Hi folks,

I really want to hear from folks that have one. Most of the stories I read talk about "$1.50/day" to operate. I am not interested in what people are paying. I want to know the kWh totals (per charge or "per day").

I think I found the answer to my question at the following link:

http://gm-volt.com/chevy-volt-reasons-for-use-and-cost-of-operation/

COST OF OPERATION:

The Volt can drive for 40 miles on a single full electric charge of it’s battery pack. It is a known fact that the battery pack will be allowed to drain down from 80% to 30% before the gas-generator kicks in. Since the battery pack holds 16 KWH of energy, that means 8 KWH will get you 40 miles.

Which is basically 8kWh per day since I only plan on using the car to commute to work (for me 26 total miles per day). Assuming 21 work days per month that means 168 kWh/month.

Is this about what people are seeing?

Thanks in advance!

-Keith

Other folks that have measurement devices (I dont) say that the volt takes 12-13 kWh to do a full charge.

Stilgar

Thanks Stilgar,

Hmmm...more math.

Worse case 13 kWh per charge (per day) * 21 days per month = 273 kWh per month

That's still not too bad in my book.

-Keith

The thread you referenced shows California average KWH price of 12 cents. In northern CA PG&E base (up to 200KWH) is 11.87 cents. Above 200% of baseline is 40.0029 cents. I usually get into the 130 to 200 % bracket and sometimes into the top bracket. I use 29 cents in my spreadsheet calcs as I feel I have to lay the cost of charging the Volt on top of my normal baseline usage. I usually use 13 KWH for a full charge. At 40 cents, if I get into that bracket, that would be $5.20. If I get into the 40 cent/KWH bracket thats no real savings over my Buick Lasabre that gets 27 MPG average . On my spreadsheet which takes cost equivalent MPG of electric/gas, at 29 cents my mileage is 34.18 equivalent mpg.

A 2010 Prius I rented for 3 days last summer got 52 MPG for similar driving.

The Volt can drive for 40 miles on a single full electric charge of it’s battery pack. It is a known fact that the battery pack will be allowed to drain down from 80% to 30% before the gas-generator kicks in. Since the battery pack holds 16 KWH of energy, that means 8 KWH will get you 40 miles.[/I]

Which is basically 8kWh per day since I only plan on using the car to commute to work (for me 26 total miles per day). Assuming 21 work days per month that means 168 kWh/month.


-Keith

Some of your assumptions are out of date but the end result is possible.

GM disclosed last September that they expanded the allowable battery usage from 50% to 65%. I not aware of an official disclosure of the actual battery State Of Charge boundaries but I assume the bounds are around 85% to 20%.

The 65% range (about 10.4 kWh) is the energy which available from the battery. Putting energy from the wall socket into the battery adds a variety of AC-DC conversion and charging inefficiencies. The EPA rating says the Volt takes 12.9 kWh to recharge an empty battery. Various individual owners and magazine reviews report anywhere from 12 kWh to 13.5 kWh. The actual number likely varies based on ambient temperature and 120v versus 240v charging (240v might be a bit more efficient).

The actual kWh per mile consumed will vary based on temperature and use of climate controls, aggressive versus conservative driving, and road speed. I'm averaging 29 kWh per 100 miles (3.45 miles per kWh) but a couple of other drivers in the same area get 40-42 kWh per 100 by driving less conservatively and using more cabin heating.

If I was driving your 26 mile commute, I would use about .290 kWh per mile and would consume 7.6 kWh each day. Others might average 10.5 kWh per day on the same commute.

Install solar PV DIY if you have space. I saw cost of $2.15/Wp if you buy them and install yourself. A 1 Wp PV produced 2 kwh per year and would be worth $0.80 cents at highest tier. So imagine an earning of $0.80/yr for an investment of $2.15.

The thread you referenced shows California average KWH price of 12 cents. In northern CA PG&E base (up to 200KWH) is 11.87 cents. Above 200% of baseline is 40.0029 cents. I usually get into the 130 to 200 % bracket and sometimes into the top bracket. I use 29 cents in my spreadsheet calcs as I feel I have to lay the cost of charging the Volt on top of my normal baseline usage. I usually use 13 KWH for a full charge. At 40 cents, if I get into that bracket, that would be $5.20. If I get into the 40 cent/KWH bracket thats no real savings over my Buick Lasabre that gets 27 MPG average . On my spreadsheet which takes cost equivalent MPG of electric/gas, at 29 cents my mileage is 34.18 equivalent mpg.

A 2010 Prius I rented for 3 days last summer got 52 MPG for similar driving.

You appear to be assuming regular E-1 PG&E rates. Have you considered switching to E-9 Time of Use rates for EV owners? The top overnight charge rate under E-9a is 18.8 cents per kWh but up to 130% of baseline it is only about 6 cents and then 15 cents between 130% to 200%. If your other household electricity use is mostly at night, in the morning, or over the weekend (laundry) then the total monthly bill increase of charging an EV can be quite a bit less than just doing a simple extrapolation based on Tier 3 kWh rates. Individual results can vary a lot.

I'm still trying to get PG&E to change me over to E-9 (they bungled my paperwork) but Patrick Wang over at mychevroletvolt posted his recent E-9 bill and commute pattern and it looks like he will be paying an extra $3 a month to drive 600 EV miles (read my comments on his article there). That is an effective rate of less than $.02 per kWh using Winter rates. Folks who use lots of power, especially during the day and in the Summer, may get very different results.

If you drove that in a 50 mpg Prius it would take 12 gallons at $3.85 for a cost of $46. The Prius would also cause emission of almost twice as much CO2 over those 600 miles because the PG&E grid is low-carbon.

^^
rack ?
electrician ?
permitting ?
inverter ?

$ 5 - 6/STC watt is more ballpark. Figure 20% derating (panel -> grid) and while 2 kwh/watt*year is certainly possible some days of the year, it will not be every day. Use PVwatts for production estimates.

The Prius would also cause emission of almost twice as much CO2 over those 600 miles because the PG&E grid is low-carbon.I have a bridge to sell you.

I have a bridge to sell you.

I've been getting 29 kWh per 100 miles. The EPA rating is 36 kWh per 100.

Prius is about 50 mpg. Gasoline is about 20 pounds CO2 per gallon (19.4, according to Wikipedia).

PG&E grid averages .524 pounds per kWh, according to PG&E. http://www.pge.com/includes/docs/pdfs/about/environment/calculator/assumptions.pdf

I am not aware of the average for off-peak hours being published for PG&E. There is at least one study which estimates off-peak emissions averaged over a larger interchange grid that includes PG&E within it's territory but that includes higher-carbon generation not actually purchased by PG&E. Although off-peak might imply coal power in other areas, PG&E uses very little coal power on average (less than 5%) and has substantial nuclear, hydro and wind generation which would operate undiminished at night. The most likely fuel source to be reduced at night would be natural gas (normally 40-50% of the overall fuel mix). Without specific evidence, there is no compelling reason to believe that PG&E off-peak generation emits more CO2 -- it may well emit less than the overall average.

