Comparative Study on Wind Power using Meteorological Data and Wind Turbine Output at Ashogoda Village, Northern Ethiopia

Abstract

The power efficiency of a wind turbine may be influenced by several parameters such as wind speed and type and age of the turbine and its accessories. This study was conducted at Ashogoda village to compare the theoretically predicted power from the wind speed of Ashogoda area with electrical power generated from the wind turbines. Daily data of 10-minute intervals of six months were obtained from the company but data of two months were excluded because they were incomplete. The data were analyzed and comparisons of different parameters were made for fifteen turbines that had full data over the four months. Both wind and turbine powers showed diurnal variability that was difficult to predict. Variability between days over the four months showed some kind of cyclic patterns with one major peak and two minor peaks every 33±4 days but consecutive peaks occurred every 3-7 days. Both turbine power output and the power coefficient were nearly 25% (250 kW output for a 1 MW rated turbine) thereby limiting the rated power to 20-30%. The efficiency of the output power decreased with increasing wind speed possibly due to high friction loss at high wind speeds. The variability among the turbines was low and none of them revealed efficiency in excess of 27%. The efficiency of the turbines claimed by the company (38%) exceeded the average actual efficiency (~25%) by about 34%.

Keywords: Turbine Power; Wind Power; Wind Power Coefficient; Wind Power Variability