Wind power output performance horizontal and vertical axis wind turbines for isolated small applications in Saudi Arabia

The study evaluated the energy output and plant capacity factor of small wind turbines in the category of 3-10 kW rated power. The effects of hub height on energy output and the PCF have been studied. To achieve the set objectives, hourly average wind speed data measured at 10, 20, 30, and 40 meter and wind direction at 30 and 40 meter above ground level during July 01, 2006 to July 10, 2008 has been utilized. The highest percentage change in annual energy yield (AEY) was obtained for an increase in hub height from 20 to 30 m for both horizontal and vertical wind turbines used in this study. Horizontal axis wind turbines HAWT-1, HAWT-2, and HAWT-6; and vertical axis wind turbines VAWT-1, VAWT-2, and VAWT-4 are recommended for various ranges of loads. Horizontal axis wind turbines were found generally more efficient than the vertical axis wind turbine in the present case. In general, all the turbines showed a maximum increase in energy yield for an increase of 10 m in hub height from 20 to 30m and the annual mean energy yield usually followed the load pattern in the study area. Lastly, the mean turbulence intensity was always less than the value recommended in IEC64100-1 standard.