Developing a successful wind power plant is a complex, multi-stage process requiring meticulous technical analysis and strategic planning from concept to completion. Our project development services guide investors and developers through every critical stage, ensuring each project is technically sound, financially viable, and fully compliant with all regulatory requirements.
Determination of the grid connection point to ensure the most suitable connection of the wind farm to the grid.
Identification of the most efficient wind turbine locations through the creation of meso-scale wind atlases, conducting measurements, and utilizing production data from neighboring wind farms.
Conducting a feasibility study based on current market costs and determining the project’s payback period.
Standards: IEC61400-50-1:2022, IEC61400-50-2:2022, FGW TG6, MEASNET Procedure v3, IEC61400-15-1, ISO/IEC Guide 98-3:2008
Reliable energy yield calculations are crucial for favorable project financing conditions. In addition to wind speed, the uncertainty of predictions plays a central role in this regard.
To minimize uncertainties in analyses conducted according to FGW and MEASNET standards, it is essential to design the measurement campaign professionally.
By developing measurement campaigns in compliance with standards, our experienced engineers provide precise results and establish a solid foundation for your project financing.
In these types of measurements, tubular or lattice measurement masts—equipped with wind speed and wind direction sensors (anemometers and wind vanes) along with other meteorological instruments—are installed on-site. These masts record local meteorological conditions with high precision. Mast measurements have long been the only permitted method for determining on-site wind characteristics for wind energy applications according to the aforementioned standards.
We possess over 20 years of experience in the installation and reliable operation of measurement masts. We exclusively use high-quality, calibrated instruments that comply with various standards (WMO, ISO, IEC, FGW, and MEASNET). Consequently, we can guarantee the lowest possible uncertainties. We offer masts up to a height of 160 m.
Ideally, wind measurements are conducted at the hub height of the planned wind turbines; this height is assumed to represent the entire rotor swept area, thereby leading to the lowest uncertainty rates in wind field modeling. Site assessment standards from MEASNET and FGW also prescribe a minimum height for wind measurements relative to the hub height.
Due to the rapid development of wind energy, particularly the continuous increase in hub heights, the tubular masts commonly used in the 90s were first replaced by lattice towers and subsequently by remote sensing methods. These technologies allow for measurements at high altitudes of up to 300 m, depending on the atmospheric conditions at the location. The new technologies of LiDAR and SoDAR systems have proven to be a time- and cost-efficient alternative, as their permitting procedures are much simpler compared to tall measurement masts.
For remote sensing systems to be utilized in energy yield assessment studies for wind power plants, the flow within the measured volume must be homogeneous. Therefore, remote sensing systems are generally suitable for flat terrain; however, they can also be used in moderately complex terrains where flow is not homogeneous, provided that CFD (Computational Fluid Dynamics) correction and/or verification with mast measurements is performed. The algorithm used for CFD correction must have proven itself in tests involving different complexity classes, and these tests must be documented in detail to verify the accuracy of the algorithm.
RSD (Remote Sensing Device) units can also be utilized in complex locations to reduce vertical extrapolation uncertainties. In such cases, the primary measurement is conducted via a measurement mast. If there is an appropriate overlap in measurement heights, the mast measurement can be vertically extrapolated using the RSD.
Consequently, a clear rule currently applies: in homogeneous flow, remote sensing alone is sufficient. In medium or high mountainous regions—namely complex locations—wind flows are not homogeneous, which limits the accuracy of remote sensing systems. Therefore, in these locations, we preferably rely on continuous verification with a reference cup anemometer.
While SoDAR systems are noted for being economical, LiDAR systems offer higher range and greater data availability, particularly in rainy weather. Furthermore, they possess a higher accuracy rate and have proven to be more robust in offshore applications and complex terrains.
For these reasons, LiDAR technology has become significantly more widespread over time. SoDAR systems continue to be a good and cost-effective option in specific cases, such as in less populated areas and where weather conditions are consistently very clear.
Wind measurement masts are exposed to extreme weather conditions. In particular, seasonal temperature fluctuations put a load on the guy wires of the steel structures. Due to differences in the expansion and contraction behavior of individual wires, the mast may lose its vertical alignment, which can have significant effects on its geometry and, consequently, on final measurement uncertainties. For example, even a minimum tilt of a few degrees in the side arms can cause serious data distortion, with errors in yield estimation reaching up to 5%. The worst-case scenario is the total collapse of the mast.