100 miles of driving a Prius emits about 39-40 pounds of CO2.

100 miles of driving a Volt on average PG&E grid power emits about 15-19 pounds of CO2 (29-36 kWh per 100 miles).

So, driving a Prius on gasoline emits roughly twice as much CO2 as a Volt driving on PG&E grid power.

One thing to add is that if you charge during off-peak, there is a good chance the power company will not increase fuel-consumption by the amount you take to fuel the Volt (or any PIEV). The plant spins the generators at a constant rate based on overall downstream load on the system and they are typically producing more potential power than is pulled in by load so plugging in a car at night should not cause "more" CO2 production. Of course, 1000 EV cars plugged in should make a noticeable dent in the load and that would cause calcuable fueld increases.

There are people more familiar with energy production and consumption configurations than myself, of course. But what I would like to see is a balance of a consumer's EV usage with their diminishing of electrical usage elsewhere - trading conservation of electricity at home and work with the power to re-charge their EV.

In the end - you can stop using oil/gas *and* have a net zero increase in grid usage with some smart planning of personal and family energy usage. Reducing waste alone can power a Volt through it's daily recharge cycle. You can also do your part by increasing renewables by going with some Solar PV arrays (if cost is ok with your family budget).

Prius is about 50 mpg. Gasoline is about 20 pounds CO2 per gallon (19.4, according to Wikipedia).

PG&E grid averages .524 pounds per kWh, according to PG&E. http://www.pge.com/includes/docs/pdfs/about/environment/calculator/assumptions.pdf

So, driving a Prius on gasoline emits roughly twice as much CO2 as a Volt driving on PG&E grid power.
This is all perfectly correct but Eric lives in La-La Prius land where you use the dirtiest grid for comparison, not the grid Volt drivers actually use. Note that if you want to do apples to apples you should use 23.7 pounds for the CO2 for each gallon of gas. That's the Argonne Lab number which accounts for processing and distribution. PG&E's number account for that so you want to use the Argonne number not the EPA number which starts with the gas in the tank (tank 2 wheels).

Where Eric has a point is that if you're driving the Volt a couple of hundred miles in a day with only one charge then, at some distance, the fact that his Prius uses less gasoline per mile than your Volt will result in his Prius emitting less total CO2 for the entire trip. Of course nobody drives a Volt on this type of drive cycle so it's a point that doesn't rise to the dignity of an argument. Even if you drove 12000 miles a year, and half or 6000 miles were driven using the genset, your Volt would still emit less CO2. And 6000 gas miles is a crazy number.

Note that CO2 is the worst possible case. For all other emissions and especially for pollutants it's never a contest since the magnitude of these depends on the number of cold starts and the Prius will have far more cold starts. This is why he always wants to focus on CO2. Everything else makes the Prius look completely lame.

One thing to add is that if you charge during off-peak, there is a good chance the power company will not increase fuel-consumption by the amount you take to fuel the Volt (or any PIEV). The plant spins the generators at a constant rate based on overall downstream load on the system and they are typically producing more potential power than is pulled in by load so plugging in a car at night should not cause "more" CO2 production. Of course, 1000 EV cars plugged in should make a noticeable dent in the load and that would cause calcuable fueld increases.
This is a great point. Even during the summer in SoCal the electrical capacity of the grid at night is about 2X the load. Obviously a lot of that capacity can't be turned off -- you don't shut down San Onorfre every night, and it would be the same for the large natural gas plants. But I've never been able to get any figures on how much of this generation goes to ground. Have you seen anything?

I wouldn't know the "to ground" opportunity costs, but it must be something that might be very interesting to find out.

My power-knowledge partly comes from growing up a mile or less from the Niagara Power Projects (five of them). http://nyfalls.com/niagara/niagara-falls-faq12.html Also it is the area that Tesla invented and perfected the AC power delivery for Buffalo and Niagara factory usage early-on. Great place to live to learn about power. Wonder why I like the Volt?? :-)

There, the US-side alone can produce constant output 2.7GW which is quite large and more than Hoover Dam. Much of it goes down to NYC and the upstate grid. Since there are five plants in use off Lake Erie water and Niagara Falls continues to look nice - there is opportunity to maybe add another plant or two for 1 more GW. But the water over the falls would slow down somewhat. I doubt more plants will be built due to costs today. One interesting thing is they pull water from the Niagara river at night to fill the holding resevoirs. on both sides of the border, which slows down the falls for a few hours.

Political rant. So. Ontario is a thriving area of farming, industry and population including Hamilton, Brampton and Toronto. Niagara/Buffalo is turning into yet another "Detroit" in squandered resources, poor politics, high taxation and poor direction by leaders. Anyone who visits the area learns this.

JiimN,

Average PGE electrical output is a combination of solar, nuclear, wind, hydro, coal, and NG -- approximately.
Lets group these energy sources as renewable, nuclear, and fossil.
Before we start with arithmetic of carbon intensities, I have a couple questions for you:

Does the sun irradiate at a higher intensity when you drive ?
Does the total rainfall increase ?
Does wind blow faster or harder (I am going to ignore DonC's contribution -- perpetual energy considerations)

2)Are you aware that nuclear is run at full capacity to supply part of system baseload ?

... to be continued

While waiting for participants in my little exercise in logic, I'll entertain with a picture. This graphic is taken from the Argonne GHG study by Elgowainy published in June 2010:
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Notice the purple rectangle which denotes HV (Prius) GHG. Even in the WECC region where NG predominates as the fuel source that will power EV, only unconstrained charging leads to a modest GHG reduction compared to the Prius of about 15%. A Volt run on a 'smart' charge program in WECC emits as much GHG as a Prius.

Now, about that bridge for sale ...

Eric post the link to this study. As with most of the crap you post I'm sure you aren't listing the entire story.

Good on you though, you seem to be the last of the trolls. That's an accomplishment.

What part of Elgowainy Argonne June 2010 do you not understand ?
But yeah, I and the Argonne researchers are trolls and live in la-la land.

That must be it. LOL

Eric post the link to this study.

Since Eric apparently can't be bothered, here's a link to the report (http://www.transportation.anl.gov/pdfs/TA/629.PDF)

Pages 20- 23 define what they mean by Parallel HEV, Series Hybrid, and Power-Split (Dual-Mode) HEV.

