Abstract

Numerous categorizations of energy forms exist, an important one of which is natural and additional energy. Natural energy includes energy received directly and indirectly from the sun and derived from other natural forces, while additional energy includes non-renewable resources as well as energy forms that do not exist naturally but are produced. These energy categories are described in this entry along with some of their applications. Also, energy forms, sources, and carriers as well as energy-conversion technologies are described. Finally, energy use, energy selection, and efficiencies are described, along with measures for efficiency improvement.