Re: Electric cars, cheap

For sure.

And that's the problem. What numbers are used. I think it's fair to use the thermal cost of energy delivered, which we've pretty much done so far, and ICE's use a refined product produced with fuel burning in a heat exchanger. We've already penalized electricity for line and charging losses, but haven't looked at gasoline/diesel transport and storage costs, which all require energy consumption. Thermal energy cost required for extraction and transport before the power plant or refinery can be added if you want, though I don't know where to find them. I'd guess natural gas wins, and coal comes in last. .

I just grabbed this when I was looking for numbers, thinking Forbes wouldn't draw argument as a source.

It was actually 2 years ago. No idea where their numbers came from. But I take EIA figures with a grain of salt too. This EIA report says coal was 42% in 2011. A 5% drop from 2011 to 2012 doesn't smell right. But this seems to support it. So I'll go with EIA figures. Looks like the best source. But not their predictions. I don't think energy sources can be predicted 27 years out, as they do.

Think it was about 8-9 cents a year ago. Then they opened the supplier market and I dropped Com Ed, though they still do the billing. Cut my monthly bill in half in an eye wink. Don't know all the details. Northern Illinois. Lots of nukes in Illinois. But gasoline price is highest in the country.

I live 15 miles outside Chicago, but still pay +$4. The Volt gets right near 4 miles per kwh with "normal" driving, which translates to 120 miles at average 11.88 kwh cost equal to a gallon of gas at average $3.63 Knock off 10% charging loss cost, so it's about

108 miles. I'd get about 290 miles for the price of a gallon of gas at my electricity/gas costs after the 10% charging loss. I'd guess the Leaf is similar in energy use, Owner reports seem to indicate the Volt is about 10% better in getting miles from kwh. The EA-Mobile-Volt might get me 400 miles on electricity cost equal to a gallon of gas.. But I do want a radio, lighted and mirrored vanity visor, back up camera, and maybe 6-7 cupholders in it. So I'll stop quibbling over a few points of thermal efficiency, concede to you on that score, and just leave it at that.

> It was actually 2 years ago. No idea where their numbers came from. > But I take EIA figures with a grain of salt too. > This EIA report says coal was 42% in 2011. > > A 5% drop from 2011 to 2012 doesn't smell right. > But this seems to support it. >

> So I'll go with EIA figures. Looks like the best source. > But not their predictions. I don't think energy sources can be > predicted 27 years out, as they do. >

> I live 15 miles outside Chicago, but still pay +$4. >

You're ignoring the costs of new power plants and upgrading the distribution system, which will raise the cost of electricity. Add in the interest on loans, and you could easily quadruple the cost of electricity in many areas.

My current rate is 7.047 cents per KWH for the first 1000 KWH plus

3.393 cents fuel charge for a total of 10.44 cents per KWH

Over 1000 KWH it's 8.282 = 4.393 for 12.675 cents per KWH.

I don't know. I suspect it's even lower for the diesel, because it's a stratified-charge engine, and s-c engines tend to run cooler at the cylinder walls.

The info is out there. The MIT books on engines almost certainly cover it, and at least the older editions may be online. I have the printed two-volume set but I'm not going looking. d8-)

Shoehorning real engines into the Carnot cycle can be tricky. Take a look at the efficiency formula for a diesel:

Under "Maximum thermal efficiency," note where compression ratio (r) comes in. It's in a denominator, but that's *subtracted* from 1.

Aha.

The heat content of the fuel doesn't come into play at all. That just influences the power output -- more power potential in, more power out. You get more power per gallon, but that has nothing to do directly with thermal efficiency.

The efficiency of a diesel comes primarily from two places. One is the higher compression ratio. The other is that it's always running at the nominal compression ratio, because you throttle only the fuel, not the air. A diesel doesn't have to run at stoichiometric air/fuel ratios. Don't ask me how it gets away with that; I knew 40 years ago, but those synapses have been cauterized by age and beer.

So its part-throttle operation is vastly more efficient than that of a spark-ignition engine, which is running at a very low, and very inefficient, effective compression ratio at anything short of full throttle. Overall, that boosts the total efficiency of a diesel by a lot. That's why trucks can sit and idle for hours at truck stups -- they're hardly burning any fuel. A spark-ignition engine would be slurping it up.

BTW, before you start putting diesels in your angstmobiles, consider the results of research from Argonne on various hybrids: A spark-ignition gasoline engine gets about a 10% efficiency boost from going hybrid. A diesel gets only 4%. Although Bosch and Citroen are fooling with them, there isn't much to gain there.

We actually have several conversations going on here at once: one on costs, another on thermal efficiency and net fuel consumption, and another on trends.

The cost issue varies so much by region that it's not very enlightening. Back in the mid-2000s, when gas ran over $4.00/gallon, one of the western states -- either Idaho or Utah -- had lots of natural gas and they weren't taxing it as motor fuel. It cost $1.70 per gas-gallon equivalent. So Honda was selling their CNG Civics out there like there was no tomorrow. It even made sense for some people to buy those $4,000 home NG compressors that Honda offered, for overnight fill-ups.

Likewise, we have regions where electricity is cheap now. But national averages make it a close call with gasoline.