Thanks to the regular maintenance intervals we determine based on the station type, we correct these structural changes at an early stage. In this way, we achieve very high availability and consistently high measurement quality for your measurements. This guarantees the lowest possible measurement uncertainties in your future wind and yield reports.
For LiDAR and SoDAR measurements, you can also benefit from our regular checks and maintenance work, such as ensuring fuel supply and controlling the orientation of the devices. Furthermore, you do not need to worry about the necessary device calibrations before and after the measurement campaign.
Our experts monitor the acquired measurement data on a daily basis. This ensures that any potential irregularities are immediately detected, their causes are identified, and appropriate measures are taken to rectify potential errors or malfunctions. This provides you with high data availability. Following a meticulous data analysis, you are sent a monthly availability summary in tabular form, along with additional information such as the last maintenance date, last connection date, and—if necessary—the reasons for any data loss. Furthermore, you can benefit from our web-based PowerBI platform to access monthly statistics.
At the end of the measurement period or after 12 months, you will receive a measurement report that complies with FGW criteria for wind measurement reports.
Standards: IEC 61400-12-1, IEC 61400-12-2, FGW TR6, MEASNET: Evaluation of Site-Specific Wind Conditions v3, IEC 61400-15-1, ISO/IEC Guide 98-3:2008
Wind Resource Assessment
Accurate assessment of the wind resource is crucial for all stakeholders involved in financing renewable energy projects, which are supply-driven. It is essential to work with an experienced and independent expert to minimise the error between energy production assessments made using methods compliant with MEASNET and FGW standards and the actual production results.
A site visit is necessary to accurately model the terrain and vegetation cover of the site. During the site visit, the wind measurement tower and equipment are also inspected. During the inspection, the compliance of the measurement station with the IEC 61400-50-1 standard and the angles of the side arms and lightning rod are examined. The side arm angles are of great importance for verifying the direction sensor measurements.
After filtering out measurement data considered to be erroneous, intra-station and inter-station data synthesis (if possible) is performed to increase the data coverage. The correlation between the long-term data sets of sufficient quality and the measurement data collected on site is checked, and the potential for use as a long-term source is investigated.
In the final stage of the analysis, the vertical profile of wind speed is derived using measurement data, and this profile is used to calculate the wind resource at hub height. The calculated average wind speed, extreme wind speeds and turbulence intensity values are used to determine the site class.
For remote sensing systems to be used in wind farm energy production assessment studies, the flow must be homogeneous in the volume where measurements are taken. Remote sensing systems can be used in moderately complex terrains where the flow is not homogeneous, provided that CFD correction and/or verification with a conventional measurement station is performed. The algorithm to be used for CFD correction must have proven itself in tests conducted on different complexity classes, and these tests must be reported in detail to verify the accuracy of the algorithm.
In areas of medium and high complexity, it is not appropriate to use remote sensing systems to measure the wind source alone with today’s technology. However, even in such areas, they can be used alongside conventional measurement systems to reduce vertical extrapolation uncertainties.
In power plants where production data is available for 12 months or more, the production data itself provides the best input for determining the wind resource in that area. The 10-minute resolution SCADA data from the wind turbines is used in the assessment.
After filtering out data considered erroneous, turbine-to-turbine data synthesis (where possible) is performed to increase the data coverage. Wind speed and Production data is scaled to a longer period if a long-term data source of sufficient quality is available.
Wind farms may have been constructed in different phases. Changes in the number of turbines affect production losses experienced by the turbines. In sites where such changes have occurred, a detailed loss study should be carried out, taking into account the commissioning date of each turbine.
Availability rates should be reviewed using historical data. The formula defined in the türbine supply agreement is used for this purpose.
As a result of the study, long-term wind frequency distribution, gross energy production, power curve and loss factors (availability, electrical efficiency, turbine performance, environmental and constraint-related) are calculated for each turbine location.
The frequency distribution at tower height obtained using SCADA data can be used as input for the energy production assessment study or SCADA analysis results can be used to correct the flow model created using wind measurement data.
Standards: IEC61400-50-1:2022, IEC61400-50-2:2022, IEC61400-50-3:2022, IEC 61400-12-6:2022, IEC61400-26-1:2019, FGW TG6, MEASNET Procedure v3, IEC61400-15-1, ISO/IEC Guide 98-3:2008
The structural integrity of a wind turbine largely depends on compliance with manufacturer-specific design requirements. Permanent protection against mechanical loads throughout the entire service life can only be ensured when the climatic conditions at the site meet these requirements. To accurately determine the suitability of a turbine type, we precisely model the relevant meteorological parameters at hub height for each turbine site. The measurement and calculation values summarized below constitute a decisive foundation in this regard.
