Using refurbished turbines to provide affordable wind energy: A case study in Africa

Abstract: When a wind farm is repowered, decommissioned turbines are discarded. This creates a stock of wind turbines that can be acquired for a fraction of the original cost, and refurbished. Taking advantage of the reduced price and the ruggedness of first generation wind turbines, new markets for sale of wind energy can be explored. This thesis first analyses the repowering background of Germany, Denmark, and other European countries, where transition to repowered or “second generation” wind farms is taking place. Then, a number of feasibility studies are reviewed to create a study framework, which will allow in-depth study of suitable energy markets. Using this framework, the suitability of four countries is analysed in detail: Djibouti, Madagascar, Mozambique, and Tanzania. Two countries are selected to perform a total of 6 site studies: Djibouti and Tanzania. Using WindPro 2.9, six model wind farms are simulated. A financial model is built, based on an NREL study, to analyse the economic viability of wind farms. Using the financial model, the levelized cost of energy is obtained, and used to evaluate the competitiveness of the model wind farms. A sensitivity study is carried out to identify the major influences on the LCOE. Using the cost data, the cost competitiveness of the proposed wind farms is discussed, including competitiveness in the target markets, and a cost comparison with commercial wind farms with new turbines is performed. Five out of six proposed wind farms are competitive in price in the target markets, and all achieve an average installation cost per kW of one third of conventional wind farms, while producing energy in the low range of commercial projects, and even lower for sites with excellent wind resources.