They've selected to model PH-40 and PH-30 as a pure series hybrid, and that's not the Volt. It's a Dual-Mode hybrid around 70 MPH. Likewise they model the PH-10 and PH-20 as Dual-Mode, but the Plug-In-Prius (and certainly the Prius) are strictly Parallel HEVs.

So while I won't argue with the graph, drawing a conclusion that it implies a Prius produces less GHG than a Volt seems quite the stretch.

I didn't see in this report where they even bothered with characterizing a parallel hybrid like the Prius. Without fulling reading it, it looks like they're just comparing traditional cars with modern technology.

Note the graphs on page 25-28. The Green bar on page 25 is representative of the current Prius, not the yellow or red ones. The Volt is ostensibly represented by the yellowish bar, but that shows ICE output of ~70 kW compared to a Volt's output of 55 kW. Figure 2.10 on page 26 shows the PH-40 modeled with a 120 kW motor, versus the Volt's 111 kW. So their PH-40 model doesn't well model a Volt on several fronts.

And so on.

So I can see why Eric didn't want to post a link.

P.S. On further quick reading the do talk about "Regular Hybrid" vehicles in section 3, as a baseline.

Nah Rusty, it was just a little psychotherapy. The patient has to be motivated to learn. You were at least willing to spend the two seconds needed to find the article.

You are right that the "PHV 30" is a simulation and not the "GM Volt," but if you read DOE and Argonne publications you will know that they have become really superb at computer simulations of cars. The differences you have found between the simulated car and the actual car are insignificant in GHG analysis. CS GHG might be different, but the analysis in this publication was CD mode for the plug-ins.

Next batter up ?

Lest anyone hope that the Volt is so much better than the simulated PHV-30, check out table 3.1 from the study:
Note that these are unadjusted numbers. If you want to compare them to EPA label, multiply by the EPA fudge factor.
Also keep in mind that no AC cooling or heating was modeled. I know you folks are staring to learn that heating is a Volt achilles heel.
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Thanks for all the feedback folks!

I really appreciate it.

@Xzlon & JeffN,

I'll have to take a closer look at the usage brackets for National Grid in Massachusetts. I use about 650 kWh/month and my bill is usually about $93/month.

The last bill I have is for Feb 2011:

Dist Chg First 600 kWh .03103 x 600 kWh = 18.62
Dist Chg Next 57 kWh .03765 x 57 kWh = 2.14 (would be $1.77 @.03103 for a difference of $0.37 which is obviously no big deal)

All the other charges were based on the total 657 kWh. So I'm curious what happens when I'm using over 900 kWh/month.

As for all of the other off topic discussions, those are always interesting as well ;)

-Keith

PS. I am not sold on the Prius and I plan on taking rhodomel's advice and generating my own power.

The results in terms of GHG production will be sensitive to the mix of fuel sources, too.

The mix in NY is rather different from the national average:

(CLICK TO ENLARGE)

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As you can see, NY state electricity is 29% nuclear and 18% hydro, and only 15% coal.

That's 47% with ZERO GHG from generation.

This is quite different from the US average which has 49% coal.

I live about 10 miles from the Indian Point nuclear station - which of course brings other issues lol!

Now, about that bridge for sale ...

Jeff N:
"The Prius would also cause emission of almost twice as much CO2 over those 600 miles because the >> PG&E grid is low-carbon <<."

EricLG:
"I have a bridge to sell you."

Jeff N:
"PG&E grid averages .524 pounds per kWh, according to PG&E [link]....
So, driving a Prius on gasoline emits roughly twice as much CO2 as a Volt driving on PG&E grid power."

In the same posting I also wrote:
"There is at least one study which estimates off-peak emissions averaged over a larger interchange grid that includes PG&E within it's territory >> but that includes higher-carbon generation not actually purchased by PG&E <<."

EricLG:
"Even in the WECC region....Now, about that bridge for sale ..."

Jeff N:
According to Wikipedia, "The WECC region encompassess the entire Western Interconnection, which comprises the states of Washington, Oregon, California, Idaho, Nevada, Utah, Arizona, Colorado, Wyoming, portions of Montana, South Dakota, New Mexico and Texas in the United States, the Provinces of British Columbia and Alberta in Canada, and a portion of CFE's system in Baja California in Mexico."

The record is clear that I was writing about the power actually delivered to and paid for by PG&E customers and used to charge actual Chevy Volts. PG&E covers most of Northern California.

Eric, congratulations on figuring out:

- Relative to most vehicles, the Prius is a great car and great for the environment

- The benefit of EV's depends heavily on what your power source is, when you charge, how you drive, where you live, personal weighting of environmental impact factors, assumptions of alternatives, and a million other details specific to the user

- Coal sucks

Again, congrats and welcome to the club.

Other utilities within the WECC region like coastal Oregon and Washington, and Idaho (I think) also provide low or ultra-low carbon electricity to their standard grid customers. Southern California is also in relatively good shape. The overall WECC numbers are pulled down by Utah, Colorado, Montana, etc. which are heavy coal producers and consumers.

If you live in these and other high-carbon areas you should probably already be buying optional "green power", if available in your market, or putting solar PV panels on your roof. If driving an EV encourages you to offset your carbon impact like this then it's a net positive.

If you are served by utilities which allow you to charge on lower carbon electricity, you might actually lower CO2 emissions more by driving an EV than by putting a typical basic solar PV panel installation on your roof. That would be true for PG&E customers who drive an EV a typical 12,000+ miles instead of driving a 30 mpg conventional gasoline car. They would even come close versus driving a Prius.

Ahh .. you think PG&E will have markedly different results compared to WECC.
Read this 2009 Elgowainy (http://www.transportation.anl.gov/pdfs/TA/559.pdf) study. If you care to read the source GREET publication, it is available online, published by Hadley at ORNL in 2008
In the meantime, a graphic from the study with the central point:
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My post #15 was meant to bring us to this juncture a bit quicker, but so be it.

Eric, congratulations on figuring out:

- Relative to most vehicles, the Prius is a great car and great for the environment

- The benefit of EV's depends heavily on what your power source is, when you charge, how you drive, where you live, personal weighting of environmental impact factors, assumptions of alternatives, and a million other details specific to the user

- Coal sucks

Again, congrats and welcome to the club.Actually, what simple reasoning tells me, confirmed by sophisticated GHG modeling by our US national energy labs, is that EV (A Volt in this case) is on par - inferior to a Prius on environmental grounds if grid charging is the energy source. It is similar when the source fuel is NG, and twice as bad if the source fuel is coal if CO2 is the pollutant in question. Other pollutants such as Nox, Sox and particulates is a question of whether coal in even small amounts is in the mix.

I do however agree 100% with Jeff N when he said that some PV is put up specifically to charge EVs, and that is great.

-- Yes, coal definitely sucks

Read this 2009 Elgowainy (http://www.transportation.anl.gov/pdfs/TA/559.pdf) study.

