Tidal energy systems create electricity by harnessing the energy in seawater. They take advantage of the Tidal energy systems use the energy in seawater to generate electricity. They take advantage of the tides’ regular movement towards and away from the coast, as well as fast-moving currents through underwater channels.
Tides can be exploited in two ways to capture energy. At first, potential energy in the head of water created behind a dam across an estuary, or in a bounded reservoir inside an estuary, such as tidal barrages or lagoons, can be used to drive a turbine.
Second, using tidal current turbines embedded directly in the flow, kinetic energy in horizontal tidal flows or streams can be captured.
Until recently, the principal focus of interest was tidal barrages and tidal lagoons. Tidal current turbines, on the other hand, have been pushed as potentially better since they are less environmentally damaging. It is also recommended that they be simpler and quicker to install, resulting in lower investment costs.
Tidal barrages look like huge, low dams built across small bays and estuaries. These coastal zones are good for barrages since their shape narrows towards the land. They divert incoming tidal water, causing the water level to increase higher than it would if the shoreline were straight.
When the tide comes in, water is trapped on the seaside of the barrage. The sluice gates on the barrage open during high tide, releasing water into the sea. To generate energy, the released water goes via turbines inside the barrage.
Tidal lagoons trap water on the landside during low tide, generating a water head. This water is released at low tide to generate electricity, which is subsequently used to power the network. Rather of being built over estuaries, the Lagoons are built within them.
Tide and Tidal Current
Tides and tidal currents must be distinguished, and their relationship is not the same at all locations: the first refers to the vertical movement of the sea level (rise and fall), while the second refers to the horizontal flow, also known as the run.
Not only in Iceland, but also in the Faroe Islands, tidal current power has been used. It was unable to obtain information regarding the plant and its operational years. The current is usually a combination of tidal and non-tidal currents at any given time.
In the open ocean, tidal currents normally run clockwise in the northern hemisphere and counterclockwise in the southern hemisphere. There are two peaks and two dips in the speed. When the directions are opposite each other at high and low tides, the fastest speed is attained; when the directions are inverted, the fastest speed is reached.
How is Tidal Energy Produced?
Tidal energy production is still in its infancy. So yet, the amount of power generated has been little. Only a few commercial-scale tidal power plants are in operation around the world. Tidal energy is presently available in three forms: tidal streams, barrages, and tidal lagoons.
The tides are used to spin turbines in tidal stream generators. Inlets and straits where water can reach high velocity when tides move in and out are among their installation locations. The most straightforward way to think of them is as underwater wind turbines.
Because these turbines are often huge, installing them on the ocean floor can be difficult. Their size, in fact, can disrupt the tides, defeating the purpose of having them down there! They could have an impact on both marine life and ships.
The moon’s gravitational pull on the oceans generates tidal energy, which is balanced by the lower attraction of the distant sun. The continual rise and fall of the tides have been used in various designs of tidal mills for millennia, but power generation using barrages across river estuaries was only attempted in the twentieth century.
A tidal barrage is a huge seawall erected to absorb tidal energy. Water goes through tunnels inside the dam. When the tide comes in and out, it drives the turbines buried inside these tunnels.
A tidal lagoon is a part of the ocean partially encircled by a natural or artificial barrier. Freshwater may flow into tidal lagoons, making them estuaries.
Similar to a barrage, a tidal energy producer based on tidal lagoons would work. Unlike barrages, tidal lagoons can be created along the natural shoreline. A tidal lagoon power plant might also provide continuous electricity. When the lagoon fills and empties, the turbines spin.
Lagoons would be filled with rock and built-in relatively shallow water, similar to causeways. They might be considered both an offshore pumped storage facility and a power plant. Segmented lagoons may also allow for phased operation and pumping between segments, similar to the twin barrage concept.
Lagoons have the downside of requiring the construction of the entire containment wall. Unlike barrages, the estuary coast provides free confinement for the majority of the water held behind it during high tide. Nonetheless, because lagoon building is expected to be simpler and faster than barrage construction, costs for producing from lagoons are expected to be competitive.
Pros of Tidal Energy
Once the infrastructure is in place, tidal energy is an environmentally friendly source of electricity. It emits fewer greenhouse gases than other forms of energy, making it more environmentally friendly. The long-term effects of a tidal power system on the ecosystem, however, are still unknown.
Highly Predictable Energy Source
In comparison to other renewable energy sources such as the sun, wind, and geothermal, tide energy is extremely reliable – so much so that you can practically set your watch by it. Because we know the tides’ cycles, calculating how much energy a tidal power plant will generate in a day is straightforward.
Low Operational and Maintenance Costs
After initial construction, most types of tidal power have reasonable operational costs. Only little maintenance will be necessary as long as everything is correctly built, and there will be no need to deal with logistics companies to transport gasoline.
Tidal energy is as clean and renewable as any other currently available sustainable resource. It produces fewer pollutants and takes up less physical space than other renewable energy sources.
Cons of Tidal Energy
Tidal power can only be generated in specified locations. Furthermore, considerable infrastructure development is required for most countries to harness the power to the grid at a large scale.
The construction of tidal power plants is now incredibly expensive. This is because they need to be exceedingly powerful in order to withstand the force of the water. Concrete is commonly used in constructing tidal barrages, which raises the initial cost.
Impact on Marine Life
Tidal barrages, like other systems, have the potential to destroy marine life. The movement of water in and out of estuaries is essential for tidal barrages. The barrages, however, alter the flow of water once they are erected. The turbines drive water through them, which can change the way marine life thrives.
Maintenance is Difficult
Due to their nature, these plants are tough to manage. No matter how well-designed a machine is, it will eventually require maintenance, and maintaining this level of power poses some significant challenges.