Waste heat, or rather residual heat refers to heat produced by equipment and industrial processes for which no useful application is found, and is regarded as a waste by-product. Power stations and manufacturing plants waste a staggering amount of energy, with power plants sometimes wasting two-thirds of the energy they produce. If the heat is at a such low temperature that it is not possible to recuperate it and generate with it any useful energy, or work (in whatever form), then it is not “wasted” (Carnot’s Law). Only if it is at a sufficiently high temperature where, if desired, it may be utilized for another process and this is not done, can it be defined as residual heat