Thank you for posting the link to the study you've excerpted. It's a courtesy as it relieves the community from having to duplicate your research, and encourages cogent discourse (and probably non-cogent discourse as well :-).

I've not read the document in question, other than a quick pass. Since I presume you have, can you tell me how the 99% reliance on NG (NGCC?) shown in table 4 for WECC-CA justified with

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which shows WECC-CA using 13.0% coal, 40.4% gas (not 99%), 17.3% nuclear, and 29.3% other (presumably green?).

The table you have posted is average fuel source, while the table I posted is marginal demand source .
It is important to understand this, and is the reason that the GREET model exists in the first place: Renewables do not scale with demand. Or, as I somewhat impolitely paraphrased earlier, there is no more rain, wind, sun or even nuclear when EVs are running about. Marginal demand is *all* fossil fuel sourced; the only questions are which and the relative amounts of each.

You are welcome for the link. Amusing and irony that suspicion that my source was "hiding something" because it required a 2 second google search to find resulted in at least one person actually at least skimming the publication. I imagine Jeff N will read the publications also if he has not already. That makes two people. Anybody else in this forum which prides itself on being more informed and smarter than the average bear ?

The table you have posted is average fuel source, while the table I posted is marginal demand source .
It is important to understand this, and is the reason that the GREET model exists in the first place: Renewables do not scale with demand. Or, as I somewhat impolitely paraphrased earlier, there is no more rain, wind, sun or even nuclear when EVs are running about. Marginal demand is *all* fossil fuel sourced; the only questions are which and the relative amounts of each.

Fair enough, though I doubt I agree with the GREET model in practice today. If EVs only recharge during off peak times, will they not add to the marginal demand? There's a fair amount of nuclear power in CA, plus geothermal and hydro in various regions here. Those should all be in fair abundance (or at least relative) in off peak times, relative to marginal demand sources.

I agree completely that once EVs permeate the population, and people recharge willie-nillie, that all such additional power will need to be satisfied by marginal supplies if the grid is at max. And yes, I agree that in CA that marginal need is almost always NG.

But that has nothing to do with how EVs are being charged today (in such quantities as they are).

While this may very well be a future problem, and a very real one, to say "your EV always pollutes at the worst level of any power plant in your area" (which, if I may, is how I take your argument as presented - please correct me if I'm wrong because I have in fact not had time to read the totality of the literature) is specious at best.

And it's not applicable to how I'll use my Volt. Even if I need a charge, I won't charge during a power alert. Not because I want to avoid bringing additional dirty power plants on line, but because I want to help avoid brownouts and blackouts.

Anybody else in this forum which prides itself on being more informed and smarter than the average bear ?

To my knowledge this forum does not so publicly or privately preen. I certainly don't claim to be any brighter than the average bear. The majority here seem simply to want to learn.

So that appears to me to be a pure ad hominem attack. I don't believe you to be actively malicious, but you do seem to relish the joy of debate (http://en.wikipedia.org/wiki/Debate).

For the most part, we're not trying to score points here. We're just trying to learn. You are, of course, welcome to contribute to the discussion. If you just wish to assault and insult, you may find the value of your debate ignored.

P.S. I really wish there was a way I could turn off that silly "Moderator" tag. And a way I could turn it on when I really needed to. I'm not speaking as a moderator, and I hope you don't take me as doing so. I'm simply posting as a member of the forum.

P.P.S. Yes, if you *REALLY* get obnoxious, I'm sure some moderator or another will have a say. But so far since you've joined the Forum you've seemed to have both learned and contributed to the debate and the discussion. It's always a good thing to have someone around willing to say the emperor has no clothes. It's also a bad thing if the naysayer is being disingenuous for the fun of it.

""your EV always pollutes at the worst level of any power plant in your area" (which, if I may, is how I take your argument as presented - please correct me if I'm wrong"

I am not saying that. Closer to the mark in practice is "we (the utility) use the cheapest available that can be brought online in a timely fashion." Utilities would *love* for that to be coal, but NG is a common component as that table I posted earlier shows. "Smart" charging is utility attempts to transition EV charging from NG to coal by folding the energy demand into baseload. "Smart" for them -- more profits.

In the US today, marginal demand sourcing has very little to do with the different fossil fuel source capacities. Read marginal as 'additional.'

"If EVs only recharge during off peak times, will they not add to the marginal demand?"
Most assuredly. The effect will be more relative coal use instead of NG. Look at the first graphic I posted.
Nuclear plants run at capacity already, while the renewables like hydro are resource limited. Use today or tomorrow, but the amount available is the same. Use it to satisfy increased energy demand from EV, and it is not powering what it had been.

In short: until renewable are in excess capacity for *total* grid energy demand, additional demand is 100% fossil fuel sourced.

I read this stuff a few months ago but had to skim them again to refresh my memory.

This study has some bizarre assumptions wired into it:

* plugins will jump from 0% to 25% of all passenger vehicles sales in 10 years. So, in 2020 there will be 5,000,000 plugins sold each year in the US since the study assumes annual car sales of 20 million by that time.

* almost all new electrical generation capacity added between 2020-2030 will be coal -- essentially no new natural gas plants etc.

* implicitly, it appears to assume that plugin car sales are spread evenly across the U.S.

* all plugins are modeled as Prius-like blended mode plugins which use the gas engine up to 20% while in battery discharging mode (battery-only cars aren't modeled at all)

The various charts and graphs are based on projected fuel mixes in 2020, not our actual current grid.

As Rusty pointed out, plugin cars sold over the next few years will have very little effect on the grid fuel mix. Even in the study's California fantasyland of 2020 plugin volumes, the increase in evening electricity generation demand is less than 3%.

EricLG:
"you think PG&E will have markedly different results compared to WECC."

Yes. My original comments were about my Volt's EV usage today, not a future CA grid that uses more coal (?) and has huge numbers of plugins charging in just the next decade. In addition, I was discussing PG&E grid power which is somewhat lower-carbon than California as a whole.

EricLG:
"Actually, what simple reasoning tells me, confirmed by sophisticated GHG modeling by our US national energy labs, is that EV (A Volt in this case) is on par - inferior to a Prius on environmental grounds if grid charging is the energy source."

For what it's worth, that's not the conclusion of the study. Both in textual description and in charts, it shows NG (WECC-CA) with lower GHG (CO2) emissions versus a prototypical gasoline HEV as battery AER is increased. It shows the national average grid being neutral and Illinois coal power emitting higher GHGs. The many other regions not covered by the study will fall along those spectrums. Some may do better than the study shows if they already have excess baseline low-carbon power at night (there must be some hydro areas like that....) and will just export less to their regional interchange partners.

