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May 02, 2007



When quotes of 100 or 150 MPG are offered I have to ask two question "what is the cost in KWhr to the customer?" and "where is the electricity coming from?" For most people the electricity is still cheaper than buying gas, but the source is very likely to be a coal-fired power plant producing the base load throughout the night. That is worse than a IC gas engine plus transmission losses.

Jim from The Energy Blog

In the U.S. electricity is usually taken at $0.10/ kWh.

The efficiency of a coal fired power plant plus electrical transmission losses is higher than an ICE plus its transmission losses.

ICE,0.20 x trans loss, 0.9 = 0.18
Coal Power plant = 0.35 x trans loss, 0.9 = 0.315

New IGCC generation power plants have an efficiency of 50% or higher.


Not to mention the fact that if you live in the NW United States, or Europe, you are more likely to be using non CO2 emitting sources of electricity. Further, as indicated in the article, utilities will be much more efficient with off peak charging. Besides, even if the source is coal, isn't it less expensive to take care of emissions at a centralized power plant rather than millions of vehicles?


Comparisons of fuel consumption in l/100km are misleading when you are comparing different fuels but meaningless when PHEV and the like are considered. Comparing the CO2 in g/km is much more sensible.

J.C., Sr.

Several decades ago I remember a tale of woe told to me by a landlord of a six family tenement building. By law, he was required to furnish lights on his back porches. Every time he went to inspect his building, he would find multiple outlets screwed into his lamp holders with the same amount of extension wires feeding his tenant's appliances.
I envision after a 6 inch snow storm on a back street in Hartford, Ct., A snow plow dragging battery equipped cars, extention cords, and even a dilapidated tenement building down the street!
Wouldn't it be a lot easier, using these Li-Ion equipped cell phones to call up a smaller more efficient bus to quickly pick up and deliver numerous passengers to a designated mass transit area?


Mike and David-- the point isn't really the savings in CO2 right now. The point is moving away from hard-to-regulate gasoline towards things like electric vehicles. In addition to being far more effecient than ICEs, using electricity allows, as Ron pointed out, the government and utilities to more easily control CO2 production.

If we continue driving cars simply because they produce a teeeny bit less CO2, we'll keep using ICEs running on petroleum. If we switch to a maturing EV industry, we will be able to much more effectively reduce CO2 emissions.

Warren Carothers

Let's face it, we must move away from petroleum. It is more than the cost of gas, a finite supply, balance of payments, CO2, sources of supply, etc. This is a big step in the right direction -- more developments will come. It is a great direction to be going.


40 miles! Fantastic, the average trip is 23 miles. That could raise average mileage to 10 times present levels.

Meaning 10% of present liquid fuel use is possible. That extends oil based fuel long enough to get better batteries that can do away with liquid fuel use completely. The end of fuel farming could be in sight if this battery technology in plugin hybrids is widely adopted.


Well, it all depends just how dirty/ineffecient the coal is to begin with.

For instance, a coal fired Tesla Roadster can be anywhere from twice as good as a Prius, to half as good given different coal plant types.

From inbetween 0.3kgCO2/KWh, to 1.1kgCO2/KWh


Although this video clip from Calcars says that plugins would be 45% cleaner if run on the existing grid which is half coal.

Wonder where they are getting that figure from.


Kit P

The ghg from PHEV depends on where and when you you plug your car in. In Virgina off peak, it would be 100% coal. In the PNW off peak in the spring, it could be 100% hydroelectric.

The way to determine where the electricity is coming from is to check the hourly bids for whole sale power. I can do this for the PJM. If power is being bid at 30MWe-hr, it is coming from coal. If power is greater than 50MWe-hr, it is coming from natural gas.

Of course, this is only one of the reasons PHEV are DOA. The people promoting them are clueless. You can testify to congress about short payback period all day long to promote tax deductions. However, not many would invest in equipment with a payback period longer than the life of the product to save the planet when there is no clear environmental benefit.


You might want to reread Jim's comment. Study the equations. They are fairly simple.

They explain why, even with the average coal power plant efficiency, a vehicle running on battery power emits less cO2 than one running on an ICE.

Of course what we are advocating is a total solution, electric vehicles powered by renewable energy, producing zero CO2. This battery pack is a 40 mile between charging step in that direction.

Without this step, oily iCE powered transportation as usual continues. ICEs that cannot be powered by renewable power. Even on coal power these vehicles reduce cO2 and reliance on oil wars.

