Economic investigation of repowering of the existing wind farms with hybrid wind and solar power plants: a case study

In Tamil Nadu, India, the old wind turbines installed in 1988 have to be repowered and replaced by modern/advanced technological wind turbines. A solar power plant can be set up using the vast area between the wind turbines on the farm. The economic evaluation must be carried out to determine whether this hybrid project is economically beneficial. This article aims to examine the financial viability of repowering old wind turbines with solar power plants’ inclusion. According to the initial investment costs specified within fixed areas and the distance between turbines, the issue is articulated as optimizing the net present value (NPV) of the project. In this study, the economic investigation on the wind farm located in Kayathar was explored by replacing 30 numbers of 200 kW old wind turbines with modern wind turbines of 2000–3000 kW and installing the solar power plant between wind turbines, excluding the shadow region of wind turbines. The HOMER Pro software and Excel spreadsheet were used to analyze the optimal allocation, economic, electricity production, and sensitivity analyses of the effective hybrid systems. The value of electricity prices was measured using the levelized cost of energy and NPV methods. Additionally, a sensitivity analysis of the chosen parameters for the internal rate of return and debt service coverage ratio was estimated for wind and solar hybridization. The economic analysis suggests satisfactory profitability for the project, even without depending on subsidies. Furthermore, sensitivity analysis helps one see the consequences of the risk on the life of the wind farm and its impact on the project’s productivity and performance.