Wind power design for high capacity factors - A techno-economic analysis of specific power reduction and wind-solar hybrid plants

Abstract

Abstract Wind power production is the fastest growing electricity producing technology in Sweden today. However, its intermittent nature and relatively low capacity factor present significant challenges. Therefore, the aim of this thesis was to investigate the feasibility of increasing the capacity factor of a wind turbine situated in southern Sweden. Two studies were conducted, implementing two different design changes on a wind turbine, for an increased capacity factor. The consequences of these design changes have been evaluated, and the results were continuous functions of levelized cost of electricity, value factor, and profit with respect to an increased capacity factor. Costs were evaluated through a combination of a bottom-up procedure, literature reviews, and discussions with industry actors, to ensure that the estimates were representative of the current Swedish market. Alternative ways of modelling hourly production of a single wind turbine, based on regional production data, have been analysed and validated against wind speed measurements from 2016 and 2017 in price area SE3 in Sweden. The first study involved decreasing specific power by reducing rated power, which resulted in a higher capacity factor and reduced costs. However, a simultaneous decrease in energy production ultimately resulted in a higher levelized cost of electricity. Additionally, Study 1 indicated a potential decrease in profitability through this design change, although the results were shown to be heavily influenced by the wind speed distribution. Despite this, the results also illustrated that the value of the produced power did increase, highlighting how a higher capacity factor can benefit the power system. For the second study, the wind turbine was complemented with solar power while keeping the grid connection constant. Similarly, it resulted in an increased levelized cost of electricity, but demonstrated a higher potential of increasing profitability. Moreover, just as Study 1 the value of produced electricity was consistently increased with the capacity factor. Overall, the second study highlighted how infrastructure such as grid connection can be utilized more effectively by combining wind and solar production, providing potential benefits on both a project and system level.