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: 669
Title Author Date Type of Contentsort ascending Technology Type Stressor Receptor
A Comparison of Numerical Modelling Techniques for Tidal Stream Turbine Analysis Masters, I., et al. July 2015 Journal Article Marine Energy general, Tidal
Economic Evaluation of the Recreational Value of the Coastal Environment in a Marine Renewables Deployment Area Voke, M., et al. January 2013 Journal Article Marine Energy general, Tidal, Wave Energy Removal Socio-economics, Aesthetics, Recreation
Using Drifting Passive Echolocation Loggers to Study Harbour Porpoises in Tidal-Stream Habitats Wilson, B., Benjamins, S., Elliot, J. December 2013 Journal Article Marine Energy general, Tidal Marine Mammals
The Effects of a Severn Barrage on Wave Conditions in the Bristol Channel Fairley, I., et al. August 2014 Journal Article Marine Energy general, Tidal Energy Removal Farfield Environment
Development and the Environmental Impact Analysis of Tidal Current Energy Turbines in China Liu, Y., Ma, C., Jiang, B. January 2018 Journal Article Marine Energy general, Tidal
Measuring Underwater Background Noise in High Tidal Flow Environments Willis, M., et al. January 2013 Journal Article Tidal Noise
Adjusting the Financial Risk of Tidal Current Projects by Optimising the 'Installed Capacity/Capacity Factor'-Ratio Already During the Feasibility Stage Bucher, R., Couch, S. June 2013 Journal Article Marine Energy general, Tidal Socio-economics
Harbour Seals Avoid Tidal Turbine Noise: Implications for Collision Risk Hastie, G., et al. March 2018 Journal Article Marine Energy general, Tidal Noise Marine Mammals, Pinnipeds
Multi-Scale Ocean Response to a Large Tidal Stream Turbine Array De Dominicis, M., Murray, R., Wolf, J. December 2017 Journal Article Marine Energy general, Tidal Energy Removal Farfield Environment
Large Scale Three-Dimensional Modelling for Wave and Tidal Energy Resource and Environmental Impact: Methodologies for Quantifying Acceptable Thresholds for Sustainable Exploitation Gallego, A., et al. October 2017 Journal Article Marine Energy general, Tidal, Wave Energy Removal Farfield Environment
Evaluating Statistical Models to Measure Environmental Change: A Tidal Turbine Case Study Linder, H., Horne, J. January 2018 Journal Article Marine Energy general, Tidal Farfield Environment
Tidal Energy: The Benthic Effects of an Operational Tidal Stream Turbine O'Carroll, J., et al. August 2017 Journal Article Marine Energy general, Tidal Static Device Benthic Invertebrates
Developing Methodologies for Large Scale Wave and Tidal Stream Marine Renewable Energy Extraction and its Environmental Impact: An Overview of the TeraWatt Project Side, J., et al. October 2017 Journal Article Marine Energy general, Tidal, Wave Energy Removal Farfield Environment, Nearfield Habitat
Comparative Studies Reveal Variability in the use of Tidal Stream Environments by Seabirds Waggitt, J., et al. July 2017 Journal Article Marine Energy general, Tidal Birds, Seabirds
Hydroacoustic Assessment of Behavioral Responses by Fish Passing Near an Operating Tidal Turbine in the East River, New York Bevelhimer, M., et al. August 2017 Journal Article Marine Energy general, Tidal Dynamic Device Fish
Challenges and Opportunities in Monitoring the Impacts of Tidal-Stream Energy Devices on Marine Vertebrates Fox, C., et al. January 2018 Journal Article Marine Energy general, Tidal Marine Mammals
Hydrodynamic Impacts of a Marine Renewable Energy Installation on the Benthic Boundary Layer in a Tidal Channel Fraser, S., et al. September 2017 Journal Article Marine Energy general, Tidal Energy Removal
Regional-Scale Patterns in Harbour Porpoise Occupancy of Tidal Stream Environments Waggitt, J., et al. August 2017 Journal Article Marine Energy general, Tidal
Seabird Conservation and Tidal Stream and Wave Power Generation: Information Needs for Predicting and Managing Potential Impacts Langton, R., Davies, I., Scott, B. September 2011 Journal Article Marine Energy general, Tidal, Wave Static Device Birds, Seabirds
Research for the Sustainable Development of Tidal Power in Maine Johnson, T., Zydlewski, G. January 2012 Journal Article Marine Energy general, Tidal Socio-economics
A Tool for Simulating Collision Probabilities of Animals with Marine Renewable Energy Devices Schmitt, P., et al. November 2017 Journal Article Marine Energy general, Tidal Dynamic Device
