Concurrent formation/control robust optimization of wave energy extraction buoys

 

CMMI-1235768

1/1/2013-12/31/2015

Large-Scale Wave Energy Arrays: Integrated Control/Array Design In Random Sea

 

Motivation:

In the transition of the US energy economy from traditional technologies to renewables, ocean wave energy technology has a significant role to play. However, our understanding of how to best harness the resource is still evolving. For Wave Energy Conversion (WEC) technologies to be relevant on a utility scale, it will be necessary to distribute vast arrays of energy-harvesting buoys across a wide expanse of ocean. Maximization of power generation from large-scale WEC arrays requires, though, a synthesis of optimal control and optimal geometry techniques. The present state-of-understanding is limited to single buoys and small array sizes. It also does not account for the limitations of power conversion systems, or the fact that sea states are random and uncertain phenomena. This collaborative project between the University of Notre Dame (P.I Taflanidis) and the University of Michigan (P.I Scruggs) constitutes an effort to rectify these issues, through a novel synthesis of two disparate research threads: robust control theory and large-scale stochastic optimization.

 

Objectives:

 

This proposed work will result in accurate techniques for assessing and optimizing the power generation potential for a given geographic location and a given array perimeter. The PIs will innovate generic techniques for large-scale WEC array design using techniques from robust control theory and advances in high-performance computing and stochastic optimization. They will integrate their respective approaches into a single computationally-efficient algorithm, which simultaneously reshapes the array and redesigns the controller upon each iteration. This will reduce the time necessary to accurately evaluate the maximum power generation capability for a given array size by several orders of magnitude.

 

The research effort will provide answers to some necessary questions for this technology to move forward: (i) Given an array perimeter, a probabilistic characterization of the sea state, and a technological characterization of the generators, what is the optimal number of WEC buoys, and how should they be arranged? (ii) How do the optimal number of buoys and configuration depend on the conversion technology used? (iii) How does the buoy configuration depend on the efficiency of energy storage and transmission systems that interface the array with the grid?

 

  WEC_project_Impacts

 

Publications:

  1. Scruggs, J.T, Lattanzio, S.M., Taflanidis, A.A. and I. Cassidy (2013). “Optimal causal control of an ocean wave energy converter in stochastic waves”. Applied Ocean Research, 42: 1-15. [Link]
  2. Jia, G. and A.A. Taflanidis (2013). “Non-parametric Stochastic Subset Optimization for optimal reliability problems”. Computers and Structures, 126: 86–99. [Link]
  3. Medina, J.C. and A.A. Taflanidis (2013). “Adaptive Importance Sampling for Optimization under Uncertainty Using Stochastic Simulation”. In Proceedings of the 54th Structures, Structural Dynamics, and Materials Conference AIAA Conference. April 8-11. Boston, Massachusetts.
  4. Jia. G. and A.A. Taflanidis (2013). “Non-parametric stochastic subset optimization for system design optimization under uncertainty”. In proceedings of the 3rd International Conference on Soft Computing Technology in Civil, Structural and Environmental Engineering. September 3-6. Sardinia, Italy.

 

Related Data:

  • Standalone tool for assessment of probabilistic performance of different array formations (to come soon)

 

 

 

 

Acknowledgment

 

This material is based in part upon work supported by the National Science Foundation under NSF grant number CBET 1235768. This support is greatly appreciated. Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.