The chart is really interesting, but I would like to know the assumptions that went into it, specifically about length of trip.  Obviously, some assumption was made about "average" length of trip, because there is a bar segment for both electric and gasoline emissions.  Whereas in reality, for a short trip, you may not use any gasoline at all.

I think that before we can conclude that plugin hybrids are really worse for the climate, we need to look at the assumptions behind the calculations, particularly as they relate to how the car is actually used.

I'll post some numbers. Cause the idea that plug-in hybrids are worse for the environment than regular hybrids is wrong. It is based on the fact the coal has higher greenhouse emissions per BTU than oil but. But what it overlooks is that fossil fuels are converted to electricity in an electric power plant with much higher efficiency than they are converted to either electricity or mechanical motion in a car. (This is true for a number of reasons including the fact that a car engine has to be light.) So you produce electricity so much more efficiently in a power plant, even from coal, than you do in a gasoline engine that all the other losses in an electric car or plug-in hybrid  don't overwhelm the gain. Neither line losses or battery losses make up for the difference in generating efficiency.

Now it is also true that plug-in hybrids or electric cars run on coal may cut emissions, but not as much as we need to.  But nobody thinks we can reduce greenhouse emissions without cutting emissions from electricity generation in any case. And a plug-in hybrid cuts overall emissions a little now, while our grid is mostly fossil fuel, and a lot more if we switch our grid to renewables.

Thanks for those awesome links about ride-hopping and high-tech hitchiking. I've had similar thoughts but I didn't know how far along people were in getting it to work. Very illuminating stuff.

I also think that taxis can benefit from technology. Instead of renting a whole car, you rent a seat on a taxi shuttle. Airport, company, and mall shuttles already do this, but if you put sharable shuttles all over the city, and compute optimal routes in real-time (and you give people the option of having a "stop" along their route like with subways, for a cheaper price, so that routes are more sharable), you could cut down on car usage alot. These sorts of schemes work really well with congestion pricing or (why the heck not?) cap-and-drive (only 1000 cars are allowed to drive in the city center at one time, handled by computerized real-time auction pricing, etc.)

[R]eplacing gasoline and diesel vehicles with electric ones will eventually be a climate plus -- assuming the electric power system gets cleaner over time. But that's a big assumption. The only guarantee of clean plug-ins ... would be a firm, descending legal limit on greenhouse-gas emissions.

Just because it's not guaranteed, it's not worth pursuing?  The existence of "clean power" programs from local utilities shows clear consumer demand for renewable energy.  If customers ask for it, and agree to pay for it, it will be built.  Even coal power gets cleaner each decade, as better and cheaper scrubbing technology becomes available.  Even if it's not guaranteed, I think it's a pretty safe bet that the grid as a whole will get cleaner over time, just as it has been over the past few decades.

I agree it's important to consider the negatives, and to consider the idea that this may just be a fad or a pipe dream like hydrogen cells, but you seem to be straining a little to find something, anything to criticize.

-- A.

Taking accounting to the extreme since 2004.

According to my understanding, overnight charging during off-peak hours contributes a negligible amount to emissions.  In other words, power plants aren't shut down at night, they simply "spin down" to a lower output than peak.  Your theory that when you plug in your car someone at the coal plant says "Hey Vinnie, start stokin' her up, we got a big one!" is incorrect.  You wouldn't even be a blip on the electric grid radar, more on par with your neighbor turning on their electric dryer or firing up the hotplate for some late night griddle cakes.

MrLee wrote: Your theory that when you plug in your car someone at the coal plant says "Hey Vinnie, start stokin' her up, we got a big one!" is incorrect.

It is not incorrect and is in fact what occurs.

Make me up when they perfect magic, jabailo.

(Until then, we only have engineering ... the science of the possible.)

the more I realize there really is no such thing as a "good" car.

eddy out, redboat

Heh, I just looked at the chart, saw that the Plug-In Hybrid would be a net win on C02 for my power mix, and called it a day.  I skipped the text because that seemed to be the bottom line.

(I get 'power mix' tags from my electric company: 16% renewables, 11% large hydro, 17% nuke, 41% natural gas, 15% coal.)

Well that's a relief, all we need is a carbon tax (so politicians can waste the money with more study of and subsidies for  nuclear, clean coal, fuel farming, oil war, and so forth.

And a "free" market in carbon emissions so that hedge funds have another trading game to scam with insider trading.

Forget about new technology, like plugin hybrids, it will take care of itself.  Once tax policy and carbon traders eliminate GHG.  

Meanwhile we can all be carfree by renting an (6% efficient according to Amory Lovins)infernal combustion vehicle from flexcar.  Thanks Alan.

You have shown the way to eliminating the 26% of GHG emission that comes from transportation.  

Really there was no need to actually drive the plugin hybrid on batteries (how many times did you drive it before the computer needed a reboot?) or have someone test drive it who understood technology well enough to reboot it.

You knew all along that plugin hybrids are just another fad and they emit more GHG than a regular hybrid.  Good for you.  Thanks for helping Cheney and friends witrh their energy policy agenda!

When will you and your kids be signing up to go to iraq, iran, syria or whatever oil war is next?  

Thanks Alan.

http://amazngdrx.blogharbor.com/blog

I think you missed a big plus point with the carsharing model.

It reverses the thinking of the car driver. When you own a car, you have already made an investment into lots of things (insurance, car, parking permit) to name a few. It makes sense to drive it, you need to get that value our of it.

With carsharing, you drive less because it costs real money when you drive, not the other way around. You get creative.

Even better, the service I use, PhillyCarShare, uses the Prius for 1/2 of their fleet.