Featured Not alone in feeling that Toyota is missing the EV-boat (article)

Yes everyone can and should offset their emissions as much as possible .. but that does not change the CO2 rating of the car. For example if I drive Prius Prime and then offset the petrol CO2 by say installing a larger set of solar panels .. does that make the Prius emission free ?

 

What is more important is the size the EV carbon footprint compared to an equivalent ICE(including hybrid) car. The battery does mean higher emissions during manufacturer, but the lower carbon intensity of electricity vs gasoline in the US means the EV will have a lower footprint in much of the US.

For national policy level planning and decisions, using a US average grid mix is fine, but the reality is that no individual can use the US average gird mix. It is physically impossible as the US grid is divided into three grids; east, west, and Texas. In theory, an electron put into a grid put into a coal plant could end up in an EV several states away. In practice, the electricity used by a household was generally made nearby though. This is because transmission losses are a thing, increasing the cost of moving electricity farther distances from the producer. There is also the impact of market regulations and agreements at play. For this reason, the EPA has divided the US grid up into PADD sites for measuring the environmental impact and other metrics of electricity in the US.

Above, "...generally an average annual value is used (ie EPA)." The EPA doesn't do this for an individual's car. On Fueleconomy.gov, when you select upstream green house emissions for a plug in, you won't get a value. you get a link to a calculator that asks for your zip code, which will get the local PADD grid.

The CO2 rating of an EV is zero. Those and emission ratings are measured at the 'tailpipe'; just the pump, or outlet, to wheels is measured. The upstream emissions can be considered, but that should be done for all fuels in question for an honest comparison.

If a household is making enough renewable electricity to cover all their needs, it can be called emission free. You can quibble over solar electricity going into the grid during the day, and grid electricity being used by the household at night, but such purist standards would mean only off grid households can qualify for emission free. This could hamper the growth of renewable energy as those looking to lower the emissions may chose to not to install solar if they have to also pay for batteries. They may not even buy green electricity as that has become dirty from the NG plant also putting power on the grid.

As for the PHEV, the purist response is that the extra solar panels have to power an e-gasoline plant to provide fuel for the ICE. However, if your extra panels are putting enough electricity into the grid to offset the local carbon emissions for the local grid production to equal the CO2 coming out of the Prius Prime's tailpipe, it can be called emission free. Depending on the local regulations, you even get renewable energy credits to make it official

When Toyota and other companies say they are reducing carbon emissions, that reduction includes them buying such credits to offset what they make.

 

Just some basic facts:

• I need personal transportation
• It needs to be cheap to operate
• Solar next year if my TSLA goes up enough

Bob Wilson

 

Yes overall life cycle is important and part of this is accounting for the CO2 relating to electricity correctly.

 

Yes Jason is presenting an analysis based on averages ... but you can then use his methodology and adjust assumptions, including the CO2 intensity of the grid in your area.

 

I don't agree that a car is (CO2) emission free, unless it's fuel was truly carbon neutral. I think what you mean is that the car has a CO2 g/km rating but if I offset that, then at a personal level my use of the car is carbon neutral and that makes sense. But the car still has a CO2 g/km impact and a rating based on tailpipe CO2 emissions as well as emissions released in the production of the fuel.

Now when we consider electricity as a fuel, the carbon intensity of the grid in your area is what is important for the your car's rating and not whether you or your neighbour has solar panels.[/QUOTE]

 

Source_1:
Plug In or Gas Up? Why Driving on Electricity is Better than Gasoline - Union of Concerned Scientists

Electricity power plant emissions data for 2019 was released earlier this year and I combined that data with the latest assessments of fuel emissions and vehicle efficiency. Based on where EVs have been sold to date, the average EV driving in the US produces global warming pollution equal to a gasoline vehicle that gets 93 miles per gallon (mpg) fuel economy. That’s significantly better than the most efficient gasoline car (59 mpg) and far cleaner than the average new gasoline car (31 mpg) or truck (23 mpg) sold in the US. And our estimate for EV emissions is about 15 percent lower than our estimate from just three years ago. Now 97 percent of people in the US live where driving an EV produces fewer emissions than using a 50 mpg gasoline car.
​

The average EV is cleaner than the average new gasoline vehicle everywhere in the US. But if you choose the most efficient EV available, your emissions reductions from switching from gasoline to electricity will be even higher. For example, driving the 2021 Tesla Model 3 Standard Range Plus (0.24 kWh/mile) in California has emissions equal to a 177 mpg gasoline car, or less than a fifth of the global warming emissions of the average new gasoline car and over 65 percent less than even the most efficient gasoline car. And in upstate New York, the emissions from driving an EV can be as low as one tenth those of an average new gasoline car. ​

Source_2: https://www.ucsusa.org/sites/default/files/attach/2015/11/Cleaner-Cars-from-Cradle-to-Grave-full-report.pdf

Cleaner Cars from Cradle to Grave
How Electric Cars Beat Gasoline Cars on Lifetime Global Warming Emissions

Together with other oil-saving approaches, such as more efficient vehicles and advanced biofuels, EVs can help cut projected U.S. oil use in half over the next 20 years. EVs will also be essential to achieving the deep emissions reduc- tions by mid-century needed to avoid the worst impacts of climate change.

