The wave energy resource of the US Pacific Northwest

The substantial wave energy resource of the US Pacific Northwest (i.e. off the coasts of Washington, Oregon and N. California) is assessed and characterized. Archived spectral records from ten wave measurement buoys, operated and maintained by the National Data Buoy Center and the Coastal Data Information Program, form the basis of this investigation. Because an ocean wave energy converter must reliably convert, and survive, the energetic resource, a comprehensive characterization of the expected range of sea states is essential. Six quantities were calculated to characterize each hourly sea state: omnidirectional wave power, significant wave height, energy period, spectral width, direction of maximum directionally resolved wave power and directionality coefficient. The temporal variability of these characteristic quantities is depicted at different scales, from hourly to interannual. Cumulative distributions of both occurrence and contribution to total energy are presented, over each of the six quantities characterizing the resource. It is clear that the sea states occurring most often are not necessarily those that contribute most to the total incident wave energy. The sea states with the greatest contribution to energy have significant wave heights between 2 and 5 m and energy periods between 8 and 12 s. Sea states with the greatest significant wave heights (e.g. > 7 m) contribute little to the annual energy, but are critical to consideration of reliability and survivability. To characterize the likelihood of successfully performing a given operation (e.g. deployment, maintenance), seasonal expectations of weather windows are depicted for two locations. Finally, a limited number of spectra are proposed to represent the conditions at a location 9 km offshore, in 40 m of water

Direct Drive Wave Energy Buoy ? Intermediate scale experiment

Columbia Power Technologies deployed a scaled prototype wave energy converter (WEC) in the Puget Sound in February 2011. Other than a brief period (10 days) in which the WEC was removed for repair, it was in the water from Feb. 15, 2011 until Mar. 21, 2012. The SeaRay, as this WEC is known, consists of three rigid bodies which are constrained to move in a total of eight degrees of freedom (DOF). The SeaRay is kept on station with a spread, three-point mooring system. This prototype WEC is heavily instrumented, including but not limited to torque transducers and encoders reporting generator torque applied to and relative pitch of the floats, an inertial measurement unit (IMU) reporting translational acceleration and rotational position of the spar/nacelle, a GPS sensor reporting position, load cells reporting mooring loads at the WEC connection points and a number of strain gauges embedded in the fiberglass reinforced plastic (FRP) hull. Additionally, wave and current data are collected using an Acoustic Wave And Current Profiler (AWAC), allowing performance and design data to be correlated to environmental input conditions. This data – quality controlled, processed and analyzed – is used to characterize the metocean conditions (i.e. sea states). The WEC response will be correlated to the metocean conditions. These results will primarily be used to validate numerical models. The validated numerical models will be used optimize the commercial scale WEC and inform the design process. This document details the SeaRay experiment, including the quality control, processing and subsequent analysis of the data. Furthermore, the methodology and the results of numerical model validation will be described

Laboratory Observation of Waves in the Vicinity of WEC-Arrays

This paper was presented at the 9th European Wave and Tidal Energy Conference held in Southampton, UK September 4-11, 2011.The ocean deployment of multiple Wave Energy Converters (WECs) in large-scale arrays appears imminent. However, there is a significant gap in our present knowledge of the near-field scattering and potential far-field environmental effects due to WEC-arrays. This gap comes from the lack of observational data. To help fill this data gap, we have performed laboratory experiments using five, moored, point-absorber WECs. These WECs are 1:33 scale models of the commercially-designed “Manta” from Columbia Power Technologies

Direct Drive Wave Energy Buoy – Intermediate scale experiment

Columbia Power Technologies deployed a scaled prototype wave energy converter (WEC) in the Puget Sound in February 2011. Other than a brief period (10 days) in which the WEC was removed for repair, it was in the water from Feb. 15, 2011 until Mar. 21, 2012. The SeaRay, as this WEC is known, consists of three rigid bodies which are constrained to move in a total of eight degrees of freedom (DOF). The SeaRay is kept on station with a spread, three-point mooring system. This prototype WEC is heavily instrumented, including but not limited to torque transducers and encoders reporting generator torque applied to and relative pitch of the floats, an inertial measurement unit (IMU) reporting translational acceleration and rotational position of the spar/nacelle, a GPS sensor reporting position, load cells reporting mooring loads at the WEC connection points and a number of strain gauges embedded in the fiberglass reinforced plastic (FRP) hull. Additionally, wave and current data are collected using an Acoustic Wave And Current Profiler (AWAC), allowing performance and design data to be correlated to environmental input conditions. This data – quality controlled, processed and analyzed – is used to characterize the metocean conditions (i.e. sea states). The WEC response will be correlated to the metocean conditions. These results will primarily be used to validate numerical models. The validated numerical models will be used optimize the commercial scale WEC and inform the design process. This document details the SeaRay experiment, including the quality control, processing and subsequent analysis of the data. Furthermore, the methodology and the results of numerical model validation will be described

Direct Drive Wave Energy Buoy

The most prudent path to a full-scale design, build and deployment of a wave energy conversion (WEC) system involves establishment of validated numerical models using physical experiments in a methodical scaling program. This Project provides essential additional rounds of wave tank testing at 1:33 scale and ocean/bay testing at a 1:7 scale, necessary to validate numerical modeling that is essential to a utility-scale WEC design and associated certification

Direct Drive Wave Energy Buoy – 33rd scale experiment

Columbia Power Technologies (ColPwr) and Oregon State University (OSU) jointly conducted a series of tests in the Tsunami Wave Basin (TWB) at the O.H. Hinsdale Wave Research Laboratory (HWRL). These tests were run between November 2010 and February 2011. Models at 33rd scale representing Columbia Power’s Manta series Wave Energy Converter (WEC) were moored in configurations of one, three and five WEC arrays, with both regular waves and irregular seas generated. The primary research interest of ColPwr is the characterization of WEC response. The WEC response will be investigated with respect to power performance, range of motion and generator torque/speed statistics. The experimental results will be used to validate a numerical model. The primary research interests of OSU include an investigation into the effects of the WEC arrays on the near- and far-field wave propagation. This report focuses on the characterization of the response of a single WEC in isolation. To facilitate understanding of the commercial scale WEC, results will be presented as full scale equivalents