Five Percent: Conserve Energy

Climate Change Is Important: Energy Conservation is the First Step


October 22, 2005

My New Car Conundrum

Category: Economics,Technology,Transportation – Tom Harrison – 10:27 am

We have a Toyota Prius. It is an incredible car and really does get great gas mileage (50+ MPG). So we have ordered another to replace my Toyota Camry, which is a V6 model, and gets maybe 25 MPG. So, from an energy standpoint it’s an obvious win, right?

Not so fast.

Sadly, my Camry will not disappear — I will sell it to someone who will continue to use it. And since my commute is so short I am putting less than 8,000 miles per year on the car now. So I’ll be driving my new Prius 8,000 miles per year at 50MPG, but will my Camry buyer be a more typical driver, driving 14,000 mile per year? The math is like this:

8,000 M / 50 MPG = 160 Gallons/year for the Prius
8,000 M / 25 MPG = 320 Gallons/year for the Camry
14,000 M / 25 MPG = 560 Gallons/year for the Camry’s new owner

so the net is that I am saving (320 – 160 =) 160 gallons per year, but the Camry is using an additional (560 – 320 =) 240 gallons per year. So me buying a Prius causes an additional (240 – 160 =) 80 gallons of gas used. Hmm.

But this assumes that the Camry buyer is using no energy now. Most likely s/he will upgrading from an earlier vehicle. If they are replacing a Ford Expedition or Chevy Suburban (or Toyota Land Cruiser) then this transaction is a win on the gasoline front. If they are replacing a car that gets the same mileage as the Camry then it’s a win. If they are replacing a Civic or Corolla or other small car, then it depends. And actually, this works out to a whole chain of buying and selling that ends when a car is put out of service. So assuming everybody else is average, it’s probably a good thing, especially if that last car in the chain is some huge boat that is getting really bad mileage.

So this analysis leaves us with one fewer bad car, and one more less bad car. Most likely a win.

However, there’s another factor. The only reason I am selling my Camry is that I will get a car that uses less gasoline — the Camry has only 60,000 miles and runs as well as the day I bought it. So back to the whole consumption thing. By not deferring or eliminating consumption (buying a new car) I will be using a lot of energy.

It takes a lot of energy and oil to create a car. Metal needs to be mined or recovered for reuse. Plastic needs to be made. All the parts need to be manufactured and delivered to the factory. When the car is assembled and finished it will be shipped (from Japan) and delivered to my car dealer, at which point it enters service. And on the other end, hopefully the story is a little less bad; with luck some of the plastic and metal and other materials from the car being junked can be recovered. But that takes energy, and in the end, my purchase will probably consume 25 times the energy that is recovered. How do I figure that? Let’s say economics works — I’ll pay $23,000 for the Prius, and the net value of the junked car is perhaps less than $1,000, for a total dollar cost of $22,000.

So first analysis says the net energy consumption is probably a small win. The second analysis says there’s a rather large dollar cost. In Measuring Energy Consumption I have argued that money is, at some level the same as energy because using money results in consumption. That’s certainly not completely true, but it’s a place to start.

So it all comes back to two principles I am focusing on here:

  1. You can save energy by shifting consumption from bad forms to less bad (Camry to Prius, inorganic food to organic food, incandescent to fluorescent light, etc.). But there’s often a smaller than expected benefit when you account for the hidden energy costs.
  2. The only sure way to reduce energy use is to consume less … of everything, not just fuel and electricity but of food, clothing, shelter and even services.

So is buying the Prius a good thing? I’m not really sure because it’s terribly difficult to do the accounting of all the energy costs.

But it’s certainly better than buying a big SUV. And that’s the main point of Five Percent — it doesn’t take much to change our current patterns of consumption such that we consume less. If we can all use 5% less, this can make a tremendous difference.

1 Comment

  1. […] when we ordered our first Prius, which took 9 months to arrive. We loved it so much, we got another. In 2005, I started writing down all the other changes we made to save energy and started reading […]

    Pingback by I Believed I Was Conserving, Until I Looked at the Facts | Five Percent: Conserve a Little Energy — September 24, 2009 @ 4:12 pm

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