Joining the European Union, for the Republic of Croatia also meant an obligation to accept European climate and energy package that promote the development of renewable energy sources. By adopting energy regulations, Croatia has established a legislative framework aligned with a goals for renewable energy sources, establishing market relations and integration into the European energy market. As fossil fuel combustion releases greenhouse gases and thus contributes to the negative impact of climate change, the energy sector economy based on fossil fuel development is becoming a thing of the past. Thanks to technological development and new technologies, effective political support, as well as financial incentives, renewable energy sources have had an increasing share in the energy mix, especially solar radiation since the Sun provides abundant clean energy to the planet Earth. The implementation of the system for stimulating the production of electricity from renewable energy sources and cogeneration (which was established on July 1, 2007), has led to an exponential growth of electricity production from renewable energy sources, that is, to an increasing number of requests for the construction of solar power plants. This paper analyzes the cost-effectiveness of constructing a non-integrated 300 kW solar power plant under three different scenarios, or three different purchase prices for the electricity produced. Depending on the purchase price, each scenario has a different return on investment and total revenue.