Tidal

Capturing energy from tidal fluctuations.

Tidal Energy

 

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. As seawater is about 800 times denser than air, tidal turbines can collect energy with slower water currents and smaller turbines than wind energy. Modern tidal power generating turbines operate on the same principles as wind turbines. While the moving water passes the turbine’s blades, the kinetic energy of moving water is converted into mechanical energy as the rotating blades spin a drive shaft. The mechanical energy in the drive shaft is then converted to electrical energy using a generator, often through a gearbox. Power may also be produced by extracting potential energy from the rise and fall of the tides in a manner similar to conventional hydropower.

 

Axial Flow Turbine

 

  • These turbines are the most similar to traditional wind turbines, 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. Turbines may use active or passive measures to yaw or vane in the direction of flow. They can have pitching blades allowing them to change their hydrodynamic performance based on flow conditions or control settings.
  • 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. 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 of the turbines 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, and affect water quality. Large-scale tidal changes in flow (from arrays) may disrupt natural physical systems to cause degradation in water quality or changes in sediment transport, potentially affecting ecosystem processes

Photo Credit: BALAO-SABELLA

Cross Flow Turbine

 

  • These turbines capture kinetic energy of moving water with spinning blades oriented perpendicular to the direction of flow. They can be mounted in either vertical or horizontal orientations. When mounted vertically, these devices can operate regardless of the direction of flow. They typically have cylindrical cross-sections amenable to placement in confined channels or allowing tight array spacing. Turbines can be open or ducted (shrouded) and placed anywhere in the water column, though bottom-mounted is the most common. The electricity production mechanism is similar to axial-flow turbines.
  • There is typically less environmental concern for collision between turbine blades and marine organisms because, depending on the design, blades are spinning in the same direction to the flow of water. Concerns about noise, electromagnetic fields, changes in flow, and impacts on water quality are similar to that of axial flow turbines. 

Photo Credit: Ocean Renewable Power Company (ORPC)

Reciprocating Device

 

  • Reciprocating devices do not have rotating components and 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. Oscillating hydrofoils operate via passive or active manipulation of one or more foils to induce hydrodynamic lift and drag forces due to pressure differences on the foils. They may be oriented horizontally or vertically, though like axial-flow turbines, they must face the direction of flow for maximum energy extraction. Linear motion of the foils may be converted to rotary motion for electricity generation, or linear generators may be used.
  • Reciprocating devices often move slower than turbines, but move more freely in the water, resulting in some concern for collision. Depending on the design and generator, reciprocating devices often produce little noise. Concerns about electromagnetic fields, impacts on water quality, and changes in flow 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 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. Electricity production is by means of a generator coupled to the turbine. Power is transferred through a cable coupled to or as part of the tether.
  • 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 can emit noise over a larger frequency than horizontal axis turbines depending on the design and generator. Concerns about electromagnetic fields, impacts on water quality, and changes in flow 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 slow rotation implies coupling to a generator through a gearbox.
  • 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, impacts on water quality, and changes in flow are similar to that of other tidal devices.

Tidal Lagoon

 

  • Tidal lagoons are comprised of retaining walls embedded with low-head turbines that surround a large reservoir of water. Functioning similar to a hydroelectric dam, tides cause a difference in the water height inside and outside the walls of tidal lagoons. The ecosystem within the reservoir undergoes significant transformation, potentially yielding positive impacts with a more diverse seabed, depending on site selection.
  • Changes to the physical environment are expected to be similar to conventional marine engineering projects and can include changes in flow and ecosystem processes. Decreased flushing of the reservoir may cause some problems for water quality. There are some collision concerns that arise if fish and invertebrates try to traverse the retaining wall through the 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 for new recreation and tourism opportunities.

Tidal Barrage

 

