Three (3) projects were selected for 2014-15. See below for an outline of each project and updates.
RESEARCH PROJECT # 1
West Coast Wave Initiative Extended Research Program
Lead: West Coast Wave Initiative, University of Victoria
Collaborators : AXYS Technologies Ltd
Cascadia Coastal Research Ltd.
Sandia National Lab
To date, the Canadian marine renewable energy sector has played a leading role in the development of international codes and standards that will shape the activities that transform the sector into a commercial industry.
In support of Canadian wave energy standards development, the proposed project will leverage a nationally unique collection of resources, contained in the West Coast Wave Initiative at the University of Victoria, to provide detailed knowledge of the three components of the wave power production spectrum: wave resource assessments; wave energy converter (WEC) device performance and grid integration (i.e. power quality).
OBJECTIVE & SCOPE
At the West Coast Wave Initiative (WCWI), we believe the development of a wave energy industry in British Columbia should be conducted as a single coordinated and collaborative effort, rather than fragmented and separate avenues of research. Through the WCWI’s academic and industrial partnerships, existing network of wave measurement hardware and extensive analytical tools, the proposed research program will investigate numerous Priority Research Areas (PRAs). By leveraging the existing WCWI resources (human, computing and equipment) the financial request made in this proposal focusses on only new hardware requirements specific to the targeted PRAs. By leveraging existing WCWI resources, an aggressive work plan can be pursued with confidence and we expect that expected outputs will have great value for Marine Renewables Canada and the TC 114 Standards Committees.
The extension of the WCWI described in this proposal is divided into three integrated Research Themes – each theme containing several of PRAs identified by Marine Renewables Canada. Table 1 on the next page summarizes the structure of the proposed research program including the three themes and the tasks that constitute each theme.
The project started in January 2014 and is scheduled to finish in March 2015.
PROJECT Final Report
CLICK HERE for the final report
RESEARCH PROJECT # 2
Evaluation of Performance Assessment Procedures for a Floating River Energy Converter
Lead: Mavi Innovations Inc.
Collaborators: University of Manitoba (Canadian Hydrokinetic Turbine Test Centre)
During development of IEC/TS62600‐200, two key discussion points were how to measure incident velocity on floating tidal energy converters (since they are typically able to move), and how to advise current profiler placement for devices of non‐circular frontal area. A lack of performance data amongst technology developers required assumptions on anticipated best practices to try and ensure accurate results are obtained.
It was decided that profilers could be mounted either on the seabed, or from the floating device as long as they are within a specified location. Mounting from a floating device is often preferred so that relative position is kept constant, and to avoid having to deploy and retrieve the profiler from the bottom. We propose to investigate the practical aspects of deploying a device mounted profiler according to IEC recommendations.
Profiler location is based on being 2 – 5 diameters from the device being tested. For devices of non‐circular frontal area, an equivalent diameter is calculated. As the aspect ratio (width / height) of converters increases, the distance from the device being tested increases due to increasing equivalent diameter. This can be the case for cross‐flow turbines of relatively small diameter, and has the potential to place undue burden on designers as they try to suspend current profilers further from floating devices. The accuracy of the assessment may also be affected as the profiler is placed further from the device.
OBJECTIVE & SCOPE
This proposed project will implement procedures from IEC/TS 62600‐200 to assess the performance of a floating turbine.
The majority of work will be completed in summer 2014 and will coincide with field testing of Mavi’s 20kW floating cross‐flow turbine at the Canadian Hydrokinetic Turbine Test Centre (CHTTC). For this project, Mavi’s floating catamaran platform will be outfitted with a boom‐mounted ADCP to measure currents upstream of the turbine.
This work will:
- Address the design and procedural challenges encountered when deploying an ADCP upstream of a floating turbine;
- Analyze the impact of the TS‐recommended ADCP locations upstream of a turbine, and resulting effect on measured turbine performance (including comparison to existing computational models);
- Inform the work of Ad‐Hoc Group (AHG) 4 (maintain IEC/TS62600‐200), as well as the pending Canada‐led New Work Item Proposal (NWIP) to develop a TS for the performance evaluation of River Energy Converters.
The project started in May 2014 and is scheduled to finish in December 2014.
– CLICK HERE for Presentation
Final Report – CLICK HERE
RESEARCH PROJECT # 3
Impact of channel blockage and free surface proximity on the performance of cross-flow hydrokinetic turbines
Lead: LMFN Laboratory, Mechanical Eng. Dept., Laval University
Different technologies are being proposed and developed to harvest the kinetic energy of water currents and to convert it to electricity. Horizontal axis hydrokinetic turbines (HAHT) are most common and are characterized by a circular harvesting plane. Cross-flow turbines such as vertical axis hydrokinetic turbines (VAHT) or oscillating foils hydrokinetic turbines (OFHT) are also being developed and present rectangular harvesting planes. This characteristic of cross-flow turbines may prove to be a significant advantage in shallow water applications both in tidal and in river streams. Indeed, for a given deployment site, a single cross-flow turbine with a large aspect ratio (much larger than high) may produce significantly more electricity than a single HAHT whose diameter is limited by the water depth. One can thus expect a growing popularity of cross-flow devices in the future especially for small-scale river applications.
It is recognized in IEC TS 62600-200 (Electricity producing Tidal Energy Converters – Power performance assessment) that TEC performances may vary depending on the degree of flow restrictions they experience at the deployment sites. This is referred to as blockage effects. There is always a certain level of blockage or confinement in practice despite the idealization of uniform unconfined flow often used in theoretical studies. Very little is precisely known at the present on these effects, but it is expected that they differ significantly between technologies especially between axial-flow turbines (HAHT) and large-aspect-ratio cross-flow turbines. Vertical confinement versus lateral confinement may have to be discriminated in addition to considering the specific effect of water surface proximity.
It is thus necessary to address this knowledge gap in order to improve current TS 62600-200 as well as to support the recent mandate of AHG2 (Power performance assessment of electricity producing River Energy Converters (REC)). Indeed, to ensure that the performance of different devices is assessed on a consistent basis, it will be necessary to take into account the blockage effects experienced by the device while being tested (in laboratory channel or at test site). Similarly, to propose a calculation method to estimate electricity production at a prospective deployment site (tidal or river), it will be necessary to incorporate eventual blockage effects.
OBJECTIVE & SCOPE
This research project thus proposes to support and complement the current effort by the group at MAVI, U. of Vic. and Clean Current (Impact of channel blockage, free surface proximity and foundations on the performance of Tidal/River Energy Converters) which mostly targets HAHT technologies. Their report with correction curves to account for blockage effects is expected for April 2014. We wish to extend this important work to include cross-flow turbines as well.
Specifically, we propose to use state-of-the-art CFD techniques (Computational Fluid Dynamics) to:
- Validate the correction curves presented in the April report by MAVI et al. for horizontal axis turbines (HAHT), and propose adjustments and/or extensions if need be;
- Demonstrate that correction formulae must be properly adapted to different technologies to take into account blockage effects;
- Investigate the need to discriminate between vertical and lateral confinements when considering blockage effects on axial-flow turbines (HAHT) and cross-flow turbines (VAHT and OFHT);
- Develop preliminary correction formulae to take into account blockage effects for cross-flow turbines (VAHT and OFHT) with and without inclusion of free-surface effects;
- Provide recommendations for future research works;
- Provide guidelines to support the current work of Ad Hoc Group 2 (AHG2) on River Energy Converters and to help improve future versions of TS 62600-200 for Tidal Energy Converters.
The project started in May 2014 and is scheduled to finish in March 2015.
PROJECT Final Report
CLICK HERE for the final report