Christmas lights and the Jevons paradox

Which weighs more: a pound of efficiency or a pound of inefficiency?

Here’s a fact: an LED requires far less energy than an incandescent bulb to produce the same amount of light. So wherever you can replace filaments with diodes, you’re using less energy, right? Makes sense. But look at this picture.


Last December I was strolling with my family around the Quincy Market buildings in Boston. This is the spectacle I beheld. Those are thousands and thousands of tiny LEDs. A few years ago, they would have been thousands of incandescents. I couldn’t help but think of the Jevons Paradox, which states that “the better you are, the more you eat.” Actually, Wikipedia puts it like this: “technological progress that increases the efficiency with which a resource is used tends to increase (rather than decrease) the rate of consumption of that resource.” In this context: more efficient light bulbs equals more electricity consumption. Let’s say that an LED is ten times more efficient than an incandescent (I’m making just this number up), but you get so excited about LEDs that you replace one incandescent with 50 LEDs. You’re using more electricity than ever! That’s what this Christmas light display appears to be doing (though I will confess I don’t have any inside information one way or the other).

Here’s a situation where I do have some data: Across many appliances and consumer gadgets, we are making remarkable improvements in efficiency. Things like furnaces, refrigerators, air conditioners, and water heaters are much better than they were a generation ago. But we’ve brought so many electric gadgets (DVRs, big screen TVs, electronics of all sizes) into our houses that it more than offsets our efficiency gains. Greentech Media: Your Gadgets Are Killing Home Efficiency Improvements. There’s a cold bucket of smugwash, eh? You’re very good, but you’re bad and getting worse.

Steve picked up this article and pointed out a depressing coda to the story. When you burn natural gas in your own house for heat, you’re doing an admirably efficient job of trading greenhouse gases for energetic value you derive. Those hydrocarbons are local workers, doing their dirty work right on your premises. But electricity doesn’t work that way. Electricity just moves the energy from one place to another. Now you’re farming out the dirty work to hydrocarbons far away, and then you’re paying electrons to ship the energy to you. A lot of it falls into the ocean on the way. Boo-hoo.

Bottom line: efficiency is good, but watch out for old man Jevons. He doesn’t have to climb on your back. But if you don’t pay attention, he probably will.

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