ABSTRACT
Numerous categorizations of energy forms exist, an important one of which is renewable and non-renewable energy. Renewable energy includes energy received directly and indirectly from the sun and derived from other natural forces, while non-renewable energy includes non-renewable resources. Non-renewable energy is also often taken to include 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 along with measures for efficiency improvement are described.
