Improvements to energy efficiency, such as LED lights, are seen by many authorities as a top priority for cutting carbon emissions. Yet a growing body of research suggests that a rebound effect could wipe out more than half of the savings from energy efficiency improvements, making the goals of the Paris Agreement on climate change even harder to hit.
A team led by Paul Brockway at the University of Leeds, UK, looked at the existing 33 studies on the impact of the rebound effect. First comes the direct rebound: for instance, when someone buys a more efficient car, they may take advantage of that by driving it further. Then comes the indirect rebound: fuel savings leave the owner with more money to spend elsewhere in the economy, consuming energy.
Although the 33 studies used different methods to model the rebound effect, they produced very consistent estimates of its impact, leading the team to conclude that the effect wipes out, on average, 63 percent of the anticipated energy savings.
"We're not saying energy efficiency doesn't work. What we're saying is rebound needs to be taken more seriously," says Brockway.
The idea that increased efficiency may not deliver the hoped-for savings dates back to the Jevons paradox(悖论), named after the economist William Stanley Jevons, who, in 1865, observed that more efficient coal use led to more demand for coal.
If the rebound effect does prove to be as big as suggested, it means future global energy demand will be higher than expected and the world will need far more wind and solar power and carbon-capture technology than is currently being planned for.
But that doesn't mean nothing can be done to limit the rebound effect. One answer is to double down on energy efficiency and do twice as much to achieve the same effect.
