How Does Tidal Energy Work?
The tides tick off every day like clockwork. There is massive energy in each and we are striving to harness it. Okay, so just how does tidal energy work and is it a realistic energy platform?The Mighty Moon
Gravity is an amazing force when you really think about it. Not only does it keep our feet firmly rooted to the ground, but we can see it moving vast, huge amounts of material on a daily basis - the oceans. This is one area of science that we understand so well that we can even accurately predict its effects on water in relation to how high and low the tides will be. If you've ever marveled at just how inaccurate your local weatherman can be, you'll realize how amazing this is!
The moon is caught in the gravitational pull of the earth. Tides occur, however, because the moon also exerts its gravitational field on the earth. While it is not strong enough to move land, it is strong enough to impact large bodies of water, primarily oceans. Ah, but what causes tides? Well, the moon does not rotate the earth at the same rate as the earth spins. This means that whatever side of the earth happens to be facing the moon at a particular time "feels" the biggest impact of the moons gravity. This causes water to be pulled in this direction, causing tides. The practical end result is we have two high and two low tides every day.
The movement of a mass of water like an ocean requires a ton of energy as you might imagine. This energy is originally gravitational in nature, but manifests as the kinetic energy of water moving. Tidal energy works by trying to capture this kinetic energy. The specific methods for doing this are pretty primitive at this point, but some are actually up and functioning. Let's take a look.
Tidal capture systems primarily work on the hydropower method. They do this by trying to run the moving water inherent in a tidal event past blades like you see on a wind turbine. These blades then spin a shaft that is connected to a generator. As the generator spins, it produces electricity. It really is as simple as that, however, applying the idea to tidal energy is a bit more difficult.
The primary problem is the range of tidal movements. The energy is spread out along coastlines that are thousands of miles long. While the entire tide contains massive amounts of energy, a 10 foot section along some coast does not. To remedy this, most projects look for places where the tide is naturally funneled. This causes the energy to be focused, which means sticking blades down into the ocean in that area will produce more energy.
What does a tidal energy device look like. Well, there isn't a static answer at the moment. Some look like a box that is anchored to the ocean floor. The box contains a large pipe with the blades in it and a second box above that contains the generator. Other approaches include building damns at river fronts in a "V" shape. This artificially concentrates the tidal movement and forces the water to the point of the "V" where the turbines are located.
How does tidal energy work? Well, it really doesn't except in isolated cases at the moment. We are very early in the process of exploring this energy platform, but it holds out huge potential. The vast majority of humanity lives along the coastlines of the world. If we could harness clean energy at these costs, the energy problems we are facing would largely be solved.
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