In recent years, researchers from the National Renewable Energy Laboratory (NREL) have been making progress in multiple avenues of wind systems engineering. This includes the study of how to integrate wind energy engineering and cost models across wind plants, finding the important interactions between various subsystems to achieve a better understanding of how to improve system-level performance and cost reductions, and hosting international, collaborative workshops.

Researchers submitted two journal articles to Wind Energy that have been accepted on work performed in 2014. Monte Carlo integration in fatigue load estimation of floating offshore wind turbines (forthcoming) described efforts to calculate long-term fatigue loads for floating offshore wind turbines, which have previously been mathematically difficult to estimate. In this paper, NREL researchers integrated FAST, a system for modeling wind turbine aerodynamics, into NREL’s systems engineering tool, the Wind-Plant Design and Engineering Model (WISDEM™). This combination gave a large improvement in computational efficiency, suggesting that there is potential in using advanced statistical methods to analyze wind turbine fatigue and extreme loads.

A second article, Wind plant system engineering through optimization of layout and yaw control (forthcoming), describes a collaboration between NREL and the Delft University of Technology. This work focused on a new method of wind plant controls that uses the yaw control of individual turbines to improve overall wind plant performance. The new model FLORISSE employs an optimizer to select the yaw position of each turbine in a way that avoids a significant wake impact from one turbine to the next, which improves plant performance (specifically when all of the turbines are yawed toward the mean wind direction). This optimization of yaw was further coupled with the selection of wind turbine positions in a plant layout to bring controls design earlier into the wind plant layout design process. Study results showed that coupled optimization may provide substantial performance benefits.

In addition, NREL partnered with DTU Wind Energy to co-host the third NREL Wind Energy Systems Engineering Workshop on January 14-15, 2015, in Boulder, Colorado. This year’s theme was on exposing interactions in wind energy systems and exploring how different wind energy stakeholders address them in new, integrated, and innovative ways.

The workshop highlights included a variety of expert panel sessions on:

• The cost of energy in today’s wind systems;
• Challenges and uncertainty in wind system design and operation;
• The evolution of wind system standards and design methodologies;
• Tools and methods for integrated wind system design and analysis; and
• Integrated design of wind systems from components to turbines to plants to operations.

More than 100 people from around the world attended the event, including representatives from academic institutions, laboratories, and government, as well as suppliers, turbine original equipment manufacturers, developers, and owners/operators. Key takeaways from the workshop were the lessons learned about the benefits of using more integrated approaches to wind turbine and plant design and operation. Additionally, future work will include pursuing an IEA Wind task proposal for integrated system modeling and participation in an IEA Wind Technical Expert Meeting 80.

NREL
www.nrel.gov