Let's be fair on the high-mileage EVs

[Jim Bullis]

Yah you do need the program because it is not about 3/7. Ernie's programs will include the efficiency of making electricity in some form or other.

[Ernie Rogers]

Originally Posted by Jim Bullis

Yah you do need the program because it is not about 3/7. Ernie's programs will include the efficiency of making electricity in some form or other.

Sorry, Jim,

The program as it is now just requires an input number for efficiency--one number for the engine and a separate one for the electric system.

But a nice thing about using a computer program is that you can make the calculation as complicated as you want and the program does the work. For example, I have a specialized fuel economy program for by VW that includes an engine model. It calculates the engine efficiency as a function of power and RPM, using a fit to experimental data. With this program, I can evaluate the impact of changing the gear ratio in 5th gear. (The possible improvement this way is huge, since the engine develops plenty of torque and hits peak efficiency when slowed down to about 1700 RPM.)

Ernie Rogers

[Concrete]

Originally Posted by RobertSmalls

....So, are you worried about running out of sources of energy, or global warming, or money in your pocket? I don't think it's Ecomodder's place to take up a position on that, so EM shouldn't compare KWh to gal, except to say it's between 15 and 34 KWh/gal.

snip

...I come across as anti-EV at times, and I believe the lifecycle GHG benefits aren't there, but both of those things will change at such a time as the grid shifts to a greener mix and battery technology improves.

Exactly

too many world views to make an acceptable comparison between EVs and gassers.

Theoretically EVs have a big leg up on efficiency & emissions
but they still lose badly in the real world

Long live Aptera - but EZ-GO is the only viable EV maker I know
and even there the gassers are squeezing the EV golf carts out!

we are missing something in the life cycle that cripples the EV cost/benefit equation
I was hoping to learn a bit of that in this thread
- but I learned a lot of other good stuff instead

[Jim Bullis]

What happened to the Ernie Rogers that argued for a 40% adjustment for the efficiency of the power plant that made the electricity?

That does not fall in the category of a complication; it is a huge difference that puts some degree of realism into the comparisons.

[dcb]

Originally Posted by Concrete

we are missing something in the life cycle that cripples the EV cost/benefit equation

Honestly I don't see that. Cost per mile the EV's wipe the floor with gas in the real world, by a factor of 2.8 by my reconing. It hasn't been accepted largely because gas is the incumbent. Lots of political machinery and pre-conceptions to keep gas in office, and there's no shortage of people who invest in oil stocks as well (whos judgement IS swayed).

Have you ever tried having a rational discussion with someone who has an addiction? It's kinda like that too.

I mean even Diesel gets basically shut out by gas in the US for consumer vehicles, even though the engines are more efficient.

[Jim Bullis]

Cost is perfectly valid as a basis of comparison, but electricity varies from 5 cents to 40 cents depending on where you are. Some states offer special night rates, some don't.

All of this depends a lot on government involvement, including the public utility regulators of each state. Throw in federal energy policy and the whole thing gets a bit uncertain.

[dcb]

If we are just looking at consumer cost, I listed my sources for the 2.8 factor based on averages for 2007:
http://ecomodder.com/forum/showthrea...tml#post101182


But I made a mistake in the cost comparison (just went btu to btu). If you put 10 gallons in a car, that is indeed enough energy in terms of BTU equivalent to send a Tesla (for example) 3300 miles. So cost per mile has to be factored in to the 2.8 energy to energy cost, because I guarantee the average car on the road didn't get 1180 miles out of 10 gallons of gas.

Lets say in the us the average passenger vehicle on the road in 2007 got 25mpg (generous), and can go 250 miles for 10 gallons worth of gas, that means that the EVs in 2007 were getting 13.2 TIMES as many miles per dollar!!.

So if we want to be "fair" on a cost basis you would have to multiply ev costs per mile by 13.2 (based on 2007 figures, probably worse in 2008) to compare them to gasoline costs per mile. And thats just consumer costs, not taxes repurposed for subsudies or military spending or nothin.

note: I do not have any stats on average watts/mile in 2007 handy, this is just based on a tesla, and a very rough guess about average mpg in 2007.

