Sourcing energy from renewable sources is currently a key theme in modern society. Consequently, the pace of development of these emerging technologies is likely to increase in the near future, particularly in marine renewables. However, the environmental and ecological impact of many of these new developments in the marine environment is largely unknown. My thesis has focused on one unknown area of interaction; the potential effect of tidal-stream devices on marine mammals. Collision risk is often cited as a key concern. Therefore, my premise was - for marine mammals to avoid a collision with a marine renewable device (assuming they are on a collision course) they must first detect the device. It is well understood that marine mammals use sound and hearing as their primary sense for communication, foraging, navigation and predator avoidance, so it is highly likely that the primary cue for device detection will be acoustic. However, it is not known how operational marine renewable devices might modify the acoustic landscape in these areas, or whether they will be audible to marine mammals in time to alert them to the presence of devices. It has been suggested that the high level of natural and anthropogenic background noise in tidal-stream areas may mask (drown out) the signal of the tidal devices. The acoustic characteristics of underwater noise in shallow coastal waters are currently not well known. My thesis adds data to this knowledge gap by measuring and mapping underwater noise levels in tidal-stream areas.

With the Scottish Government's commitment to sourcing 100% of the national electricity demand from renewable sources by 2020, within the global framework of climate change mitigation, the potential of the marine environment around the Highlands and Islands Region of Scotland to add to Scotland's renewables portfolio has led to the expansion of the wave and tidal industries in recent years. Nevertheless, to date, there has been limited research conducted on the social systems around marine renewable energy development, excluding offshore wind. In answer to this deficit, this study explores a well-established concept within the academic arenas of business, health, and rural development, among others, of agents for change (AFCs), within the context of the rapidly emerging wave energy sector. Two case studies, Lewis in the Outer Hebrides, and Orkney, were chosen based on their localities and the interest that they have garnered from wave energy developers due to their high energy marine environments. A grounded approach was taken to data collection and a social power analysis was conducted in order to find AFCs working within or closely with the wave energy industry that were not part of structured or hierarchical organisations. One emergent theme was that there was a noteworthy barrier to wave energy development in the case studies and to the work that the agents for change were doing in the form of a complex dynamic between financial investments in the sector, national grid, national energy policy, and the technology itself. The agents for change were found to act as catalysts for the wave energy industry through their perseverance and visionary approach to development. The motivations of the AFCs is discussed and the shifting roles that they took as a project progresses is described and compared to other change process models, namely Lewin (1958) and Kotter (1995).

This thesis investigates the effects of wave energy converters (WECs) on water waves through the analysis of extensive laboratory experiments, as well as subsequent numerical simulations. Data for the analysis was collected during the WEC-Array Experiments performed at the O.H. Hinsdale Wave Research Laboratory at Oregon State University, under co-operation with Columbia Power Technologies, using five 1:33 scale point-absorbing WECs. The observed wave measurement and WEC performance data sets allowed for a direct computation of power removed from the wave field for a large suite of incident wave conditions and WEC array sizes. To numerically represent WEC effects the influence of the WECs upon the wave field was parameterized using the power absorption data from the WECs. Because a large driver of the WECs influence on the wave field is absorbed wave power by the WEC, it is reasonable to attempt a parameterization based on this process. It was of interest as to whether this parameterization, which does not account for wave scattering among other physics, could provide a good estimate of far-field effects. Accurately predicting WEC-array effects in the far-field requires empirical validation. Previous WEC analysis and modeling studies had limited data available for model verification, and additionally had used idealized WEC performance. In the present work we develop a WEC-array parameterization for use in phase-averaged wave models (e.g. SWAN). This parametrization only considers the wave absorption effects of the WECs and the model predictions of far-field effects are compared to observations. Further testing of the SWAN model was performed against a phase-resolving model, WAMIT, to determine the significance of physics the WEC absorption parameterization does not capture, such as scattered waves. Considering the complexity of the problem, the parameterization of WECs by only power absorption is a reasonable predictor of the effect of WECs on the far field. / Graduation date: 2013

Thesis (M.S.)--California Polytechnic State University, 2010. / Title from PDF title page; viewed on May 15, 2010. Major professor: Robert S. Crockett, Ph.D. "Presented to the faculty of California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirements for the degree [of] Master of Science in Engineering." "March 2010." Includes bibliographical references (p. 64-65).

Effective, economic extraction of ocean wave energy requires an intimate under- standing of the ocean wave environment. Unfortunately, wave data is typically un- available in the near-shore (<150m depth) areas where most wave energy conversion devices will be deployed. This thesis identities, and where necessary develops, ap- propriate methods and procedures for using near-shore wave modelling software to provide critical wave climate data to the wave energy industry. The geographic focus is on the West Coast of Vancouver Island, an area internationally renowned for its wave energy development potential. The near-shore computational wave modelling packages SWAN and REF/DIF were employed to estimate wave conditions near-shore. These models calculate wave conditions based on the off-shore wave boundary conditions, local bathymetry and optionally, other physical input parameters. Wave boundary condition were sourced from theWaveWatchIII off-shore computational wave model operated by the National Oceanographic and Atmospheric Administration. SWAN has difficulty simulating diffraction (which can be important close to shore), but is formulated such that it is applicable over a wide range of spatial scales. REF/DIF contains a more exact handling of diffraction but is limited by computational expense to areas less than a few hundred square kilometres. For this reason SWAN and REF/DIF may be used in a complementary fashion, where SWAN is used at an intermediary between the global-scale off-shore models and the detailed, small scale computations of REF/DIF. When operating SWAN at this medium scale a number of other environmental factors become important. Using SWAN to model most of Vancouver Island's West Coast (out to the edge of the continental shelf), the sensitivity of wave estimates to various modelling param- eters was explored. Computations were made on an unstructured grid which allowed the grid resolution to vary throughout the domain. A study of grid resolution showed that a resolution close to that of the source bathymetry was the most appropriate. Further studies found that wave estimates were very sensitive to the local wind condi- tions and wave boundary conditions, but not very sensitive to currents or water level variations. Non-stationary computations were shown to be as accurate and more computationally efficient than stationary computations. Based on these findings it is recommended this SWAN model use an unstructured grid, operate in non-stationary mode and include wind forcing. The results from this model may be used directly to select promising wave energy development sites, or as boundary conditions to a more detailed model. A case study of the wave climate of Hesquiaht Sound, British Columbia, Canada (a small sub-region of the medium scale SWAN model) was performed using a high resolution REF/DIF model. REF/DIF was used for this study because presence of a Hesquiaht Peninsula which has several headlands around which diffraction was thought to be important. This study estimates the most probable conditions at a number of near-shore sites on a monthly basis. It was found that throughout the year the off-shore wave power ranges from 7 to 46kW/m. The near-shore typically has 69% of the off-shore power and ranges from 5 to 39kW/m. At the near-shore site located closest to Hot Springs Cove there is on average 13.1kW/m of wave power, a significant amount likely sufficient for wave power development. The methods implemented in this thesis may be used by groups or individuals to assess the wave climate in near-shore regions of the West Coast of Vancouver Island or other regions of the world where wave energy extraction may be promising. It is only with detailed knowledge of the wave climate that we can expect commercial extraction of wave energy to commence. / Graduate

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 105-106). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 45-48). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2005. / Printout. Includes bibliographical references (leaf 89). Also available online.

Thesis (M.S.)--Oregon State University, 2010. / Title from PDF title page (viewed Aug. 22, 2009). Includes bibliographical references (leaves 45-48).

Thesis (M.S.)--University of Wyoming, 2008. / Title from PDF title page (viewed on June 24, 2009). Includes bibliographical references.