Tidal

Capturing tidal fluctuations with turbines, reciprocating devices, kites, screws, barrages, or lagoons.

Gravity from the moon and sun cause water in the ocean to bulge in a cyclical pattern as the Earth rotates, causing water to rise and fall relative to the land in what are known as tides. Land constrictions such as straits or inlets can create high velocities at specific sites, which can be captured with the use of devices such as turbines. Since seawater is about 800 times denser than air, tidal turbines can collect energy with slower water currents and smaller turbines than wind energy. While tidal currents are very predictable, challenges arise due to the need for devices to collect flow from opposite directions and survive the harsh corrosive marine environment.

 

Environmental effects will vary between the seven most common approaches: axial flow turbine, cross flow turbine, reciprocating device, tidal kite, Archimedes screw, tidal lagoon, and tidal barrage.

 

Axial Flow Turbine

 

These turbines are the most similar to traditional windmills, where the kinetic energy of moving water is captured by spinning blades facing the direction of flow. Turbines can be open or ducted (shrouded) and placed anywhere in the water column, though bottom-mounted is the most common.

 

The main environmental concern is collision between turbine blades and marine organisms due to natural animal movements, attraction to the device, or inability to avoid the turbines within strong currents. It should be noted that these turbines spin much slower than propellers on ships. There is also concern that noise from turbines can affect animals that use sound for communication, social interaction, orientation, predation, and evasion. As with all electricity generation, there is a slight concern that electromagnetic fields generated by power cables and moving parts may affect animals that use Earth's natural magnetic field for orientation, navigation, and hunting. Likewise, chemicals such as anti-corrosion paint and small amounts of oil and grease may enter the waterbody during spills, though some turbine designs do not require lubrication. Large-scale tidal energy removal (from arrays) may disrupt natural physical systems to cause degradation in water quality or changes in sediment transport, potentially affecting the ecosystem.

Cross Flow Turbine

 

These turbines are generally cylindrical on a horizontal axis, where kinetic energy of moving water is captured by spinning blades oriented transversely to the direction of flow. Turbines can be open or ducted (shrouded) and placed anywhere in the water column, though bottom-mounted is the most common.

 

There is typically less environmental concern for collision between turbine blades and marine organisms because blades are spinning in the same direction to the flow of water, depending on the design. Concerns about noise, electromagnetic fields, chemicals, and energy removal are similar to that of axial flow turbines.

Reciprocating Device

 

Reciprocating devices do not have rotating components, but instead have a hydrofoil that is pushed back and forth transverse to the flow direction by lift or drag. Oscillating devices are the most common form of reciprocating devices.

 

Reciprocating devices often move slower than turbines, but move more freely in the water, resulting in some concern for collision. Reciprocating devices often produce little noise, though this depends on the design and generator. Concerns about electromagnetic fields, chemicals, and energy removal are similar to that of other tidal devices.

Tidal Kite

 

A tidal kite is comprised of a hydrodynamic wing, with a turbine attached, tethered by a cable to a fixed point that leverages water flow to lift the wing. As the kite 'flies' loops through the water, the speed increases around the turbine, allowing more energy extraction for slower currents. The kite is neutrally buoyant so as not to fall as the tide changes direction.

 

Collision risk may be of some concern with tidal kites. Although animals are more likely to collide with the tether than the kite itself, little is known about the ability of animals to detect the free movement of some tidal kites. Tidal kites emit noise over a larger frequency than horizontal axis turbines, though this depends on the design and generator. Concerns about electromagnetic fields, chemicals, and energy removal are similar to that of other tidal devices.

Archimedes Screw

 

Historically designed to efficiently transfer water up a tube, an Archimedes screw is a helical surface surrounding a ventral cylindrical shaft. Energy is generated as water flow moves up the spiral and rotates the device.

 

The helical turbine moves very slowly relative to other tidal technologies, and is likely to have little collision risk. Archimedes screws often produce little noise, though this depends on the design and generator. Concerns about electromagnetic fields, chemicals, and energy removal are similar to that of other tidal devices.

Tidal Lagoon

 

Tidal lagoons are comprised of retaining walls embedded with reversible low-head turbines that surround a large reservoir. Tides cause a difference in the water height inside and outside of the walls, functioning very similar to a low-head conventional hydrokinetic dam that works in both direction.