[Ernie Rogers]

Hello, Coyote,

I loved your comment at the end about free electricity. Good job!

You asked about conversions between other fuels (other than electricity) and gasoline. I can't remember if I have posted this already, so I will do it again. Here are the fuel conversions for energy content and also the WTW greenhouse gas produced for each kind of fuel. /Ernie

UPDATED CO2 CALCULATION TABLE (6-06-08)

Gasoline...........11,800 gm CO2e /gallon gasoline
….Energy content: 116,090 BTU /gallon, or 34 kWh per gallon

Diesel #2..........12,700 gm CO2e /gallon diesel
....Energy equivalent: 0.90 gal = 1 gal gasoline

Corn ethanol.......6,135 gm CO2e /gallon ethanol (from Wang)
....Energy equivalent: 1.52 gal = 1 gal gasoline

Electricity.............777 gm CO2e /kWh (U.S. power plant mix)
...or..................26,400 gm CO2e /gallon gasoline equivalent
....Energy equivalent: 34 kWh = 1 gal gasoline

Compressed NG...111.1 gm CO2e /SCF
....Energy equivalent: 118 SCF = 1 gal gasoline

H2 gas................34.2 gm CO2e /SCF
....Energy equivalent: 400 SCF = 1 gal gasoline

Biodiesel...........5940 gm CO2e /gallon biodiesel
....Energy equivalent: 1 gal = 1 gallon gasoline

CO2e refers to equivalent CO2 effect of all greenhouse gases combined, "Well-To-Wheels." All of these numbers come from Wang, Argonne National Laboratory, via a spreadsheet at WELCOME | Progressive Automotive X PRIZE

Originally Posted by Coyote X

Just to be annoying to everyone, what about other sources of making a car go?

natural gas, propane, diesel, etc? The energy output/creation cost of diesel is different than gasoline so should there be a conversion for a gallon of gas to a gallon of diesel? The other two are gasses so a gallon by volume doesn't mean much without pressure and temperature. Also the same issues as electric are present with the gasses in how you compare to gasoline.

None of them are similar so to get a comparison to compare one to the other is not easy. There are so many ways to measure them. Well to tires natural gas locally here would win since it is just coming straight out of the ground and ran to the houses and a small pump that doesn't take that much power to build pressure slowly and refill the tank. So there is no transmission loss of any sort on natural gas here it would be just the bit of power used for the pump and the engine efficiency.

Pretty much any measurement is going to be arbitrary and can be argued either way so I just say admit it is an arbitrary decision and just explain it as best as possible. I would rather have the top 10 split up into categories just for the people who want to see how good they are doing in relation to similar vehicles(be good for categories and searches). But an overall top 10 is always going be biased and give an advantage to one type of car over the others. I would also say double the pollution output of the coal plant. You guys have no idea how much pollution the mines generate to mine coal. Imagine 50 large rock truck tires dumped in a hole and burned. That is typical for tire disposal

For my car I am not sure if I am even going to bother with measuring electric usage regularly. My electric bill is always the minimum amount and charging the car isn't going to change it so to me it is basically free

[Ernie Rogers]

Originally Posted by dcb

<SNIP>
If you put 10 gallons in a car, that is indeed enough energy in terms of BTU equivalent to send a Tesla (for example) 3300 miles.

Well, DCB, I thought to divide these numbers for the Tesla---

(10 gallons x 34,000 watt-hrs /gal) / 3300 miles = 103 watt-hrs /mile.

Hmmm, do you think maybe they were coasting downhill?

Ernie Rogers

[dcb]

Don't know if the tesla "coasts" because it is direct drive, the armature is always turning if the car is moving (doesn't engine brake like a gasser) but it does regenerate. According to their site it has a range of 220 miles "based on EPA combined city/highway cycle", and I took the 220 into account.

Of course 25mpg is a swag too, here's a list of cars with similiar 0-60 performance specs to the tesla, wonder what their average mpg is?

• McLaren F1
• Lamborghini Murcielago
• Porsche 911 GT2
• Corvette Z06
• Viper SRT
• Mercedes SLR

Course this is for cost per mile comparisons measured at the pump/wall too.