Exergy and renewability assessment of off-shore wind turbine power production and benchmarking with on-shore wind power

Abstract

This paper presents a study on the performance, efficiency and renewability of an off-shore wind turbine through an exergy-based analysis applied to different wind speed conditions representing a real–world scenario. A comparison with an on-shore wind turbine is also included. Temperature and pressure were measured to obtain the thermodynamic variables of enthalpy and entropy, while velocity was assessed in a wind tunnel to characterize the flow conditions. Based on experimental for the purpose model tests and a comprehensive thermo-mechanical analysis of governing variables, the research provides a benchmarking methodology to evaluate the exergy efficiency and the renewability index of a wind turbine under off-shore and on-shore scenarios, more specifically the reversible nature of wind generation process and the extent to which the renewable resource is involved. The results show that off-shore turbines reach an exergy efficiency range of 0.86 − 0.98, compared to 0.47 − 0.96 for on-shore turbines, within wind speed conditions ranging from 5 to 20 m/s. Additionally, the renewability index for off-shore wind turbines reaches values up to 70, while on- shore conditions remain around 27 on average. Moreover, it is shown that the renewability index of off-shore wind turbines reaches an average value of almost 30.0, while for on-shore wind turbines it is obtained 10.0 as an average, additionally providing with further advantage in terms of power production and improved overall performance