But, isn't the lifetime of the battery pack significantly lower than the (presumed) lifetime of the actual car? If your Model S stays on the road 20 years but requires 3-4 battery replacements, that's several big hits against its environmental friendliness.
The lifetime of the battery will likely be much longer than it's life in the car - if the plans for 'second life' re-use as static energy storage devices come to pass.
The lifetimes of battery packs have been greatly underestimated by detractors for quite some time. Hybrids have been on the US market since 1999, and battery life has never been a serious issue. The new batteries are far higher quality than the old ones anyway.
3-4 battery replacements over 20 years isn't anything close to what a Model S will require. Do you have a source for those figures?
