Energy yield assessments considering climate change


GEO-NET Umweltconsulting GmbH from Hanover (GEO-NET) can now perform wind energy yield assessments considering various climate scenarios.


Not least due to climate change, an increased expansion of renewable energies must be driven forward. GEO-NET makes an important contribution to the financing of wind energy projects by providing bankable reports and measurement campaigns.


In the last year, the question of how climate change will affect the energy yield of wind farms during their operating period was increasingly raised at various conferences and industry meetings. Additionally, the November 2022 BWE standard for a well-managed wind farm with direct financial citizen participation from the German Wind Energy Association also calls for future developments such as climate change to be appropriately described and adequately considered when preparing wind and yield assessments. In order to forecast how the influence of climate change will affect meteorological variables and thus the yield of wind farms, GEO-NET has added a new service to its product portfolio.


This is based on a coupling of coarse climate models with the CFD model FITNAH-3D, which has been tested for many years and is constantly being further developed. As climate models, regional climate projections from the CORDEX initiative for various RCP (Representative Concentration Pathways) scenarios are used.


Do you want to assess the risk of climate change on the yield of your wind farm? We look forward to receiving your request at: wind(at)

Research and LiDAR performance verification mast

200 m mast for LiDAR and SoDAR performance verification by GEO-NET near Hanover

GEO-NET built a 200 m wind measurement mast for the performance verification of LiDAR and SoDAR devices near Hanover. The site is particularly suitable for verification due to its location, as it is almost free of significant obstacles and allows representative verification even for onshore sites and the large hub heights of current wind turbines. The good wind conditions ensure that the verification can be carried out quickly.


Further information: Lidar Verification

Peace for Ukraine

Solidarity with Ukraine

Thorsten Frey and Peter Trute, CEO´s of GEO-NET:

"We are deeply shocked by Russia's attack on Ukraine. 
We strongly condemn this violation of international law.
The people in Ukraine deserve our support and solidarity. The primary goal must now be to stop the acts of war. For this purpose, the EU must react united and determined to Putin's aggressions. GEO-NET supports the primacy of politics - and so we have decided to stop all emerging business with Russia, even if we are sorry for the hard-working Russian population. Peace is the basic prerequisite for our security and not least for our prosperity in Europe and Russia. We sincerely hope that this war can be stopped. 
In the last days we think especially of the employees of our office in Kiev and our Ukrainian colleagues who still have their families in Ukraine."


Husum Wind again at last!


Great that so many found their way to Husum Wind 2021 despite Corona and the hygiene regulations and made the trade fair a complete success. Wind energy is still one of the most important key energies for the energy transition and this was impressively shown by the industry.


Our stand was always well attended and we were pleased of each visitor we were able to inform about our well-known wind farm planning services such as TR6-compliant wind assessments with the validated CFD model FITNAH-3D, stability verifications and accredited wind measurements as well as our new products.

For those of you whom we were unfortunately unable to welcome personally in Husum, we will be happy to provide information on the following new products in particular via the known contact options, because: The wind drives us!


  • Determination of site quality after commissioning according to TR10 as an accredited service
  • Yield loss calculation now also including bat "night tenth method"
  • Germany-wide 10-minute time series of wind energy-relevant parameters from in-house WRF downscaling
  • LiDAR verifications on our own 200 m mast from 2022
  • LiDAR verification with simplified procedure at the measurement site according to TR6


Successful round robin test for TG 10

Successful participation in the round robin test lays the foundation for accreditation according to TG 10

GEO-NET has successfully completed the round robin test conducted by the working group Methodology and Validation of the Fördergesellschaft Windenergie und andere Dezentrale Energien e.V. (FGW) for the correct application of Technical Guideline 10 (TG 10) on 27.07.2021 as one of the first expert offices in Germany and thus fulfilled all requirements for accreditation according to TR 10. This guideline regulates the determination of site quality after 5, 10 and 15 years after commissioning, as introduced by the EEG 2017. For participation, GEO-NET had developed its own software package to efficiently process wind turbine operating data and determine the relevant yield losses for reasons of permitting law, non-availability, restrictions through feed-in management or through optimised marketing. Thus, in addition to the CFD model FITNAH-3D for wind field modelling, GEO-NET is also pursuing the approach of an in-house solution for the management of the proof of site quality after commissioning, in order to be able to react more quickly to new requirements of the TG10. For a continuous claim to remuneration, plant operators whose wind turbines are subsidised under the EEG 2017 must submit the proof of site quality after commissioning to the grid operator within a period of 4 months after the first 5, 10 or 15 years of operation. If the site quality determined in this way deviates by more than 2 % after commissioning from the site quality submitted before commissioning, additional payments or refunds will be due. Therefore, from GEO-NET's point of view, it makes sense to carry out the review well before 5 years of operation have been completed, in order to form provisions at an early stage if necessary.

