Wind Energy Resource Analysis: A Case Study of Aysha Wind Farm
Creators: name: Wudu, Mengesha
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2015

description: Ethiopia satisfied 92 % of its energy demand using biomass sources while petroleum and electricity (hydropower) only contribute 7 % and 1 %, respectively, in 2009. Due to this limited electricity availability, among the total population only 23.3 % had access to electricity and among 82.7 % of Ethiopians living in rural areas only 2 % in 2011. In addition 99 % of the electricity production is from hydropower source which is highly vulnerable to fluctuations in energy supply due to varying water inflow to reservoirs. However, the country is well endowed with other renewable energy resources (solar, wind and geothermal) that can be used to develop electricity. Among these resources, harnessing Ethiopian wind energy potential (10,000 MW) is a promising solution as it offers better generation mix and seasonal complementarity to avoid vulnerabilities associated with hydropower. It also helps in improving the life of population who are unlikely to have access to electricity supply in foreseeable future. Accordingly, this study is conducted at Aysha Wind Farm with the aim to analyze its wind energy resource based on 10 minute mean data for the year 2008 G.C. Using different software and statistical model, the wind data has been analyzed to: select wind turbine class, power density &amp; estimate farm AEP, develop site wind resource map and perform preliminary turbine micro-sitting. Based on the analysis and site survey, site roughness and wind shear exponent are also determined. Detail wind energy resource study is performed for the site using MS Excel, MATLAB and WAsP software. Analyzing a wind-mast data at a height of 10 m using MATLAB and MS Excel, mean wind speed of 8.455 m/s and average power density of 571 W/m2 have been found at the farm. To take the effect of the roughness of the site in to consideration, a wind resource map of 28.44 km x 36 km area is performed on the site. This is done based on two nominated wind turbines namely: Sany SE8220III 2 MW and Gamesa G80 2 MW at respective hub heights of 70 m and 67 m using WAsP software. Considering the nearby transmission line capacity i.e., 300 MW, 150 sets of each type of turbine has been put at the farm, analyzed and compared to each other. Accordingly, Gamesa G80 2 MW is selected for its least wind farm cost of 0.0193 USD per kWh. As per the preliminary analysis of the farm based on the selected turbine, total gross AEP of 1819.21 GWh and total net AEP of 1183.62 GWh (after considering total loss factor of 0.651 on the total gross AEP) have been found. In addition the average power density and CF at the wind farm are estimated at 1392.6 W/m2 and 44.92 %, respectively. Moreover the mean wind speed at hub height (67 m) is 11.83 m/s whereas the average Weibull shape factor (k) and scale factor (A) are estimated at 3.13 and 13.22 m/s, respectively. In conclusion, according to the wind power classes, Aysha wind farm is categorized as class 7 (excellent wind energy resource) which is promising to construct large wind farm. It is, therefore, recommended that Ethiopian government consider investing on Aysha wind farm as the farm has an excellent wind resource potential at a capacity of 300 MW. KEYWORDS: Wind Farm, Wind Climate, Energy Production, Wind Resource, Wind Shear Exponent, WAsP, Wind-Mast, Capacity Factor, Ethiopia, Power Density, Wind Turbines