Learn all there is to know about tidal energy generators and how it functions.
Resources for renewable energy come in a wide variety. Tidal energy, which depends on shifting tides in the ocean to generate electricity, is one source with the greatest potential. We’ll examine tidal power plants, how tidal energy functions, the places it’s currently used, and what the future holds for it.
About Tidal Power Plants
a facility for producing electricity using tidal current energy. Hydroelectric turbines are powered by the height (head) difference between high and low tides. Current power plants run their turbines during falling and low tides, using the potential energy of water stored behind a dam during a rising tide.
The kinetic energy of both rising and falling tidal currents is directly utilized in some promising tidal turbine plant projects. Further Reading: Is Tidal Renewable Energy?
Main Components of Tidal Power Plants
The three main components of a tidal power plant are a dam or barrage, a powerhouse, and sluiceways.
- Dam or barrage: A dam is used to form a barrier between the sea and a basin. It is typically made of reinforced concrete with channels for turbines and is built to withstand the force of tidal waves. Usually, the dam is constructed close to the mouth of a sizable bay.
- Powerhouse: The heart of a tidal power plant is made up of a number of crucial parts, such as electric generators, turbines, and auxiliary parts. The design of the power plant may also include provisions for pumping water between the basin and the sea in either direction.
- Sluice ways: The sluiceways are used to fill the basin with water during high tide and empty it during low tide, as needed.
How Does Tidal Energy Work?
Tidal turbines, tidal barrages, and tidal fences are the three main techniques for capturing the energy produced by tides and currents in a body of water.
Tidal turbines are very comparable to wind turbines, with the exception that they are submerged in the water as opposed to being above or on land. The turbine, which is attached to a generator that generates electricity, is propelled by the water’s current.
Tidal turbines are able to produce much more electricity than wind power plants, mainly because water is much denser than air. Although tidal turbines are more expensive to produce than wind turbines, this is due to the high density of water, which also means that they must be much stronger.
Even though tidal turbines are enormous, the ecosystem they are located in is only minimally affected. However, they could harm marine life through collisions, similar to wind turbines, but this is less of a problem because the blades usually move slowly. Additionally, they produce low-level noise that may bother marine mammals.
Low-walled dams called tide barrages are typically built at estuaries or tidal inlets. Sluice gates are used to build a reservoir on one side of the barrage, much like traditional hydroelectric dams do. The top of the barrage is just slightly above where the water level hits during the highest tide, and it is anchored to the ocean floor.
Near the bottom of the barrage, inside a tunnel, are tidal turbines that let water pass through. Tidal barrages look like traditional hydropower dams. Turbines located along the bottom of the barrage are turned with the incoming and outgoing tides.
During an incoming high tide, water flows over the turbines as the water rises. Low tide follows, at which point the water returns to the turbines. The generator that generates the electricity is connected to the turbines. Tidal barrages are the most efficient way to harness tidal energy, but they’re also the most costly.
They call for the construction of an entire concrete structure, which can be quite expensive. Barrages also affect the ecosystem around them more adversely than tidal fences or wind turbines.
They essentially act as an underwater wall that prevents fish and other marine life from passing through, which has a variety of negative effects on the local ecosystem.
In some ways, tidal fences resemble a cross between tidal barrages and tidal turbines. The vertical tidal fence turnstiles are installed together in a ‘fence-like’ structure, hence the name ‘tidal fence’. Tidal fences rotate like turnstiles as opposed to propellers.
Tidal current energy pushes the turnstile blades, which are connected to a generator, producing electricity.
Tidal fences have vertical blades that are propelled by flowing water. These vertical turbines are installed together like a fence, but they don’t require the large, concrete structure that tidal barrages do.
They are typically placed in places like inlets and swift-moving streams that are between land masses. They have little effect on the local ecosystem because they are completely underwater.
Where is Tidal Energy Used?
Currently, there is not much energy coming from tidal power. In the entire world, there are only nine tidal power plants in use.
Although more are being planned as tidal power technologies are improved. While many of the proposed tidal power plants are only intended for research, more and more of them are being built for commercial energy.
In order to better understand how tidal energy systems function, testing sites for tidal power generation have been springing up everywhere. The Bay of Fundy in Canada is one of the most prominent test locations.
From what we know now, it seems that tidal power holds a lot of potentials to help us move away from fossil fuels in the future.
The World’s Five Biggest Tidal Power Plants
Here, we profile five of the largest tidal power projects taking place in different parts of the world. Tidal power has a lot of potentials to become a major global renewable energy source.