Jeff N:

"This study has some bizarre assumptions wired into it:"

Yes, I looked at this paper a little while back. I remember a few things standing out to me that are certainly dependent on the individual (beyond the already dominant where you live/ what your power source is individualism):

- Assume a PHEV-40 is driven on gasoline 51% of the time

- Give the pure HEV starting theoretical mpgs of 62/56 and the PHEV-40 46/48 (this completely depends on the size of the car, series vs. dual-mode, etc)

- Basically assume our grids are going to get dirtier rather than cleaner

- Basically assume the extra EV load is always from fossil fuels

None of these things are strictly wrong or true for the individual and are best attempts at averaging over the population and situations. This paper is very good and interesting work, and assumptions and averaging is typically necessary for a coherent study. They also make the proper conclusion that it truly depends on your power source (not even your regional mix, but your actual power), which is at strong odds with Eric's "conclusion":

Eric:
"Actually, what simple reasoning tells me, confirmed by sophisticated GHG modeling by our US national energy labs, is that EV (A Volt in this case) is on par - inferior to a Prius on environmental grounds if grid charging is the energy source."

Paper:
"The primary conclusion is that electrification of transportation significantly reduces petroleum energy
use, but GHG emissions strongly depend on the electricity generation mix for battery recharging."

Eric, while I appreciate your relatively decent familiarity with some of the issues at hand, I do not appreciate your biased agenda, nor your snarky, argumentative approach. You seem to favor insults, half-truths, and scoring points rather than education and healthy debate.

For what it's worth, that's not the conclusion of the study. Both in textual description and in charts, it shows NG (WECC-CA) with lower GHG (CO2) emissions versus a prototypical gasoline HEV as battery AER is increased.True, about 15% lower as I posted earlier. That is the best case scenario, not the 50% reduction you wrote that prompted me to start this debate with my bridge comment I apologize for. In turn I should clean up my "par to inferior" statement to exclude on-peak, CA-WECC as noted above.

Zod: I'll try to reign in my snarkines. The general hype and ignorance so rampant in Volt and EV discussions makes me cranky.
And yes, I contend that today (and for quite a while into the future) moving a petrol car to the grid is an exercise in fossil fuel substitutions. The Oak Ridge and ANL reports come to the same conclusion. Would you like to argue this point ?

Sure, you can come to a different conclusion if you limit the context just to yourself, but if that results in your neighbor emitting what you "saved," I call that a disingenuous argument.

Please refrain from implying some negative agenda, when I am happy to straight out tell you what it is: discussion of rational environmental and energy public policy.

I looked at the study also. Wayyy too complicated. It's easy arithmetic to calculate it.

For the gas burner: every gallon of gas burned is 19.4 lb CO2
for a hybrid that gets 49 MPG
185 g/mile

for an EV: Volt=2.9 miles/kwh

for power plants:

coal plant= 970 g/kwh CO2

combined cycle natural gas=385 g/kwh

Volt on electricity from coal= 276 g/mile
Volt on electricity from CCNG=133 g/mi

why make it more complicated than that.

Eric,

Fair enough. The "agenda" comment was perhaps my previous interpretation of the "crankiness" you referred to, as it sometimes seemed a preferred desire to knock a Volt enthusiast down a notch over just informing them.

In any case, if you can get your car to "prius equivalent" GHG while also removing the physical, political, and economic dependencies on foreign oil, I consider that a win. Plus add to the fact that many people do have very clean energy sources, providing and developing EV's are great things. Then add that we as a society will eventually be forced to cleaner energy sources one way or another, the availability and infrastructure for EV's is a fantastic thing to have in place.

For all those reasons, I think the enthusiasm is well placed. And if you think the pro-EV "hype and ignorance" is bad, I encourage you to read blog posts in more "anti-EV" discussions. It usually devolves into a discussion on how Obama is secretly a ****** and not really a citizen, or some such garbage.

Fair enough. The "agenda" comment perhaps my previous interpretation of the "crankiness" you referred to, as it sometimes seemed a preferred desire to knock a Volt enthusiast down a notch over just informing them.



Zod this is my first post on this thread. I'm pro Volt. Not sure what you meant.

Oops never mind you were responding to Eric. Sorry

Zod this is my first post on this thread. I'm pro Volt. Not sure what you meant.

Oops never mind you were responding to Eric. Sorry

Sorry about the confusion. I edited the last post.

I looked at the study also. Wayyy too complicated. It's easy arithmetic to calculate it.

For the gas burner: every gallon of gas burned is 19.4 lb CO2
for a hybrid that gets 49 MPG
185 g/mile

for an EV: Volt=2.9 miles/kwh

for power plants:

coal plant= 970 g/kwh CO2

combined cycle natural gas=385 g/kwh

Volt on electricity from coal= 276 g/mile
Volt on electricity from CCNG=133 g/mi

why make it more complicated than that.Well, to convince people that we are in fact in a fossil fuel substitution game and that it is fallacious reasoning to discount the GHG emission in EV use by renewable fraction of any arbitrary grid source mix. Once that is out of the way, your approach is the way I think about it too as a first approximation, but there parts of the energy stream we are not including. E.g., EPA estimates 17% losses in petrol refining and distribution which works out to a refinery-wheels GHG for the Prius of 185/.87 g/mile CO2. On the electric side we should include transmission losses of about 7%, and plant waste of about 9%. It just so happens these losses are remarkably similar, although that is just coincidence. Left out is the mining of coal vs oil drilling, and transport of these unprocessed fuels.

Aren't you picking the most efficient possible NG power plant, rather than what is actually used ? This site (http://www.global-greenhouse-warming.com/gas-vs-coal.html) says that the US average NG power plant emits 1.135 pounds/kwh. That works out to 185 grams CO2/mile for the Volt using EPA numbers before we correct for transmission and plant waste losses.

Eric,
The diff on the NG power plant emissions is probably the difference between a NG combined cycle power plant (cycle eta=60%) versus a NG gas turbine topping power plant (no steam bottoming cycle, cycle eta= approx 43%).

Yes I know we can start at different points in the refining process and include the DF2 it takes to get the gas to the gas station etc etc. but my way of looking at it is close enough.

The main reason most people buy a Volt is to stop buying gas....and most don't care if it costs a tad more or emits a tad more CO2. For me, I've got my PV in so it doesn't apply. Oh wait we need to consider how much oil it took to make the solar cells, and how much diesel it took to deliver the solar cells to me. Sometimes it's not worth over complicating matters.

Of course that's what engineers are trained to do,,right??

While we're talking national averages, it is important to remember that as a society we are not talking about "Volt vs. Prius", or even "PHEV vs. HEV". The real issue at hand is "PHEV/BEV/HEV vs. ICE". Now, if we must argue PHEV vs. HEV, then I see a lot of benefits to PHEV. But that doesn't mean it's better in *every* way and to every person and situation.

