Site Assessment

DTU Wind and Energy Systems (DTU Wind) is a member of the MEASNET site assessment expert group and we offer site assessment in accordance with the MEASNET procedure Evaluation of Site-specific Wind Conditions.

A site assessment estimates the site-specific wind conditions (wind direction frequency distribution, wind speed distribution, temperature, humidity, pressure, air density, turbulence, wind shear, extreme winds and flow inclination) as well as the site-specific energy yield of wind turbines (including systematic operational losses and uncertainty). Calculations are made applying the WAsP, WAsP CFD and WAsP Engineering software packages.

The work will involve at least the following main tasks:

• Collection of data and information, i.e. generation of all necessary inputs to the analyses, which normally requires a site visit by an expert from DTU Wind
• Analyses and reporting, which most often will be done home-office at DTU Wind’s Risø campus

The report will contain the DTU Wind evaluation of site-specific wind conditions for a) the mast position and b) one layout of one wind turbine type, prepared in accordance with the MEASNET procedure. As such, the report will include the following sections:

• “General Elements” includes a description of the task and a summary of the report and the results
• “Wind Measurement” includes a summary of the available wind measurement documentation (site, measurement system and measurement procedure)
• “Measurement Data” contains the results of the measured quantities, including data quality assessment, filtering and filling
• “Site Assessment” includes site assessment results based on the available wind data and documentation as well as wind turbine hub height, wind turbine rotor diameter, wind turbine power curve and wind turbine thrust curve
• “Energy Yield” includes results for energy yield, systematic operational losses and uncertainty

Note that a bankable site assessment in accordance with the MEASNET procedure can be carried out when there is:

• At least twelve consecutive months of quality assessed and filtered wind data
• Without data gaps (arising from the quality assessment and filtering), which introduce systematic errors in the measurement