Research Projects 2015-16

Six (6) projects were selected for 2015-16. See below for the outline of each project and associated final reports.

RESEARCH PROJECT # 1

Long-Term Simulated Wave Energy Converter Deployments

PROPONENTS

Lead:Cascadia Coast Research Ltd. – Clayton Hiles, Principal Engineer
Collaborators : The West Coast Wave Initiative (the University of Victoria) – Scott Beatty, Senior Researcher
The Institute for Energy Systems (the University of Edinburgh) – Adrian de Andres, Post-doctoral fellow

BACKGROUND

There are virtually no publicly available, unencumbered wave energy converter performance data-sets. Field deployment and monitoring of prototypes and full-scale wave energy converters (WECs) provides essential data that can be used to evaluate and characterize the performance of the device. To date, many smaller scale prototype WEC deployments and a handful of full-scale WEC deployments have occurred throughout the world. However the useful data from such deployments is typically not available because business interests and intellectual property concerns usually prevent public release of data.

The working groups PT100 and PT102 of the TC114 are tasked with generating equitable and standardized methods for evaluating and characterizing the performance of WEC technologies. IEC/TS-62600-100 edition 1.0 was published by PT100 in 2012. This specification provides guidance on power performance assessment at a single site based on a specified set of measurements. IEC/TS-62600-102 is currently being drafted by PT102. This specification will provide guidance on how to estimate WEC performance at a second location based on an IEC/TS-62600-100 type analysis.

Lack of public WEC performance data-sets makes it difficult for the TC114 project teams to test the methods and procedures they are developing and also makes it difficult for the project teams to develop informative examples. Testing of the performance characterization methodologies is particularly important for WEC technologies because of the diversity of operating principles which are currently under development. For example, methods which may be appropriate for a point absorber may not be appropriate for a shoreline over-topping device.

OBJECTIVE & SCOPE

Scope:
To generate, through computational modelling, comprehensive performance and resource data for two different WECs at four strategic locations throughout the world.

Objective:
Two computational WEC models will be used for the simulated deployments: a floating two-body point absorber similar to the WaveBob device and a bottom mounted pitching flap similar to the Oyster device. Both are time domain models using the Cummins impulse response approach.

The models will be used to simulate 10 year deployments at four strategic locations: the Pacific and Atlantic Coasts of North America, the Atlantic Coast of the United Kingdom, the North Sea. The simulations will use as input fully directional wave spectra at each time-step. To ensure completeness of the resulting data-sets, wave re-analysis will be used rather than buoy measurements.

For each simulated deployment, the project will deliver a time series of data that includes WEC performance metrics and spectral wave parameters. This data will be summarized in a data package which will be made freely available for download through the websites of the other project partners.

PROJECT FINAL REPORT: CLICK HERE

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

RESEARCH PROJECT # 2

River energy converter environmental condition and load verification

PROPONENTS

Lead: Dynamic Systems Analysis, Ltd. – Ryan Nicoll, Director
Collaborators: University of Manitoba / Canadian Hydrokinetic turbine test center – Dr. Eric Bibeau, Director
MAVI Innovations: Bill Rawlings – Director of Operations
New Energy Corporation Inc.: Clayton Bear, President; Derek Neufeld, Engineer

BACKGROUND

For an accurate and reliable deployment of river energy converter systems, the resource in terms of flow rates, device inputs and loading conditions, and mechanical response must be well understood. Limited data that encompasses all these factors for river and tidal energy converters is publically available. Data and techniques for assessing resources ensures reliable planning and development while data for refining loading conditions and mechanical response ensures reliable and robust deployed technology and controlled cost of energy. Developing specifications within IEC TC114 on performance assessment for river and tidal systems (TS 62600-200/-300) require additional information to assess techniques for resource assessment and measurement of inflow for performance assessment. Developing specifications on general and mooring design (62600-2/-10) require additional data to better understand loading conditions, load response, and appropriate levels of safety. As a result, the data gathered and processes developed through this work will directly enhance Canada’s ability to contribute to standards development.

OBJECTIVE & SCOPE

The scope of the research is to support development of marine renewable standards by providing a cohesive dataset that encompasses resource assessment, loading, performance, and safety margin for several different turbine devices installed and tested at a single location. This will include data and techniques developed to assess river environmental conditions for inputs and load factors on devices and to verify safety margin of the system from measured parameters via engineering dynamic analysis software. Commercially available sensors and software will be used as much as possible.

These objectives are intended to refine test procedures to determine equipment settings and processes necessary to measure environmental conditions, loading data, and verify mooring and anchor loads to support standard development with regards to resistance and safety factors for general and mooring design as well as providing feedback on power performance assessment testing procedures for tidal and river energy converter systems. Measurements of flow conditions in the testing location will also be made available and may be used for additional information for resource assessment purposes.