  • Tidal barrages capture water in a holding area, making use of the difference in water height from one side of the barrage to the other. Water is then released through a large turbine or turbines as it flows out with the ebb of the tide. They are typically built across the entrance to a bay or estuary and generate electricity using the difference in water height inside and outside of the structure. A minimum height fluctuation of 5 meters (16.4 feet) is typically required to justify the construction of tidal barrages, so only 40 locations worldwide have been identified as feasible.
  • Installing a tidal barrage impacts bay or estuary ecosystems due to changes in flow 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 marine 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 and tourism opportunities due to calmer waters.
Total Results: 681
Title Author Date Type of Content Technology Type Stressor Receptorsort descending
RITE Monitoring of Environmental Effects (RMEE) Reports (DRAFT ver. Mar 2016) RITE Project (FERC No. P-12611) Smith, R. March 2016 Report Marine Energy (General), Tidal
Modelling impacts of tidal stream turbines on surface waves Li, X., et al. January 2019 Journal Article Marine Energy (General), Tidal Changes in Flow Physical Environment
Tidal Turbine Collision Detection: A review of the state-of-the-art sensors and imaging systems for detecting mammal collisions Jha, S. May 2016 Report Marine Energy (General), Tidal Collision Marine Mammals
Tidal stream energy impacts on estuarine circulation Ramos, V., et al. April 2014 Journal Article Marine Energy (General), Tidal Changes in Flow Physical Environment
Assessment of the impacts of tidal stream energy through high-resolution numerical modeling Ramos, V., et al. November 2013 Journal Article Marine Energy (General), Tidal Changes in Flow Physical Environment
The impacts of tidal turbines on water levels in a shallow estuary Garcia-Oliva, M., Djordjević, S., Tabor, G. September 2017 Journal Article Marine Energy (General), Tidal Changes in Flow Physical Environment
Tidal stream energy impact on the transient and residual flow in an estuary: A 3D analysis Sanchez, M., et al. March 2014 Journal Article Marine Energy (General), Tidal Changes in Flow Physical Environment
Tidal energy machines: A comparative life cycle assessment study Walker, S., et al. May 2015 Journal Article Marine Energy (General), Tidal Human Dimensions, Life Cycle Assessment
Life cycle comparison of a wave and tidal energy device Walker, S., Howell, R. November 2011 Journal Article Marine Energy (General), Tidal, Wave Human Dimensions, 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 Human Dimensions, Life Cycle Assessment
The trade-off between tidal-turbine array yield and environmental impact: A habitat suitability modelling approach du Feu, R., et al. May 2019 Journal Article Marine Energy (General), Tidal Changes in Flow Invertebrates
Predictable changes in fish school characteristics due to a tidal turbine support structure Williamson, B., et al. October 2019 Journal Article Marine Energy (General), Tidal Attraction Fish
Comparing nekton distributions at two tidal energy sites suggests potential for generic environmental monitoring Wiesebron, L., et al. July 2016 Journal Article Marine Energy (General), Tidal Fish
TidGen Power System Commercialization Project Final Technical Report ORPC Maine December 2013 Report 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) Human Dimensions, Life Cycle Assessment
Marine renewables and coastal communities—Experiences from the offshore oil industry in the 1970s and their relevance to marine renewables in the 2010s Johnson, K., Kerr, S., Side, J. March 2013 Journal Article Marine Energy (General), Tidal, Wave Human Dimensions
Public Willingness to Pay and Policy Preferences for Tidal Energy Research and Development: A Study of Households in Washington State Polis, H., Dreyer, S., Jenkins, L. June 2017 Journal Article Marine Energy (General), Tidal Human Dimensions, Social & Economic Data
Interaction between instream axial flow hydrokinetic turbines and uni-directional flow bedforms Hill, C., Musa, M., Guala, M. February 2016 Journal Article Marine Energy (General), Ocean Current, Tidal Physical Environment
Empirical Determination of Severe Trauma in Seals from Collisions with Tidal Turbine Blade Onoufriou, J., et al. March 2019 Journal Article Marine Energy (General), Tidal Marine Mammals, Pinnipeds, Marine Spatial Planning
Monitoring getijdenturbines Oosterscheldekering Jaarrapportage 2018 Leopold, M., Scholl, M. March 2019 Report Marine Energy (General), Tidal Marine Mammals, Cetaceans, Pinnipeds
