Glossary | Tethys Engineering

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).
- Levelized Cost of Energy: Analysis of energy cost over the lifetime of a device.
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