Wednesday, June 22, 2011

Comparing Costs

How much does a car cost? The purchase price is just the beginning. Most of us stop there in our comparisons. A car is only useful when it carries us for miles and those miles require energy. Of course, that costs more money. How much?

Our Suburu Forester has 98,000 miles and gets 24 MPG. It has used… 98,000 / 24 = 4,083 gallons of gas. We'll simplify the price of gas, even though it changes. In the past, gas has cost less; in the future, it will cost more. For planning purposes, let's just split the difference and use today's prices. We're lazy and the answer is good enough. You get more MPG (more value) with higher octane gas, but we'll assume Regular since most of us are short-sighted cheapskates. :-D

Today's gas is $3.65 / gallon. Using that, the Suburu has consumed 4,083 gallons * $3.65 / gallon = $14,903 in gasoline. For comparing to electric cars, oil changes cost 98,000 miles / 3,000 miles per change * $50 per change = $1,633 for oil changes so far.

The total so far for gas and oil is $16,536. How much will you spend?

Electricity has a price, too. Most of us don't have a sense yet of what is a good deal in terms of KWH / mile. Still, it is typically a fraction of the price compared to operating a regular gas car.

The purchase price of an electric car is higher. With the tax break though, it turns out to be competitive. As gas prices creep up next year, it becomes an even better deal.

Serious Recycling

We were going to wait until the project was complete to post all this. But it should be interesting along the way, so here we go.

Susan and I picked up a donor car last weekend for conversion to electric. It has lots of miles and too few oil changes. It's 14 years old, a 1997 BMW Z3 Roadster.

The engine will be removed soon, along with the exhaust system and gas tank. We're hoping to sell the engine.

The plan is to add a WarP 9 electric motor, a Soliton 1 speed controller, a bunch of lithium batteries and a variety of smaller hardware.

The range should be 100 miles, enough for my daily commute to Tyson's Corner and back. That's twice the range of a Nissan Leaf. The office landlord is installing charging stations, too. All the better.

The performance may be on par with the original engine, maybe even better. Here's the first photo: