The main topics in this paper are wind power plants and photovoltaic power plants. In theoretical part of the paper, wind power potential in Croatia is compared to that in the rest of the world. Also, main characteristics of wind power plants and photovoltaic plants are introduced. Goal is to get the insight into design, construction and maintenance of both types of power plants. In the calculation part of the paper, power characteristics of wind power plants and photovoltaic power plants are compared. By choosing several wind power plants and photovoltaic plants, the average peak times are obtained, they are then compared which leads to conclusion that wind power plants have greater average peak time. The comparison of the investment costs of the equal installed power of a wind power plant and a photovoltaic power plant was carried out in such a way that the collected data on the percentage of the investment cost per power plant component lead to the price in kuna per kilowatt, or euro per kilowatt. A lower price is determined for photovoltaic power plants per unit of power. In order to compare the investment costs for the same amount of electrical energy produced, it was necessary to scale the photovoltaic power plant, i.e. increase its installed power in order to obtain approximately the same amount of electricity produced for its lifetime, which caused the value of investment to rise. Photovoltaic power plants have a lower investment cost for the same amount of energy produced, despite the fact that the investment cost has increased, the main contributing factor is the longer lifespan of photovoltaic power plants. Using the collected data, it was determined that photovoltaic power plants have a significantly higher distribution of power and energy per unit area, due to the fact that wind farms are spread over a significantly larger area.