Lesson: Tidal Power


In this lesson, we will learn how to describe the advantages and disadvantages of generating electricity from tidal barrages.



Sample Question Videos

  • 03:29
  • 01:16
  • 01:18



Water is allowed to pass through a tidal barrage until the tide is at its highest. The barrage is then closed, and the tide beyond the barrage lowers, while the water behind it stays at the same height. The water behind the barrage is then allowed to flow back through the turbines into the sea.

If the mass of the extra water held back by the barrage is 2.4×10 kg, and it has an average height of 1.5 m above the water in the sea beyond the barrage, what is the gravitational potential energy of the water held back by the barrage? Use a value of 9.8 m/s2 for the acceleration due to gravity.


A proposed tidal barrage power station has an expected maximum power output of 950 MW. If the tidal barrage has 38 turbines, what is the maximum power output of each turbine?


Which of the following statements correctly describe the disadvantages of building a tidal barrage?

  1. Tidal barrages can alter the habitat of wetland wildlife.
  2. Tidal barrages have very high maintenance costs.
  3. There are only a few locations where tidal barrages can be built. Only some river estuaries are suitable for tidal barrages.
  4. Once built, tidal barrages release large quantities of methane into the atmosphere.
  5. Once built, tidal barrages release large quantities of carbon dioxide into the atmosphere.
  6. Tidal barrages can only generate electricity at certain times of the day. Tidal barrages can only generate electricity following the peak of a high or low tide; they can not adjust to changes in demand.

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