Developing regional locational guidance for wave and tidal energy in the Shetland Islands Tweddle, J., et al. December 2014 Journal Article Marine Energy (General), Tidal, Wave Human Dimensions, Marine Spatial Planning, Stakeholder Engagement
Three‐dimensional movements of harbour seals in a tidally energetic channel: Application of a novel sonar tracking system Hastie, G., et al. March 2019 Journal Article Marine Energy (General), Tidal Marine Mammals, Pinnipeds
A framework to evaluate the environmental impact of OCEAN energy devices Mendoza, E., et al. June 2019 Journal Article Marine Energy (General), Ocean Current, OTEC, Tidal, Wave, Offshore Wind Human Dimensions, Environmental Impact Assessment
Seapower GEMSTAR System March 2012 Project Site OES-Environmental Marine Energy (General), Tidal
Future policy implications of tidal energy array interactions Waldman, S., et al. October 2019 Journal Article Marine Energy (General), Tidal Changes in Flow Human Dimensions, Legal & Policy
Current Policy and Technology for Tidal Current Energy in Korea Ko, D., et al. May 2019 Journal Article Marine Energy (General), Tidal Human Dimensions, Legal & Policy
Effects of a Tidal Lagoon on the Hydrodynamics of Swansea Bay, Wales, UK Horrillo-Caraballo, J., et al. May 2019 Conference Paper Marine Energy (General), Tidal
Working Group on Marine Benthal Renewable Developments Vanaverbeke, J., et al. January 2019 Report Marine Energy (General), Tidal, Wave
Guidance for Communities on the Development of Wave and Tidal Projects Edwards, C., et al. September 2013 Report Marine Energy (General), Tidal, Wave Human Dimensions, Legal & Policy, Stakeholder Engagement
Marine Spatial Planning from an Irish perspective: Towards Best Practice in Integrated Maritime Governance Flannery, W. July 2011 Thesis Marine Energy (General), Tidal, Wave Human Dimensions, Marine Spatial Planning
Analysing the potentials and effects of multi-use between tidal energy development and environmental protection and monitoring: A case study of the inner sound of the Pentland Firth Sangiuliano, S. August 2018 Journal Article Marine Energy (General), Tidal Human Dimensions, Marine Spatial Planning
Numerical Simulations of the Effects of a Tidal Turbine Array on Near-Bed Velocity and Local Bed Shear Stress Gillibrand, P., Walters, R., McIlvenny, J. October 2016 Journal Article Marine Energy (General), Tidal Changes in Flow Physical Environment, Sediment Transport
Sound of Islay Demonstration Tidal Array: Inter-tidal Survey of Potential Cable Routes Trendall, J. August 2009 Report Marine Energy (General), Tidal Physical Environment, Environmental Impact Assessment
Sound of Islay Demonstration Tidal Array: Inter-tidal Survey of Potential Cable Routes Trendall, J. August 2009 Report Marine Energy (General), Tidal Physical Environment, Environmental Impact Assessment
Winter and summer differences in probability of fish encounter (spatial overlap) with MHK devices Viehman, H., Boucher, T., Redden, A. August 2018 Conference Paper Marine Energy (General), Tidal Collision Fish
Refinements to the EFDC model for predicting the hydro-environmental impacts of a barrage across the Severn Estuary Zhou, J., Falconer, R., Lin, B. February 2014 Journal Article Marine Energy (General), Tidal Physical Environment, Nearfield Habitat
A Political, Economic, Social, Technology, Legal and Environmental (PESTLE) Approach for Risk Identification of the Tidal Industry in the United Kingdom Kolios, A., Read, G. October 2013 Journal Article Marine Energy (General), Tidal Human Dimensions, Legal & Policy, Stakeholder Engagement
Assessing the impact of tidal stream energy extraction on the Lagrangian circulation Guillou, N., Chapalain, G. October 2017 Journal Article Marine Energy (General), Tidal Changes in Flow Physical Environment
Increased integration between innovative ocean energy and the EU habitats, species and water protection rules through Maritime Spatial Planning van Hees, S. February 2019 Journal Article Marine Energy (General), Ocean Current, Salinity Gradient, Tidal, Wave Human Dimensions, Legal & Policy, Marine Spatial Planning
3D modelling of the impacts of in-stream horizontal-axis Tidal Energy Converters (TECs) on offshore sandbank dynamics Chatzirodou, A., Karunarathna, H., Reeve, D. October 2019 Journal Article Marine Energy (General), Tidal Changes in Flow Physical Environment
Agent-Based Modelling of fish collisions with tidal turbines Rossington, K., Benson, T. May 2019 Presentation Marine Energy (General), Tidal Avoidance, Collision Fish
