ERA5: The new champion of wind power modelling?

Output from meteorological reanalyses are used extensively in both academia and industry for modelling wind power. Recently, the first batch of the new ERA5 reanalysis was released. The main purpose of this paper is to compare the performance of ERA5 and MERRA-2 (a commonly used reanalysis today) in terms of modelling i) the aggregated wind generation in five different countries and ii) the generation for 1051 individual wind turbines. In conclusion, ERA5 performs better than MERRA-2 in all analysed aspects; correlations are higher, errors are in average around 20% lower and distributions of both hourly data and changes in hourly data are more similar to those for measurements. It is also shown that the uncertainty related to long-term correction (using one year of data to predict the energy production during the remaining 1–5 years) is 20% lower for ERA5. In fact, using one year of measurements long-term corrected with ERA5 gives more accurate estimates than using two years of measurements long-term corrected with MERRA-2. Additionally, a new metric for quantifying the system size and dispersion of wind farms is proposed.

Jon Olauson