A design of experiments/response surface methodology approach to study the economic sustainability of a 1 MWe photovoltaic plant

To obtain a rigorous investment analysis for photovoltaic power generation plants, a dynamic Business Plan has been studied. It allows us to determine, in real time, the investment parameters (Net Present Value, Internal Rate of Return, Return on Investment, etc) starting from the technical, economical, financial and positional data. The Business Plan provides, as output, the exact values of the parameters (dependent variables or objective functions) basing on the exact values of the input variables (independent variables). By suitably varying the independent variables it is possible to obtain a sensitivity analysis on the dependent variables due to which different evaluations about the investment in multiple pre-set scenarios can be obtained. On the other hand, by using the Business Plan as data creator and then applying the Response Surface Methodology techniques, it has been possible to obtain mathematical functions (regression meta-models) which are able to explain the link among dependent and independent variables in the definition range. This approach allows to generate a sort of k dimensional state equation of order n for the different investigated economic parameters. These equations provide, in the chosen dimensional space (two or three-dimensional), a view of the dependent variable behaviour (e.g. Net Present Value, Internal Rate of Return) while changing one or two independent variables (e.g. government incentives, discount rate). The descriptive ability of this approach has a higher level in terms of quality and reliability than a traditional sensitivity analysis. In this paper, a case study about a 1 MWe photovoltaic plant located in Liguria (North-Italy) and a comparison with a similar plant located in Sicily (South-Italy) are also presented.