 

The ecosystem within the reservoir undergoes significant transformation, potentially yielding positive impacts with a more diverse seabed, depending on site selection. The changes to the physical system are similar to conventional marine engineering projects and can include altering water flow and shoreline processes partially due to energy removal. Decreased flushing of the reservoir may cause some problems for water quality. There are some collision concerns that arise if fish and benthic invertebrates try to traverse the retaining wall through turbines. Impacts from noise depend on turbine selection. There is little concern for electromagnetic fields because cables are embedded in the retaining wall and are not openly exposed to water. The new reservoir may also create calmer waters that allow better recreation.

Tidal Barrage

 

Tidal barrages are dams built across the entrance to a bay or estuary that captures potential tidal energy, similar to tidal lagoons. Energy is collected when the height difference on either side of the dam is greatest, at low or high tide. A minimum height fluctuation of 5 meters (16.4 feet) is required to justify the construction, so only 40 locations worldwide have been identified as feasible.

 

Installing a tidal barrage impacts bay or estuary ecosystems due to the alteration of tidal flows and can have negative effects such as changing the shoreline and important tidal flats. Inhibiting the flow of water in and out of the bay, may also lead to less flushing of the bay or estuary, altering the water quality, and potentially causing additional turbidity (suspended solids) and less saltwater, which may result in the death of fish that act as a vital food source to birds and mammals. Migrating fish may also be unable to access breeding streams, and may attempt to pass through the turbines and risk collision. Impacts from noise depend on turbine selection, similar to tidal lagoons. Decreasing shipping accessibility can become a major socio-economic issue, though locks can be added to allow slow passage. However, the barrage may improve the local economy by increasing land access when used as a bridge and allowing for more recreation opportunities due to calmer waters.

