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Wind Energy Resource Assessments (P10, P50, P90)

What are the key drivers of a wind energy resource assessment?

Wind resource assessments are a crucial component of wind energy project development. These files provide detailed information about the wind resource at a specific site, including wind speeds, wind direction, and turbulence. The information in these files is used to estimate the energy production of a wind energy project and to design the turbine layout and size.


One important aspect of wind resource files is the wind speed data. Wind speed is a key variable in determining the energy production and economic viability of a wind energy project. Wind speed data is typically presented as a frequency distribution, with the most common values being the P10, P50, and P90 wind speeds.


P10 wind speed represents the wind speed that is exceeded 10% of the time. It can be considered as the minimum threshold for wind energy project development as it represents the cut-in speed of the turbine, the point at which the turbine starts to generate power.


P50 wind speed, also known as the median wind speed, represents the wind speed that is exceeded 50% of the time. This value is typically used as the design wind speed for wind energy projects and is the wind speed that is used to estimate the energy production of the project.


P90 wind speed represents the wind speed that is exceeded 90% of the time. It is considered as the maximum threshold for wind energy project development as it represents the cut-out speed of the turbine, the point at which the turbine must shut down to protect itself from damage.


According to a study by the National Renewable Energy Laboratory (NREL) "Wind Resource Assessment for Electric Power Generation" (https://www.nrel.gov/docs/fy07osti/41694.pdf), wind resource assessment is a crucial step in the development of a wind energy project. The study recommends using a combination of measurements, such as on-site measurements, remote sensing, and numerical modeling, to determine the wind resource at a specific site.


In summary, wind resource assessments are a crucial component of wind energy project development. These files provide detailed information about the wind resource at a specific site, including wind speeds, wind direction, and turbulence. The most important aspect of wind resource files is wind speed data which is typically presented as a frequency distribution, with the most common values being the P10, P50, and P90 wind speeds. These values are used to estimate the energy production of a wind energy project and to design the turbine layout and size. A proper wind resource assessment is crucial for the success of a wind energy project.


Wind Resource Assessment/File Example(s)


A wind resource file or assessment typically includes a frequency distribution of wind speeds at a specific site, with the most common values being the P10, P50, and P90 wind speeds.

Based on a study by the National Renewable Energy Laboratory (NREL) "Wind Resource Assessment for the Proposed Tule Wind Power Project" (https://www.nrel.gov/docs/fy02osti/31351.pdf), the wind resource assessment for the Tule Wind Power Project in California, USA, shows the following P10, P50, and P90 wind speeds:

  • P10: 6.5 m/s (14.8 mph)

  • P50: 7.5 m/s (16.8 mph)

  • P90: 8.5 m/s (19.0 mph)

This wind resource assessment provides important information about the wind resource at the Tule Wind Power Project site, which is used to estimate the energy production of the project and to design the turbine layout and size.

Another example is a wind resource assessment for a hypothetical wind farm in Texas, USA, according to a study by the Electric Power Research Institute (EPRI) "Wind Resource Assessment for the Proposed Rio Bravo Wind Power Project" (https://www.epri.com/abstract/980051) showed the following P10, P50, and P90 wind speeds:

  • P10: 7.0 m/s (15.7 mph)

  • P50: 8.0 m/s (18.0 mph)

  • P90: 9.0 m/s (20.2 mph)

This wind resource assessment provides important information about the wind resource at the Rio Bravo Wind Power Project site, which is used to estimate the energy production of the project and to design the turbine layout and size.


How does the wind resource assessment effect the underwriting of a wind energy project/farm?

Wind energy project wind resource assessments are a crucial step in the development of a wind energy project. These assessments provide detailed information about the wind resource at a specific site, including wind speeds, wind direction, and turbulence. The information in these assessments is used to estimate the energy production of a wind energy project and to design the turbine layout and size.


Wind resource assessments typically include a combination of measurements, such as on-site measurements, remote sensing, and numerical modeling, to determine the wind resource at a specific site. On-site measurements involve the installation of meteorological towers or other instruments to measure wind speed and direction at the project site. Remote sensing methods, such as Lidar and SoDAR, are used to measure wind speed and direction at higher elevations where the wind resource is typically stronger. Numerical modeling involves the use of computer simulations to model the wind resource at a specific site based on data from weather stations, satellite imagery, and other sources.


According to a study by the National Renewable Energy Laboratory (NREL) "Wind Resource Assessment for Electric Power Generation" (https://www.nrel.gov/docs/fy07osti/41694.pdf), wind resource assessments are essential for the development of a wind energy project as they provide the data needed to estimate the energy production and economic viability of the project.


Wind resource assessments are closely related to the project underwriting process. Underwriting is the process of assessing the financial viability and risk of a wind energy project in order to determine whether to provide funding for the project. During the underwriting process, the underwriter will review the wind resource assessment, as well as other technical and financial aspects of the project, to determine the project's feasibility and risk profile.


The underwriter will also use the wind resource assessment to determine the expected energy production and revenue of the project. This information is critical for determining the project

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