Regulating wave and tidal energy: An industry perspective on the Scottish marine governance framework Wright, G. March 2016 Journal Article Marine Energy (General), Tidal, Wave Human Dimensions, Legal & Policy
ICES SGWTE Report 2012: Report of the Study Group on Environmental Impacts of Wave and Tidal Energy International Council for the Exploration of the Sea May 2012 Report Marine Energy (General), Tidal, Wave, Wind Energy (General), Offshore Wind Human Dimensions, Environmental Impact Assessment
ICES SGWTE Report 2013: Report of the Study Group on Environmental Impacts of Wave and Tidal Energy International Council for the Exploration of the Sea March 2013 Report Marine Energy (General), Tidal, Wave, Wind Energy (General), Offshore Wind Human Dimensions, Environmental Impact Assessment
Offshore Renewable Energy Development Plan (OREDP) For Ireland: Strategic Environmental Assessment (SEA): Volume 1: Non - Technical Summary (NTS) Sustainable Energy Authority of Ireland October 2010 Report Marine Energy (General), Tidal, Wave, Wind Energy (General), Offshore Wind Human Dimensions, Environmental Impact Assessment
Alteration to the shallow-water tides and tidal asymmetry by tidal-stream turbines Potter, D January 2019 Thesis Marine Energy (General), Tidal Changes in Flow Physical Environment, Sediment Transport
The impacts of tidal energy development and sea-level rise in the Gulf of Maine Kresning, B., et al. November 2019 Journal Article Marine Energy (General), Tidal Changes in Flow Physical Environment, Human Dimensions, Climate Change
Assessment of array shape of tidal stream turbines on hydro-environmental impacts and power output Ahmadian, R., Falconer, R. August 2012 Journal Article Marine Energy (General), Tidal Changes in Flow
Simulation Study of Potential Impacts of Tidal Farm in the Eastern Waters of Chengshan Cape, China Liu, X., et al. August 2019 Journal Article Marine Energy (General), Tidal Changes in Flow Physical Environment
Optimising tidal lagoons: an environmental focus Elliott, K. July 2019 Thesis Marine Energy (General), Tidal Human Dimensions, Social & Economic Data
The interplay between economics, legislative power and social influence examined through a social-ecological framework for marine ecosystems services Martino, S., Tett, P., Kenter, J. February 2019 Journal Article Marine Energy (General), Tidal, Wave, Wind Energy (General), Offshore Wind Human Dimensions, Social & Economic Data
The Kyle Rhea Tidal Stream Array Volume II: Environmental Statement Royal Haskoning, Sea Generation (Kyle Rhea) Ltd. January 2013 Report Marine Energy (General), Tidal Human Dimensions, Environmental Impact Assessment
Modeling effects of a tidal barrage on water quality indicator distribution in the Severn Estuary Gao, G., Falconer, R., Lin, B. April 2013 Journal Article Marine Energy (General), Tidal Changes in Flow Physical Environment, Sediment Transport
Tidal Lagoon Environmental Interactions: Regulator Perspective, Solution Options and Industry Challenges Mackinnon, K., Smith, H., Moore, F. October 2016 Journal Article Marine Energy (General), Tidal
Simulating the environmental impact of tidal turbines on the seabed Vybulkova, L., Vezza, M., Brown, R. September 2013 Conference Paper Marine Energy (General), Tidal Changes in Flow Physical Environment, Sediment Transport
Evaluating the potential impacts of tidal power schemes on estuarine waterbirds Burton, N., et al. January 2010 Conference Paper Marine Energy (General), Tidal Birds, Waterfowl
Underwater sound on wave & tidal test sites: improving knowledge of acoustic impact of Marine Energy Convertors Giry, C., Bald, J., Uriarte, A. June 2018 Conference Paper Marine Energy (General), Tidal, Wave Noise
Buried Alive: The Behavioural Response of the Mussels, Modiolus modiolus and Mytilus edulis to Sudden Burial by Sediment Hutchison, Z., et al. March 2016 Journal Article Marine Energy (General), Tidal, Wave, Wind Energy (General), Offshore Wind Invertebrates
Improving visual biodiversity assessments of motile fauna in turbid aquatic environments Jones, R., et al. August 2019 Journal Article Marine Energy (General), Tidal, Wave, Wind Energy (General), Offshore Wind Fish, Invertebrates, Marine Mammals
Turbines’ effects on water renewal within a marine tidal stream energy site Guillou, N., Thiébot, J., Chapalain, G. December 2019 Journal Article Marine Energy (General), Tidal Changes in Flow
Measuring waves and currents at the European marine energy centre tidal energy test site: Campaign specification, measurement methodologies and data exploitation Sellar, B., et al. June 2017 Conference Paper Marine Energy (General), Tidal, Wave