Total Results: 693
Title Author Datesort ascending Type of Content Technology Type Stressor Receptor
Marine Renewable Energy Strategic Framework for Wales: Stage 1 Report Final Kazer, S., Golding, T. November 2008 Report Marine Energy general, Tidal, Wave
Tidal Flows in Te Aumiti (French Pass), South Island, New Zealand Stevens, C., et al. November 2008 Journal Article Marine Energy general, Tidal
Limits To Tidal Current Power Garrett, C., Cummins, P. November 2008 Journal Article Marine Energy general, Tidal
Ramsey Sound Tidal Energy Limited Scoping Report Tidal Energy November 2008 Report Marine Energy general, Tidal Benthic Invertebrates, Birds, Fish, Marine Mammals, Socio-economics
The Ecological Impacts of Tidal Energy Development October 2008 Research Study Annex IV Marine Energy general, Tidal Benthic Invertebrates, Fish
Measurement and Assessment of Background Underwater Noise and its Comparison with Noise from Pin Pile Drilling Operations During Installation of the SeaGen Tidal Turbine Device, Strangford Lough Nedwell, J., Brooker, A. September 2008 Report Marine Energy general, Tidal Noise Fish, Marine Mammals
Impacts of TEC and WEC Array Operation on Sediment Dynamics August 2008 Research Study Annex IV Marine Energy general, Tidal, Wave Energy Removal Farfield Environment, Nearfield Habitat
Assessment of Tidal Current Energy in the Minas Passage, Bay of Fundy Karsten, R., et al. August 2008 Journal Article Marine Energy general, Tidal Energy Removal Farfield Environment
Strangford Lough - MCT (SeaGen) July 2008 Project Site Annex IV Marine Energy general, Tidal
OpenHydro at EMEC May 2008 Project Site Annex IV Marine Energy general, Tidal
Atlas of UK Marine Renewable Energy Resources ABP Marine Environmental Research May 2008 Website Marine Energy general, Tidal, Wave, Wind Energy general, Offshore Wind
The Extractable Power From A Channel Linking A Bay To The Open Ocean Blanchfield, J., et al. May 2008 Journal Article Marine Energy general, Tidal
A Review of the Application of Lifecycle Analysis to Renewable Energy Systems Lund, C., Biswas, W. April 2008 Journal Article Marine Energy general, Riverine, Tidal, Wave, Wind Energy general Socio-economics, Life Cycle Assessment
Life cycle assessment of the Seagen marine current turbine Douglas, C., Harrison, G., Chick, J. February 2008 Journal Article Marine Energy general, Tidal Socio-economics, Life Cycle Assessment
Marine Energy: More than Just a Drop in the Ocean? Armstrong, J., Consultancy, F. January 2008 Report Marine Energy general, Tidal, Wave Farfield Environment, Socio-economics
Strategic Tidal Stream Assessment for Alderney Craig, J. January 2008 Report Marine Energy general, Tidal, Wave Energy Removal, Static Device Benthic Invertebrates, Birds, Seabirds, Fish, Marine Mammals, Socio-economics, Environmental Impact Assessment
The Efficiency Of A Turbine In A Tidal Channel Garrett, C., Cummins, P. September 2007 Journal Article Marine Energy general, Tidal
Marine Renewable Energy Development in Scotland (MREDS) May 2007 Research Study Annex IV Marine Energy general, Tidal, Wave Benthic Invertebrates, Birds, Seabirds, Fish, Marine Mammals, Nearfield Habitat
Scottish Marine Renewables Strategic Environmental Assessment Environmental Report Faber Maunsell, Metoc PLC March 2007 Report Marine Energy general, Tidal, Wave Chemicals, Dynamic Device, EMF, Energy Removal, Noise, Static Device Benthic Invertebrates, Birds, Seabirds, Fish, Marine Mammals, Socio-economics
Fri-El Seapower - Messina Project January 2007 Project Site Annex IV Marine Energy general, Tidal
Summary Report on Environmental Monitoring Related to the Pearson College - ENCANA - Clean Current Tidal Power Demonstration Project at Race Rocks Ecological Reserve Thuringer, P., Reidy, R. December 2006 Report Marine Energy general, Tidal EMF, Noise Benthic Invertebrates, Birds, Seabirds, Fish, Marine Mammals, Nearfield Habitat
Roosevelt Island Tidal Energy (RITE) Project Demonstration December 2006 Project Site Annex IV Marine Energy general, Tidal
Environment Description for the EMEC Tidal Test Site Fall of Warness, Orkney Finn, M. December 2006 Report Marine Energy general, Tidal Nearfield Habitat
The Tidal-Stream Energy Resource in Passamaquoddy-Cobscook Bays: A Fresh Look at an Old Story Brooks, D. November 2006 Journal Article Marine Energy general, Tidal
Aqua Renewable Energy Technologies (Aqua-RET) October 2006 Research Study Annex IV Marine Energy general, Tidal, Wave Socio-economics
The Regulation of Tidal Energy Development Off Nova Scotia: Navigating Foggy Waters Doelle, M., et al. September 2006 Journal Article Marine Energy general, Tidal Socio-economics
Race Rocks Tidal Energy Project September 2006 Project Site Annex IV Marine Energy general, Tidal
