How you use tidal energy today?

Answer 1

There are two ways at present of using tidal power:

# Barrage systems. This system, built like a dam across a river, holds back the water till the tide has gone out, then uses the potential energy of the water to turn turbines in the barrage. This is an expensive system with many disadvantages.

# Tidal Stream systems. This consists of using turbines, rather like wind turbines, to use the kinetic power of the moving water to generate electricity. This is easier and cheaper to install.

There are three Barrage systems operating throughout the world.

# One large 240 MW plant on the Rance River in France, and two small plants,

# one in the Bay of Fundy in Canada, and

# another in Kislaya Guba in Russia. There is only one Tidal Stream system working commercially:

* A fullsize turbine prototype, SeaGen, was installed in Strangford Lough in Northern Ireland in 2008, with a capacity of 1.2 MW. A large number of smaller tidal stream pilot schemes are being trialled.

* In Hammerfest, Norway a turbine, generating 300 kW, started in 2003. * A 300 kW Periodflow marine current propeller type turbine was tested in Devon, England in 2003. * Since April 2007 a prototype project in the East River in New York City has been running. * An Open-Centre Turbine, has a prototype being tested at the European Marine Energy Centre (EMEC), in Orkney, Scotland. * A Gorlov turbine, an improved helical design, is being prototyped on a large scale in S. Korea. * Neptune Renewable Energy has developed Proteus which uses a barrage of vertical axis crossflow turbines for use mainly in estuaries. * During 2003 a 150kW oscillating hydroplane device, the Stingray, was tested off the Scottish coast. * Successful commercial trials of highly efficient shrouded tidal turbines on the Gold Coast, Queensland, Australia in 2002. * Shrouded turbines are being installed for a remote Australian community in northern Australia, two small turbines will provide 3.5 MW. * Another larger 5 meter diameter turbine, capable of 800 kW in 4 m/s of flow, is planned as a tidal powered desalination showcase near Brisbane Australia in October 2008. * The Hydro Venturi, is being tested in San Francisco Bay. * In April 2008, a turbine-generator unit (TGU) prototype was successfully tested at Cobscook Bay and Western Passage tidal sites near Eastport, Maine. * Trials in the Strait of Messina, Italy, started in 2001 of the Kobold concept.

Answer 2

Tidal power is used today to generate electricity for thousands of homes.

• The first tidal power station in the world is at the mouth of the River Rance, in Brittany, France (1966, 240 MW).
• The biggest one in the world is the Sihwa Lake Tidal Power Station in South Korea (2011, 254 MW).
• The smallest one in the world is Strangford Lough in Northern Ireland (2007, 1.2 MW)

Answer 3

Tidal power can be used in a variety of ways (these are for electrical generation purposes):

1. Undersea Turbines - these are basically underwater wind turbines, can generate a lot of power with very little maintenance. Fairly high starting costs though.

2. Tidal Barrages - Such as the proposal for the Severn Barrage. These are dams built across tidal areas, when the tide comes in it fills up, as the tide outside the dam drops the water is let back out running generators. This can generate vast quantities of power but is very expensive/damaging to the surrounding environment.

3. Various wave energy devices - these aren't exactly tidal sources but units such as Pelamis use the motion of the waves to drive internal generators which provide reasonable amounts of power. Or you can have static units on the coast which use the motion of the waves in a vertical tube to drive a generator (that's simplified a bit).

Unsurprisingly that is just a few ways of using tidal energy, there are loads of ways of utilising it, and not just to generate power.