This report compares battery-electric vehicles (BEVs) with similar gasoline vehicles by examining their global warming emissions over their “life cycles”—from the raw ma- terials to make the car through manufacturing, driving, and disposal or recycling. Toward that end, we performed up-to- date assessments of the carbon footprints of BEVs, taking into account the latest information about electricity generation and BEV models. The two BEVs we modeled, midsize and full-size, are not specific to any particular manufacturer but are based on the two most popular BEV models sold in the United States today: the Nissan LEAF and the Tesla Model S. Our analysis reflects the BEVs available to American consum- ers and comparable gasoline vehicles.

Our analysis revealed that:

• From cradle to grave, BEVs are cleaner. On average, BEVs representative of those sold today produce less than half the global warming emissions of comparable gasoline-powered vehicles, even when the higher emis- sions associated with BEV manufacturing are taken into consideration. Based on modeling of the two most popu- lar BEVs available today and the regions where they are currently being sold, excess manufacturing emissions are offset within 6 to 16 months of average driving.
. . .
​

Unlike some fragmented, partial postings, these articles do a deep dive and well worth the read. Always be cautious of postings that may omit important data.

Bob Wilson

ps. I don't buy my cars for CO{2} or other emissions. I buy them for low operating costs.

 

I used the study to get a better ball park figure of what real co2 impact is of a long range tesla battery pack. After it was published because of better figures one of the high value 2017 studies was revised to reflect a similar number. That is this long range pack will add about 40 g/CO2/mile when driven 250,000 km or 150,000 miles and then disposed of without second use.

For ghg impact of charging I used the larger epa number from fuel economy.gov which I believe uses old figures of 640 g/kwh in colorado and 477 g/kwh in the US. The US was actually 419g/kwh in the most recent eia analysis. Definitely a fair critism of the study which is why I used much higher numbers.

For figures it is even worse than that. I stated problems with the old figures are that they did not count on the mass production figures, which this study uses much lower production factories. This is a common problem with old figures. The reply was tesla is not more efficient, with only hand waving. All the new large factories should be more efficient. The Bill of materials used for the smaller packs at lg chem and nissan were quite differerent than the current NCA produced. No effort was to actually look at materials, it just was they are the bulk. Well even this poor paper states materials only make up about 1/3 of the ghg impact. Change the materials and it drops significantly.

 

Most of this discussion is about emissions from a car for an individual. Using a national grid average would not be correctly accounting for that CO2.

I was applying the same accounting used by corporations to individuals.

If we extend that logic, then the solar panels on a home shouldn't be considered for the household's carbon footprint, but just the local grid's carbon intensity.

We say most home EV charging is overnight, but EV owners don't wait for the sun to set before plugging in. Many do get home before it is dark, and it is probably a safe assumption those with solar panels aren't using a timer to delay charging until it is dark out.

 

​

Bob, this report is well written but it makes assumptions that suit the case for EV's rather than being more balanced. For example it compares the Leaf to ICE cars with fuel use of 29 mpg. Now probably that's OK for as an average, but why not also compare to a Prius with 50 mpg as a separate category?

 

Yes that is correct ... home solar is best considered a a generator and they included along with all the other generators to come up with an average intensity that everyone relies upon. If people with panels claimed all the own solar was separate ... then the average CO2 intensity of the grid for everyone else would be much higher. It is an accounting fallacy to assign a grid connected generator to a particular person or use.

 

Written in "November 2015," the available EVs were limited. But if we want to do a head-to-head, 2021 Std Rng Plus Model 3 vs 2021 Prius Prime:









Bob Wilson

 

It doesn't do that. The very first report only used the Leaf, because that was the only BEV available at the time.

"Also since our 2012 report, the combination of recent model introductions and upgrades to existing models has affected the overall efficiency of the full electric vehicle fleet. Given the few models available at the time, the efficiency of the 2011 Nissan LEAF—0.34 kWh/mile—was chosen as representative of EV efficiency. However, there are now sufficient sales of EVs to use an average EV efficiency; based on sales data for the 2014 calendar year, that average efficiency is now 0.33 kWh/mile—a 3 percent improvement from the efficiency of the 2011 LEAF."