An Experimental Investigation on Cavitation, Noise, and Slipstream Characteristics of Ocean Stream Turbines Wang, D., Altar, M., Sampson, R. August 2006 Journal Article Marine Energy general, Tidal Energy Removal, Noise
Skerries Tidal Stream Array: Environmental Impact Assessment Scoping Report Project Management Support Services July 2006 Report Marine Energy general, Tidal Socio-economics, Environmental Impact Assessment
Review and Analysis of Ocean Energy Systems Development and Supporting Policies AEA Energy & Environment June 2006 Report Marine Energy general, OTEC, Tidal, Wave Socio-economics
Methodology for Estimating Tidal Current Energy Resources and Power Production by Tidal In-Stream Energy Conversion (TISEC) Devices Hagerman, G., Polagye, B. June 2006 Report Marine Energy general, Tidal
Instream Tidal Power in North America: Environmental and Permitting Issues Devine Tarbell & Associates June 2006 Report Marine Energy general, Tidal Ecosystem, Socio-economics
Wave and Tidal Energy Its Emergence and the Challenges it Faces Ferro, B. May 2006 Journal Article Marine Energy general, Tidal, Wave Socio-economics
Tidal Current Energy Technologies Fraenkel, P. March 2006 Journal Article Marine Energy general, Tidal
Tidal Barrages and Birds Clark, N. March 2006 Journal Article Marine Energy general, Tidal Energy Removal, Static Device Birds, Nearfield Habitat
Tidal Current Energy Assessment For Johnstone Strait, Vancouver Island Sutherland, G., Foreman, M., Garrett, C. March 2006 Journal Article Marine Energy general, Tidal Energy Removal
Pentland Firth Tidal Stream Modelling Using Stanford Unstructured Non-hydrostatic Terrain-Following Adaptive Navier-Stokes Simulator (SUNTANS) January 2006 Research Study Annex IV Marine Energy general, Tidal Energy Removal
San Remo January 2006 Project Site Annex IV Marine Energy general, Tidal
Galway Bay Test Site January 2006 Project Site Annex IV Marine Energy general, Tidal, Wave, Wind Energy general, Offshore Wind
An Overview of the Environmental Impact of Non-Wind Renewable Energy Systems in the Marine Environment OSPAR Commission January 2006 Conference Paper Marine Energy general, Tidal, Wave
Flow Structure Determination in French Pass NZ January 2006 Research Study Annex IV Marine Energy general, Tidal Nearfield Habitat
Pilot Installation of Tidal Current Turbine in Kvalsundet, Tromsø County, Norway - Status and Possible Consequences for the Environment Systad, G., et al. December 2005 Report Marine Energy general, Tidal Dynamic Device, Energy Removal, Noise, Static Device Benthic Invertebrates, Birds, Seabirds, Fish, Marine Mammals, Socio-economics
The Benthic Environment of the North and West of Scotland and the Northern and Western Isles: Sources of Information and Overview Wilding, T., Hughes, D., Black, K. October 2005 Report Marine Energy general, Tidal, Wave Energy Removal Benthic Invertebrates, Nearfield Habitat
EMEC Fall of Warness Wildlife Observation Data July 2005 Dataset Marine Energy general, Tidal Birds, Marine Mammals
EMEC Fall of Warness Grid-Connected Tidal Test Site July 2005 Project Site Annex IV Marine Energy general, Tidal
Strangford Lough Marine Current Turbine: Environmental Statement Davison, A., Mallows, T. June 2005 Report Marine Energy general, Tidal Socio-economics, Environmental Impact Assessment
EMEC Tidal Test Facility Fall of Warness Eday, Orkney: Environmental Statement Foubister, L. June 2005 Report Marine Energy general, Tidal Benthic Invertebrates, Marine Mammals, Socio-economics, Environmental Impact Assessment
The Power Potential Of Tidal Currents In Channels Garrett, C., Cummins, P. April 2005 Journal Article Marine Energy general, Tidal
Stingray Tidal Steam Energy Device - Phase 3 The Engineering Business January 2005 Report Marine Energy general, Tidal
A Finite Element Circulation Model for Embayments with Drying Intertidal Areas and its Application to the Quoddy Region of the Bay of Fundy Greenberg, D., et al. January 2005 Journal Article Marine Energy general, Tidal
Wanxiang-II Project January 2005 Project Site Annex IV Marine Energy general, Tidal
Renewable Energy Resources: Environmental Impact Chapter Tiwari, G., Ghosal, M. January 2005 Book Chapter Marine Energy general, OTEC, Tidal, Wave Chemicals, Dynamic Device, EMF, Energy Removal, Noise, Static Device
The Impact of Energy Extraction on Tidal Flow Development Couch, S., Bryden, I. July 2004 Conference Paper Marine Energy general, Tidal Energy Removal
Silt-Proof Measures: Following Analysis of Data Measured out of Baishakou Tidal Power Station, Measures were Proposed to Control Sediment in the Reservoir Yunchen, L. February 2004 Magazine Article Marine Energy general, Tidal Energy Removal Nearfield Habitat
Initial Consultation Document for the Roosevelt Island Tidal Energy Project Verdant Power October 2003 Report Marine Energy general, Tidal
