Think improving the energy efficiency of today's technology is the answer to reducing fossil fuel consumption and curbing greenhouse gases? Think again.
"The Rebound Effect", a recent study by the UK Energy Research Center (UKERC) finds that more energy-efficient technology doesn't always translate to as much overall energy savings as you might expect. The problem stems from the "rebound effect."
To put it simply, the rebound effect happens when energy efficiency encourages people to use more energy than they would have otherwise. For example, after buying a more fuel-efficient car, people might tend to drive more, figuring they're saving more money and fuel than they could with their older vehicle. That's a direct rebound effect.
There's also an indirect rebound effect, which happens when energy savings in one area encourages people to consume more energy in another area. A family that saves several hundred dollars in heating and air-conditioning costs after improving its home's energy efficiency, for instance, might be more tempted to spend the savings on a long-distance vacation -- something that requires more fossil-fuel consumption and generates more carbon dioxide emissions.
There's an even more insidious effect, though, dubbed "backfire." This happens when a dramatic improvement in energy efficiency actually causes an overall increase in energy consumption. While Steve Sorrell, the author of the UKERC study, doesn't foresee today's efficiency improvements leading to economy-wide increases in energy use, it has happened before. Overall energy consumption rose, for example, after the development of the steam engine in the 19th Century. It also increased following the introduction of the electric motor.
So why should we care about the rebound effect? Because, Sorrell says, it might be causing us to overestimate how much energy we're saving through improved efficiency. Depending on the technology and the user, the rebound effect might be causing real energy savings to be anywhere from 10 to more then 50 percent lower than we might expect, he says.
Sorrell says policy-makers seeking to create energy-saving and carbon-reducing programs need to include some "headroom" in their estimates to account for the rebound effect. Increasing the cost of energy and carbon as efficiency increases could also help to stem the rebound effect and make sure greenhouse gas emissions are reduced as intended, he says.
