1. Ocean Energy Kim Cobb with slides from Dr. Alam, MIT

2. Edwards 2001 YEAR Estimates of 21st Century World Energy Supplies A barrel (42 U.S. gallons) of crude oil = 5.8 × 10^6 BTU = = 6000 MJ or about 1.70 MWh.

3. Overview of Ocean Energy -ocean energy is replenished by the sun and through tidal influences of the moon’s and sun’s gravitational forces -near-surface winds induce wave action and cause wind-blown currents at about 3% of the wind speed -tides cause strong currents into and out of coastal basins and rivers -ocean surface heating by some 70% of the incoming sunlight adds to the surface water thermal energy, causing expansion and flow -wind energy is stronger over the ocean due to less drag

4. How much energy and what types? -250 Billion barrels of oil worth of energy coming into ocean every day -80 million barrels of oil per day produced kinetic potential

5. -250 Billion barrels of oil worth of energy coming into ocean every day -80 million barrels of oil per day produced How much energy and what types? Theoretical global resource of ocean energy: 8,000-80,000 TWh/yr for wave energy 800 TWh/yr for tidal current energy 2,000 TWh/yr for salinity gradient energy 10,000 TWh/yr for ocean thermal energy World’s electricity consumption 17,000 TWh/yr

6. Source of Ocean Wave Energy

8. Wave Energy Extraction Technologies Point Absorber (OPT, Finavera) Oscillating Water Column (Energetech/Oceanlinx) Attenuator, Pelamis WP Overtopping, Wave Dragon

9. Power From Ocean Waves kW/m crest length

10. Power From Ocean Waves Wave energy is strongest on the west coasts and increases toward the poles. At approx. 30 kW/mcl in the Northwest (yearly avg.), a single meter (3.3 feet) of wave has the raw energy to power about 23 homes.

11. Point absorber buoys: most common

13. Oscillating Water Column Installations: LAND NOTE: Plant Bowen (Georgia Power) operates at 3,200,000 kW

14. Oscillating Water Column Installations: OCEAN

15. “Overtopping” Wave Energy

16. “Sea Snake” Wave Energy 121m long, 3.5m tall!

18. Tidal Energy Conversion

19. Ocean Thermal Energy Conversion

20. 210 kW OTEC test plant, 1993-1998, Hawaii

21. Future OTEC plant: grow food and fuel?

22. Ocean Energy: Where are we today? Wave Energy (grid-connected): -0.4MW and 0.5MW OWC off the coast of Pico and Islay by 2008 -2.25MW Pelamis off Portugal by 2008 -0.5MW section of Wave Star Energy off Denmark by 2009 -7MW Wave Dragon off Wales by 2010 Tidal: - barriers: 240MW France in 1966 and 20MW in Canada -Current: 1.2MW off Ireland by 2009, 1MW France Thermal: -0.2MW Hawaii 1993-1998

23. Ocean Energy: PROS and CONS?