Electric cars are not a new invention, nor are they as popular as they once were. (They debuted in 1890 and by 1900 electric cars accounted for around a third of all vehicles on the road.) But over the past decade, thanks to Elon Musk and Tesla Motors, electric cars have e much more interesting.

Tesla rolled out the first fully electric sports car in 2008 and a fully electric luxury sedan in 2012. And earlier this month they unveiled the Model 3, a premium sedan for $35,000.

The Model 3 won’t be produced until 2017 but it’s already something of a success. You can “reserve” a Model 3 for $1,000, and so far pany has over 325,000 reservations. As Tesla brags, this corresponds to about $14 billion in implied future sales, making this “the single biggest one-week launch of any product ever.”

I confess that if I had $35k I’d gladly trade in my 2004 Toyota Prius for a car that goes 0 To 60 MPH in under 4 seconds. But as a conservationist and a conservative the idea of driving a car powered by coal and subsidized by the government gives me pause.

What’s that? You didn’t realize electric cars were powered by coal? That’s not surprising since you won’t find it mentioned in Tesla’s brochures. But it’s true that they are “fueled” by electricity that is created by coal or other fossil fuels (at least mostly in some states, exclusively in others). And it’s also true the government will, in the name of protecting the environment, give you a tax break for buying a car that runs on coal.

Tesla’s electric cars are beautiful, but they aren’t necessarilybetterfor the environment. As environmental economist Bjorn Lomborg explains in this video, electric cars aren’t necessarily greener than conventional gasoline cars.