Tuesday, January 04, 2011

The Limits of Energy Efficiency

Ever heard of the Jevons Paradox?

Neither had we until we happened across the Dec. 20 New Yorker (thanks to Mrs. Curmudgeon) and an article by David Owen, "The Efficiency Dilemma: If Our Machines Use Less Energy, Will We Just Use Them More?"

William Stanley Jevons, an English engineer of the 19th century, postulated that the more we conserve energy, the more energy we'll use.

Recently, some scientists have returned to Jevons', wondering whether we can solve our current energy problems through increases in energy efficiency, i.e., conservation. Perhaps not.

The problem, of course, is that as a technology becomes less expensive, it becomes more widely used. Contrary to Jevons' paradox, however, it's not just the cost of the energy input that matters. It's the total cost, particularly as a proportion of one's income.

Thus, as Owens points out, while the cost of the energy needed to provide lighting has declined over time, the overall cost of all the materials needed, especially in proportion to income, has gone down dramatically. Yale economist William Nordhaus has estimated that it would have taken an ancient Babylonian 41 hours of work to acquire enough lamp oil to provide 1000 lumens of light (the equivalent of a 75-watt bulb burning for one hour). By Thomas Jefferson's time, it would take about 5 hours of work to get the same amount of light (with a tallow candle).

Today? It would take the average American less than half a second to get 1000 lumens. Pretty incredible. But, of course, our per capita use of light has exploded since Babylonian and Jeffersonian times (as I write this, I'm bathed in energy efficient light from compact fluorescent bulbs; pretty much half the lights in our house are on right now).

Another example is refrigeration. Today's refrigerator uses just 25% of the energy of its smaller counterpart in the 1950's. That's great progress, but today, refrigeration is far more widespread than it was 50 years ago. Refrigerators, freezers and coolers are ubiquitous--just about every hotel room now has a small fridge; most houses have more than one; just about every retail store has a drink cooler and supermarkets sport many square feet of refrigerated and frozen food. Most likely, we're using more energy in total today for refrigeration than we were in the 1950's. That's not just because of energy efficiency gains--the relative cost of the appliances that refrigerate has also plummeted.

We could go on and on (and Owens does, to some degree).

The big growth in energy use today is in developing countries, like China and India. The first time we went to China, in the 1980's, air conditioning was almost non-existent and refrigerators were rare. On our last trip, four years ago, our Chinese relatives were rapidly catching up with us. And there's no stopping it. We can't tell the rest of the world that they can't have the benefits of air conditioning, refrigeration and a personal automobile--they deserve to get just as obese as we are!

That's not to say we shouldn't try to achieve energy efficiency; indeed, the market will probably do this regardless of what we want. But the potential result of that efficiency may not be to "save" energy--rather, it might instead just help someone else in the world catch up to our gluttonous standard of living.

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