Sihwa Lake Tidal Power Station
Currently, the world’s largest active tidal power project, the Lake Sihwa Tidal Power Station has a capacity of 254 megawatts (MW). It is situated on Lake Sihwa, about 4 kilometers outside of Siheung, in the South Korean province of Gyeonggi.
The $560 million project, which was completed in 2011, was financed by the South Korean government and is run by the Korea Water Resources Corporation. The facility has a 12.5 km sea wall constructed for agricultural and flood-reduction purposes.
La Rance Tidal Power Plant
The 240 MW La Rance power plant in Brittany, France, was built between 1961 and 1966 and is situated on the estuary of the Rance River. During construction, a 163-meter-long dyke and a 145-meter-long barrage with six fixed wheel gates were installed.
Electricite de France (EDF) runs the facility, which for more than 40 years prior to the opening of the Sihwa Lake facility in 2011 was the largest tidal power plant in the world. 24 reversible bulb turbines with a rated capacity of 10 MW each power the facility.
Annapolis Royal Generating Station
The 20 MW Annapolis tidal power generating station was put into service in 1984 and is situated in the Annapolis Basin, a subbasin of the Bay of Fundy in Canada. The power plant was built by Nova Scotia Power Corporation and has a single four-blade turbine and sluice gates. It uses a causeway constructed in the early 1960s to harness the tidal difference produced by the strong tides in the Annapolis Basin.
The causeway was initially intended to serve as both a transportation route and a water management system to prevent flooding. It is the only tidal power project in North America and generates around 30 million kilowatt hours (KWh) each year – enough to power 4,500 homes.
MeyGen Tidal Energy Project
The MeyGen Tidal Energy Project, which is currently being built, is anticipated to produce about 400 MW of tidal power, making it the world’s largest such facility. The project, which is owned and managed by Scottish Enterprise and Tidal Power Scotland, is situated in the Inner Sound of the Pentland Firth off the northern coast of Caithness, Scotland.
The Phase 1A project’s construction was finished in April 2018 by the international power generation company Atlantis Resources. The first phase of development involves the installation of four 1.5 MW turbines on gravity turbine support structures, as part of the project’s “deploy and monitor strategy”.
While Phase 1C will add an additional 49 turbines with a total capacity of 73.5 MW, Phase 1B entails the installation of four additional 1.5 MW turbines. The MeyGen project’s Phases 2 and 3 will raise the system’s overall capacity to 398 MW, and full operation is anticipated in 2021.
Swansea Bay Tidal Lagoon
The world’s first tidal lagoon power plant is expected to be built in Swansea Bay, Wales, and will have a capacity of approximately 320 MW. For the construction of a $1.12 billion facility, Tidal Lagoon Swansea Bay received planning approval from the UK Department of Energy and Climate Change in June 2015.
The tidal power project’s future is uncertain, though reports suggest it might proceed without government support, as the UK government has since rejected plans to build it.
If approved, it will capture high tides and release water through its turbines to produce energy, and it is anticipated to contribute to a reduction of more than 236,000 tonnes in the UK’s annual carbon dioxide emissions. The 9.5 km breakwater wall and 16 hydro turbines in the tidal lagoon power plant will provide 155,000 homes with electricity for the next 120 years.
You can learn more about other types of power plants, such as Nuclear Power Plants, Hydroelectric Power Plants, Thermal Power Plants, Geothermal Power Plants, Solar Power Plants, Wind Power Plants, and Biomass Power Plants.
The Future of Tidal Energy
In some nations, tidal energy is thriving. In Scotland, a 600-ton windmill that is anchored just off the Orkney Islands is already producing electricity. The O2 turbine is expected to supply 2,000 homes’ energy needs for the ensuing 15 years. A fresh set of incentives supporting tidal energy was recently introduced in the UK.
The tide may also turn in the US: last year, the Department of Energy announced a $27 million investment in research and development around tidal and wave energy technology.
Howland believes that tidal power will be a piece of the renewable energy pie and used in tandem with other forms, but it’s not yet clear how large that piece will be. “Oftentimes, discussions frame renewables as being against one another,” says Howland. “We can’t choose one option if our society wants to decarbonize the way we produce electricity. They’re all things we have to do simultaneously.”
Why is Tidal Power Not Used?
Tidal power is a promising renewable energy source, but production costs, a limited number of suitable locations, and technological challenges hinder its expansion. Tidal power uses the rise and fall of oceanic tides to harness potential or kinetic energy and transform it into other energy forms, frequently electricity.
What is the Efficiency of a Tidal Power Plant?
Tidal energy technologies are sometimes very effective. Engineering company N-Sci says tidal turbines convert 80% of the energy of the tides to electricity. That’s more efficient than current wind or solar energy systems and much more efficient than coal, oil, or natural gas.