Alpine wind energy project Windsfeld

Milestone in wind farm development in the alpine region

In the EWiNo research project, the use of new technologies to improve wind modeling and the optimization of wind farms in complex terrain was successfully developed under the leadership of the Fraunhofer Institute for Wind Energy Systems IWES in cooperation with GEO-NET Umweltconsulting GmbH and other renowned partners from the wind industry.


The methods and research approaches developed in the research project are now being further developed for use at alpine sites in cooperation with GEO-NET, Fraunhofer IWES and Windsfeld GmbH. The often very complex flow conditions in the mountains lead to special challenges for project developers, since locations with unfavorable and locations with very good wind conditions are often very close to each other.


In order to validate and further optimize the accuracy of the flow models under these conditions, Fraunhofer IWES, in collaboration with Windsfeld GmbH and the wind experts from GEO-NET, is conducting practical research at the Windsfeld site in Salzburg, using a so-called 'scanning lidar' measuring device. This device is used to measure the wind conditions at almost every point in the planned wind farm area. Using the measurement results and flow models such as FITNAH-3D, which have been specially optimized for this procedure, it is then possible to directly compare the measurement and model results, which significantly reduces the uncertainty.


The very challenging alpine location of Windsfeld, where planning is carried out with turbines that are commonly available on the market, requires an innovative approach to project development. As new standards are set for the development of alpine sites in the course of the project realization, Windsfeld GmbH has set itself the goal of combining various innovative concepts along the wind energy value chain in the project.


The focus here is in particular on the validation and adaptation of the latest technologies for bird detection, the survey and strategic treatment of the topic "icing on site" as well as the energetic densification of the wind farm. In the context of park densification, a process that is seen as an essential component for wind power in the alpine region from both an ecological and economic point of view, there are innovative approaches that Windsfeld GmbH is subjecting to practical tests in the complex alpine terrain at the Windsfeld site. In this way, Windsfeld GmbH contributes to a successful energy transition.


More Information

Get ready for round 5 – new bidding round in South Africa

Good news from South Africa: the Department of Mineral Resources and Energy (DMRE) of the Republic of South Africa has launched the long awaited bid window five, tendering 1.6 GW of wind energy, plus another 1 GW for solar projects! This is definitely a good sign for an industry that has waited five years for the next tender!


With a local office in Cape Town, MEASNET membership and international accreditation to ISO/IEC 17025 and MEASNET, GEO-NET is ideally placed to provide energy yield assessment services and bankable AEP reports to project planners, developers and investors. With our experience of more than 25 years and 2 GW of assessed projects in South Africa, we offer the expertise and services to make your projects fit for the current bidding round.


We wish all participants every success in the tendering process!

GEO-NET is proud to support this year's Windaba conference in South Africa as a Gold Sponsor.

South Africa is a thriving wind power market with high wind potential and a huge demand for renewable energy, which offers a lot of opportunities in the wind power business. In order to facilitate business and transactions with South African clients and customers GEO-NET established a subsidiary in Cape Town, GEO-NET South Africa (Pty) Ltd. which provides all the services, experience and know how of GEO-NET to support the development of wind projects in South Africa.


The Windaba is the most important event of the South African wind industry, which is conducted as a pure online event this year due to the current pandemic restricitions. Nevertheless there is still many opportunities to meet, talk and discuss at this online event, during the conference, in direct B2B-meetings, or in the virtual exhibition. Meet GEO-NET at their virtual booth or at their presentation in the firstt Breakaway Session and learn about site assessment, the potential of complex terrain sites and the chances of looking beyond the low hanging fruits.