From Scotland to New Scotland: Constructing a Sectoral Marine Plan for Tidal Energy for Nova Scotia Sangiuliano, S., Mastrantonis, S. October 2017 Journal Article Marine Energy general, Tidal Legal and Policy
Modelling the Hydrodynamic and Morphological Impacts of a Tidal Stream Development in Ramsey Sound Haverson, D., et al. October 2018 Journal Article Marine Energy general, Tidal Energy Removal Farfield Environment
First in situ Passive Acoustic Monitoring for Marine Mammals during Operation of a Tidal Turbine in Ramsey Sound, Wales Malinka, C., et al. January 2018 Journal Article Marine Energy general, Tidal Dynamic Device Marine Mammals
Black Guillemot Ecology in Relation to Tidal Stream Energy Generation: An Evaluation of Current Knowledge and Information Gaps Johnston, D., et al. March 2018 Journal Article Marine Energy general, Tidal Birds, Seabirds
Fish Distributions in a Tidal Channel Indicate the Behavioural Impact of a Marine Renewable Energy Installation Fraser, S., et al. November 2018 Journal Article Marine Energy general, Tidal Static Device Fish
Simulating Current-Energy Converters: SNL-EFDC Model Development, Verification, and Parameter Estimation James, S., et al. July 2017 Journal Article Marine Energy general, Tidal Energy Removal Farfield Environment
Modelling Study of the Effects of Suspended Aquaculture Installations on Tidal Stream Generation in Cobscook Bay O'Donncha, F., James, S., Ragnoli, E. March 2017 Journal Article Marine Energy general, Tidal Energy Removal Farfield Environment, Socio-economics, Fishing
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
Harbour seals (Phoca vitulina) around an operational tidal turbine in Strangford Narrows: No barrier effect but small changes in transit behaviour Sparling, C., Lonergan, M., McConnell, B. February 2018 Journal Article Marine Energy general, Tidal Marine Mammals, Pinnipeds
Underwater operational noise level emitted by a tidal current turbine and its potential impact on marine fauna Lossent, J., et al. June 2017 Journal Article Marine Energy general, Tidal Noise Benthic Invertebrates, Fish, Marine Mammals
Multi-Dimensional Optimisation of Tidal Energy Converters Array Layouts Considering Geometric, Economic and Environmental Constraints González-Gorbeña, E., Qassim, R., Rosman, P. February 2018 Journal Article Tidal
Environmental Interactions of Tidal Lagoons: A Comparison of Industry Perspectives Mackinnon, K., et al. April 2018 Journal Article Marine Energy general, Tidal
Characterisation of Tidal Flows at the European Marine Energy Centre in the Absence of Ocean Waves Sellar, B., et al. January 2018 Journal Article Marine Energy general, Tidal
Operational Noise from Tidal Turbine Arrays and the Assessment of Collision Risk with Marine Mammals Marmo, B. June 2017 Journal Article Marine Energy general, Tidal Dynamic Device, Noise Marine Mammals
Strategic Priorities for Assessing Ecological Impacts of Marine Renewable Energy Devices in the Pentland Firth (Scotland, UK) Shields, M., et al. July 2009 Journal Article Marine Energy general, Tidal EMF, Energy Removal, Noise Benthic Invertebrates, Birds, Fish, Marine Mammals, Nearfield Habitat
Confronting the Financing Impasse: Risk Management through Internationally Staged Investments in Tidal Energy Development MacDougall, S. June 2017 Journal Article Marine Energy general, Tidal Socio-economics
The Value of Delay in Tidal Energy Development MacDonald, S. December 2015 Journal Article Marine Energy general, Tidal Socio-economics
Three-Dimensional Hydrodynamic Modelling of Inland Marine Waters of Washington State, United States, for Tidal Resource and Environmental Impact Assessment Kawase, M., Thyng, K. November 2010 Journal Article Marine Energy general, Tidal Energy Removal Farfield Environment, Nearfield Habitat
Tidal Barrages and Birds Clark, N. March 2006 Journal Article Marine Energy general, Tidal Energy Removal, Static Device Birds, Nearfield Habitat
The Ebb and Flow of Tidal Barrage Development in Zhejiang Province, China Li, Y., Pan, D. December 2017 Journal Article Marine Energy general, Tidal
A Review of the Current Understanding of the Hydro-Environmental Impacts of Energy Removal by Tidal Turbines Nash, S., Phoenix, A. December 2017 Journal Article Marine Energy general, Tidal Energy Removal
Tidal Current Energy Technologies Fraenkel, P. March 2006 Journal Article Marine Energy general, Tidal
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
Impact assessment of marine current turbines on fish behavior using an experimental approach based on the similarity law Zhang, J., et al. June 2017 Journal Article Marine Energy general, Tidal Dynamic Device Fish