That average EV figure is then used to determine the MPG(ghg) ratings for each grid region on that US map. That report is from 2015. The map Bob posted is the one using the most recent data for the grid and EV sales, which is a cleaner grid with more efficient plug ins.

Those figures can be compared to the average fleet fuel economy, though that isn't a truly same comparison, since available EVs don't cover all the vehicle segments at this time. The pick up and van models haven't arrived yet. Or it can be compared to an individual car model.

I've only saw the 29mpg mentioned in an example of how MPG(ghg) works, "if one were to charge a typical midsize BEV using electricity generated by coal-fired power plants, that BEV would have an MPG(ghg) of 29. In other words, the global warming emissions from driving it would be equivalent to the emissions from operating, and producing the fuel for, a gasoline vehicle with a 29 MPG fuel economy rating over the same distance."

 

OK makes sense. EPA should list the figure they use somewhere and then you can adjust. Also with EIA figures, does it include transmission losses ? Jason from EE used 8% as I recall.

 

Yes I realise that, but my point related to the first report using average ICE mpg figures and that is fine but they also should compare to hybrid and PHEV categories. At the end of the day EV's are cleaner on fuel life cycle than hybrid, if the grid intensity is low, but they are not the only clean solution and given EV's are not accessible to everyone, groups like the concerned scientists should broaden their reporting to include a range of clean options. After all if a person says EV's are not for me (for whatever reason) and they buy a conventional ICE as most people do, it is a poor CO2 emissions outcome for the planet.

Certainly the map approach to providing MPG equivalent data is a good way to present the information but my questions are;
1. How does this compare to EPA data?
2. have they included grid transmission losses to the house ?
3. Have they included charging losses for the EV battery ?

Is there a link for where they documents their method and assumptions ?

 

UCS is one of the best resources I have found.

They give full references and links to their studies.
They blogs are very good at communicating in everyday terms.
Here is a good summary from a bit over a year ago. https://blog.ucsusa.org/dave-reichmuth/are-electric-vehicles-really-better-for-the-climate-yes-heres-why/
(In there you will find links to exactly where the data comes from).

For your questions:
1)The UCS data is far more granular.
2) In all the pieces I have seen, yes, grid losses are included.
3) Yes

 

The appendix of the report Bob posted gives more details for the methodology.

The average EV efficiency includes that mode PHEVs; the Volt and PiP were included in the 2015 report. For the 2019(2017 grid data) update to the map, UCS also included one based on the efficient plug ins available, and it included the Prius Prime. The Model 3,and maybe the Ioniq Electric, were the others. They treat PHEVs as separate EV and ICE cars, because a PHEV's actual emissions depends on how it is used by the driver. The range of that makes a single value impractical.

The EPA hybrid segment includes mild hybrids like Jeeps and Ram pick ups. An honest value for full hybrids will include GM's two mode trucks and the F150 and Explorer. The RXh's ratings will also pull down the average of what people would think hybrid's should have. Besides, the average US fleet economy figure includes hybrids and plug ins.

If you want to compare an individual car model, or your subset of models, the UCS's map with MPGghg values has made it really easy.

1. Which EPA data precisely? Most of the data the UCS uses was published by the EPA or EIA.
2. They do. How is included in the report appendix.
3. The MPGe and kWh/100mi ratings for a plug in are for from the wall, so include charging losses. The test car is charged with the manufacturer EVSE provided with the car. https://www.fueleconomy.gov/feg/pdfs/EPA%20test%20procedure%20for%20EVs-PHEVs-11-14-2017.pdf

PS - I made a mistake. The use of PADD above should have been eGRID.

 

But when you charge using stored/generated solar, you are not delivering power to the house or the grid. So they have to use more non-solar-generated power.

 

If the solar/battery system isn't sized for the car and home, then yes.

When the A/C is running at max during a heat wave, that is solar energy not going to the house or grid. So non-solar sources are needed. This is true of any electricity use that exceeds what the panels or battery can provide.

Unless the car has its own meter for what power is used for charging, it is silly the separate it from household energy use.

On a related note, the presence of a meter means we can determine how much grid electricity is used. If a home with solar panels(or wind turbine) doesn't draw in any grid electricity, then it can said the car it charges is zero carbon emission.

 

Similar situation in our household. I work an irregular schedule with many weekends and a fair number of evening and night shifts. Wife works part time. We almost exclusively charge our vehicles at home in the mid morning to early afternoon when we can usually self consume home solar PV and the grid has the lowest demand.

Despite the house now being 100% electric for the last few years, we actually use less annual grid energy than when we moved in 10 years ago and less peak grid power/energy when the grid is dirtiest. In the mean time, our PG&E grid has also become substantially cleaner.