This comment applies to the Fisker, the Tesla, or any plug-in, whether by conversion or production by Detroit.
Switching from gasoline to electric methods of propelling cars has a benefit of reducing USA dependence on foreign oil. Emissions are quite another matter. First, the "Zero emission" claim is offensive. No person should be allowed to graduate from high school who believes this nonsense. It had some historical validity when the "zero" meant that there were no local emissions, but even then it just meant someone else got to deal with them, and maybe if diluted it was ok. But now that we know CO2 to be a problem, the "zero emission" claim is idiotic beyond belief.
As far as CO2 goes, the only possible redemption for electric cars is if they use a lot less energy. Tesla has a very low frontal area so it works ok in that regard. However, the high performance is not without cost. Sure they get some of their energy back with regenerative braking. (But try to find out what the battery charging and discharging efficiency is.) Correction, the original little Tesla had that low frontal area - - not so low with the big one. Fisker Karma is worse yet, having no redeeming efficiency in its vehicle form.
Now to address the never ending claims that somehow coal will not be the fuel source used to respond to additional load of each EV. Even if we in California switch to more natural gas, the effect of using that natural gas, under basic economic rules, would be to increase the market price of natural gas. The rest of the USA will have none of that, so they will buy less of that natural gas, and of course, they will buy and use more coal. Thus, the intended accomplishment in California is a myth.
The problem is that there is no real way to change this without greatly penalizing coal. That might happen with "cap and trade" or simpler taxation; if and when it does the marginal (response to incremental increase in use) fuel will shift to natural gas. Watch out for the price of natural gas under that scenario.
Now look at the NRDC-EPRI study (widely quoted as proof that plug-ins are great)at
IEEE Spectrum: Why Plug-Ins Will Make (Dollars and) Sense and look at comments for references, to see that for natural gas based electricity, there could be some reduction in CO2 emitted by making a Prius into a plug-in, but not a lot; but for coal which is the more probable source, the plug-in substantially degrades the production Prius and CO2 emissons increase.
Now think about a Hummer converted into a hybrid and then into a plug-in hybrid. (Yes that could happen. Look at what Andy Grove says at
McKinsey: What Matters: An electric plan for energy resilience ) Do you think converting the Hummer to a hybrid Hummer will be a big efficiency gain? There will be some gain, but I can assure you it will not begin to perform like the Prius. Now make that Hummer hybrid into a plug-in and see what will happen. By comparison with the Prius plug-in we should expect the plug-in Hummer to be worse than the hybrid Hummer for coal based electric power; probably the CO2 will be worse than the original gasoline guzzler Hummer. For natural gas based electric power some time in the future there will be a slight gain in CO2 as a result of making conventional cars into plug-ins.
If you think I am being silly about the Hummer, check out how GM planned to proceed about a year ago.
http://fastlane.gmblogs.com/PDF/presentation-sm.pdf Watch for the bait and switch when they pretend to be developing fuel efficient vehicles in response to government demands.
And wait to see how the games start when we get to CAFE mileage standards. We already have our national laboratory, Argonne, willing to fake the calculation of electric "miles per gallon equivalent" by pretending the heat needed to produce electricity is the same as the heat that can be produced with that electricity. Maybe someone with this level of idiocy could be allowed to pass out of high school, but they certainly should not have passed freshman physics in college. And Argonne and even SAE fails on this. The published SAE standard on equivalent mileage of electric vehicles carries forward this error as well.
To see apparent bias in promoting plug-ins by Argonne, see
Miastrada Motors - References for the Argonne paper on testing the Hymotion Prius where they accidentally let out that the production Prius engine efficiency for UDDS cycle driving is 38% but the plug-in mod degrades it down to 33%.
In the end we will have continued production of large, inefficient vehicles, and a public believing that something significant was accomplished. For global warming mitigation, that will be a disaster because it will be the ruination of any future efforts that could have real merit.