SLATE - The quick answer: If current trends hold, it could be pretty darn green in the long run. But as of today, the calculation isn't as straightforward as you might think. Depending on whom you ask, what assumptions you make, and how you quantify environmental impact, the answer could range from "greener than a Prius" to "as dirty as an SUV." And where the Tesla falls on that spectrum depends to a surprising extent on where you live and how much you drive it.
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