These are simple arguments and explanations. If you can't get them, either you aren't trying or you are lying. I see no cogent argument against them being offered.

Sophistry and obsfucation only, and very cranky at that. Maybe you should get away from your keyboard and take a walk. get some exersize. I bet things will look a bit brighter that way. Hehey.

Trolling in the dark is not a healthy or happy lifestyle.



No offense, but what the heck is your point? "No clear environmental benefit"? Did you even read the original post or any of the comments? Have you thought about the implications of average commute distance, "smart grid" technology, or grid efficiency? And, what difference do the hourly bids for wholesale power make? What matters is what the end user pays to charge the vehicle, and it is much cheaper than what you would pay for gas. I trade electricity in the PNW and I can tell you that hydro is more than just a springtime resource, it is year round. There are constraints and negative environmental impacts, but there is no denying that it is CO2 free. I'm sorry, but judging by your post you just seem willfully obtuse.

Nick G

Ron, please note that the name of the poster is at the bottom of the post, not the top.

Bill Hannahan

Improvements in battery technology will shrink the spread between peak and off-peak electricity pricing. Peak prices will fall but increasing use of electricity will drive the average and nighttime prices up because the cheep sources, coal, hydro and nuclear, will provide a smaller fraction of the total.

The supply of electricity is fairly stiff, like the supply of refining capacity in the U.S.. A moderate increase in demand could result in a large overall price increase for electricity. If you want electric cars that are environmentally clean and affordable to drive we should be building more nuclear plants as fast as possible.

Jim’s calculations are somewhat incomplete.

ICE,0.20 x trans loss, 0.9 = 0.18
Coal Power plant = 0.35 x trans loss, 0.9 = 0.315

0.315 x charger efficiency, 0.95, x battery efficiency, 0.85, x power controller efficiency, 0.9, x motor efficiency, 0.92, x gearbox efficiency, 0.9 = 0.19

This may be optimistic. Round trip loss in flow batteries is 30% and the transportation application is very harsh since most energy is transferred at high rates during acceleration and deceleration.

Kit P

Ron, could I get you to go back and look at what I wrote without filtering it through your agenda.

What I said was that ghg of an EV could be between 0% and 150% of an ICE. Again, there is no clear environmental benefit. This is a simply declarative sentence stating a fact. It is incumbent on those making claims about environmental and economic benefit to back them up.


Bill - "ICE,0.20 x trans loss, 0.9 = 0.18
Coal Power plant = 0.35 x trans loss, 0.9 = 0.315

0.315 x charger efficiency, 0.95, x battery efficiency, 0.85, x power controller efficiency, 0.9, x motor efficiency, 0.92, x gearbox efficiency, 0.9 = 0.19"

While Jim's calculations may be optimistic the Tesla calculations are from real world applications. I extended them a bit to incorporate coal:

Example Car Fuel CO2 content Efficiency CO2 Emissions
Tesla Roadster Natural Gas 52.8 g/MJ 1.15 km/MJ 46.1 g/km
Tesla Roadster Coal (Black) 91.0 g/MJ 0.68 km/MJ 133.8 g/km
Tesla Roadster Coal (Lignite) 101.0 g/MJ 0.68 km/MJ 148.5 g/km
VW Jetta Diesel Crude Oil 73.0 g/MJ 0.48 km/MJ 152.7 g/km
Honda Jazz Crude Oil 73.0 g/MJ 0.41 km/MJ 178.0 g/km
Toyota Camry Crude Oil 73.0 g/MJ 0.28 km/MJ 261.7 g/km

Coal Figures from http://www.acfonline.org.au/uploads/res_climate_brown_coal.pdfhttp://www.maf.govt.nz/mafnet/rural-nz/sustainable-resource-use/climate/greenhouse-gas-energy-use/greenhouse-technical-paper-03-03.pdf
Coal efficiency is estimated to be 36% - efficiency of Tesla on coal is therefore 36% x 92% x 97.5% x 97.5% = 31.5%.

I am sorry the table is a bit unreadable however the representative car the Toyota Camry which is a pretty efficient car gets .28KM/MJ where the Tesla even on Lignite (Brown Coal) gets .68KM/MJ and emits half the emissions (148.5 g/km V 261.7 g/km).

I am sure that a large SUV would be much worse than a Camry. The main point is that an electric car on brown coal is twice as good as a IC car.


