Although energy efficiency has recently received more political attention, there are still questions over the effectiveness of particular policies.
Several energy economists have questioned whether energy efficiency measures really do bring energy savings on a macro-economic scale. Building on the work of nineteenth century economist Stanley Jevons, they have looked at the "rebound" or "take-back" effects of energy efficiency policies. This effect takes place when the energy savings produced by the measure are taken back by consumers in the form of higher consumption. An example: a household, which has made big energy savings over the year might, at the end of the year, decide to buy a new car with the money they saved. It is questionable therefore whether, on a macro-economic level, they contributed to less energy consumption.
A report produced in 2005 by the UK House of Lords's Science and Technology Committee as a response to the EU's Green Paper drew attention to this issue, which in academic circles is also known as the "Khazzoom-Brookes postulate".
