This paper presents the energy output of wind farms in terms of unadjusted energy, gross energy, renewable energy delivered, specific yield and wind farm capacity factor. The analysis also includes the comparison of energy output from two methods: (i) the RETScreen model and (ii) the actual frequency and wind turbine power curve. The energy output analysis is done using three wind energy conversion systems of rated capacity 600, 1000, and 1500 M. The study is performed for 30 MW installed capacity wind farms at five coastal locations in Saudi Arabia. Furthermore, the RETScreen software is also used to perform the economical feasibility study of the wind farms at these locations. The study concludes that of the five wind parks, Yanbo and Dhahran are the only two sites where wind park development is economically feasible. Finally, wind park development at Yanbo will result in a reduction in greenhouse gases of 31369, 23601, and 26087 tons each year, corresponding to 1500, 1000, and 600 M machine wind parks, respectively. On the other hand, at Dhahran, installation of wind machines of 1500, 1000, and 600 M sizes will reduce the GHGs by 26183, 19247, and 21533 tons per year. (C) 2004 Elsevier Ltd. All rights reserved.