Kit P, where are your actual numbers? I see nothing comparing ICE to Electric. You can't make a measurement between a "coal powered" electric car and an ICE car without some efficiency numbers of your own. You don't even bother to actually say 0% to 150% until someone calls you on it. Assuming you do have numbers, and are not just making something up. Your filter seems to need a change, as it is clearly clogged. Saying something is a fact doesn't make it so.

Kit P

mjtimber, of course I do not have any real world data. But then no one else does either. It is interesting that you have the expectation that I provide numbers for something that does not work but you are will to accept BS from a CEO. David Vieau lied to congress. If 'the payback period for a fleet owner with $3.00/gallon gas is 2.5 years' was true, then he would be too busy to testify.


I ran some of this math myself.
But I converted it to kgCO2/KWh

PG&E puts their natural gas at 0.19 kgCO2/KWh

Which lines up perfectly with Tesla's carbon emmisions quote for natural gas.

Coal, you tend to see a range of values

From as low as 0.3 kgCO2/KWh, to as high as 1.1 kgCO2/KWh

At worst, I pegged it at around "a car with half the mileage of a Prius"

Which is yes, right around the mileage of a Camry.


That said, not all of our grid is the "dirtiest coal possible"

Whats more, not all of our grid is even coal.

Kit P

GreyFlcn, it looks life you have not taken into account the conversion factors (heat rate) for converting thermal energy to electrical energy.


so this is for all hybrids? What about the civic hybrid?


Can we please drop this stuff about charging an EV from Coal fired power stations?

Even in Australia I can buy 100% Green electricity (sun, wind, biomass or hydro)from my electricity utility. I assume the same would be true for the US? Else why not?

Alternatively I can even use PV panels on my roof to generate the electricity.

If I'm environmentally conscious enough to pay the premium for an EV, then I'll probably also want to fuel it with 100% clean electrity.

kit p

No, Chris, you are not environmentally conscious; you are environmentally deluded. I understand why you would not want me to point this out.

For example, two cities claim their PUD electricity is 100% ghg free. These cities used to own an 1100 MWe coal plant but sold it when faced with the cost of installing pollution equipment. However, nothing changed other than the ownership of the coal plant.

Greenenergy is a marketing scam. I am in favor of RPS that encourage the construction of renewable energy projects. This way we can learn about the economics and environmental impact.

All we have learned so far is that renewable energy is not a very good way to make electricity and has significant environmental impact.


Kit p,
Me thinks you are the one suffering delusions. I am in Australia also, and it's quite clear that the green energy market works. Not only that, people like Chris, are willing and quite happy to pay a small premium for green energy. By making such a blanket statement that it is a scam is testament to your 'head in the sand' ignorance. Do you have any idea about RECS, and the way green energy and 'black' energy are used to ensure that those able and willing to buy green energy actually get what they pay for?

I find your ignorant,inflammatory, attitude tedious. You put the last nail in your own coffin with this comment "renewable energy is not a very good way to make electricity and has significant environmental impact." That is possibly the dumbest thing I've ever heard. Yes it has a "significant environmental impact", but not in the negative way you infer!!

Chris mentioned PV as a source of energy. Did you know that it only takes 2-5 years for a solar panel to generate more energy than what it required to manufacture it? Are you aware of the advancements in PV? Sliver Cells? Bio Fuels?

You should take your dogged plebian ignorance elsewhere.

Kit P

Well Scotty, a lot of name calling and not very much substance. I would be happy to hear how the green energy market works in Australia to promote new generation of electricity with renewable energy. In the US, it is a scam for the most part.

I am in favor of renewable energy portfolio standards (RPS) and production tax credits because they work to promote renewable energy.

It is always fun with mane callers only demonstrate they are guilty of what the accuse of others of doing. Scotty wrote:

“Yes it has a "significant environmental impact", but not in the negative way you infer!!

Chris mentioned PV as a source of energy. Did you know that it only takes 2-5 years for a solar panel to generate more energy than what it required to manufacture it?”

Oh gosh, they way some of you talk windmills and solar panels are made with a magic wand. I wonder if their could be other environmental impacts involved when they are manufactured?

Many who claim to be 'environmental conscious' about making electricity and the process to minimize environmental impact.

Tours of the Vatican

I love that the lithium ion battery technology is now in computers and how that has changed the battery life for our computers... I can't wait to see what they come out with next.

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Batteries/Hybrid Vehicles