Tidal Energy
Tidal energy is a form of power produced by the natural rise and fall of tides caused by the gravitational interaction between Earth, the sun, and the moon. Tidal currents with sufficient energy for harvesting occur when water passes through a constriction, causing the water to move faster. Using specially engineered generators in suitable locations, tidal energy can be converted into useful forms of power, including electricity.
Other forms of energy can also be generated from the ocean, including waves, persistent ocean currents, and the differences in temperature and salinity in seawater.
Tidal turbines can be installed in places with strong tidal activity, either floating or on the seafloor, individually or in arrays. They look and operate much like wind turbines, using blades to turn a rotor that powers a generator, but must be significantly more robust given their operating environment and, as tidal turbines are much smaller than large wind turbines, more turbines are required to produce the same amount of energy.
Tidal energy does not create air, water, or thermal pollution. Once a dam, barrage or tidal fence is built, the energy production is free since tidal power harnesses the natural power of tides. It does not require the transport of fuels or disposal of waste products.
South Korea has the largest electricity generation capacity at 254 megawatts.
There are many pros and cons to tidal energy
Pros
Renewable
Tidal energy is a renewable source of energy, which means the energy doesn’t deplete as it is used.
So, as you are harnessing energy from the changing tides, you don’t decrease the amount of energy the tides can produce in the future. The gravitational pull from the sun and the moon, which controls the tides, won’t cease to exist anytime soon.
Zero-carbon emissions
In addition to being a renewable energy source, tidal power stations do not emit greenhouse gasses during electricity generation.
Because greenhouse gas emissions are one of the leading causes of climate change, finding zero-emission energy sources is more important than ever.
Predictable energy generation
Tidal currents are highly predictable. Low and high tides follow well-known cycles, making it easier to know when power will be produced throughout the day.
It also makes it easy to know how much power will be produced by turbines, since the power of the tides and currents can be forecasted accurately.
High power output
Tidal power plants are able to produce high amounts of electricity. One of the main reasons for this is because water is so dense - almost 800 times more dense than air.
This means that a tidal turbine will produce substantially more energy than a wind turbine of the same size.
Plus, even when water is moving at low speeds, the density of water allows it to power a turbine. So, tidal turbines have the potential to produce large amounts of electricity even if the conditions of the water aren’t ideal.
Cons
Limited site availability.
Limited installation sites
In order for a tidal power plant to be built, the potential installation site must meet very specific requirements. First, they need to be located on a coastline, which limits potential station sites to coastal states. There are additional requirements a potential site must meet.
Expensive
Tidal power projects are simply more expensive than other clean energy sources relative to the amount of power they generate. Tidal turbines must be more durable than wind turbines in order to withstand ocean currents, while tidal barrage projects can cost millions to construct.
Environmental Impact
Tidal power can damage marine life, as tidal turbines with their rotating blades may lead to deaths of living creatures in the sea. Noise from the rotation of the turbines may also impact fish habitations in tidal power locations
Energy demand
The total energy contained in tides worldwide is 3,000 gigawatts (GW; billion watts), though estimates of how much of that energy is available for power generation by tidal barrages are between 120 and 400 GW, depending on the location and the potential for conversion.