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Tidal stream generators look and work like underwater wind turbines. As opposed to using the rising and falling movement of the tides, tidal stream generators take advantage of the fast moving sea currents (tidal streams), which flow when tides are moving in and out. These tidal streams cause the turbines to rotate, turning the generators which generate electricity. Tidal stream generators have the advantage of being much cheaper to build, and do not have as much of an environmental impact as a tidal barrage. The turbines turn relatively slowly, hence do not affect sea life. This is different to tidal barrages which can disrupt fish migrating up rivers from the sea.

Except for South Korea,not other government in the world is really pushing Tidal Wave Energy which needs massive government support at this stage of development.

Tidal Technology is still in the baby phase

Most of the tidal power plants using the modern tidal turbine technology are still in the pilot phase and generate negligible power.However tidal power stations have the potential to generate large amounts of energy in a non-polluting way

idal power can be harnessed using a barrage (dam) built across an estuary that captures the potential energy generated by the change in height (or head) between high and low tides. As the tide goes in and out, the water flows through tunnels in the dam. The ebb and flow are used to either turn a water turbine or compress air through a pipe that then turns a turbine, which generates electricity. Tidal Fences and Turbines Tidal fences and turbines can also be used to capture tidal power. Tidal fences are turbines that operate like giant turnstiles, while tidal turbines are similar to wind turbines. In both cases, electricity is generated when the turbines are turned by the tidal currents that occur in coastal waters. Ocean currents generate relatively more energy than wind (air currents) because ocean water has a higher density than air and therefore applies greater force on the turbines.

Tidal turbines use similar technology to wind turbines, although their blades are much shorter and stronger. So a good way to think of them is as underwater windmills. Basically the water currents turn the turbines, which in turn activate a generator that produces electricity. These systems work best where there are very strong tidal zones (Norwegian and British coastlines.) and although it is still in it’s infancy it does show great promise.The upfront cost of these tidal stream systems is very high and also installation and maintenance is difficult.

Tidal power, often referred to as tidal energy, is a type of hydropower that harnesses the energy of our ocean’s tides or other flowing waterways to produce power, usually in the form of electricity.  As sea levels rise and fall or the currents flow underwater a potential energy is created.  By using equipment such as tidal energy generators and underwater turbines in areas of high tidal movements, the kinetic motion of the ocean can be used to turn the turbines, thus producing electricity. 

Tremendous potential exists for clean energy in waves and tides. Lockheed Martin Mission Systems and Sensors (MS2) is leveraging decades of experience in designing and developing maritime systems into wave and tidal power systems. To do that, we have strategic relationships with key wave and tidal power technology providers. They will provide the technology to convert waves and tides into energy, and MS2 will provide the expertise to help make the systems work in harsh ocean environments and scalable for large-scale production. Wave power generates electricity using special buoys that use the rising and falling of ocean waves to generate electricity. MS2 is partnering with Ocean Power Technologies, Inc. (OPT) and WaveBob LLC to develop their respective wave energy systems for use in future utility-scale power generation projects. MS2 provides its expertise in systems integration, lean manufacturing, and test and optimization analysis to enhance OPT's and Wavebob’s wave power generation technology to utility-scale. Tidal power generating systems use underwater turbines designed to capture the kinetic motion of ebbing and surging ocean tides to produce power. MS2 provides design and manufacturing support to Singapore-based Atlantic Resources Corporation (ARC), which is testing its tidal turbines at the European Marine Energy Centre in Orkney, Scotland. MS2 is also exploring related technologies that can be adapted to shallow and low-rate tidal flows.

BC Hydro’s 2002 Green Energy Study for BC estimated the realistic energy potential for tidal current energy generation in BC to be 20 TWhrs/year. The estimated cost was 11 cents/kWhr for a large (800 MW) site, and 25 cents/kWhr for a small (43 MW) site. The best sites are in the Strait of Georgia and Johnstone Strait, which are both relatively close to the main centers of consumption.

trictly, tidal power comes from the mov

It was used in the watermills along the shores of England during the Roman age and also used along the shores of France and Spain. This period was around 900 AD. The water rising from the tides was impounded in barrages and it was allowed to flow through waterwheels and other energy capturing devices thus capturing the energy and converting it into useful work used to grind grains and produce flour. The first tidal mill in the US was built in Salem, MA in 1635.

The argument for tidal power is overwhelming: it’s a practically infinite supply of clean energy and has one of the smallest carbon footprints of any power source; it’s reliable, cost-efficient, has minimal effect on the marine environment and virtually zero effect on sea-gazing aesthetics. Most importantly, The World Energy Council estimates that the energy that can be harvested from world’s oceans is equal to twice the electricity that the world produces now

Tidal power traditionally involves erecting a dam across the opening to a tidal basin. The dam includes a sluice that is opened to allow the tide to flow into the basin; the sluice is then closed, and as the sea level drops, traditional hydropower technologies can be used to generate electricity from the elevated water in the basin. Some researchers are also trying to extract energy directly from tidal flow streams.

Another form of ocean energy is called tidal energy. When tides comes into the shore, they can be trapped in reservoirs behind dams. Then when the tide drops, the water behind the dam can be let out just like in a regular hydroelectric power plant.

Can Already Cost Under $.06 per Kilowatt Hour * Pneumatic devices, such as the oscillating water column (OWC), use wave motion to compress and decompress air, and drive a turbine. * Float-based devices utilise a buoyant float moving with the waves, reacting against a sea bed anchor in order to harness energy. * Spillover devices utilise wave height to replenish a reservoir of seawater, which runs a turbine. * Raft-type devices use the relative motion of adjacent rafts or pontoons to harness wave energy. * Moving-body devices articulate in the water, inducing motion, which may be used to drive a hydraulic motor.

Tidal stream devices extract energy from the diurnal flow of tidal currents (caused by the gravitational pull of the moon). Unlike wind and wave power, tidal streams offer entirely predictable output. However, as the lunar cycle is of around 25 hours’ duration, the timing of peak outputs differs by around an hour each day and tidal energy cannot be guaranteed at times of peak demand.

However, several large grid-connected demonstration projects are expected to enter the water in the near future. Tidal stream is thus a few years behind wave energy.