Wind potential and energy yield calculation
Precision in modeling — security for your investment. We use detailed local measurement data and validated flow models to determine wind conditions at hub height in detail, taking into account air density and wind direction. To obtain a precise digital image of your location, we include highly accurate maps regarding elevation gradients, roughness, forested areas, and obstacles in our calculations.
More security in complex terrains: Since linear flow models are generally insufficient in medium and high mountainous regions, we evaluate the necessity of more comprehensive models. These non-linear numerical flow models can reduce modeling uncertainties and are utilized by us when required.
In wind farm expansions, we place special emphasis on minimizing wake effects by considering existing constraints; this maximizes the economic efficiency of your wind farm.
The result of our modeling is ultimately the free gross energy yield of the wind farm. The term “Free” means that no losses are included in the calculation, nor are wake losses within the planned plant included. In contrast, the gross energy yield of the plant includes only plant efficiency as a loss, i.e., the shadowing of wind turbines by each other.
Our detailed analysis of systematic losses, conducted according to FGW TR6, reveals the net energy yield required for financing. In wind farm expansions, production data is directly available on-site. In this case, we determine actual losses by evaluating SCADA data.
Every step of the calculation process and every single loss involves an uncertainty. We quantify these fully and combine each uncertainty component according to its relationship with other uncertainties. From the resulting total uncertainty of annual energy production, we derive exceedance probabilities (P-values) under the assumption of normal distribution.
Standards: IEC61400-1:2019, IEC61400-12-5:2022, IEC61400-26-1:2019, IEC61400-12-4:2020, IEC 61400-50 series, FGW TG5, FGW TG6, FGW TG10, MEASNET Procedure v3, IEC61400-15-1, ISO/IEC Guide 98-3:2008
Wind power plants are increasingly being operated in conjunction with battery energy storage systems (BESS). We support you in the optimum design of the storage unit in terms of required storage capacity and ideal times for storage or sale. This is achieved through the analysis of annual fluctuations and the determination of the average expected hourly power output.
Standards: IEC61400-1:2019, IEC61400-12-5:2022, IEC61400-26-1:2019, IEC61400-12-4:2020, FGW TG6, MEASNET Procedure v3, IEC61400-15-1, ISO/IEC Guide 98-3:2008
Fluctuations in energy production over the 8,760 hours of the year are calculated by following the steps below:
Using selected long-term sources, speed and direction data are extended to a representative long-term period.
A theoretical year that best represents the extended time series is calculated. Thus, we obtain a data set representing long years, including 8,760 hours of wind speed and wind direction data.
Using the flow model for each wind turbine, we determine sectoral time series for wind speed and direction with air density correction.
Gross energy is calculated per turbine based on the 8,760-hour time series; in this calculation, plant performance is aggregated and efficiency losses are corrected. Naturally, a higher time resolution in the calculation of hourly energy production leads to higher uncertainties in the calculation of annual energy production.
Net energy production is calculated by taking into account direction-dependent losses—such as tracking and sector effects—and seasonal losses, such as icing, based on temperature and humidity.
Wind power plant production may be constrained for the reasons summarised below.
Losses due to limitations are predicted using hourly energy production for factor 1 and 3. For factor 2, sectoral limitations are applied to each turbine depending on turbine technology and approach distances, and losses due to this are predicted.
Standards: IEC61400-1:2019, IEC61400-12-5:2022, IEC61400-26-1:2019, IEC61400-12-4:2020, FGW TG6, MEASNET Procedure v3, IEC61400-15-1, ISO/IEC Guide 98-3:2008
Environmental or social constraints (bats, noise, flicker etc.)
Sectoral restrictions due to interaction between wind turbines
Grid limits in wind and hybrid energy production plants
The information and documents to be submitted in the EPDK Preliminary License and License Application are specified in the “List of Information and Documents to be Submitted”. These documents are submitted to the institution in full after performing the necessary studies and obtaining document approvals.
The site boundary is created in accordance with the “Technical Evaluation Regulation” published by EIGM, using the turbine layout created for the project site or wind potential maps.
During the completion phase of construction permits for WPP projects, opinions must be obtained from relevant institutions. USENS prepares the application files and shares the document tracking numbers with the Employer after forwarding them to the institutions. Upon request, the status of the applications is monitored monthly, and a restriction status summary is shared with the Employer after opinions are received from all institutions.