1. Renewable Energy Nov 19

2. Wind Power

3. Vertical axis machine Horizontal axis machine

4. Wind Power

6. Winds arise from differential heating of the Earth’s surface on a local, regional, or worldwide scale. Global winds Local winds

7. Wind Power Environmental Impacts – Visual impact – Electromagnetic interference: potential to interfere with radio, tv, and radar signals and with microwave communication links – Ecological impacts – Noise

8. Wave Power Water has a higher density than air, so has higher energy densities Have little effect on general flow of water around them Central issue: economics of harnessing power in harsh marine environments Need sites with regular waves

9. Wave Power

10. Onshore devices – Must be located in deep water areas adjacent to coasts to avoid loss of energy through friction Tapered channel wave energy converter

11. Wave Power Offshore devices – Can produce more energy, but at a higher cost – Passing waves force joints to pump high-pressure oil through hydraulic motors – Motors then drive the electrical generators to produce electricity – Power is fed from the device via cable to the seabed, and then to shore Pelamis sea snake

12. Tidal Power The regular rise and fall of the tides represents a shifting store of potential energy powered by the drag of the moon and sun Water collected at high tide and then drained through a water turbine to generate electricity or use of spin turbine The Earth experiences 2 tides a day, allowing tidal power dams to be filled every 12 hrs More tidal energy in Atlantic Ocean basin than Pacific

13. Tidal Power Spin turbine Tidal dam

14. Small-Scale Hydropower Doesn’t have the environmental and social impacts of large-scale hydropower Can be used in areas where local geography doesn’t allow for large dams Plant sits on one side of the river Little water is held back and diverted, so the river is unaffected Less powerful

15. Small-Scale Hydropower

16. Biomass Fuel GJ/t Grass (fresh-cut) 4 Domestic waste (as collected) 9 Straw (baled) 14 Sugar cane (air-dried stalks)14 Wood (air-dried, 20% moisture) 15 Paper (stacked newspaper) 17 Commercial wastes ( UK average) 16 Dung (dried) 16 Calorific value of various biomass feedstocks [data from BOY96,p143].

17. Biomass

18. Geothermal Derived from radioactive decay of isotopes deep within the Earth or from heat left over from the original coalescence of matter that formed the Earth Heat accessed in 1 of 2 ways: – Hot dry rock technology – drill close to radioactive sources – Wet rock technology – natural output of energy higher because of presence of water

19. Geothermal Wet-rock technology

20. Geothermal Environmental concerns – New boreholes would have to built every 10 years as local heat is diminished – Dry-rock technology required water to be pumped into the ground – Odors could be released – Land subsidence – Increased seismicity

21. Fast Breeders and Fusion Fast breeder reactors and fusion reactors use uranium more efficiently than thermal nuclear reactors These expand the world’s resource of uranium from 70 years to 9930 years They do this by producing more fissionable fuel than they use Also produce less radiation and radioactive waste