### High voltage

So let’s see if I’ve got this right…

GM claims 230 MPG for its Volt plug-in hybrid, coming in 2010.

Of course that number is fairly meaningless. If you never drive more than 40 miles before a recharge, you won’t burn any gas at all. On long highway trips I’ve seen estimates of about 60 MPG.

Suppose you don’t go more than 40 miles. Ever. Then you save a bundle, right? Of course there’s the cost of electricity, but that’s estimated at \$0.40 a day.

But there’s also the cost of the car. The Volt is expected to have a sticker price of about \$40,000.

A 2010 Prius, depending on configuration and options, costs about \$25,000. It’s rated at 51 MPG city, though in our driving we probably average something closer to 40. Drive a Prius at 40 MPG for 150,000 miles and you burn 3,750 gallons of gas.

Let’s assume the price of gas during the lifetime of a car purchased in 2010 will average \$4 a gallon. Then you spend \$15,000 on gas to run your Prius. Add that to the purchase price and you get \$40,000. The same as the cost of the Volt.

Except — that assumes a rather low MPG for the Prius. Part of the reason we don’t get higher is we live in an area with cold winters. Summertime average is higher. (And we probably average more than 40, I just rounded down.) It also assumes you spend \$25,000 on the Prius: if you buy the entry level Prius it’s \$21,750. It also assumes gas averages \$4 — which could be optimistic or pessimistic, who knows? And it assumes you never burn a gallon of gas in the Volt. If you do — if you get the mythical 230 MPG — then in 150K miles you spend \$2600 on gas.

(There are operating costs besides gas, of course, and there’s resale value to consider; I’m assuming for the moment these are comparable.)

YMMV, as they say, but I don’t think there’s an economic case to be made for the Volt. Yet. It won’t be on the market until late 2010, though — and if gas is \$5/gal by then and heading up, I’ll need to revise this post.