As for thernal efficiencies, and system losses, it's also a very close call. There was talk about the lower emissions of generating plants for a while but cars are so much better now, and the fugitive NG losses seem to be going up, not down (freaking fracking), so that one looks like a wash, too. We won't even mention coal.

Whether to buy some kind of electric now seems to depend on one's individual situation. There aren't a lot of situations in which it provides a net economic advantage, but there are some.

I'm tending to agree with those who say that the N. Dakota oil fields and widespread gas fracking are game-changers. The economics now are going to depend a lot on whether the gummint allows the majors to export LNG. If they do, all of the benefits will go into their pockets. If they don't, it looks like we're about to enter a low-energy-cost regime, and a possible manufacturing resurgence, that will last for a century.

All bets are on the table. I won't get to see mine play out, probably, but I'm very optimistic.

Don't plan on keeping that rate for long:

Duke recently bought Progress energy, and that will raise the rates as well.

My head is about to explode. AND, PV = nRT let me down.... again!!! LOL

Good stuff, tho.

Yo're trying to figure out engines from a theoretical gas law. You really do like making it hard on yourself.

It's interesting -- to me, anyway. Or it used to be. It's getting so complicated now, with all the new engines that researchers are analyzing. They've been trying every combination of fuels you can think of, and stratified charge, homogeneous charge, compression ignition, spark ignition, and spark-assisted compression ignition.

Reading the SAE white papers will drive you nuts. I just hope they settle on something.

I tole you electric cars were intrinsically simpler.... :) :)

Actually, I think PV = nRT DOES apply, and pretty simply, AND interestingly. The T is basically a property of the combustion of fuel. OK.... The compression ratio then comes in, where when the gas explodes, the smaller the volume it explodes in, the *greater the value of the standard integral Work = S(PdV)*, which calcs out to a standard log function of pressure. or some shit, when you substitute the gas law back in for dV..

That's why hp output is not linear with CR, bec the work done is logarithmic in pressure..... !!!

BUT, when the CR is doubled, tripled, you really should see substantial work and efficiency improvements. And, of course, you do, at least in gas-gas comparisons.

So for a given displacement and a given mass of fuel, how much more power, efficiency will a diesel yield? Ballpark... IF you can even say "for a GIVEN displacement AND fuel mass"....

What makes this really inneresting is that this increase in efficiency seems NOT to be Carnot in nature (since the temps seem not to be different), but an integral PdV thingy.... perty neat, imo.

I tole you electric cars were inherently simpler.... LOL

Using the gas law, though, misses the heat transfer to cylinder wall, piston crown, and combustion chamber. Those heat transfers are neither isothermal nor adiabatic -- it isn't perfect heat transfer, and it isn't perfect insulation. So you get into a real mess of calculus if you try to cope with it from gas laws.

However, don't let me discourage you. If you ignore a lot of it, you

*do* get to your next paragraph by using gas laws, and that's an important point.

Right.

Don't try to do that from gas laws alone, because of all the heat-transfer/heat-loss problems I alluded to above.

You can go to that Wikipedia page I listed before:

...and take a look at the efficiency formula. This combines several heat transfer effects into single values that you can just plug in, and you'll see what's going on with a lot less head-scratching.

Also take a look at this, if you want the big picture on diesels:

Note that some stationary diesels are running with thermal efficiencies of over 50%. The record is over 54%. For comparison, the record for combined-cycle (gas turbine/steam turbine) powerplant engines is just over 61%. That's why electric cars have a serious competitor. Automotive diesels are running as high as 45% already, and are expected to go higher.

Higher compression means higher pre-combustion pressures and temperatures. But combustion temperatures are the product of several things; not just compression and heat content of the fuel.

Happy reading.

Oh, yeah? Tell us that when you start dealing with eddy currents and hysteresis, copper IR^2 losses and so on, throughout the rpm and torque range of one of those motors, when it's in regenerative-braking mode versus driving mode.

'Ain't so simple. And don't ask me, because I haven't a clue. d8-)

Google,,, CORE Outdoor Power CORE (Polson, Montana) Outdoor Power has developed a new electric motor technology that may someday benefit electric cars.

LOL

Don't forget about the Air Powered cars. Google,,, Peugeot Citroen Air Powered Car

BINGO!

I used to think that EV's were going to be the Saviors of the working man. Until I realized that I was trading one limited resource for another - Oil for electricity.

Nuke power is "The Bomb" when it comes to EV's. Not gonna happen on the Le ft Coast. And until it does - the Working Man will be "kicking against the pricks" for many decades to come.

Oh, and someone tell me how GM built the EV-1 in the 90's to run on 13 deep cycle lead-acid batteries, and got a virtual 200 miles on a charge (test t rack). Again - on an EV. Lead-Acid batteries. Not ultra-rare Lithium, no t Nickel-Metal Hydride. In the 90's. "Who Killed the Electric Car?".

. Until I realized that I was trading one limited resource for another - O il for electricity.

Left Coast. And until it does - the Working Man will be "kicking against t he pricks" for many decades to come.

ep cycle lead-acid batteries, and got a virtual 200 miles on a charge (test track). Again - on an EV. Lead-Acid batteries. Not ultra-rare Lithium, not Nickel-Metal Hydride. In the 90's. "Who Killed the Electric Car?".

Google,,, Stella Solar Car