This study aims to investigate the methodological differences of wind power project economic analysis and to indicate the preferred methodology among the considered cases. The study compares the economic appraisals of onshore wind power projects. The economic appraisals of wind power projects are for evaluating wind power projects' impact on an economy. Economic appraisals of wind power projects include economic justifications of projects in comparison with the next best alternative projects, consider negative and positive externalities but exclude transfer payments such as taxes and subsidies. Also, in wind power project economic appraisals, the valuations of costs and benefits are at shadow prices and discounting of future costs and benefits at a social discount rate. There are methodological guidelines from different institutions on how to conduct project economic analysis. This study compares methodologies of three onshore wind power project economic appraisals conducted by the European Investment Bank, the Asian Development Bank, and the Mott MacDonald and discusses methodological differences for each case study in comparison with each other. The results of this study are for any investors, institutions and government authorities involve in wind power projects and seek not only corporate profits but also social benefits. They may consider the methodological differences identified in this study to improve the assessment of wind power project economic impacts. The results indicate that the identified methodological differences complement each other rather than substitute. The preferred methodology for onshore wind power projects economic analysis would be the methodology that considers the identified differences for the comprehensive evaluations.