Which bias correction factors are used?

Thanks for the Renewables Ninja website, it’s been a useful resource.

I’ve got a few questions about how the bias correction is applied to the MERRA2 wind data:

  1. Has bias correction been applied?

When downloading wind capacity factors from the website GUI, I can tell if bias correction has been applied by the filename (for example: ninja_wind_45.5889_-19.4434_uncorrected.csv and ninja_wind_51.6260_1.4960_corrected.csv). However this data is not in the “header”, so is there anyway to determine this when downloading data using the API?

  1. What bias correction factors have been applied?

The supplementary material to “Using Bias-Corrected Reanalysis to Simulate Current and Future Wind Power Output” contains bias correction factors for various European countries. However, when downloading offshore data, it is not obvious where one country’s boundary ends and another begins. Further, the website GUI provides corrected bias capacity factors for locations outside the countries listed in the paper. For example: 32.2568,2.8809 in Algeria. Is it possible to determine what bias correction factors have been used?

  1. Are bias correction factors different for offshore locations?

The paper states that for offshore windfarms the country’s “bias should be multiplied by 1.16”, and hence would change the bias correction factors. Does the website API adjust for this? It appears that this is not the case, I’d just like to confirm.

  1. Is the “raw” wind speed also bias corrected?

From experimenting with the data it appears that the raw wind_speed data downloaded from the website is bias corrected, but again I’d just like to confirm.


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