Collaborative Research: Large-Scale Wave Energy Arrays -- Integrated Control/Array Design in Random Seas

University Of Notre Dame, Notre Dame IN

Investigators

Abstract

PI: Scruggs, Jeffrey / Taflanidis, Alexandros Proposal Number: 1235732 / 1235768 Institution: University of Michigan Ann Arbor / University of Notre Dame Title: Collaborative Research: Large-Scale Wave Energy Arrays -- Integrated Control/Array Design in Random Seas 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 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 constitutes an effort to rectify these issues, through a novel synthesis of two disparate research threads: robust control theory and large-scale stochastic optimization. The proposed work will focus on accurate techniques for assessing and optimizing the power generation potential for a given geographic location and a given array perimeter. This 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? The PIs will integrate their respective approaches (the optimal power generation control algorithm for a WEC system, and stochastic sampling methods) into a single computationally-efficient framework, 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. In this work the PIs will innovate generic techniques for large-scale WEC array design using techniques from robust control theory and advances in high-performance computing. This collaborative project will provide a clear insight into the true potential of large-scale WEC arrays to meet future energy needs. Also the project has the potential to lift technology adoption barriers and to promote advocacy among the public. This will be accomplished via diffusion mechanisms that enhance ambassadorship among students and awareness among stakeholders. The PIs will adopt a two-pronged strategy, involving: 1. development of open-access online resource assessment software, and 2. educational outreach initiatives focused on ocean energy. In the first component, the online application, supported by a friendly user-interface, will assess the optimized annual power output and array configuration for a user-specified geographic location and array perimeter. A more technical offline version targeted at WEC developers will also be made freely available. The second component will be achieved through interdisciplinary REU initiatives that target underrepresented groups and through the development of project-based learning modules, leveraging the proposed online assessment tools. This will motivate and empower the student participants to advance this research both within their profession and the public at large, thus propagating the broader impacts of this research.