In every wind plant, operators are looking to maximize turbine performance to increase their AEP and their top-line revenue number. There are countless methods to optimize turbine performance, including OEM and third-party power curve upgrade solutions. Something as simple as washing turbine blades will have an impact on performance.
No matter which solution you choose to implement, you need to assess the change in performance in your wind plant to quantify your return on investment (ROI).
Challenges of Measurement
Ideally, we could compare power output before and after an upgrade was made to quantify changes in performance. Unfortunately, it's not that simple. Wind is constantly changing. You cannot account for variables such as wind speed, direction, shear, veer, air density, and turbulence when comparing two inputs. All of these factors affect turbine performance, so the inability to take them into account creates a blind spot and makes it impossible to assess changes in performance accurately.
Methods of Measurement
Two main methods were specifically designed to measure wind turbine performance changes and account for the variable nature of wind:
IEC 61400-12-1 Power Curve Tests. The most recent edition of the IEC 61400-12-1 Standards contains specific procedures for measuring and quantifying energy production and improvement. It is the most common and traditional method of measurement. However, it requires the use of met towers or LiDAR systems, which not every plant has readily available. Ultimately, that means that this standardized measurement process can be prohibitively expensive and time-consuming.
SCADA Data. In response to the problems posed by using IEC 61400-12-1, methods developed that use only the plant's existing SCADA data. This eliminates the high cost and long time frames, but these methods may lack sophistication and transparency. Because of this, wind plant owners and operators are often skeptical and feel they can't accurately deduce whether turbine upgrades improved their energy production.
Elements of a Solid Measurement Strategy
There are definitive challenges to measuring your power improvement. Even so, we still believe that all wind plants should perform an energy improvement assessment when you invest in a turbine upgrade. Therefore, it's essential to understand the elements of a sound measurement method. Any sound methodology should be:
Cost-effective. Assessments may be performed multiple times per year, so they shouldn’t require expensive equipment.
Accurate. Uncertainty should be estimated and be low enough to detect the magnitude of performance change.
Reproducible. The analysis should be transparent enough to reproduce the results independently.