The same mistake is made by many who oppose expanding nuclear power because they favor renewables. Well, pretty much everyone favors renewables, but that's not the issue at hand. Renewables just can not contribute a majority share of our energy needs in the near term. It's really Renewables *AND* Nuclear vs. Coal (and other fossil fuels) that is the socioeconomic/environmental issue at hand.

It's really Renewables *AND* Nuclear vs. Coal (and other fossil fuels) that is the socioeconomic/environmental issue at hand.

Don't forget combined cycle natural gas. It's the way we should be going also.

The main reason most people buy a Volt is to stop buying gasTheir choice, and certainly not a bad reason.
But it is not a 'green' reason, and Volts used as an EV are typically not greener than a Prius, and in the majority are worse environmentally.

Sounds like we agree ?

As for the car costing a 'tad' more -- hah. I wonder what fraction of the population views an extra $25k/car on the national bill as a 'tad.' Hopefully they all spend another half-tad and put up PV.

Don't forget combined cycle natural gas. It's the way we should be going also.

I agree that that's a huge improvement over coal. That's why I singled coal out.

If I had my way, we'd be working towards replacing every coal plant with a new nuclear plant right now. Instead, the U.S. is building new coal plants at the highest rate in 20 years.

It's really a shame the U.S. hasn't built any new reactors in 30 years based primarily on unfounded fear and political reasons. But that's starting to change... slowly.

It's really a shame the U.S. hasn't built any new reactors in 30 years based primarily on unfounded fear and political reasons. But that's starting to change... slowly.

Don't worry China is doing it for us Ha!

Hopefully they all spend another half-tad and put up PV.

Good one. PV is almost as justifiable on a payoff basis as a new Volt.

Oh who cares I like it anyway.

While we're talking national averages, it is important to remember that as a society we are not talking about "Volt vs. Prius", or even "PHEV vs. HEV". I disagree, because the costs are so different. The $7500 tax subsidy on the Volt is proof if the msrp does not convince you.


As a public policy and neutral tax, imagine if petrol taxation increased over time to force a national fleet fuel economy improvement of 10% a year, with the tax collected returned as a credit upon vehicle purchase. Or phrased differently, what is the least national cost to reach a fleet fuel economy of 50 mpg (EPA) ? 100 mpg (EPA) ?

I think about this way: A garden variety mid-size ICE car 25 mpg costs about USD 18k, a Prius 21k for 50 mpg, and an PHEV 40k for 150 mpg. Where is the highest utility for taxpayer money ?
The conventional ICE car consumes 0.04 gallons a mile;
The Prius 0.02 gallons a mile; and
The Volt .0.0067 gallons a mile.

Spending 22k (the difference between ICE and Volt) subsidizes one Volt and saves 0.0393 gallon a mile
Spending 22k subsidizes 7.33 Prius, and saves 0.147 gallons a mile.

From this point of view of subsidy/taxation to decrease petrol, Volt subsidy has a 374% opportunity cost.

Eric,

You're really trying too hard. My comment had nothing to say or do about the rationale, or lack there of, for government incentives. You're really going out of your way to make this Volt vs. Prius, and I'm really not that interested.

I haven't been in the market for a Prius, can you really get it below invoice (21k?). Even so, I'd argue that the Volt is a superior vehicle (in the classic performance, driver satisfaction, non-environmental sense) and I think you get a lot more in the base model. In the same sense, an 18k ICE is a lot more "car" than a base model prius, imo.

Anyway, you're point about the Volt price and government incentives is taken, even if it is completely off topic and the metric is arbitrarily devised with one outcome in mind.

Good one. PV is almost as justifiable on a payoff basis as a new Volt.
Said tongue in cheek ?

Without subsidy PV is about the same cost to the consumer as grid electricity if the analysis is taken out to end of life.

"Anyway, you're point about the Volt price and government incentives is taken, even if it is completely off topic and the metric is arbitrarily devised with one outcome in mind."

Once again you are mistaken about my intentions. I do not support a public policy that pushes people to buy Prius, I want public policy that efficiently and rationally decreases fossil fuel consumption to a low level in 20 years. I showed a Volt vs Prius opportunity analysis because it is so lopsided, but I actually do not think the Prius is the best opportunity cost for 35 mpg (EPA) fleet which should be our first big 5 year step.

Sorry you have lost interest in the topic.

I agree that that's a huge improvement over coal. That's why I singled coal out.

If I had my way, we'd be working towards replacing every coal plant with a new nuclear plant right now. Instead, the U.S. is building new coal plants at the highest rate in 20 years.

It's really a shame the U.S. hasn't built any new reactors in 30 years based primarily on unfounded fear and political reasons. But that's starting to change... slowly.

(bangs head on desk)

It has very little to do with the "unfounded fear" and "political reasons." Nukes are MASSIVELY capital intensive, have long lead times and at the moment, gas is cheeeeap. Capital cost has always been nuclear's problem. Factory-built reactors could help with that situation.

Of course, one man's "unfounded fear" is another's "reasonable concerns." There's quite a few Curies in the average reactor core and an untimely release could ruin your whole day. This has more to do with siting the reactor than anything else. People are OK with reactors, in the abstract, but generally don't want them at the end of their street.

Bang your head on the desk all you want, but I'm fully aware of the large up-front capital costs and lead times of new nuclear facilities. The fact is, unfounded fear and litigation from the uninformed make reactor funds high-risk loans, which is what tips the scales and makes them a little too risky and expensive for the average investor. That's why when the government steps in and helps provide guaranteed loans (at little cost to the government) which effectively reduces the risk and interest rates, new reactors finally get built as they are just starting to now.

And yes, a "plug-and-play" reactor design and production would go a long way to making things cheaper. I'm hoping that eventually happens in this country. And if the government ever imposes even a modest carbon tax (not necessarily saying they should), nuclear power would quickly become the cheapest source of energy (over the plants lifetime) available.

I do sympathize with peoples fear, but their fear is largely from just not understanding the facts. A nuclear plant and a nuclear bomb are two completely different things. A Chernobyl style plant doesn't exist in this country and never will. Three Mile Island is a success story: It's the worst thing that can happen to the styles of plant in this country and not a single person was hurt. No other significant energy source can claim that. Anyway, I could go on forever, but let's just say that if I were overly worried about insignificant levels of excess radiation, I'd rather live at a nuclear power plant than go on a few commercial flights a year.

True, about 15% lower as I posted earlier. That is the best case scenario, not the 50% reduction you wrote that prompted me to start this debate

Okay, after some more google research, the best estimate for "CO2" (combined impact of all emitted global warming gasses converted to a CO2 equivalent) for electricity generated "on the margin" that I could find for my area is not for PG&E but for California overall. PG&E has a cleaner average mix than California, for what it's worth.

