The argument as to whether there are still sufficient energy supplies available has always been surrounded by controversy. However, there can be no doubt about the finite nature of fossil fuel supplies and the global increase in energy consumption. Just how long supplies will last is still a matter of dispute. This is the situation today when we have both proven and unproven geological supplies in earth.
In the meantime, virtually all experts agree that increasing energy efficiency, i.e., the saving and optimum usage of energy, is of vital importance in closing the gap between finite supplies and increasing demand. Globally, considerable energy efficiency potential is seen in the construction industry.