LOSS & UNCERTAINTY

Once a PARK calculation is performed there are still several issues to be considered before a wind farm project is ready to get financed. The LOSS & UNCERTAINTY module is an efficient and structured way of addressing these remaining issues, as well as the possibility to correct for systematic errors as e.g. in complex terrain (RIX correction) or to calculate the losses for various curtailment.

Losses

In a wind farm project several important losses must be considered, and their resulting reduction calculated; the module helps the user through this process with a full list of the relevant losses. Several loss types can be calculated within the module e.g.

• High Wind Hysteresis
• High/Low Temperature control
• Wind Sector Management and other customizable curtailment settings.

Additional losses can be entered, such as:

• Tree growth
• Performance Degradation
• Icing

All losses are grouped and organized according to international practice and documented in the report.

Uncertainties

The assessment of project AEP uncertainties is an equally important step to enable evaluation of the risk of the investment. In the module all the important uncertainty components are grouped according to origin.

The main uncertainty components resulting from horizontal and vertical extrapolation may be calculated using a setup based on EMD’s vast experience from projects in Denmark and around the world.

Uncertainty due to the power curve may also be calculated according to the IEC61400-12 standard. In total, LOSS & UNCERTAINTY enables input for 12 different uncertainty  parameters.

Bias correction

In complex terrain industry standard flow models like the WAsP model may come short. In the bias correction part of the module it is possible to correct for such model shortcomings with a RIX correction. Alternatively, RIX calculations can be included in the PARK calculation, and then afterwards transferred directly to LOSS & UNCERTAINTY.

Integrates energy and environment

The LOSS & UNCERTAINTY module requires a PARK calculation, but for accurate calculation of different loss and uncertainty components the module also offers to import data from e.g.:

• METEO Object – time series with relevant parameters for e.g. curtailment
• DECIBEL, SHADOW – for calculation of losses due to environmentally given reduction modes

In the basic approach the user can simply insert values for each loss and uncertainty component in a well-structured way based on own experience and hints in module text. In the more thorough approach it is possible to calculate many of the losses and several uncertainty components within the module based on detailed calculation algorithms and extended data describing how the loss or uncertainty is linked to site-specific parameters. If there are known problems with the measuring equipment or a RIX (terrain Ruggedness IndeX) calculation is included in the loaded PARK calculation, it is also possible to calculate and correct for such systematic errors for each turbine position in the Bias correction part of the module. Likewise, any curtailment included in the PARK calculation is automatically transferred to LOSS & UNCERTAINTY.

Reports

The LOSS & UNCERTAINTY module provides the user with thorough documentation via its extensive report options. The main report page can be shown either for the wind farm or for the turbines individually, depending on how the project is sold (if so). The main report page gives a solid overview with all the key figures and illustrative, easy to understand graphics, also emphasizing where the project calculations or data background might be improved. Following the main report, the major loss and uncertainty (and bias if included) components are summarized with the important assumptions made in each calculation. Finally, the module provides a detailed calculation report for each component calculated in the “thorough” approach.

Data to file – Detailed WTG-wise results and sub-results can be copied to clipboard/text-file for further analyses in other software tools.