12.1 Site Characterization and Resource Assessment

Site characterization and resource assessment are crucial steps in tidal and wave energy projects. They involve measuring tidal ranges, current velocities, and wave energy flux to identify promising locations. These assessments help developers understand the energy potential and feasibility of potential sites.

Detailed surveys and mapping provide essential data for project planning. Bathymetry, geotechnical studies, and sediment transport analysis inform device design and installation. Environmental impact assessments are also vital, ensuring projects minimize harm to marine ecosystems and comply with regulations.

Tidal Resource Assessment

Measuring Tidal Range and Current Velocity

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Top images from around the web for Measuring Tidal Range and Current Velocity

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  OS - Internal tide energy flux over a ridge measured by a co-located ocean glider and moored ... View original

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  Frontiers | Innovative Closely Spaced Profiling and Current Velocity Measurements in the ... View original

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  Frontiers | Innovative Closely Spaced Profiling and Current Velocity Measurements in the ... View original

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  OS - Internal tide energy flux over a ridge measured by a co-located ocean glider and moored ... View original

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• Tidal range quantifies the vertical difference in water level between high and low tide
  • Measured using tide gauges or pressure sensors deployed at the site
  • Tidal range varies with location and is influenced by factors such as coastal geometry and bathymetry
  • Higher tidal ranges generally indicate greater potential for tidal energy extraction (Bay of Fundy, Canada)
• Current velocity refers to the speed and direction of tidal currents
  • Measured using acoustic Doppler current profilers (ADCPs) or electromagnetic current meters
  • Current velocity varies throughout the tidal cycle and is typically highest during mid-tide
  • Tidal currents are driven by the gravitational pull of the moon and sun and are influenced by local bathymetry and coastline shape (Pentland Firth, Scotland)

Tidal Stream Atlas and Data Analysis

• Tidal stream atlas provides a comprehensive map of tidal current velocities and directions for a specific region
  • Created using a combination of field measurements, numerical modeling, and satellite data
  • Helps identify potential sites with high tidal current velocities suitable for tidal energy development
  • Tidal stream atlases are available for many regions worldwide (UK Atlas of Marine Renewable Energy Resources)
• Acoustic Doppler Current Profiler (ADCP) is a device used to measure current velocities and directions throughout the water column
  • Uses sound waves to measure the Doppler shift caused by moving water particles
  • Deployed from a boat or mounted on a seabed frame for long-term measurements
  • ADCP data is processed and analyzed to characterize the tidal resource at a specific site and inform the design of tidal energy devices (Admiralty Inlet, Washington State)

Wave Resource Assessment

Wave Energy Flux and Measurement Techniques

• Wave energy flux quantifies the power available in ocean waves per unit width of wavefront
  • Calculated using wave height, period, and water density
  • Wave energy flux varies with location and is influenced by factors such as wind patterns, fetch, and bathymetry
  • Higher wave energy flux indicates greater potential for wave energy extraction (West coast of Ireland)
• Wave buoys are floating devices used to measure wave height, period, and direction
  • Equipped with accelerometers, gyroscopes, and GPS to measure wave motion and position
  • Data is transmitted to shore for analysis and resource assessment
  • Wave buoys provide long-term measurements of wave conditions at a specific site (NDBC buoys, US)

Hydrodynamic Modeling for Wave Resource Characterization

• Hydrodynamic modeling simulates the propagation and transformation of ocean waves over a specific domain
  • Uses numerical methods to solve the governing equations of fluid motion
  • Incorporates bathymetry, wind forcing, and boundary conditions to predict wave conditions
  • Hydrodynamic models can be used to assess the wave resource over a large area and identify potential sites for wave energy development (SWAN model)
• Hydrodynamic modeling can also be used to optimize the layout and design of wave energy converters
  • Simulates the interaction between waves and wave energy devices
  • Helps determine the optimal spacing, orientation, and configuration of wave energy arrays
  • Hydrodynamic modeling is an essential tool for assessing the performance and impacts of wave energy projects (WaveDyn model)

Site Surveys and Mapping

Bathymetry and Geotechnical Surveys

• Bathymetry is the measurement of water depth and underwater topography
  • Conducted using echo sounders, multibeam sonar, or LiDAR
  • Provides a detailed map of the seabed morphology and features
  • Bathymetric data is essential for site selection, device installation, and cable routing (Pentland Firth bathymetry survey)
• Geotechnical surveys investigate the physical properties of the seabed sediments and underlying geology
  • Involves collecting sediment samples and conducting in-situ tests (cone penetration tests)
  • Determines the bearing capacity, stability, and suitability of the seabed for anchoring or foundation systems
  • Geotechnical data informs the design and installation of tidal and wave energy devices (Meygen project geotechnical survey)

GIS Mapping and Sediment Transport Analysis

• GIS (Geographic Information System) mapping integrates various spatial datasets to create a comprehensive site characterization
  • Combines bathymetry, geotechnical data, environmental constraints, and infrastructure information
  • Helps identify suitable sites for tidal and wave energy development and optimize the layout of devices
  • GIS mapping is a powerful tool for site selection, permitting, and stakeholder engagement (Marine Scotland Interactive)
• Sediment transport analysis assesses the movement of seabed sediments due to tidal currents and waves
  • Uses numerical models to simulate sediment dynamics and morphological changes
  • Helps predict the potential impacts of tidal and wave energy devices on seabed stability and coastal processes
  • Sediment transport analysis is important for assessing the long-term sustainability and environmental impacts of marine energy projects (Severn Estuary sediment transport study)

Environmental Considerations

Environmental Impact Assessment

• Environmental impact assessment (EIA) is a process for identifying and evaluating the potential environmental effects of a proposed tidal or wave energy project
  • Considers impacts on marine life, habitats, water quality, and other users of the marine space
  • Involves baseline surveys, impact prediction, mitigation measures, and monitoring plans
  • EIA is a legal requirement in many countries and is essential for obtaining project consents and licenses (Swansea Bay Tidal Lagoon EIA)
• EIA typically includes the following key stages:
  • Screening: Determines whether an EIA is required based on the project's characteristics and location
  • Scoping: Identifies the key environmental issues and sets the terms of reference for the EIA
  • Baseline studies: Collects data on the existing environmental conditions and establishes a reference point for impact assessment
  • Impact assessment: Predicts and evaluates the likely environmental impacts of the project, including cumulative effects
  • Mitigation and monitoring: Proposes measures to avoid, reduce, or offset adverse impacts and outlines plans for long-term monitoring and adaptive management
• Stakeholder consultation is an integral part of the EIA process
  • Involves engaging with local communities, regulators, and other interested parties
  • Helps identify potential concerns, gather local knowledge, and build public support for the project
  • Stakeholder consultation is essential for ensuring the social acceptability and sustainability of tidal and wave energy development (Orkney Marine Renewable Energy Forum)