BrianPetersen]

https://www.iea.org/news/the-worlds...ongly-with-2024-sales-set-to-reach-17-million

 

[GregLocock]

Maybe there's enough chargers. 80% of charging takes place at home, there's one charger for every 20 EVs, so on average each charger gets little use. That is a dangerous argument of course.


Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[BrianPetersen]

The number and location of charging stations will eventually find an equilibrium with the number of EVs on the road, just as it has with petrol stations.