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Inefficient efficiency

When we buy a new, more efficient appliance, we usually think that its savings in water or energy will be proportional to the improvement in efficiency. ”It’s only logical!” But, hold on, Spock, we do not live on Vulcan. Sometimes we, humans, think that the more we are saving, the more we can afford to spend. For instance, now that you have a more efficient air conditioner, you might be tempted to let it run a little longer. The same thing can happen on a larger scale: the more efficient the technology, the cheaper it becomes, and the more people will consume and overuse it. This is called “the rebound effect”, also known as the Jevons paradox (“The Coal Question”, Stanley Jevons, 1865). It is measured as the percentage of the savings you get from the improvement in efficiency. In short, a rebound of 30% means that only 70% of your potential improvement in efficiency will end up in actual savings.

So, are the improvements in efficiency doomed to be wasted away by our blissful ignorance? Not entirely. Fortunately, there is a limit to the consumption and comfort needs of a human being, above which, we are unlikely to consume more just because we can. Besides other factors that curtail our consumption, such as laws and environmental awareness, there is still much discussion about the phenomenon of Jevons paradox on energy and water saving policies.

Ideally, the rebound effect should be zero percent. Larry Dale, from the energy efficiency standards group at Lawrence Berkeley National Laboratory, estimates the rebound effect for household energy and transportation to be close to 10% on average, but it can be as high as 30% in developed economies (Scientific American, 2013 - see link below). Nonetheless, despite controversies, increasing efficiency is still one of the easiest ways to save energy and water, another being a change of habits in consumption.

In short, don’t let the efficiency that you expected from your brand-new gadget be washed away by the rebound effect. For instance, if you install light bulbs that use 75% energy less than the ones you are replacing, don’t fall victim to Jevons Paradox and leave your lights on 75% more of the time. That would be a rebound effect of 100%! Be the master of your consumption habits. After all, a gadget`s efficiency is only as effective as the person who uses it.

Reference:

http://www.scientificamerican.com/article/how-bad-is-the-rebound-from-energy-efficiency-efforts/