What's the environmental footprint of that electric vehicle, in sum total, as Art's link discusses with respect to the Toyota Prius vs. Hummer? I'm talking about the electrical generating plant on the other end of that EV's battery charger, is it coal, natural gas, bunker crude, nuclear, geothermal, wind turbine, or solar photovoltaic?
First, I'm mostly an advocate of 'one or the other'. IE you switch to full-electric or switch to bio-diesel/ethanol. This is mostly to reduce reliance on oil. If you choose the electric option and need the extra range occasionally, that's time to rent a hydrocarbon fueled vehicle. Either that or there's an intriguing idea involving what's essentially a lawnmower-powered generator in a trailor. The idea's simple: You hook up a trailer with a hydrocarbon generator in the back. Along with the hitch you look up some power and control leads. The generator churns along, producing just enough power to keep you at highway speeds, or maybe even a little lower. After all, you should have a hundred miles or so in your batteries. Oversize the trailor a bit to give you more storage space for the trip. Heck, I've even heard of one that uses a sort of one-gear automatic transmission that acts as a 'pusher'. When you hit the brakes, regenerative braking puts the power from the pusher into the batteries. At a lower speed the pusher shuts off.
As the very length of power sources you posted point out, it's a very complex issue. Even battery replacement gets complicated, as a hybrid or EV battery is almost certainly going to be recycled, which limits it's enviromental impact. Then there's battery chemistry to consider; the big three are lead-acid; NiMH, and LiIon. They're listed in order of increasing cost and density, though there are projections that have the LiIon eventually being cheaper than NiMH, as Lithium is a more common metal than Nickel. As for power sources, well, partially due to the decreased overall power requirements for an electric vehicle because of the increased efficiency and the greater efficiency of a modern* power plant at controlling pollution, an EV is, at least in operation, less polluting than an average car. This will get better if we ever stop building coal plants(if oil keeps getting more expensive, the few oil plants in the USA will shut down), in favor of nuclear/wind/solar.
Please also note that I posted conditionals where the vehicles are being used in areas that are especially pollution sensitive; Lots of vehicles and people in small areas like a city. While nickel production at the one plant may be a disaster; that does not mean that it HAS to be a disaster. It's kinda like why many warehouses have electric forklifts. It's not because they're more economical or enviromentally clean overall; it's because the fumes from a hydrocarbon motor is more hazardous there in the warehouse than the extra waste elsewhere.
Oh, and I may be getting the threads confused, but I've been reading about people talking about the evolution of electric/hybrids to be even more efficient. I have to point out that while hybrid cars may indeed be a fairly new idea, all the technologies used in them are VERY mature. Electric motors-out for at least the last hundred years, and used in industry ranging from microscopic to 'crush puny semi into pancake' huge. The size range needed for an electric car is a known science. Batteries are the same story, NiMH has been out since the 1980's, LiIon went commercial in 1991. There is still development going on, but that's gradual, not breakthrough stuff.
*Yes, I know many power plants can't be considered modern.
