The primary aim of this study was to assess the investment activity of basic local government units in the development of renewable energy sources co-financed by EU funds depending on CO2 emissions and other socio-economic conditions in terms of regions of Poland in the years 2007–2020. Empirical studies aimed at the verification of the research hypothesis that “the greatest investment activity in local projects co-financed from EU funds related to the development of renewable energy sources is observed for local government units in regions with highest CO2 emissions”. Empirical studies were conducted based on data from the Ministry of Investment and Economic Development in Poland, the Local Data Bank, and the National Centre for Emissions Management. Thus, the conducted analyses provide both cognitive and applicatory values for the establishment of an appropriate energy transition policy in individual regions of Poland, which may be implemented by local government authorities within the current financial framework. Data concerning CO2 emissions at the regional level were estimated by applying the original disaggregation method as modified by the authors, which made it possible to fill the research gap resulting from the lack of data on emissions at the regional level. In order to show the regional diversification in investment activity of local government units in terms of renewable energy sources, its multi-faceted analysis was conducted by applying the Ward method. Clusters of regions with similar investment activity of local government units were described based on characteristics included in the typological classification (so-called active characteristics) and selected indexes showing CO2 emission levels, as well as selected socio-economic indexes (so-called passive characteristics). Based on the empirical studies, the research hypothesis presented in this paper was negatively verified. Considering both multiannual financial frameworks, the EU financial support for the development of renewable energy sources was used primarily by local government units of a predominantly agricultural character, and less advanced in terms of their development but exhibiting conditions conducive to renewable energy development.