Transformity
In 1996 H.T. Odum defined transformity as, "the emergy of one type required to make a unit of energy of another type. For example, since 3 coal emjoules (cej) of coal and 1 cej of services are required to generate 1 J of electricity, the coal transformity of electricity is 4 cej/J" The concept of transformity was first introduced by David M. Scienceman in collaboration with Howard T. Odum.