Fraunhofer IWES Releases First Offshore Wind Index for German Bight

The Fraunhofer Institute for Wind Energy and Energy System Technology (IWES) has released an Offshore Wind Energy Index, the first wind index for offshore wind farms in the German Bight in the North Sea.

The Fraunhofer IWES Offshore Wind Energy Index (FROENIX) is said to provide an opportunity to estimate the inter-annual power density variation at offshore wind farm sites.

It reveals the percentage deviation of the average wind power density during one year compared to the average wind power density of the past five and ten years. As such, it allows wind farm operators and owners as well as grid operators to assess their wind farms’ power output in comparison with the long-term average and to identify the causes of power losses, Fraunhofer IWES said.

The index is computed separately for each of the 13 offshore wind farm clusters as defined in the 2012 Federal Plan for the North Sea.

It is calculated from more than a decade of mesoscale simulations of the wind conditions over the German Bight with a resolution of 30 minutes in time. The horizontal resolution of the simulations is 2.1 km.

Data including time series, wind fields and statistics can be made available on request. Furthermore, Fraunhofer IWES can also provide simulations which take the follow-on effects of large offshore wind clusters into account.

The simulations did not take any wind farm effects within the German Bight into consideration. Consequently, the impact of the expansion of surrounding wind farms can be estimated by comparing the actual production data with the wind index data, Fraunhofer IWES said.