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Acoustic Pollution

Adverse effects that result from noise generated by a turbine or turbine blades


Anything that takes place in water


A dam used to increase the depth of water or to divert water into a channel for navigation, irrigation, or flood control


Of or relating to the bottom of a body of water. The sea floor is a unique benthic habitat that must be protected during tidal power scheme installation


The board, flat (or slightly rounded) arms of some turbines that capture kinetic energy from a fluid and convert it to mechanical energy


A continuous movement of ocean water in s specific direction. Currents have been likened to rivers within the larger ocean itself. Famous currents include the Gulf Stream (Eastern North America and Western Europe), the Antarctic Circumpolar, the California, The South Equatorial, the Monsoon, and the North Equatorial


Excavation under water to gather up bottom sediment. Dredging is often necessary during building and maintenance of barrages.

Dynamic Tidal Power

A type of tidal power in which a long (30 km or more) dam is built perpendicular to the land and jutting out into the ocean. It interferes with tidal flows to create head and thus generate electricity


A community of living organisms along with their related physical and chemical environment


The trapping of smaller aquatic life in filters, sluices, etc.


Any location where fresh river water meets salty ocean water. Estuaries are critical habitat for spawning and early life cycle stages of many ocean organisms as well as birds


The movement of a fluid in a stream

Francis Turbine

A reaction turbine in which water moves through a spiral trajectory to push curved blades connected to the rim or a wheel


One billion watts

Gorlov Turbine

A turbine that makes use of a helical blade or foil. It is not directional and can be mounted horizontally or vertically


A reference to the electrical supply lines that connect electricity producers to consumers


The highest part of a body of water where water pressure is measured from

Horizontal Axis Turbine

A turbine in which the axis is parallel to the ground


A wing-shaped structure that is design to alter the flow of water and react to it


The energy of moving fluid

Impulse Turbine

A turbine in which rotation is derived by jets of fluid impinging against the blades. There is no pressure difference for the fluid between inflow and outflow of an impulse turbine, but there is a velocity difference.

Kaplan Turbine

A reaction turbine with adjustable blades


One thousand watts


A shallow pond that can connect with or communicate with a larger body of water. A tidal lagoon is constructed of a 360 degree barrage in a tidal basin or estuary


Having to do with the moon

Lunar Tide

The part of the tide that results from the gravity of the moon


Anything having to do with the sea or seashore


One million watts

Neap Tide

A tide that occurs when the difference between high tide and low tide is the least. In other words, the lowest high tide in a month that occurs when the moon is ¼ or ¾ full. Neap tides occur when gravitational forces from the sun and moon are at right angles (perpendicular) to one another.

Ocean Thermal Power

Power derived by exploiting differences in water temperature between the surface of the ocean and deeper parts of the ocean

Osmotic Power

Power derived from water flowing between areas of low solute concentration and high solute concentration

Pelton Wheel

An impulse turbine in which cup-shaped buckets attached to the rim of a wheel are pushed by gets of water moving at high velocity.

Rance River

A river and estuary system in France that is the site of the first commercial-scale tidal barrage power system

Reaction Turbine

A turbine with curved blades in which rotation results from the pressure of a fluid. There is a pressure drop in the fluid between inflow and outflow


The level of salt dissolved in a given quantity of water

Saltwater Intrusion

The movement of salty ocean water into fresh lake or groundwater


In tidal energy, a scheme is a reference to the specific type of technology used to harness tidal energy. For instance, a tidal barrage scheme.

Sediment Damming

The trapping of sediment, by a dam or barrage, that would normally have flowed into the open ocean


Sand and clay that is captured by moving water and eventually deposited by it


An artificial passage for water that usually has a gate to obstruct flow as desired

Solar Tide

The part of the tide that results from the gravity of the sun

Spring Tide

The tide that occurs when the difference between high and low tides is greatest. In other words, the highest high tide in a month. It occurs when the moon is new or full. Spring tides result when the gravitation forces of the sun and moon are parallel to one another.


One trillion watts

Tidal Kite

A buoyant hydrofoil that is tethered to the ocean floor by a capable and can thus “fly” or move about in the water as currents and waves push it

Tidal Mill

A system that converts energy from the tides into mechanical energy to do work

Tidal Phase

A reference to whether water is at its highest point during a 24 hour cycle (high tide) or at its lowest point (low tide)

Tidal Range

The vertical difference between high tide and low tide

Tidal Stream Generator

A tidal power scheme that uses the kinetic energy of water moving with tides to produce energy.


The measure of the clarity of water as a result of debris and silt


A rotational machine that spins under force of a fluid (water, wind, steam, ammonia, etc.)

Turbine Death

The death of wildlife as a result of direct contact with the blades of a turbine

Venturi Tube

A simple, hollow structure that is widest at both ends and narrowed in the middle. It accelerates a fluid flowing through it

Vertical Axis Turine

A turbine in which the axis is perpendicular to the ground


A unit of power, defined as one joule per second that measures the rate of energy conversion or transfer.

Wave Energy

Kinetic energy that results from the oscillation of water