GEO-NET Umweltconsulting GmbH is expanding its portfolio with a new service: site- and hub-height-specific extreme wind assessments for wind energy projects throughout Germany.

An extreme wind analysis is required as part of a structural stability analysis. If a comparison of wind zones based on the DIBt wind zone map and the published wind zone in the design of the planned wind turbine type is unsuccessful or not possible, and if the design value is also exceeded according to the calculation method specified in DIN 1991-1-4 NA—based on the wind zone and terrain category data at the project site— a more precise estimation of extreme wind is required to verify whether structural stability is ensured. This is carried out as part of an extreme wind estimation service newly developed and offered by GEO-NET. This allows you to obtain both the structural stability analysis and the extreme wind estimation from a single source, saving you time and reducing communication efforts.

The new product from GEO-NET Umweltconsulting GmbH is based on a spatially representative 20-year time series of wind data, which is derived from a simulation using the mesoscale WRF model with a resolution of 3 km and was processed using a proven method based on machine learning and a spectral method. This GN-WRF_ML-Spek time series enables a realistic representation of wind conditions over two decades with a temporal resolution of 10 minutes. The extreme wind estimation is based on a method of extreme value statistics, assuming stochastic behavior of the event under investigation. Annual wind speed maxima are extracted from the underlying GN-WRF_ML-Spek time series, and it is assumed that the extracted maxima can be described using the Gumbel distribution, which is widely used in the industry. The extreme wind is estimated based on the Gumbel distribution fitted to the extracted maxima. To validate the results, the method was internally validated at 60 real measurement sites in Germany. As part of the in-house validation of the extreme wind determination, a scaling factor was determined that is taken into account when calculating the extreme wind. This factor incorporates a safety margin of half a standard deviation to adequately account for the uncertainties in the model chain. 

The new product offers numerous advantages:

Location- and hub-height-specific extreme wind estimates using the high-quality GN-WRF_ML spectral time series
An extreme wind analysis may be required as part of the structural stability verification. GEO-NET offers you everything from a single source

Feel free to contact us about our new product: wind@geo-net.de 

GEO-NET Umweltconsulting GmbH of Hanover (GEO-NET) can now, at the client’s request, conduct wind energy yield analyses that take various climate scenarios into account.

Not least due to climate change, efforts to expand renewable energy are being accelerated. GEO-NET plays an important role in financing wind energy projects by providing bankable reports and conducting measurement campaigns.

Over the past year, the question of how climate change will affect the energy yield of wind farms over their operational lifespans has been raised with increasing frequency at various conferences and industry meetings. Furthermore, the BWE Standard for a Well-Managed Wind Farm with Direct Financial Citizen Participation, published by the German Wind Energy Association (BWE) in November 2022, requires that future developments such as climate change be appropriately described and adequately taken into account when preparing wind and yield assessments. To forecast how climate change will affect meteorological variables and, consequently, the output of wind farms, GEO-NET has therefore added a dedicated service to its product portfolio.

This service is based on coupling coarse-grained climate models with the FITNAH-3D CFD model, which has been tried and tested over many years and is continuously refined. Regional climate projections from the CORDEX initiative for various RCP (Representative Concentration Pathways) scenarios are used for this purpose.

Since September 2022, we have been operating a new 200-meter wind measurement mast near Hanover for the verification of LiDAR and SoDAR devices. The site offers numerous advantages: It is centrally located, easily accessible via the A2, A7, and A27 highways, and provides good wind conditions. This allows GEO-NET to perform verification more quickly, and the verified devices can begin actual measurements sooner.

GEO-NET offers verification at fixed prices as well as part of a comprehensive package that includes a wind measurement campaign, yield assessments, and turbulence reports, with a consistent focus on the smooth and time-optimized execution of the entire package.