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a tidal energy project is moving ahead in Maine, with high costs but high hopes too. But the 180-kilowatt unit that the Ocean Renewable Power Company hopes to put under water next week is really just a first step. The big question is, how well will it withstand the force of the rushing water?

The region, the Bay of Fundy, is famous for strong tides, but the company has picked a spot called Cobscook Bay, where the current is relatively slow, an average of 5.8 knots, or 6.7 miles an hour. That is the speed at which the hardware will produce 180 kilowatts.

idal turbines are very much like an underwater windmill where the blades are driven by consistent, fast-moving currents.  The submerged rotors harness the power of the tidal streams to drive generators, which in turn produce electricity. Water is 832 times denser than air so consequently tidal turbine rotors can be are much smaller than wind turbine rotors generate equivalent  amounts of electricity, and they can be deployed much closer together. Devices that harness tidal stream energy present a unique set of engineering challenges in terms of design, installation and maintenance. During operation, the force of the tidal flow in Strangford Lough is equivalent to a 345 mph wind generating a 100 tonnes of thrust on the rotors. The unique SeaGen design allows capture of the maximum amount of tidal energy whilst keeping maintenance and connectivity costs low.

Tidal turbines are very much like an underwater windmill where the blades are driven by consistent, fast-moving currents.  The submerged rotors harness the power of the tidal streams to drive generators, which in turn produce electricity. Water is 832 times denser than air so consequently tidal turbine rotors are much smaller than wind turbine rotors generate equivalent  amounts of electricity, and they can be deployed much closer together. Devices that harness tidal stream energy present a unique set of engineering challenges in terms of design, installation and maintenance. During operation, the force of the tidal flow in Strangford Lough is equivalent to a 345 mph wind generating a 100 tonnes of thrust on the rotors.

As far as producing electricity goes, tidal energy is one of the cheapest kinds.

Since the tidal cycle repeats itself every 24 hours, there is a guarantee that power can be produced this way every day of the year.

can help protect delicate coastal areas from storm damage, as well

April 4, 2008 Bristol based renewable energy company Marine Current Turbines has completed the first installation phase of the 1.2MW SeaGen Tidal System at Northern Ireland’s Strangford Lough - a site chosen for its combination of fast tidal current and ability to provide shelter from bad weather which may hinder the construction process.

More than 70% of Earth's surface is covered by oceans which contain two types of energy: mechanical energy from waves and tides and Thermal energy from solar radiations falling on the ocean surface making them the world's largest solar collectors

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.

450 TWh is the estimated yearly potential of electric power that can be produced from tidal energy. In addition to this comes a large and not yet estimated potential in river flows.

Tidal stream generators are very similar to wind turbines except their below the water surface instead of above or on land. The turbine and generator converts the movement of water coming from change in tide, the kinetic energy, into electricity. Water is 830 times denser than air and therefore can generate electricity at lower speeds than wind turbines.

A benefit is very little pollution. However, there is a very serious potential draw back. It can be very hard of fish populations. The proposal for tidal power is to put turbines on the bottom of a bay and let the water rushing in and out with the tide turn them and generate electricity. However, along with the water will come fish and other marine animals. What do you think will happen when these critters get sucked into the turbines. Can you say sushi, boys and girls? Putting some kind of screen in front of the turbine to prevent this would just mean that the animals would be sucked up against the screens, obstructing the flow of water through the turbines.

Potential

Wave energy resources are best between 30º and 60º latitude in both hemispheres, and the potential tends to be the greatest on western coasts

While no commercial wave or tidal projects have yet been developed in the United States, several projects are planned for the near future, including projects in the Northwest

This ultimately reduces the cost these power plants can sell their electricity