Tidal Energy

By Leah Holman

How It Works

Tidal energy is produced by utilizing the sun and moon's gravitational forces, or tides. The energy comes from the tide shifting from low to high. The supply of energy that we get from tidal underwater turbines is plentiful and reliable, but it's not easily converted into electrical power. This in turn makes it expensive. It's considered a renewable energy source because the tides rise and fall consistently in a fairly regular pattern. The only real drawback to tidal energy is the altering of the ecosystem when the turbines other means of harnessing the energy are put in place. The damages can include reduced flushing, winter icing, and erosion. These things can change the vegetation of the area and disrupt the balance. Tidal energy is a great, reliable energy source because it is consistently capable of producing the energy we need.

Tidal Energy Facts

Although it is likely that you haven't heard much or know too much about tidal energy, that doesn't mean it's a new thing. In fact, it's one of the oldest forms of energy, dating back to 787 A.D. It was used Spanish, French, and British coasts and they were called tide mills. These mills consisted of a pond that the water would fill (coming in through a sluice, which is like a sliding gate that is used to control the flow of water) when the tide was coming in, and then when the tide went back out, the water exited through a water wheel which was the main harnessing source. Tidal energy has an 80% efficiency of converting the tidal power into electricity. It also has other advantages like being able to build bridges and roads over the tidal generators. Just to compare tidal energy to wind power, an 8 knot current would be equivalent to about a 236mph wind storm.
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Future

Right now, the cost for a kilowatt-hour of tidal energy is about $.08-.12. It is predicted to be half that as it progresses. There are many studies being done on tidal energy, and a new analysis of these suggests that tidal power could provide up to 20% of the UK's power if it were to be gathered efficiently. Most of tidal energy's future is dependent on the cost. More research has to be done on how to keep the generators and turbines safe and in-tact in rough seas and on how to bring the cost down. It can be hard to compete with companies who use cheaper, non-renewable sources like coal. It seems that the UK is more for tidal energy at the time and has more plans for it's future than the US. There are plans in the UK to build a 10 mile long structure between England and Wales that would hold about 300 turbines and just that itself would be capable of producing 5% of the UK's electricity need. The output of this project (expected to be 8.6 billion watts) would be equivalent to the output of eight nuclear power plants. It seems that tidal energy is becoming more and more popular and is likely to be utilized more in order to provide us with more clean, reliable energy.
Turn the tides into energy