2. Tidal power This is the power achieved by capturing the energy contained in moving water mass due to tides. This is the power achieved by capturing the energy contained in moving water mass due to tides. There are two types: Kinetic energy and Potential Energy. There are two types: Kinetic energy and Potential Energy.

3. One method of extracting tidal energy involves building a barrage and creating a tidal lagoon. One method of extracting tidal energy involves building a barrage and creating a tidal lagoon. The largest of this type of tidal power has been working on the Rance River (Bretagne, France) since 1967 and produces 600 million KWh annually. The largest of this type of tidal power has been working on the Rance River (Bretagne, France) since 1967 and produces 600 million KWh annually.

4. Modes of Operation Ebb Generation Ebb Generation Flood Generation Flood Generation Pumping Pumping Two basin schemes Two basin schemes Tidal ‘wind farms’ Tidal ‘wind farms’

5. Disadvantages of tidal power They do not produce energy 24 hours a day, but for more like 6-12 hours each day. They do not produce energy 24 hours a day, but for more like 6-12 hours each day. The tide cycle is based on the moon and changes daily. The demand for electricity is based on the rotation of the earth- so the energy production cycle will not always be the same as the demand cycle. The tide cycle is based on the moon and changes daily. The demand for electricity is based on the rotation of the earth- so the energy production cycle will not always be the same as the demand cycle.

6. Environmental Impacts Tidal Energy Efficiency- 80% Tidal Energy Efficiency- 80% Turbidity and Salinity Decreases Turbidity and Salinity Decreases Sediment Movements Sediment Movements Pollutants less efficiently displaced Pollutants less efficiently displaced Fish Fish

7. Tidal Power case studies Rance tidal power plant built over a period of 6 years from 1960 to 1966 at La Rance, France. It has 240MW installed capacity and was the first tidal power plant in the world. Rance tidal power plant built over a period of 6 years from 1960 to 1966 at La Rance, France. It has 240MW installed capacity and was the first tidal power plant in the world. The first (and only) tidal power site in North America is the Annapolis Royal Generating Station, Annapolis Royal, Nova Scotia, which opened in 1984 on an inlet of the Bay of Fundy. It has 20MW installed capacity The first (and only) tidal power site in North America is the Annapolis Royal Generating Station, Annapolis Royal, Nova Scotia, which opened in 1984 on an inlet of the Bay of Fundy. It has 20MW installed capacity

8. Wave Power refers to the energy of ocean surface waves and the capture of that energy to do useful work Wave power generation is not a widely employed technology, with only a few experimental sites in existence.

9. A simplified electricity generator

10. Waves! Generally large waves are more powerful Generally large waves are more powerful Wave size is determined by wind speed and fetch and by the depth and topography of the seafloor (which can focus or disperse the energy of the waves). Wave size is determined by wind speed and fetch and by the depth and topography of the seafloor (which can focus or disperse the energy of the waves). Wave motion is highest at the surface, and diminishes exponentially with depth. Wave motion is highest at the surface, and diminishes exponentially with depth.

11. Challenges of wave power Efficiently converting wave motion into energy Efficiently converting wave motion into energy Constructing devices that can survive storm damage and saltwater corrosion Constructing devices that can survive storm damage and saltwater corrosion Low total cost of electricity. Low total cost of electricity.

12. Potential Wave power could yield much more energy than tidal power The energy potential of waves is certainly greater, and wave power can be exploited in many more locations. C Countries with large coastlines and strong prevailing winds (notably, Ireland and the UK) could produce five percent or more of their electricity from wave power. Excess capacity (a problem common with intermittent energy sources) could be used to produce hydrogen or smelt aluminium

13. Wave Power case studies The first commercial power plant was opened in 2000 on the island of Islay, Scotland The first commercial power plant was opened in 2000 on the island of Islay, Scotland Provides 500kW of energy for the Island and the national Grid Provides 500kW of energy for the Island and the national Grid