Whether marginal or average CO2 emission is the correct method to use is an interesting philosophical question. Using margin rates "makes sense" in some ways but it implies that other uses are somehow non-margin. When does a use transition from margin to non-margin. Every use can't equally be at the same margin boundary.

In any case, California has a new Low Carbon Fuel Standard (LCFS) which recently went into effect. As part of those regulations, the California Air Resources Board (CARB) established a table detailing carbon impact per million Joules of available energy. Among those listed are the gasoline formulation sold in California and marginal electricity generation (as opposed to average generation). The values are calculated under a modified GREET model which accounts for additional indirect carbon emissions.

http://www.arb.ca.gov/fuels/lcfs/010611lcfs_lutables.pdf
http://www.arb.ca.gov/fuels/lcfs/lcfs.htm

California gasoline: 95.86 gCO2e/MJ

California marginal electricity: 104.71 gCO2e/MJ

Translated into more familiar U.S. terms:

California gasoline:
95.86 / ~92.6 = 1.035 LCFS gas multiplier vs. Standard GREET gas
95.86 gCO2e/MJ = approximately 25 pounds CO2e/gallon (24.5-25.5 or so depending on conversion calculation)

California marginal generation electricity:
104.71 * .0022046 = .23084367 pounds CO2e/MJ
.23084367 * 3.6 = .8310372 pounds CO2e/kWh

2011 Volt EPA:
.8310372 * 36 kWh/100 = 29.92 pounds CO2e/100 miles

2011 Leaf EPA:
.8310372 * 34 kWh/100 = 28.26 pounds CO2e/100 miles

2011 Volt personal average:
.8310372 * 29 kWh/100 = 24.10 pounds CO2e/100 miles

2004 Prius personal average estimate:
25 * (100 / 45mpg) = 55.55 pounds CO2e/100

2011 Toyota Prius EPA:
25 * (100 / 50mpg) *= 50.00 pounds CO2e/100


This shows the 2011 Toyota Prius with 2/3 more (50 vs 30) greenhouse gas emissions using California reformulated gasoline than the 2011 Chevy Volt using a California marginal electricity mix, according to the California Air Resources Board.

For my own personal average driving pattern, it also shows that my driving pattern on my 2004 Prius with 130% more greenhouse gas emissions than when driving my 2011 Volt on electricity.

Last month I drove 957 miles (799 EV and 157 gas at 43.3mpg) so my total blended CO2e/100 was 29.59. The 55.55 I would have gotten on the same basic driving pattern using my 2004 Prius would have been roughly 88% higher.

Of course, all of these numbers vary slightly depending on conversion factors but those are the numbers according to California.

Last month I drove 957 miles (799 EV and 157 gas at 43.3mpg) so my total blended CO2e/100 was 26.11 or less than half of the 55.55 I would have gotten on the same basic driving pattern using my 2004 Prius.


Oops, I was in a rush to post this and added the last paragraph or so at the last minute and didn't have time to double check it. The blended person number should have been 29.58 CO2e/100 miles, not 26.11.

Ya know, when it comes to simple typos - if no one has helped me by pointing them out, silently editing the offending note takes care of it.

If someone's helped me by pointing out a flub, correcting the note in question and responding with a "fixed" seems like a nice idea.

[posted as a forum user, not as a moderator - wish I could turn on and off that silly status sometimes]

Thanks Jeff for the interesting post. It will take me a while to digest and read the source, but I'll get there. The results are at least 1.5x different than ANL and a the simple calc George Bowers and I have used, so finding the reasons for the differences will be interesting.

Cheers

We have tons of NG. It's cheap and non polluting. ( around 1/3 less CO2 for each BTU). The arguments presented here are mostly a function of the power plant's emissions not about the energy conversion efficiency of the electric car.

That is why natural gas and electric cars go so well together.

Jeff,

ELC002 (electricity) is titled "mix of NG and renewable energy sources," and is rated 104.71 CO2e.
I have no idea what the mix is, and as I argued earlier I do not think *any* renewables or nuclear fuel can be considered in a realistic marginal energy demand calculation.

I think the best scenario is to start from NG, rated at about 68 grams CO2e/MJ
Assuming 40% power-plant efficiency gives 68/.4 = 170 grams CO2e/MJ of electricity coming out of the plant.

1 MJ = 1/3.6 kwh = 170 grams CO2e -> 1 kwh = 170*3.6 grams CO2e
1 Volt miles = 0.36 kwh by EPA -> = 0.36*170*3.6 = 220 grams CO2e/mile = 0.484 pounds CO2e/mile
Prius (by EPA fuel economy) 0.5 pounds CO2e/mile

Not surprisingly this comparative result is identical to George's calculations, but it reinforces the point that the parts of the energy stream he ignored are in fact close to identical in energy losses whether we consider NG or petrol.

Anyway, we are back to the question of whether it is reasonable to exclude renewables from the marginal supply CO2 calculation. The answer seems like a self-evident yes to me, but that is not going to convince you so I'll try to rationalize the argument. Are you familiar with the economic notion of opportunity cost ? The general idea is you have multiple choices, but can only pick one. The other choices are lost to you, and their associated benefits. You do not lose the cumulative benefit of course, just any one benefit you did not choose. Lets say I can run a car on either petrol or renewables, and the renewables are currently being used to supply other demand. If I run the car on petrol, the renewables continue to offset whatever they are powering at the moment; if I run the car on those renewables, then the power that had been renewable based must now by sourced from non-renewables. Works out to be a wash. The sobering extension to this argument is that until renewables supply is in excess of current demand, EV use will be 100% fossil fuel sourced.

We have tons of NG. It's cheap and non polluting. ( around 1/3 less CO2 for each BTU). The arguments presented here are mostly a function of the power plant's emissions not about the energy conversion efficiency of the electric car.The car matters. How else do we end up with very similar CO2/mile outputs between the Prius and the Volt or LEAF, when the source fuel for the EV (NG) has 2/3rds the CO2 of petrol per btu from the get go, and NG plants are at least as efficient as the Prius ICE ?

The most obvious answer is car weight, which is not dropping any time soon, and is a high fixed cost as far as batteries/range goes.

I also want to comment on our 'tons of NG.' I have seen statements that the US has decades and decades of reserves, but this arithmetic is always predicated on *current* consumption rates. Switch over 50% of the US transportation fleet to NG and the time to exhaustion shrinks dramatically. The US needs NG to run its agriculture; wasting NG on cars is uncomfortably similar to the ethanol misadventure.