Understanding and Informing Permitting Decisions for Tidal Energy Development Using an Adaptive Management Framework Jansujwicz, J., Johnson, T. January 2015 Journal Article Marine Energy general, Tidal 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
Changing Tides: Acceptability, Support, and Perceptions of Tidal Energy in the United States Dreyer, S., Polis, H., Jenkins, L. July 2017 Journal Article Marine Energy general, Tidal Socio-economics
Cumulative Impact Assessment of Tidal Stream Energy Extraction in the Irish Sea Haverson, D., et al. June 2017 Journal Article Marine Energy general, Tidal Energy Removal Farfield Environment, Socio-economics, Environmental Impact Assessment
Hydrokinetic Turbine Effects on Fish Swimming Behaviour Hammar, L., et al. December 2013 Journal Article Marine Energy general, Tidal Dynamic Device Fish
Using a Spatial Overlap Approach to Estimate the Risk of Collisions between Deep Diving Seabirds and Tidal Stream Turbines: A Review of Potential Methods and Approaches Waggitt, J., Scott, B. February 2014 Journal Article Marine Energy general, Tidal Dynamic Device Birds
Modelling the Far Field Hydro-Environmental Impacts of Tidal Farms - A Focus on Tidal Regime, Intertidal Zones and Flushing Nash, S., et al. October 2014 Journal Article Marine Energy general, Tidal Farfield Environment
Turning of the tides: Assessing the international implementation of tidal current turbines Sangiuliano, S. December 2017 Journal Article Marine Energy general, Tidal Socio-economics
Multi-Scale Temporal Patterns in Fish Presence in a High-Velocity Tidal Channel Viehman, H., Zydlewski, G. May 2017 Journal Article Marine Energy general, Tidal Fish
Structure of Turbulent Flow in EMEC's Tidal Energy Test Site Osalusi, E., Side, J., Harris, R. May 2009 Journal Article Marine Energy general, Tidal Energy Removal Nearfield Habitat
Understanding the Potential Risk to Marine Mammals from Collision with Tidal Turbines Copping, A., et al. September 2017 Journal Article Marine Energy general, Tidal Dynamic Device Marine Mammals
Ten Years of Experience at the La Rance Tidal Power Plant Andre, H. December 1978 Journal Article Marine Energy general, Tidal
The Efficiency Of A Turbine In A Tidal Channel Garrett, C., Cummins, P. September 2007 Journal Article Marine Energy general, Tidal
The Environmental Interactions of Tidal and Wave Energy Generation Devices Frid, C., et al. January 2012 Journal Article Marine Energy general, Tidal, Wave Static Device Farfield Environment, Nearfield Habitat
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
Biodiversity Characterisation and Hydrodynamic Consequences of Marine Fouling Communities on Marine Renewable Energy Infrastructure in the Orkney Islands Archipelago, Scotland, UK Want, A., et al. July 2017 Journal Article Marine Energy general, Tidal, Wave Static Device Benthic Invertebrates
The Impact of Tidal Stream Turbines on Large-Scale Sediment Dynamics Neill, S., et al. December 2009 Journal Article Marine Energy general, Tidal Energy Removal Farfield Environment
Modelling Seabed Shear Stress, Sediment Mobility, and Sediment Transport in the Bay of Fundy Li, M., et al. September 2015 Journal Article Marine Energy general, Tidal Energy Removal
Variability in Suspended Sediment Concentration in the Minas Basin, Bay of Fundy, and Implications for Changes due to Tidal Power Extraction Ashall, L., Mulligan, R., Law, B. January 2016 Journal Article Marine Energy general, Tidal Energy Removal
Application of Tidal Energy for Purification in Fresh Water Lake Jung, R., Isshiki, H. January 2015 Journal Article Marine Energy general, Tidal
Habitat characterization of a tidal energy site using an ROV: Overcoming difficulties in a harsh environment Greene, H. September 2015 Journal Article Marine Energy general, Tidal Benthic Invertebrates
The Power Potential Of Tidal Currents In Channels Garrett, C., Cummins, P. April 2005 Journal Article Marine Energy general, Tidal
A Holistic Method for Selecting Tidal Stream Energy Hotspots Under Technical, Economic and Functional Constraints Vazquez, A., Iglesias, G. June 2016 Journal Article Marine Energy general, Tidal Socio-economics
Modeling of In-Stream Tidal Energy Development and its Potential Effects in Tacoma Narrows Washington USA Yang, Z., et al. October 2014 Journal Article Marine Energy general, Tidal Energy Removal Nearfield Habitat

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