Taylor, A.E.B.; O'Callaghan, P.W.; Probert, S.D. - In: Applied Energy 44 (1993) 4, pp. 315-335
The energy ratio for a food-producing process is defined as the energy outputted in the form of crops, animals and … wastes to the quantity of commercially supplied energy invested. This ratio should well exceed unity because of the …, for which the problems associated with the use of fossil fuels have been examined and energy-thrift opportunities …