Glossary

The Glossary lists and defines all of the terms used to tag content (e.g., documents, events) on Tethys Engineering. Click on a term to view its full definition and a searchable table of all the documents with that tag. Visit the Tethys Glossary to explore additional terms and content on the environmental effects of marine and wind energy development. 

Technology

  • Current: Capturing energy from tidal channels, ocean currents, or rivers. 
    • Axial Flow Turbine: Water flows parallel to the device's axis of rotation. 
    • Cross Flow Turbine: Water flows perpendicular to the device's axis of rotation.
    • Oscillating Hydrofoil: Water induces oscillating translation of hydrodynamic surface.
    • Kite: A device that 'flies' in the tidal stream, swooping in a figure-eight shape.
    • Archimedes Screw: A helical surface surrounding a ventral cylindrical shaft.
    • Vortex-Induced Vibration: Constant water flow applied to a rounded object will cause vibrations.
    • Tidal: Capturing energy from tidal fluctuations using turbines, tidal barrages, or tidal lagoons.
    • Ocean Current: Capturing energy from ocean currents.
    • Riverine: Capturing energy from river currents.
  • Wave: Capturing energy from waves. 
    • Attenuator: Floating device that operates parallel to the wave direction.
    • Oscillating Water Column: Hollow structure that uses wave action to compress air through a turbine.
    • Overtopping: Storage reservoir filled by breaking waves that exit through turbines.
    • Oscillating Wave Surge Converter: Pendulum that oscillates as waves pass by.
    • Point Absorber: Device that absorbs energy from the relative motion between a wave-activated, moving body and a fixed structure.
    • Pressure Differential: Submerged or semi-submerged devices that use differences in pressure to generate electricity.
  • Ocean Thermal Energy Conversion: Capturing energy using temperature gradients across water depths.
    • Closed-Cycle: An OTEC system in which working fluid with a low-boiling point is circulated.
    • Open-Cycle: An OTEC system in which warm, surface seawater is the working fluid.
    • Hybrid-Cycle: An OTEC system in which both seawater and a working fluid are circulated. 
  • Salinity Gradient: Capturing energy using salinity gradients where freshwater meets seawater. 
    • Pressure-Retarded Osmosis: Salinity gradient technology in which osmotic pressure is used to generate electricity. 
    • Reverse Electrodialysis: Salinity gradient technology in which cation and anion exchange membranes are used to create a "salt battery".

Collection Method

  • Field Data: Data collected in a real-world scenario.
  • Lab Data: Data collected in a laboratory setting.
  • Modeling: A system or device that is modeled. 
  • Test Center: Data collected at an established test center. 
  • Full Scale: Devices deployed or modeled at full scale. 
  • Scale Device: Device deployed or modeled at smaller than full scale. 

Resource

  • Extreme Events: Events such as hurricanes, storms, rogue waves, and tsunamis. 
  • Instrumentation: Instruments placed around the device to monitor it or its effects. 
  • Site Characterization: Surveying a potential site for bathymetry, energy potential, etc. 

Engineering

  • Acoustics: Analysis or measurement of the noise made by a device.
  • Array Effects: Impacts of multiple devices deployed together or their interaction.
  • Control: Component of the device that optimizes electricity generation, minimizes stall, etc. 
  • Grid Integration: How devices integrate with the electrical grid, including storage.
  • Hybrid Devices: Devices collecting energy from multiple sources (e.g., wind and wave).
  • Hydrodynamics: Interactions between fluids and device structures.
  • Materials: The substances from which a device is made.
  • Mooring: Cables and anchors that hold a device in place.
  • Performance: Analysis of device performance in various conditions or operating modes.
  • Power Take Off: Component of a device that converts absorbed energy into a usable form.
  • Structural: Structural design of a device or device component (e.g., blade design, loading).
  • Substructure: Base/foundation of a device (e.g., pile, floating substructure).

Operations

  • Deployment: Installation of a device. 
  • Maintenance: Work done on a device after it is operational. 
  • Condition Monitoring: Monitoring the health of a device while in operation. 
  • Safety and Security: Safety and protection of personnel and assets during the life cycle of the project.
  • Survivability: How a device survives in the ocean (e.g., planned lifespan, fatigue studies).
    • Debris: Floating or submerged objects that may pose a threat to the survivability of a device.
    • Ice: Movement of ice in various forms that may pose a threat to the survivability of a device.
  • Decommissioning: Removal of a device at the end of its lifespan.

Economics

  • Cost Assessment: Analysis of a device's cost, economic feasibility, or other cost-related factors (e.g., techno-economic assessments, cost optimization).
  • Manufacturing: Descriptions of manufacturing process or costs. 
  • Alternative Markets: Markets and potential applications for marine energy other than commercial electricity generation. 
  • Standards: International or country standards related to marine energy. 
  • Supply Chain: Network of suppliers used to produce a specific device.

Signature Projects

Acronyms

  • AIS: Automatic Identification System
  • BOEM: U.S. Bureau of Ocean Energy Management
  • CEC: Current Energy Converter
  • DOE: U.S. Department of Energy
  • GIS: Geographic Information Service
  • IEA: International Energy Agency
  • kW: Kilowatt
  • LCA: Life Cycle Assessment
  • LCOE: Levelized Cost of Energy
  • MHK: Marine and Hydrokinetic
  • MRE: Marine Renewable Energy
  • MSP: Marine Spatial Planning
  • MW: Megawatt
  • NOAA: U.S. National Oceanographic and Atmospheric Administration
  • NREL: National Renewable Energy Laboratory
  • OES: Ocean Energy Systems
  • ORE: Ocean Renewable Energy
  • OTEC: Ocean Thermal Energy Conversion
  • OWC: Oscillating Water Column
  • PNNL: Pacific Northwest National Laboratory
  • PRO: Pressure-Retarded Osmosis
  • RED: Reverse Electrodialysis
  • SWAC: Sea Water Air Conditioning
  • WEC: Wave Energy Converter