EVALUATION OF THE FEASIBILITY OF ALTERNATIVE ENERGY-SOURCES FOR GREENHOUSE HEATING

Four greenhouse heating systems were compared by computer simulation i n seven European locations: a conventional fossil-fuel system and thre e hybrid systems, in which part of the heating demand was covered by s olar collectors, a heat pump and a cogeneration system, respectively. Flat solar collectors were found to be of no interest for greenhouse h eating. There were possibilities of economic feasibility for heat pump s in northern European countries with electricity/fuel-price ratios (w hen buying electricity from the grid) of between 2.1 and 3.0 (or lower ). Cogeneration systems were found to have the best possibilities, esp ecially in northern European countries with electricity/fuel-price rat ios (when selling electricity to the grid) of between 2.3 and 3 (or hi gher). Heat storage improved the economical performance of the cogener ation systems: life-cycle costs decreased by about 4%. The electricity /fuel-price ratios are calculated with the prices of electricity and f uel which give the same amount of energy. (C) 1998 Silsoe Research Ins titute.