When someone invents new and more energy-efficient technology you might think it automatically will lead to energy savings – but you might end up of with no savings at all, or maybe even an increase in energy consumption.
The estimates have not taken the human factor into consideration: in effect, improvements in energy efficiency can encourage a change in behaviour towards increased use. Result: the gains made by improved technology is offset by changed behaviour, and the net energy consumption could paradoxically end up being larger.
This ‘rebound effect’ was described by economists Daniel Khazzoom and Leonard Brookes in the 1980s, although originally presented in the 19th century book The Coal Question in relation to more efficient steam technology. The Khazzoom-Brookes hypothesis states that increased energy efficiency leads to increased energy consumption. Although the energy consumption at the micro level (for the individual) goes down, overall energy consumption at the macro level (for societies) increases due to the combined increase in use from all individuals.
The rebound effect is particularly relevant for changing towards more sustainable lifestyles - suggesting that it’s not sufficient to improve technology without considering behaviour.