SuperGen Marine Energy Research October 2003 Research Study Annex IV Marine Energy general, Tidal, Wave Dynamic Device, Energy Removal, Static Device Benthic Invertebrates, Birds, Marine Mammals
Kvalsund Tidal Turbine Prototype August 2003 Project Site Annex IV Marine Energy general, Tidal
European Marine Energy Centre European Marine Energy Centre January 2003 Website Marine Energy general, Tidal, Wave
Yell Sound September 2002 Project Site Annex IV Marine Energy general, Tidal
Wake Effects in Tidal Current Turbine Farms Macleod, A., et al. January 2002 Conference Paper Marine Energy general, Tidal Energy Removal Nearfield Habitat
Wanxiang-I Project January 2002 Project Site Annex IV Marine Energy general, Tidal
The Practice of Comprehensive Silt Proof Measures in Tide Power Stations Liu, X., Fagong, L. September 2001 Report Marine Energy general, Tidal Energy Removal Nearfield Habitat
Enermar Project January 2001 Project Site Annex IV Marine Energy general, Tidal
Changes in Area, Geomorphology and Sediment Nature of Salt Marshes in the Oosterschelde Estuary (SW Netherlands) Due to Tidal Changes de Jong, D., de Jong, Z., Mulder, J. May 1994 Journal Article Marine Energy general, Tidal Energy Removal Nearfield Habitat
Macrotidal Estuaries: A Region of Collision Between Migratory Marine Animals and Tidal Power Development Dadswell, M., Rulifson, R. January 1994 Journal Article Marine Energy general, Tidal Dynamic Device Fish, Marine Mammals
Intertidal Ecology and Potential Power Impacts, Bay of Fundy, Canada Gordon, D. Jr. January 1994 Journal Article Marine Energy general, Tidal Energy Removal Benthic Invertebrates, Birds, Shorebirds, Fish, Nearfield Habitat
Tidal Power and the Aquatic Environment of La Rance Retiere, C. January 1994 Journal Article Marine Energy general, Tidal Energy Removal Birds, Fish, Nearfield Habitat
Potential Impact of Large-Scale Tidal Power Developments in the Upper Bay of Fundy on Fisheries Resources of the Northwest Atlantic Dadswell, M., Rulifson, R., Daborn, G. July 1986 Journal Article Marine Energy general, Tidal Energy Removal, Static Device Fish
The Annapolis Tidal Power Project Head Pond Water Levels - Impacts and Mitigations Rice, R. September 1984 Report Marine Energy general, Tidal Energy Removal
Update on the Marine Environmental Consequences of Tidal Power Development in the Upper Reaches of the Bay of Fundy Gordon, D., Dadswell, M. June 1984 Report Marine Energy general, Tidal Farfield Environment, Nearfield Habitat
Annapolis Tidal Station January 1984 Project Site Annex IV Marine Energy general, Riverine, Tidal
Assessing the Environmental Impact of the Annapolis Tidal Power Project Tidmarsh, W. January 1984 Journal Article Marine Energy general, Tidal Fish, Nearfield Habitat, Socio-economics, Environmental Impact Assessment
Jiangxia Pilot Tidal Power Plant January 1980 Project Site Annex IV Marine Energy general, Tidal
Ten Years of Experience at the La Rance Tidal Power Plant Andre, H. December 1978 Journal Article Marine Energy general, Tidal
BaiShakou Tidal Power Station August 1978 Project Site Annex IV Marine Energy general, Tidal
Haishan Tidal Power Plant December 1975 Project Site Annex IV Marine Energy general, Tidal
La Rance Tidal Barrage November 1966 Project Site Annex IV Marine Energy general, Tidal
Kyle Rhea Tidal Stream Array Project Planned Project Site Annex IV Marine Energy general, Tidal
OpenHydro Alderney Planned Project Site Annex IV Marine Energy general, Tidal
Anglesey Skerries Tidal Stream Array Planned Project Site Annex IV Marine Energy general, Tidal
Admiralty Inlet Pilot Tidal Project Planned Project Site Annex IV Marine Energy general, Tidal
Minesto Holyhead Deep - Phase 1 (0.5MW) Planned Project Site Annex IV Marine Energy general, Tidal
Swansea Tidal Lagoon Planned Project Site Annex IV Marine Energy general, Tidal
Fair Head Tidal Array Planned Project Site Annex IV Marine Energy general, Tidal
Western Passage Tidal Energy Project Planned Project Site Annex IV Marine Energy general, Tidal
West Islay Tidal Project Planned Project Site Annex IV Marine Energy general, Tidal
Sound of Islay Demonstration Tidal Array Planned Project Site Annex IV Marine Energy general, Tidal
Brims Tidal Array Planned Project Site Annex IV Marine Energy general, Tidal
Torr Head Project Planned Project Site Annex IV Marine Energy general, Tidal
Argyll Tidal Demonstrator Project Planned Project Site Annex IV Marine Energy general, Tidal
Perpetuus Tidal Energy Centre (PTEC) Planned Project Site Annex IV Marine Energy general, Tidal
Westray South Tidal Project Planned Project Site Annex IV Marine Energy general, Tidal
Clarence Strait Tidal Energy Project Planned Project Site Annex IV Marine Energy general, Tidal

Pages

Subscribe to Tidal
Find Tethys on InstagramFind Tethys on FacebookFind Tethys on Twitter
 
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Subscribe to Tidal