I agree with many of your comments, but here too there are "a few inaccuracies that I feel obligated to clear up."

What matters is the grid average...

Not so. As the EPRI report says, "Marginal GHG intensity of the PHEV charging load can vary significantly from average GHG intensity." I don't  know what each utility will crank-up to charge PHEVs, but it won't be the grid average.

1. The average car today produces about 12,000 pounds CO2 and moves about 12,000 miles annually.
2. A Prius produces about 6000 pounds CO2 annually if driven the same miles.

The EPRI report shows per-mile CO2 emissions for a "conventional vehicle" as about 50% higher than an HEV.

If that were so the bars on the following chart would all be the same length...

Not so. Utilities choose when to use their hydro capacity, but the total energy is limited by the water behind the dam, and that's not easily increased.

The report says that every plug-in hybrid that hits the road from today on will produce far fewer greenhouse gases even with today's mix of power generation.

Not so. It says that every scenario shows cumulative GHG reductions over the period 2010-2050. As for today (or rather 2010, from Fig. 5.1 in the report), a PHEV is certainly better than a conventional car, but may or may not be better than a HEV depending on what is used to charge it.

  From the latest data I have (2005), the U.S.
utility grid consists of 49% of coal power electricity - here I'm referring to the actual amount of power produced (kilowatthours), not
caapcity (kilowatts). Nuclear and hydroelectric are the only significant producers of carbon-free power at 20% and 7% respectively. Most renewable generation produces loads of carbon - biomass, etc. Wind and solar photovoltaic produce negligible amounts of power (less than 1% combined). The only sources of new and plentiful carbon-free power will come from nuclear (32 new
plants producing about 8% of our power, replacing coal plants almost exclusively as base load generators) and solar thermal. Solar thermal has the capacity to produce dispatchable power (unlike wind and solar photovoltaic and most wave
technologies) and at a much cheaper cost, and in very large amounts, without despoiling the environment and making vast tracts of land unusable, as wind does. In several years look for solar thermal to cost 1/4 the price of photovoltaic and 1/2 the price of wind and be totally controllable and predictable.  Wind and photovoltaic (and most wave technolgies) are
basically living on borrowed time and cannot
possibly compete either economically or environmentally or in terms of quality.  

Alan says any new electrical demand will be met with coal power.  And plugins are a new demand.

Let's all go out and rent gas guzzlers, that'll solve the problem.

We all know wind, solar, wave power and other renewables will never be more than 1% of grid power, because they aren't now.  That's why we are all still driving buggies (whoops?!), cars provided less than 1% of transportation in the 1890s and therefore the same condition exists right now (whoops).

Once carbon taxes and carbon trading kick in, nuclear powered fuel refining (of tar sands, coal, and biomass)will provide plenty of gas for gas guzzling for centuries!  only the rich will be able to afford to rent gas guzzlers, but for the rest there will be nuclear powered trains and buses.

Give it up, even though Alan couldn't reboot the computer in the plugin, he has beaten plugin hybrid advocates.  I'm going out to rent a hummer today, in order to save the planet!  Thanks again Alan.

http://amazngdrx.blogharbor.com/blog

Logic would indicate that most plug in hybrids will be recharged at home, at night. I've seen the suggestions that at work parking chargers will be a big deal, but I doubt that most parking lots will add that cost.

This would suggest that recharging will rely mostly on base load type generation that is surplus capacity at night. This seems to translate directly into coal and nuclear capacity and argues against intermittant renewables (solar and wind) as the primary source.

I think this question of what's on the margin is really important and would like to see more discussion of this.

On a given day would increased demand translate to dirtier or cleaner energy use?  Could plug-in owners be required to have time-of-use metering to encourage them to charge off peak?

Generally coal is not on the margin (plants produces at fairly fixed capacity and can't easily be ramped up and down), but sources like natural gas are and can quickly be turned off and on.

Whether a shift from oil to electricity would get new plants built is a question.  If plug-ins are charged off-peak, I can't see how power plants which are used to very high daily loads would be stressed by moderate increases at night.  You might just fire up some gas plants that would otherwise be idle.  Wind also tends to run at night and can't be ramped up and down like gas, so I'd think you'd see wind/coal/nukes powering plug-ins.  

Does that seem right?

=Could plug-in owners be required to have time-of-use metering to encourage them to charge off peak?=

Maybe.
Or maybe they could be required to use it in order to get some sort of a sweet deal.

For instance a contract with the local utility.

Make sure that it is automated.

Kind of like a Tivo.

Even if plug-ins were all charged with 100% green sources (say 20 cents per kwh) then the gasoline-equivalent cost would be about $2.00 per gallon.  NOT AN ISSUE.

What is an issue is the cost of batteries for PHEVs.  They are still very high, and dominate the cost-of-use of the vehicle, not the electricity it uses.  Since a PHEV can spend 90% of its existence plugged into an outlet, they are the perfect sheddable load needed when RPS begin to take effect in many states.

Even if PHEVs are charged from existing sources, since they can be charged at night (when demand is low) then no additional capacity is needed at all for a population of up to 20 million vehicles or more.

Build plugin hybrids that run on renewable methane. That's all that's needed.

Jim, I've got to ask what you have in mind. I get this vision of millions of cows hooked up to piping systems.

More seriously, SCE's energy mix is only "cleaner" because of California's huge reliance on natural gas. Moving the national grid in this direction would entail huge importation of LNG from the middle east. Unless we see a huge increase in deep well geothermal, the SCE renewables are of little use in supporting a PHEV network.