Date of Award

2020

Degree Type

Dissertation

Degree Name

Doctor of Philosophy in Ocean Engineering

Department

Ocean Engineering

First Advisor

Reza Hashemi

Abstract

Ocean renewable energy technology - including tidal-streams, wave power, and offshore wind - can help provide a clean energy source, particularly for coastal communities located near the ocean. However, the development of ocean renewable energy projects faces many challenges due to the interaction of ocean renewable energy farms and the natural environment. For instance, ocean energy devices need to survive the extreme and uncertain environmental loads particularly during storms; on the other hand, deployment of large scale arrays of energy devices (e.g., offshore wind farms or tidal energy farms) can lead to significant physical, ecological, and social impacts in an area. In the US Northeast and Canada, both tides and offshore wind have great potentials to supply a significant percentage of the energy demand. About 7 GW of tidal stream resource in Minas Passage and the Gulf of Maine (one of the best spots in the world), and more than 110 GW of offshore wind energy resource along the US east coast have been estimated. This research employed a coupled ocean-wave model (COWAST: Coupled Ocean Atmosphere Wave Sediment Transport) to investigate the interactions of energy farms and the ocean environment in the Gulf of Maine (tides) and offshore Rhode Island (wind). In particular, using process-based (i.e., COAWST and OpenFAST) and statistical approaches (bivariate and multivariate extreme value analysis), the physical impacts of tidal energy development in the Gulf of Maine and the impacts of severe storms on planned offshore wind farms were assessed. This dissertation includes an introduction and 3 manuscripts as follows: 1) The impacts of tidal energy development and sea-level rise in the Gulf of Maine, 2) Assessment of hurricane-generated loads on offshore wind farms, and 3) Sources of uncertainty in assessments of extreme wind and wave loads for the wind farm sites off the US Northeast coast. In each manuscript, a more detailed and specific abstract that discusses the objectives and results of each study has been provided. Results of this study provide more insights about challenges of ocean renewable energy development and some numerical tools to understand, predict, and address them.

Available for download on Monday, October 31, 2022

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