Discussions about market introduction of grid connected photovoltaics (PV) and its costs usually concentrate only on the gross energy produced without taking the time dependency of electricity prices and, thus, the time dependency of the value of PV electricity into account. To make a first approximation of what the effect of the time variance of electricity cost on the value of PV electricity is, the correlation with spot market prices is analysed in this paper. PV is not dispatchable by nature, but is relatively well predictable in the range of one day, if the average of spatially dispersed systems is considered. Thus, this correlation gives a good indication for the additional value of PV electricity. (C) 2004 Elsevier Ltd. All rights reserved.