Improving energy efficiency by 5% and more per year?

Reduction of specific energy consumption by 1 – 2% per year is typically what is considered feasible for end-use energy applications. This article tries to answer the question whether much higher rates, for example 5% and more are feasible for new equipment, installations and buildings. After examining some end-use functions in industry, buildings and the transport sector, it is concluded that for the foreseeable future – and this is not more than 10 – 20 year – such high rates of reduction of the specific energy consumption are indeed possible. For the longer term no positive proof is available, but there are also no indications that such high rates could not be maintained. The effect of the reduction of specific energy consumption on total energy use depends on the growth of energy-using activities and on the replacement rates of capital stock. Taking these into account, it is estimated that for industrialized countries a reduction of absolute total energy use by 50% in 50 years compared to the current levels is possible. Such a reduction requires a huge effort in innovation. However, the possibilities for stimulating innovation seem not to be exhausted yet.