Stimulating measures for the production of electrical energy from renewable energy sources (RES) are guaranteed over certain period of operation. Their aim is that the wind power plants (WPP) and other RES are brought to a concurrent position with the conventional power plants at the open market of electrical energy. In perspective, power market conditions should be made equal for all electricity producers. In such conditions, the economy aspects of a WPP are affected not only by the amount of produced electricity but also by the daily and yearly production profiles. The paper defines correlation indices between the price profile of electricity at the open market and seasonal and daily profiles of WPP production. These indices could serve as a quantitative measure of the influence of the seasonal and daily profiles of wind speed on the economy of the project of a WPP. (C) 2012 Elsevier Ltd. All rights reserved.