Tuesday Aug 18, 2009

Drive Your Car for Free!?

We need MPK - a new way to measure the energy effiency of cars.

For many years, we've used MPG (miles per gallon; apologies to the the parts of the world that use a sane measurement system...) to measure fuel efficiency of cars. But as the automotive industry converts from fossil fuels to electric cars, we will have confusion - until the government establishes a new method.

In the news last week, GM claimed that the Chevy Volt will get 230 MPG. That leads me to picture a conversation at a car dealer:

Car Salesperson: "...and the Volt gets 230 MPG!"
Customer: "Wow! It doesn't use much gas, does it?"
Sales: "That's right, it doesn't. And for the first 40 miles, it only uses the battery. Do you drive more than 40 miles most days?"
Customer: "No, just 20 miles to work and back. So usually I won't use any gas?"
Sales: "That's right."
Customer: "So... basically I drive it for free?"
(The salesperson knows that's not entirely true, and doesn't want to lie to the customer, so he just smiles.)
Customer: "And if I drive it more than 40 miles, I'll be getting 230 MPG... that's ten times better than the car I drive now! It will cost less than one-tenth what I pay now!"

Of course the problem is that electricity isn't free, and the rules allow a car company to publish a number which has little bearing on real life. As the article mentions, the Volt's battery must be recharged regularly. The GM CEO said that should cost "about 40 cents at off-peak electricity rates in Detroit." GM is not lying to the public, nor are they pretending that the only expense of operation is the cost of gasoline. Evidently the number 230 was derived by following the rules.

Unfortunately, most of us don't live in Detroit. For the USA, the average residential rate is 11.6 cents per kilowatt-hour (kWh), according to the Energy Information Administration.

What does it really cost to drive the Volt? According to the article, GM says it estimates 10 kWh to charge the Volt. That means For the first 40 miles per day, it costs $1.16. The article also says the Volt "might get as much as 50 mpg" when running on the gasoline engine. That's much better than almost every other car on the road, but not 230 MPG. If you drive 80 miles in a day, you will use a full battery charge plus at least 0.8 gallons. Together, that will cost:

  • $1.16 for the first 40 miles
  • $2.00 for the next 40 miles (average gas price of $2.50 from www.eia.doe.gov)

Total: at least $3.16.

My car gets about 26 MPG. Driving 80 miles costs me $7.69 - more than double. (The quoted "as much as 50 MPG" means I pay less than double, but we don't really know how much more I pay than I would with a Volt.) Most of us would save money by driving the Volt.

The most important benefit of the Volt is reducing fossil fuel emissions. (I won't get into the fossil fuel emissions at the electric generation plant, 50% of which comes from burning coal...) But the misperception that the Volt - at 230 MPG - is ten times less costly than your car may become widespread, unless GM is required to report energy efficiency in some other way.

Don't get me wrong: I am happy that GM has developed the Volt, and I know that they didn't just make up the number 230. We do need to pay more attention to gas mileage and fossil fuel emissions. I hope that the Volt is successful.

And I hope that soon there will be other electric cars. But how will we compare their energy efficiency? A competing car company may state that their electric car is more efficient than the Volt. How will we know?

For electric cars, we need a new metric: miles per kilowatt-hour (MPK). That will allow us to compare the cost of driving two different electric cars.

And for mixed-energy cars (like the Volt) we will need to compare the efficiency of the gas engine (MPG), and the electric engine (MPK), and we need to know how far the car will go on its electric engine. The last one could be MPC: miles per charge. Without all of those numbers, we can't compare the costs of driving two different cars.

Sound complicated? You bet, especially when you include the need for highway vs. city driving. But until we have more information, as consumers, we'll be confused, perhaps misled, by claims like "230 MPG."

Saturday Aug 30, 2008

Mad Cows, Lame Ducks

I rarely blog about politics, but a recent news article incensed me enough that I thought it worth sharing.

It seems that the current executive branch of the United States government doesn't like its citizens. Back in April 2004, the N.Y. Times reported that the U.S. Department of Agriculture "refused to allow a Kansas beef producer to test all of its cattle for mad cow disease."

One might think that testing food for the ability to cause a fatal, untreatable disease would be encouraged by the US government. But in this case, apparently the Agriculture Department is choosing sides in a business struggle, putting the interests of one group of corporations - large meat packers - ahead of another group - small meat packers. In all of this, the Bush administration is putting business before public health, yielding to the wishes of "larger meat packers opposed to such testing" who "fear they too will have to conduct the expensive tests" in order to remain competitive in the US. (recent Associated Press article)

To be sure, Creekstone is not acting on a wholly altruistic basis. They want to be able to sell their products into the Japanese beef market, which has repeatedly prohibited beef imports from the US because of concerns over "mad cow" disease. Creekstone wants to enhance its competitiveness by proving that its beef is safe.

I'm not suggesting that a government should require this test on beef products. But if one company wants to take steps that protect public health, the federal government should not get involved, especially if the goal is merely to protect the profits of Big Business.


Jeff Victor writes this blog to help you understand Oracle's Solaris and virtualization technologies.

The views expressed on this blog are my own and do not necessarily reflect the views of Oracle.


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