Tidal Energy Pros and Cons Plus Where Is It Used Today
The perfect energy source doesn’t exist. In fact, each and every type of source has its own advantages and compromises. It’s the same with tidal energy pros and cons; you can’t have one without the other. At least not yet. But there’s something tremendous about the way people have learned to harness the tides, advancing technology and producing energy for themselves.
Day and night, the boundless waters of the ocean tirelessly flow in and out along the shorelines of the planet’s every continent. Influenced by the celestial movements of the sun and the moon, the tidal movement is rather pretentious. Because it’s more pronounced in certain areas than others, people have few chances to transform its power into energy.
Exploiting the Tides
Innovators have been developing ways to control the great amounts of free, renewable energy from these tides for hundreds of years. Records of ocean power exploitation go all the way back to 900 A.D., when the tidal movement helped people grind their grains. Today, water spins turbines to produce electricity. The main method of harnessing the tides includes tidal barrages – a type of dam that closes off a reservoir with gates, seizes the tidal flow, and then releases it back via a turbine. Other types include tidal fences and turbines.
Because tidal energy devices are purely mechanical, requiring no heat transfers or boiling fluids, productivity is rather high. The average across tidal station is generally around the 80 percent mark. Better than solar or wind energy, the power coming from these tidal systems is quite predictable. The tides follow a well-known pattern. But just like the other renewable energies, it is also not continuous. Tidal surges occur in roughly 10 hour cycles per day.
Seeing as there are many benefits and disadvantages involved in this type of renewable energy, it is useful to make a list racking up the pluses and minuses. Keep in mind that this is not an exhaustive list; other bullet points could be included in both sections of our list.
Pros of Tidal Energy
This energy source, resulting from the gravitational pull of the sun and the moon, is definitely renewable. The difference between high and low tides is where the potential tidal energy lies. Harnessed through tidal barrages, stream generators, or the more recent technology, dynamic tidal power (DTP), the power of the tides is reliable and efficient. Moreover, when compared to nuclear reserves or fossil fuels, the moon’s and sun’s gravitational pulls won’t cease to exist any time soon.
In addition to being renewable, tidal power is also an eco-friendly energy source. It does not give off any greenhouse gas emissions and it doesn’t occupy a lot of space. However, the tidal stations are still few, which means their effects on the environment may be yet unknown. The solution would be to study and evaluate these things.
This is one of the advantages making tidal energy so efficient. The high and low tidal currents are predictable, developing within well-known cycles. This way, it’s easier to build the right dimensions for a system that will be capable of facing the forces of nature. So even though tidal stream generators look a lot like wind turbines, they have other limitations. The physical size and the required robustness differ phenomenally.
4. Effective & Durable
Water is 1000 times denser than air, which means turbines can generate electricity even at low speeds. According to estimations, a tidal stream station can generate power even at 1m/s (about 3ft/s). In addition, experts have found no reason to believe tidal power plants are not long lived. For example, the tidal barrage power plant La Rance, in France, has been operating ever since it opened in 1966. More than fifty years later, the power plant still generates massive amounts of electricity.
Cons of Tidal Energy
1. Environmental Effects
As we’ve already mentioned, researchers have yet to determine the full effects of tidal power plants. What we know is that these tidal stations generate green electricity. But because tidal barrages rely on manipulating ocean levels, their potential environmental effects may be similar to those of hydroelectric dams. Several companies are working on finding technological solutions to resolve some of these problems.
2. Too Close to Land
Due to their nature, tidal power plants must be built close to the shore. This may interfere with various ecosystems, as well as human activities. However, technological solutions are being worked on in this area, as well. Hopefully, we will soon be able to exploit tidal currents located further out in the sea. A few years may pass, however.
The technological advancements used for generating electricity from tidal energy are relatively new. That’s why developing new power plants to harness the energy of the tides comes with a high initial cost. However, projections show tidal power will become more commercially profitable by 2020, thanks to better technologies.
4. Impact on Wildlife
Tidal barrages and turbines can interfere with marine life, fish, and birds alike. Some ecosystems may even be dislocated to make room for the power plant. Meanwhile, the technology also impacts adversely mud flats, popular feeding spots for many bird species.
Tidal Energy Giants
- South Korea: Sihwa Lake Tidal Power Station, 254MW
Situated on Lake Sihwa, some 4 km from the city of Siheung in Gyeonggi Province, this tidal power station boasts an output capacity of 254MW. It is also currently the largest tidal power plant in the world.
- France: La Rance Tidal Power Plant, 240MW
Located on the estuary of the Rance River in Brittany, the La Rance tidal station has been operating since 1966. La Rance is thus the oldest tidal power station and the second largest on Earth. The renewable power plant has a generation capacity of 540GWh per year.
- United Kingdom: Swansea Bay Tidal Lagoon, 240MW
While officially not a tidal power plant yet, the Swansea Bay Tidal Lagoon is the first tidal project in the UK. When built, it will become the world’s biggest tidal power project and the third biggest tidal station. The government approved the planning request for the £850m ($1.4bn) project in March 2013.
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