tidal energy

Tidal energy is produced by the surge of ocean waters during the rise and fall of tides.

Tidal energy is a renewable source of

energy

During the 20th century, engineers developed ways vĩ đại use tidal movement vĩ đại generate electricity in areas where there is a significant tidal range—the difference in area between high tide and low tide. All methods use special generators vĩ đại convert

tidal

energy

into

electricity

Tidal

energy

production is still in its infancy. The amount of power produced sánh far has been small. There are very few commercial-sized tidal power plants operating in the world. The first was located in La Rance, France. The largest facility is the Sihwa Lake Tidal Power Station in South Korea. The United States has no tidal plants and only a few sites where

tidal

energy

could be produced at a reasonable price. Đài Loan Trung Quốc, France, England, Canada, and Russia have much more potential vĩ đại use this type of

energy

In the United States, there are legal concerns about underwater land ownership and environmental impact. Investors are not enthusiastic about

tidal

energy

because there is not a strong guarantee that it will make money or benefit consumers.

Engineers

are working vĩ đại improve the technology of tidal energy generators vĩ đại increase the amount of

energy

they produce, vĩ đại decrease their impact on the environment, and vĩ đại find a way vĩ đại earn a profit for

energy

companies.

Tidal Energy Generators

There are currently three different ways vĩ đại get

tidal

energy

: tidal streams, barrages, and tidal lagoons.

For most

tidal

energy

generators

, turbines are placed in

tidal streams

. A

tidal stream

is a fast-flowing toàn thân of water created by

tides

. A

turbine

is a machine that takes

energy

from a flow of fluid. That

fluid

can be air (wind) or liquid (water). Because water is much more dense than thở air,

tidal

energy

is more powerful than thở wind energy. Unlike wind,

tides

are predictable and stable. Where tidal

generators

are used, they produce a steady, reliable stream of

electricity

Placing

turbines

tidal streams

is complex, because the machines are large and disrupt the

tide

they are trying vĩ đại harness. The

environmental impact

could be severe, depending on the size of the

turbine

and the site of the

tidal stream

Turbines

are most effective in shallow water. This produces more

energy

and allows ships vĩ đại navigate around the

turbines

. A tidal

generator

turbine

blades also turn slowly, which helps marine life avoid getting caught in the system.

The world's first tidal power station was constructed in 2007 at Strangford Lough in Northern Ireland. The

turbines

are placed in a narrow strait between the Strangford Lough inlet and the Irish Sea. The

tide

can move at 4 meters (13 feet) per second across the

strait

Barrage
Another type of

tidal

energy

generator

uses a large dam called a

barrage

. With a

barrage

, water can spill over the top or through

turbines

in the

dam

because the

dam

is low.

Barrages

can be

constructed

across tidal rivers, bays, and estuaries.

Turbines

inside the

barrage

harness

the power of

tides

the same way a river

dam

harnesses

the power of a river. The

barrage

gates are open as the

tide

rises. At

high

tide

, the

barrage

gates close, creating a pool, or

tidal lagoon

. The water is then released through the

barrage

turbines

, creating

energy

at a rate that can be controlled by

engineers

The

environmental impact

of a

barrage

system can be quite

significant

. The land in the

tidal range

is completely

disrupted

. The change in water level in the

tidal lagoon

might harm plant and animal life. The salinity inside the

tidal lagoon

lowers, which changes the organisms that are able vĩ đại live there. As with

dams

across rivers, fish are blocked into or out of the

tidal lagoon

Turbines

move quickly in

barrages

, and

marine

animals can be caught in the blades. With their food source limited, birds might find different places vĩ đại migrate.

barrage

is a much more expensive

tidal

energy

generator

than thở a single

turbine

. Although there are no fuel costs,

barrages

involve more

construction

and more machines. Unlike single

turbines

barrages

also require constant supervision vĩ đại adjust power output.

The tidal

power plant

at the Rance River estuary in Brittany, France, uses a

barrage

. It was built in 1966 and is still functioning. The plant uses two sources of

energy

tidal

energy

from the English Channel and river

current

energy

from the Rance River. The

barrage

has led vĩ đại an increased level of silt in the habitat. Native aquatic plants suffocate in

silt

, and a flatfish called plaice is now extinct in the area. Other organisms, such as cuttlefish, a relative of squids, now thrive in the Rance

estuary

Cuttlefish

prefer cloudy,

silty

ecosystems.

Tidal Lagoon
The final type of

tidal

energy

generator

involves the

construction

tidal lagoons

. A

tidal lagoon

is a toàn thân of

ocean

water that is partly enclosed by a natural or manmade barrier.

Tidal lagoons

might also be estuaries and have freshwater emptying into them.

tidal

energy

generator

using

tidal lagoons

would

function

much lượt thích a

barrage

. Unlike

barrages

, however,

tidal lagoons

can be

constructed

along the natural coastline. A

tidal lagoon

power plant

could also

generate

continuous power. The

turbines

work as the lagoon is filling and emptying.

The

environmental impact

tidal lagoons

is minimal. The lagoons can be

constructed

with natural materials lượt thích rock. They would appear as a low breakwater (sea wall) at

low

tide

, and be submerged at

high

tide

. Animals could swim around the structure, and smaller organisms could swim inside it. Large predators lượt thích sharks would not be able vĩ đại penetrate the lagoon, sánh smaller fish would probably

thrive

. Birds would likely flock vĩ đại the area.

But the

energy

output from

generators

using

tidal lagoons

is likely vĩ đại be low. There are no

functioning

examples yet. Đài Loan Trung Quốc is

constructing

tidal lagoon

power plant

at the Yalu River, near its border with North Korea. A private company is also planning a small

tidal lagoon

power plant

in Swansea

Bay

, Wales.