1. Tidal Energy Presented by: Courtney Winter and Quinn Foley

2. Overview *How Tidal Energy Works *Environmental Impact *Advantages/Disadvantages *The Four Outputs * Conclusion

3. Where Does Tidal Energy Come From?  Form of hydropower from the movement of water caused by tidal currents or the rise and fall of the sea levels due to the tides  Comes from waves that start from wind  This forms as a result of the sun's heating of the Earth  As the wind hits the water, ripples form which then push until they grow to be large waves

4. Relevant History  Eight main sites around Britain where tidal power stations could usefully be built  The “Swan turbine” is a design that is different to other devices. The blades are connected to an electrical generator without a gearbox in between.  The largest tidal power station in the world is in the Rance Estuary in northern France, in which it was built in 1966. Swan turbine

5. The Process Turbine and generator Estuary

6. Produced in a motion that can be transformed into power Channel or tube that flows the water An efficient design that can be lifted on a ship for maintenance Keeps the generator on the ocean floor

7. Statistics  A Tidal Reef across the Severn Estuary is being proposed --- mud flats could still be exposed at low tide, and this makes it to generate power for more hours in the tidal cycle ---can also make sections of it to allow shipping to go through, control tidal levels further upstream, prevent storm surges, and to avoid flooding on low-lying land Tidal Reef across the Severn Estuary

8. Statistics (continued)‏  Tide mills ---mill operated by the tidal movement of water examples:

9. Statistics (continued)‏  Ebb and Flow (Flood and Drain) ‏ ---this invention relates to a system for a method of moving sea water by utilizing the tidal flow and ebb

10. Environmental Impact  Many birds rely on the tide uncovering the mud flats so that they can feed  Tidal energy is a renewable source of electricity which does not result in the release of gases responsible for global warming or acid rain associated with fossil fuel generated electricity  Use of tidal energy could also decrease the need for nuclear power, with its associated radiation risks

11. Advantages  Tidal Power produces no fuel and produces electricity reliably  It produces no greenhouse gases or other waste  Not expensive to maintain  Tides are predictable  Does not have a large environmental impact

12. Disadvantages  There are few suitable sites for tidal barrages  Only provides power for around 10 hours each day, when the tide is actually moving in or out  Damages like reduced flushing, winter icing and erosion can change the undergrowth of the area and disrupt the balance  Only is available in small regions

13. Four Outputs  Type 1- Expected and Desired --- produces electricity reliably  Type 2- Expected and Undesired ---can destroy marine life  Type 3- Unexpected and Desired ---generator can make the sea level go down  Type 4- Unexpected and Undesired ---(could possibly) put the generator in a wrong place in which it would not generate electricity

14. Conclusion (and citations)‏  Tidal Power is a good way to modernize our energy systems and help improve our environment  Citations ---Darvill. 21 Dec. 2008 http://www.darvill.com.http://www.darvill.com ---Dictionary. 21 Dec. 2008 http://www.dictionary.com.http://www.dictionary.com ---How Stuff Works. 21 Dec. 2008 http://www.howstuffworks.com. http://www.howstuffworks.com ---Wikipedia. 21 Dec. 2008 http://www.wikipedia.com.http://www.wikipedia.com Questions?