Natural gas runs in a pipeline to the powerstation and the produced electricity along the grid to the car
But to get that gallon of gasoline to the pump I wonder how much CO2 is created by the various trucks that move it fom the refinery to bulk distribution, local distribution, then to the filling station?
How does that accounted for in your Prius calcs LG?
Did I miss something?
WOT

I also want to comment on our 'tons of NG.' I have seen statements that the US has decades and decades of reserves, but this arithmetic is always predicated on *current* consumption rates. Switch over 50% of the US transportation fleet to NG and the time to exhaustion shrinks dramatically. The US needs NG to run its agriculture; wasting NG on cars is uncomfortably similar to the ethanol misadventure.

Eric,
my vision is not running ICE cars on NG (like the Honda NG Civic). It is natural gas combined cycle power plants making electricity at a 60% cycle efficiency and 385 g/kwh. Then using this as charging source for EV's. I could be wrong but I think NGCC would be base load not marginal load. These plants would be a great replacement for aging coal plants. The other adantage is that the infrastructure for refueling a lot of NG/ ICE's is not required.

You can make an arguement that if we start using NG as a fuel for transportation it will drive up the price.,,but that's no reason to not do it. Besides, you and I have very little to say about it. It is going to happen anyway, by default. The oil companies are already using the supply to balance lost oil reserves.

Check out a map of how many new fracking wells are already installed. Sh*t they are putting 'em in peoples back yards.

Jeff,

ELC002 (electricity) is titled "mix of NG and renewable energy sources," and is rated 104.71 CO2e.
I have no idea what the mix is, and as I argued earlier I do not think *any* renewables or nuclear fuel can be considered in a realistic marginal energy demand calculation.

I think the best scenario is to start from NG, rated at about 68 grams CO2e/MJ
Assuming 40% power-plant efficiency gives 68/.4 = 170 grams CO2e/MJ of electricity coming out of the plant.

1 MJ = 1/3.6 kwh = 170 grams CO2e -> 1 kwh = 170*3.6 grams CO2e
1 Volt miles = 0.36 kwh by EPA -> = 0.36*170*3.6 = 220 grams CO2e/mile = 0.484 pounds CO2e/mile
Prius (by EPA fuel economy) 0.5 pounds CO2e/mile


Here is the supporting document for the CARB calculations. They talk about use of renewables for marginal generation but that appears to be a goal (up to 33%) and is not currently detailed. They assume NG plant efficiency is an average 39%. An earlier draft (2.0) included an example EV g/mile calculation assuming 31.11 kWh/100 miles that closely matched my earlier conversion results. I haven't fully gone through what they are doing to arrive at their marginal number.
http://www.arb.ca.gov/fuels/lcfs/022709lcfs_elec.pdf

This CARB calculation has been criticized in a UC Davis paper (according to it's abstract) that I just found. I haven't had time to read it yet. http://pubs.its.ucdavis.edu/publication_detail.php?id=1362

WOT,

The refinery and distribution energy costs of the source fuels are included in GREET. The 'low carbon pathways' work that CARB is doing relies on GREET, so that is not an independent accounting. However, the EPA takes those energy costs into account in its (in other ways political) accounting of fuel economy for CAFE and estimates 17% losses. For comparison, the GREET based calc from CARB of petrol in CA comes up with 25 pounds carbon intensity for petrol although the end combustion in a car is 19.3 pounds. The ~ 30% difference is their estimate of upstream costs. I cannot explain the discrepancy of 30% vs 17%, although CA may have regulatory requirements that increase processing. Certainly the higher cost of fuel at the station points towards that being the case.

Sorry for the long winded reply. Yes, taken into account. Welcome to the conversation

Jeff,

Nice find! I forgot about this article. Yang and McCarthy are well known and respected authors. I cannot remember, but they may be part of Andy Frank's academic powerhouse. I have to spend some time to read the article, but this graphic looks like a nice executive summary:
1334

I am not sure why the Prius was rated 46 mpg. If this is a correction for upstream costs it is more than fair or arguably opitmistic; if it is only actual road miles then they are about 10% lower than EPA. Come to think of it, 50% of the difference is explained by the authors using a Gen 2 Prius which is rated about 5% lower than the current Gen 3 being sold. If the Prius result is discounted 5% we once again are looking at numbers quite similar to the 2009 Elgowainy study.

By the way, this article makes it easy to split the energy stream into car and not car:
1335
The BEV works out to 306 wh/mile. If the battery charging losses of 15-20% have been included then they modeled the EV about 20% optimistic compared to the EPA Volt and LEAF end results and conclusions mostly flip. For those two cars anyway.

Eric,
my vision is not running ICE cars on NG (like the Honda NG Civic). It is natural gas combined cycle power plants making electricity at a 60% cycle efficiency and 385 g/kwh. Then using this as charging source for EV's. I could be wrong but I think NGCC would be base load not marginal load.Fair guess that a plant running 60% efficient will run at capacity. But that just tells you once again that marginal load will be the less efficient, less expensive, (to the utility) and (likely) dirtiest plants.

An NGCC build is not driven [sic] by EV adoption. EVs are just another appliance demanding energy. You can no more reserve NGCC electricity for your EV than you can for your toaster; and even if you could it means the other appliance now uses the less appealing stuff. I tried to explain this argument above in a post to Jeff.

I suppose it seems illogical for me to always place the EV at the end of the line, to get the crap fuel. My reasoning is that unlike a toaster, we have a a choice how to fuel this (auto) appliance.

Jeff, Eric,

You guys are away ahead of me on this....and I'm not sure I want to spend tons of time getting up to speed. But If I could ask a question:

On the first summary graph (executive summary):


What power plant types and emission level (g CO2/kwh) are they assuming for the pure EV.

George,

The table at the bottom of the bar graph has two rows:
The top is well to tank
The bottom is tank to wheel.

The Y axis is the multiple of these two values, in grams CO2e/km.

George,

The table at the bottom of the bar graph has two rows:
The top is well to tank
The bottom is tank to wheel.

The Y axis is the multiple of these two values, in grams CO2e/km.

Shoot, I'll have to do the conversion. no problem.
These numbers seem fairly different than mine which were a gross simplification at best. I understand I left out transmission losses for the the EV side. also I guess we need to include the energy req'd to get the fuel for the power plant out of the ground. and on the gasoline side the energy to refine the oil and get it out of the ground...and as wot said the energy to get the gas to the gas station.

Let me know if you figure out where the differences are and if they are included in the study. Oh and I guess the study needs to have the correct kwh/mile # in it for the EV. Very complicated.

Thx, gsb

Shoot, I'll have to do the conversion. no problem.lol.
I start sighing when confronted with US units of measure.

lol.
I start sighing when confronted with US units of measure.

kwh are the primary units. not megajoules.
and besides my Pratt and Whitney handbook has me having to convert first to BTU's then to kwh. so I will have to tackle this problem later.