GEO-NET is now a member of MEASNET

Since July 2020 GEO-NET is MEASNET member in the field of site assessment. MEASNET (International Network for Harmonised and Recognised Measurements in Wind Energy) is an international association of various measurement institutes which, on the one hand, jointly develop standards for site analysis and evaluation and, on the other hand, commit themselves to comply with these standards. The standards serve to ensure high data quality and good comparability


Membership in the MEASNET expert group Site Assessment opens up the possibility to actively participate in the design and improvement of the standards and to draw on the knowledge and experience gained from over 3000 projects worldwide and from numerous research projects to ensure a safe and reliable site assessment in the future.

EWiNo improves wind field modeling and wind farm operation in complex terrain

The aim of the research project EWiNo has been to examine the use of new technologies for the improvement of wind modeling and optimization of wind farms in complex terrain. Under the management of the Fraunhofer Institute for Wind Energy Systems IWES, ENERTRAG, GEO-NET, and other well-known industrial partners are working together to put new ideas and research approaches into practice with the aim of not only being able to harness wind energy in the North in the future.


Bremerhaven/Hanover/Dauerthal, April 21, 2020 | The new generations of wind turbines make it possible to use sites in uplands and forests, which would previously have been impossible to develop for economic wind farm operation. However, along with the ever-larger rotors, the growing hub heights, and the complex flow conditions over forests, mountains, and valleys, the forecasting of energy yields is also becoming increasingly challenging.

Simple linear models like those developed and deployed in the early days are no longer suitable for accommodating complex wind conditions and satisfying the high demands on precision – sophisticated and computationally intensive 3D models have long since become the standard. To enhance the accuracy of these models even further, in cooperation with ENERTRAG, one of the leading project developers, the experienced wind experts at GEO-NET, and other well-known industrial partners from the wind sector, Fraunhofer IWES was conducting the EWiNo project (Development of a two-stage procedure for assessing the wind potential of wind locations as per the German Renewable Energy Act (EEG) amendment 2017). The project is being funded by the Federal Ministry for Economic Affairs and Energy on the basis of a decision by the German Bundestag (FKZ 0324225 A/B).

When planning a wind farm, the wind conditions are measured using a LiDAR device or measuring mast, which record the wind speed and direction at one location in the farm. A model is then used to transpose the wind conditions from this location to the actual sites of the turbines in the farm.

This project also employs a new technology to record the accuracy of this process more effectively and to improve the models even further. The use of a scanning LiDAR system allows measurement of the wind conditions at virtually any location in a wind farm. These measurements can subsequently be used to validate various 3D models such as FITNAH-3D and OpenFOAM, including under difficult conditions in forests and in complex terrain, so as to optimize the models. Furthermore, methods were developed to allow the measurements recorded with such scanning LiDAR devices to be employed in normal wind farm planning too. As an operator of numerous wind farms, primarily on lowlands, ENERTRAG is also planning wind farms in the complex terrain of German uplands. ENERTRAG has provided a development site in North Hesse for the purpose of the EWiNo project. This site offers ideal research conditions for the use of the scanning LiDAR technology.

The results will help to render yield forecasts more precise, including in forests and on complex terrain, and will thereby facilitate the planning of wind farms under such conditions in order, ultimately, to make their subsequent operation more efficient. As such, this project is making a further contribution to the success of the energy transition.




Fraunhofer Institute for Wind Energy Systems IWES • Dr. Julia Gottschall • Senior Scientist • Am Seedeich 45 • 27572 Bremerhaven, Germany • Telephone: +49 471 14290 354 •


GEO-NET Umweltconsulting GmbH  • Johannes Becker • Authorized Officer, International Projects, Wind Measurements • Große Pfahlstraße 5a • 30161 Hanover, Germany • Tel.: +49 511 3887200 •


ENERTRAG AG • Dr. Nadine Haase • Head of Department for Communication and Marketing • Tel.: +49 39854 6459368 • nadine.haase(at)


GEO-NET with booth at the Ukrainian Energy Week in Kiev


Sergei Roife and Johannes Lange visited the Ukrainian Energy Week in Kiev. Their conclusion is quite positive: despite the strained foreign policy situation and the announced introduction of an auction system instead of a fixed feed-in tariff, the Ukrainian wind industry is optimistic about the future. This is also pleasing to GEO-NET - the wind experts from Hanover have been active in the Ukraine since 2008 and are among the most experienced wind experts in this country.

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