Camera technology for monitoring marine biodiversity and human impact Bicknell, A., et al. October 2016 Journal Article Marine Energy (General), Tidal, Wave, Wind Energy (General), Offshore Wind Fish, Invertebrates, Human Dimensions
Optimisation of tidal turbine array layouts whilst limiting their hydro-environmental impact Phoenix, A., Nash, S. February 2019 Journal Article Marine Energy (General), Tidal Changes in Flow Physical Environment
Influence of Tidal Energy Converters on sediment dynamics in tidal channel Auguste, C., et al. September 2019 Conference Paper Marine Energy (General), Tidal Changes in Flow Physical Environment, Sediment Transport
Baseline Presence of and Effects of Tidal Turbine Installation and Operations on Harbour Porpoise in Minas Passage, Bay of Fundy, Canada Tollit, D., et al. January 2019 Journal Article Marine Energy (General), Tidal Avoidance, Noise Marine Mammals, Cetaceans
Wave & Tidal Consenting Position Paper Series: Impacts on Fish and Shellfish Ecology Freeman, S., et al. October 2013 Report Marine Energy (General), Tidal, Wave Fish, Invertebrates
Comparing environmental effects of Rance and Severn barrages Kirby, R., Retière. C. March 2009 Conference Paper Marine Energy (General), Tidal Nearfield Habitat
An Offshore Renewable Energy Environmental Research & Innovation Strategy for the UK Natural Environment Research Council December 2019 Report Marine Energy (General), Tidal, Wave, Wind Energy (General), Offshore Wind Human Dimensions, Legal & Policy
Wave & Tidal Consenting Position Paper Series: Ornithological Impacts Kirby, A., et al. October 2013 Report Marine Energy (General), Tidal, Wave Birds
Use of Static Passive Acoustic Monitoring (PAM) for monitoring cetaceans at Marine Renewable Energy Installations (MREIs) for Marine Scotland Embling, C., et al. October 2014 Report Marine Energy (General), Tidal, Wave, Wind Energy (General), Offshore Wind Noise Marine Mammals, Cetaceans
Integration of wave energy and other marine renewable energy sources with the needs of coastal societies Manasseh, R., et al. January 2017 Journal Article Marine Energy (General), Ocean Current, OTEC, Tidal, Wave, Wind Energy (General), Offshore Wind Human Dimensions, Social & Economic Data
Modeling Hydro-environmental Impacts of Tidal Range Renewable Energy Projects in Coastal Waters Falconer, R., Angeloudis, A., Ahmadian, R. February 2018 Book Chapter Marine Energy (General), Tidal Changes in Flow Physical Environment, Sediment Transport, Water Quality
Changes in Relative Fish Density Around a Deployed Tidal Turbine during on-Water Activities Staines, G., Zydlewski, G., Viehman, H. November 2019 Journal Article Marine Energy (General), Tidal Avoidance Fish
Interaction of Marine Renewable Energy and Marine Organisms: Active Acoustic Assessment Williamson, B., et al. September 2019 Conference Paper Marine Energy (General), Tidal Collision Fish
Ecological Effects of Electricity Generation, Storage and Use Henderson, P. May 2018 Book Marine Energy (General), Ocean Current, OTEC, Tidal, Wave, Wind Energy (General), Offshore Wind Human Dimensions, Climate Change, Environmental Impact Assessment, Social & Economic Data
The assessment of extactable tidal energy and the effect of tidal energy turbine deployment on the hydrodynamics in Zhoushan Hou, F., et al. May 2015 Journal Article Marine Energy (General), Tidal Changes in Flow Physical Environment, Water Quality
Environmental Monitoring Report EMEC AK-1000 Rigg, D. September 2019 Report Marine Energy (General), Tidal Environmental Impact Assessment
Assessing the consistency of in-stream tidal energy development policy in Nova Scotia, Canada Carlson, J., Adams, M. November 2019 Journal Article Marine Energy (General), Tidal Human Dimensions, Legal & Policy
Baseline assessment of underwater noise in the Ria Formosa Soares, C., et al. November 2019 Journal Article Marine Energy (General), Tidal Noise
Marine Renewable Energy in the Mediterranean Sea: Status and Perspectives Soukissian, T., et al. September 2017 Journal Article Marine Energy (General), OTEC, Salinity Gradient, Tidal, Wave, Wind Energy (General), Offshore Wind Human Dimensions, Environmental Impact Assessment, Marine Spatial Planning, Social & Economic Data
Three-dimensional modelling of suspended sediment transport in the far wake of tidal stream turbines Li, X., et al. November 2019 Journal Article Marine Energy (General), Tidal Changes in Flow Physical Environment, Sediment Transport

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