Mathematical models for the construction of a twice renewable energy plant

In order to develop renewable energy sources technology in stand-alone power supply plants, it is necessary to provide designers with tools capable of recognising at short notice any areas of convenience in their utilisation, including projects with twice renewable generators. Typical renewable sources considered are solar and wind energy, but the results are general anywhere energy sources with random emissions are available. For this purpose it is necessary to know in advance the Cost-Law for this kind of power plant in order to make possible comparisons with the costs for traditional power supply plants, and therefore to be in a position to make a correct decision. Block diagram of the plants includes: two renewable generators (P_S and P_W), storage battery (B) and electronics. Project data and power emission law, in turn customised by the meteorological parameters with probabilistic-statistic algorithms are processed to define sizing parameters evaluating cost/load-power Q/P_L that depends on three factors: a=P_S/(P_S+P_W) P_L sharing factor of the two nominal power P_S, P _W assigned of each of the sources S and W; b=battery-energy/P _L autonomy assigned to the battery; and u=estimated maximum unavailability. The overall cost can be therefore determined through a minimum cost algorithm, such a cost being a function, for a fixed u, of the two variables a and b