Caught On the Rebound

If you’re on a diet and someone offers you a tasty, low-carb alternative to fattening snacks, what happens? You’re liable to eat more of them, canceling out many of the intended benefits.

Offer consumers a more energy-efficient refrigerator, and what happens? Joe Sixpack buys one for the kitchen, but fills the old one with cases of Bud in the garage. (The nation’s 30 million secondary refrigerators use an estimated 25 million megawatt hours of electricity annually.)

Give a driver anti-lock brakes for safety, and what happens? She’s likely to take just a few more risks. Now put that driver in a fuel-efficient hybrid to cut down on gas consumption, and what happens? She drives farther because the cost per mile has gone down. Result: lower fuel savings than expected.

These are all examples of the “rebound effect,” first documented by the British scholar William Stanley Jevons in 1865. He found that when the introduction of the steam engine made the use of coal much more efficient, overall demand for coal went up, not down as widely expected.

 

The principle is as simple as supply and demand. When efficiency lowers the price of something, people tend to consume more of it.

 

The latest example of this effect, which bedevils energy efficiency proponents, is a new study led by researchers at Sandia National Laboratories suggesting that efficient light-emitting diodes (LEDs) will help us illuminate the dark corners of our world but do little to cut overall energy consumption.

They find that over the course of three centuries, as technology has undergone radical innovations (whale oil, anyone?), spending on artificial lighting has remained remarkably constant at 0.72 percent of the world’s per capita gross domestic product. They don’t see any reason for that to change in the foreseeable future.

 

“A principal conclusion is that there is a massive potential for growth in the consumption of light if new lighting technologies are developed with higher luminous efficacies and lower cost of light,” they declare.

 

Looking on the bright side, they suggest that more lighting might increase human productivity. Particularly for us geezers, it could “help mitigate losses in visual acuity in an ageing world population.”

 

The answer is to make the price of energy reflect its full environmental cost, either through a green tax, cap-and-trade or other means. Higher prices will drive consumers to adopt energy-efficient products, while keeping overall energy consumption in check.

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