A new method for estimating the annual energy production of wind turbines in hot environments

Accurately estimating wind turbines' annual energy production (AEP) is a paramount for planning and performance assessment of wind power projects. Inaccurate estimates during the planning phase could result in lower/higher project economic feasibility. This leads to financial consequences in the project’s contractual agreement. Furthermore, comparing the effective turbine’s operational performance under operational site conditions to the guaranteed performance is also critical. The current standard practice of the International Electrotechnical Commission (IEC) for calculating the AEP consists of using the site’s Weibull parameters derived only from the wind speed measurements and ignoring the air temperature measurements impact wind turbine operation. This is inadequate under high-temperature environments, where various meteorological processes impact the wind frequency distribution function. Moreover, wind turbine output power typically starts derating at high air temperatures to prevent overheating the electric and mechanical systems. The current study proposes a new method by categorizing the wind speed data into bins of 0.5 °C each, where the frequency distribution and Weibull parameters are produced for each bin. Therefore, calculating the AEP by the new method requires creating several wind speed distribution functions for the temperature ranges ranging between derating cut-in temperature and shutdown temperature. The Weibull parameters are found to change significantly during high-temperature conditions. Validation conducted using multiple years of wind resource assessment and Shagaya wind farm power data has shown the newly developed method has higher accuracy than the standard IEC method in hot environments and can better predict the energy losses in the upcoming wind farms in the region.