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What is Tidal Energy?
March 1, 2017

Turbine under water (NASA)
Tidal turbines generate electricity (NASA)

What comes to mind when thinking of renewable energy resources? Wind? Solar? How about tidal energy? Tidal energy is not commonly thought of when considering the types of renewable energy resources even though it is one of the oldest forms of renewable energy. Tides are caused by the moon’s gravitational forces.

Tidal energy is a form of hydropower that relies on the rising and falling of the sea levels and tidal energy devices convert the energy gained from the tides into electricity.

Tidal energy can be captured through a variety of ways. Surface devices lay on the ocean surface and capture electricity through the movement of waves. Underwater devices consist of a vertical or horizontal turbine, similar to that of a wind turbine, which creates electricity as the tide moves through the turbine. Reservoirs collect water and electricity is created as the water moves out of the reservoir through turbines. Tidal energy is most efficient when the height, mass, and speed of the water are at their optimum level.

The different varieties of tidal technologies indicate how the electricity from the tidal energy is harnessed. Tidal barrages are similar to dams in that once the reservoir is filled, the turbines spin to create electricity. Tidal turbines are individual turbines that are placed in an area with a strong tidal flow where electricity is created when the water moves through the turbine, and tidal fences are a line of tidal turbines.

Tidal energy is the most reliable source of renewable energy because of the continuous change in tidal movements that occur twice a day from the moon’s gravitational force. Tidal energy runs 24 hours a day, 7 days a week, 365 days a year.

Another benefit to tidal energy is that it does not produce any form of pollution. It also does not require any use of nonrenewable resources, such as oil, to power the technology. Tidal energy even has an 80 percent success rate when converting to electricity.

Unfortunately, very few coastal countries are using tidal energy because it can be very expensive, and it can interfere with marine life. The cost for tidal energy can be anywhere between $1.3 million to $1.8 million. Also, a country must be on an ocean coastline to reap the benefits of tidal energy.

There are incredible benefits to using tidal energy despite the drawbacks and high cost. As tidal energy technology begins to advance, the cost of incorporating tidal energy as a renewable energy resource in countries will decrease. It is important to incorporate all forms of renewable energy resources into countries in order to combat the effects of climate change.

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The views and opinions expressed here belong to the author or interviewee and do not necessarily reflect those of the YALI Network or the U.S. government.