The paper presents the institutional, legislative and regulatory framework for the production of electricity from solar power plants in the Republic of Croatia, with a clear link to the strategic documents of the European Union. Given the importance of climate change and the use of renewable energy sources, the paper emphasizes the energy transition as a key point of the ambitious goals of the Paris Agreement and clearly defined and targeted policies of the EU Green Deal. In this sense, the organization of the market, market prices, basic documents for the implementation of a photovoltaic power plant and the position of photovoltaic power plants with construction laws and regulatory frameworks, are analysed. The paper includes detailed analysis of good practice examples of successful projects and potential possibilities of installing photovoltaic power plants on the roofs of apartment buildings in Australia and the Republic of Slovenia. In this context, two case studies have been prepared for the Republic of Croatia, i.e., potential investment models in photovoltaic power plants to produce electricity on existing multi-apartment buildings. Following this paper, the potential and cost-effectiveness of installing photovoltaic power plants on the roof of an existing apartment building from the position of apartment owners and private investors was investigated, but also taking in consider how it has a positive effect on reducing energy poverty and encouraging energy independence. A detailed analysis concluded that it is technically and legally possible to install a photovoltaic power plant on the roof of an existing apartment building with the thesis that there are currently a small number of cost-effective models. Also, a recommendation is that before replicating such a model, it is necessary to adjust the legislative framework and conduct detailed analysis concerning technological, regulatory and financial possibilities.