How to increase wind turbine power output?

Once sited, commissioned and operating, the chief method of increasing output of a wind turbine generator is through significant hardware upgrades to the unit. This can be a long, difficult, and expensive program for many wind operators who may not have the resources to undertake such an effort or feel confident about the results it would yield. Fortunately, deploying modern, advanced control strategies can improve wind turbine power output—without altering any mechanical components—making it both highly effective and cost efficient.

Improving the wind turbine’s efficiency often leads to an increase in power output, as more of the wind's energy is converted into electricity. The following discussion is primarily focused on increasing the annual energy production (AEP) via tailored advanced control technologies.

Advanced Control Solution - Power Boost
The Power Boost algorithm improves the front-end of the rated portion of the power curve by increasing the power setpoint as it transitions from sub-rated. The momentary boost adds a fraction of a percent AEP each transition and is more prevalent in windier conditions. Importantly, there are no significant trade-offs associated with utilizing this advanced control feature.

Advanced Control Solution - Power Uprate
The Power Uprate solution is designed to enhance the power output of wind turbines through two distinct approaches: Maximized Uprate and Balanced Uprate. Both methods aim to increase annual energy production, though they come with specific considerations and trade-offs. A significant feature of this option is the ability to manually or automatically enable this feature when certain market and/or operating conditions are ideal to counter the trade-off on mechanical wear. It should be noted that for each, additional electrical auxiliary capacity may be required to handle the increased output.

Maximized Uprate
Maximized Uprate allows for a significant increase in power output, contingent on the temperature of critical components, by operating above the rated power curve for all rated level wind speeds. This method requires both mechanical and electrical overhead to manage the enhanced performance. The benefit of this approach is a substantial potential increase in earnings, with up to a 7% rise in AEP, depending on the uprate level and site conditions. However, this method can reduce the turbine's overall lifespan due to the increased operational wear.

Balanced Uprate
Balanced Uprate also focuses on increasing power output, but it does so based on prevailing wind speeds and component temperatures. Like the Maximized Uprate, this algorithm operates the unit above the rated power curve, but only at a select wind speed range. As such, it does not require the same mechanical trade-off as the Maximized Uprate. The potential earnings increase with Balanced Uprate is up to 2.5% in AEP, depending on the uprate level and site conditions.

Advanced Control Solution - Extended Cut-out
The Extended Cut-out solution is designed to enhance the operational range of wind turbines by allowing them to continue functioning even at wind speeds above the normal cut-out threshold. This is achieved by decreasing the power curve beyond the normal cut-out speed. This, in effect, gradually derates the unit at high wind conditions to protect the turbine from potential damage while extending operation beyond the previous cut-out wind speed.

One of the primary benefits of derating power is that it eliminates abrupt cut-outs, which significantly improves grid stability. This smoother transition reduces the wear and tear on main components, as there are fewer stops and starts at high wind speeds. Consequently, this leads to more stable and reliable power output.

Moreover, the Extended Cut-out feature can result in increased earnings, particularly in high wind sites where the wind speeds frequently exceed the normal cut-out limits. By extending the operational range, wind turbines can capture more energy, thereby boosting annual energy production.

However, it is important to consider that there is a trade-off associated with this approach. Extended operation at higher wind speeds causes additional strain on components, which can lead to a decrease in the overall lifespan of the wind turbine.

Self-Calibrating Yaw Control
Self-calibrating yaw control algorithms are designed to constantly identify and adjust static yaw misalignments, thereby enhancing the turbine's performance by ensuring the nacelle is facing into the wind. Utilizing machine learning, these algorithms generally need a short auto-calibration phase following installation. If any changes or deterioration occur in the wind vane or yaw calibration, the system will automatically adjust itself. This allows accurate rotor alignment and improves the power output of the turbine generator, potentially boosting annual energy production by 3-5%.

Automatic Rotor Imbalance Correction
Advanced control systems in modern turbines incorporate rotor imbalance detection algorithms to identify and rectify blade-to-blade misalignment. Upon detecting pitch misalignment, the system autonomously adjusts the pitch setpoints to ensure the blades are correctly aligned. This technology not only boosts annual energy production by up to 0.7% but also decreases fatigue loads on the wind turbine rotors.

Tailoring Turbine Power Output to Meet Operational Demands
Advanced control solutions such as power boost, power uprate, and extended cut-out - along with wind turbine efficiency techniques - can significantly increase annual energy production while having minimal impact on load.

Emerson provides a range of wind turbine retrofit solutions tailored to improve turbine power output according to your specific operational requirements.