PROJECT FINAL REPORT: CLICK HERE

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

RESEARCH PROJECT # 3

Quantifying Extractable Power in a Stretch of River Using an Array of Marine Hydrokinetic Turbines (MHKs)

PROPONENTS

Lead: Mavi Innovations Inc. 
Collaborators: Ocean, Coastal and River Engineering – National Research Council of Canada
Laboratoire LMFN, Departement de Genie Mecanique – Universite Laval
Lambda2 – Engineering Simulations

BACKGROUND

There is a growing international interest in using MHKs to extract power from fast flowing rivers. Canada (NRC/NRCan, Hatch) and the US (EPRI) have recently worked through a reconnaissance level study of major rivers to place an upper bound on the power generation potential. There is; however, no methodology provided to translate this predicted power into actual extractable turbine power. There is also a lack of basic guidelines for project developers to consider when building out a site with an array of turbines. Turbine arrays are recognized to be the key step in commercializing marine energy devices and improving the economics. This sub-project will work through a full feasibility study of an actual river location to achieve the following objectives: develop formulas and guidelines for turbine spacing along and across a section of a river; compare numerically the wake structure and dissipation length between turbines to better estimate overall extractable turbine array power.

OBJECTIVE & SCOPE

The primary objectives of the project are as follows:

• Develop formulas/curves/guidelines for turbine spacing along the length of a river & associated power extraction.

• Compare the wake structure, dissipation length and level of turbine interactions between porous/drag elements currently used to represent turbines in turbine layout studies and actual 3D cross-flow turbines.

• Inform the River Resource Assessment Standard and the River Turbine Performance Standard.

These objectives will be met by working through a full feasibility and array layout study for a specific Canadian river site. The first task of the project will be to develop a set of requirements for the site selection (min depth, velocity, data on discharge and bathymetry, etc.). These requirements will then be used to select a stretch of river previously studied by NRC at a pre- feasibility level that will serve as a case study for the project.

The stretch of river of interest will then be modeled using a 2D river model (Telemac2D), a 3D river model (Telemac3D) and 3D CFD model (Star CCM+) for several conditions encompassing seasonal variations. The results of the models will be analyzed to identify turbine deployment locations. The model comparison will clearly address the strengths and weakness of each modeling approach for the purposes of full feasibility studies.

Turbines (represented as drag elements) will then be introduced into the models to quantify the power extraction potential at the site and develop an understanding of how the river flow will be affected by turbines deployment. This project will focus on two specific cases:

Case 1: Single row of Turbines: Extractable power for a single row of turbines, ranging from a single turbine to multiple turbines blocking the majority of the river crossVsection.

Case 2: Two rows of Turbines: Extractable power for 2 rows of turbines to quantify the minimum distance between rows.

In parallel to the river modeling effort, the team will be working through a CFD wake study focused on a crossVflow turbine. The study will compare the wake generated by a porous element to simulations of actual 3D turbines deployed in rivers. This work will ensure that the limitations and validity of using drag elements to represent turbines in the river models are well understood.

The matrix of simulations completed as part of this study will form the basis of design guidelines for array layouts in rivers as well provide a method of quantifying the extractable power.

This work will also feed directly into the development of the river performance and resource standards.

PROJECT FINAL REPORT: CLICK HERE

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

RESEARCH PROJECT # 4

Guideline for Reliability Assessment of Marine Energy Conversion Systems (MECs) and Design Parameters for River Current Energy Conversion Systems for Different Safety Levels

PROPONENTS

Lead: University of British Columbia
Collaborators: Gouri Bhuyan Consulting Services (GB Consulting)
Mavi Innovations Inc.

BACKGROUND

The design of Marine Energy Conversion Systems (MECs) must determine the reliability under mechanical and environmental demands over their service life and represents a key requirement in the design and performance specifications. Reliability studies include the impact of uncertainties, both in the demands as well as in the capacity of the structure to withstand these demands. Current draft standards define various limit states, (such as: ultimate, fatigue, serviceability, etc.) and partial load factors based on the knowledge gained from the offshore wind industry. These load factors are not calibrated to the external conditions relevant to wave, tidal and river current energy conversion systems. This sub-project will develop a technical guideline for the reliability assessment of a MEC system, for different limit states using an alternate design approach based on probabilistic methods. The sub-project will also establish relevant load factors for river current energy conversion systems for different safety levels, considering several design concepts provided by a Canadian technology developer. 

OBJECTIVE & SCOPE

The objectives of the proposed project are:

  • to research reliability-relevant design issues identified by the Canadian stakeholders and to support the Canadian TC 114 PT 2 project team;
  • to develop a technical guideline for MECs and to establish relevant design parameters for river current energy conversion Systems (RECs).

The scope of the proposed research includes the following:

  • Establishing relevant load factors for river current energy conversion systems (RECs), for different safety levels, as defined in the IEC 62000-Part 2 CD, considering generic design concepts;
  • Developing a general methodology for the reliability assessment of a Marine Energy Conversion (MEC) system, for different limit states, for enabling use of an alternate design approach based on probabilistic methods.

