Analysis of Investments in RES Based on the Example of Photovoltaic Panels in Conditions of Uncertainty and Risk—A Case Study

The aim of this study is to examine the profitability of investment in a photovoltaic microinstallation, to analyze the impact of legal changes on its profitability, and to perform a sensitivity analysis of the investment profitability to energy price changes. The novelty of the research applies to the financial analysis of two legal systems of discount called net-metering and net-billing. The two systems and the change in energy prices present legal and macroeconomic risks. Climate neutrality strategy implementation is the analysis background. The authors formulate the hypothesis that, firstly, the solar panel installations in Poland are aimed at reducing the operating costs of the building; secondly, the investment motivation is environmental. The main research conclusion is that taking into consideration the solar panel ‘boom’ in Poland, the ‘regulator’ has achieved its intended goal connected with progress toward climate neutrality. This research used the method of logical design, experiment, and comparative analysis. The tools applied to calculate project profitability included the internal rate of return (IRR) and net present value (NPV). The case study method has been applied. The analysis uses real-world assumptions and is conducted for weather conditions in Gdańsk, Poland.