PROJECT FINAL REPORT: CLICK HERE

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

RESEARCH PROJECT # 5

Tidal and River Energy Converter Debris Impact Load and Cable Snag Risk Quantification

PROPONENTS

Lead: Dynamic Systems Analysis
Collaborators: Mavi Innovations Inc.
SRM Projects

BACKGROUND

Debris and ice impact issues are common concerns for tidal installations at FORCE and for many of the potential river installations. The scope of this sub-project is to provide numerical analysis results characterizing impact loads and snagging risk from marine operations. The results will indicate characteristic impact loads for various sizes of debris and ice using surface floating and mid-water-column MECs. Furthermore, snag risk of mid-water-column MEC technologies will be evaluated through numerical analysis of operational towlines and by assessing the depth proximity of towline catenaries to potential MEC installations. This impact loading data will be provided directly to the design requirements and mooring design documents. In addition to generic load cases, actual environmental data (hydrodynamic current and bathymetry) for a potential turbine site will be used to ensure a realistic case study will provide a reference point for the work completed.

OBJECTIVE & SCOPE

The scope of this research project is to support development of marine renewable standards by providing numerical analysis results characterizing impact loads and snagging risk from marine operations. The scope is limited to tidal and river MEC technology. The results will indicate characteristic impact loads for various sizes of debris using surface floating and mid-water-column MEC technologies. Furthermore, snag risk of mid-water-column MEC technologies will be evaluated through numerical analysis of snagging operational towlines and assessing the depth proximity of towline catenaries for potential MEC installations.

These objectives are intended to provide impact loading data to support standard development for general and mooring design. Furthermore, assessing snag risk will offer data to facilitate standards design recommendations and guidelines for positioning mid-water-column moored structures to avoid towline motion and general design and mooring configurations to minimize snagging risk in the event of towline contact.

In addition to generic load cases to characterize impact and snag effects, environmental data (hydrodynamic current and bathymetry) for a potential turbine site will be used to ensure a realistic case study will be assessed to provide a reference point for the work completed.

 PROJECT FINAL REPORT: CLICK HERE

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

RESEARCH PROJECT # 6

Characterization of Low-Frequency Tidal Turbine Noise

PROPONENTS

Lead: OpenHydro Technology Canada Ltd. / Emera Inc.

BACKGROUND

Acoustic measurement of tidal turbine noise has so far proved problematic due to contamination from flow noise in high flow environments. Accurate and representative measurement of acoustic noise is a key input in the assessment of tidal energy devices’ impact on marine life. The scope of this sub-project will include long-term acoustic measurements using fixed sound recorders and subsequent data analysis to characterize the tidal turbine noise relative to the low-frequency recorder flow noise. Acoustic measurements will be collected use two autonomous acoustic recorders, housed in high-flow moorings to reduce turbulent flow around the hydrophones. One hydrophone will measure actual turbine noise in the near-field area (approx. 100m from the turbine) and a second will measure far field (2km) for direct comparison. The recorders will be deployed for two months to provide data collected in a variety of sea conditions and during different turbine operational phases. This research is complementary to FORCE’s environmental monitoring programme, another project funded by NRCan, as it is intended to focus on the mid-field (between 100 and 1000m from a turbine.

OBJECTIVE & SCOPE

The proponents of this proposal Emera Inc. and OpenHydro Technology Canada Ltd. are both Canadian companies, headquartered in Halifax and Dartmouth, Nova Scotia respectively. 

The scope of the project will include long-term acoustic measurements using fixed sound recorders and subsequent data analysis to characterize the tidal turbine noise relative to the low-frequency recorder flow noise. Acoustic measurements will be collected use two autonomous acoustic recorders, housed in high-flow moorings to reduce turbulent flow around the hydrophones (Figure 1). The recorders will be deployed for two months to provide data collected in a variety of sea conditions and during different turbine operational phases. One recorder will be placed at 100 m range from the turbine and the other at a control location approximately 2 km away. Current data will be collected simultaneous to the acoustic measurements using Acoustic Doppler Current Profilers (ADCPs) located on the turbine structure. Sound levels will be compared between the two recorders to identify the frequencies at which the turbine noise is discernable. Received sound levels will be correlated with tidal state and current speed to assist with characterization of sound levels attributed to flow noise.

The objectives of the project are to:

1. Characterize the spectral content of flow noise in relation to tidal turbine acoustic measurement and its correlation with current speed;

2. Determine the cut-off frequency below which flow noise contaminates the acoustic measurements;

3. Provide guidance on standard methodologies for performing acoustic measurements in close proximity to tidal turbines and processing of acoustic data to mitigate effects of flow noise.

 PROJECT FINAL REPORT: To be released soon

Comments are closed.