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Wave Energy. Winds. Turbulent Air Flow. Shear Stress on Surface of Water. Wind Flow on Upwind Wave Faces. Solar Radiation Wind Waves Wave Size Factors Wind Speed Wind Duration Distance Over Which Wave Travels. Wave Energy. The energy resource available:
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Wave Energy Winds Turbulent Air Flow Shear Stress on Surface of Water Wind Flow on Upwind Wave Faces • Solar Radiation Wind Waves • Wave Size Factors • Wind Speed • Wind Duration • Distance Over Which Wave Travels
Wave Energy • The energy resource available: • (W per m of crest) • = density of water T = period of wave (s) H = wave height (m) Swells formed by storms can travel great distances. Power is lost when water depth < 200 m. Wave has 1/3 of original power when water depth reaches 20 m.
Wave Energy • Magnitude of the Resource: • In U.S., approximately 2,100 TW-hr is available at a depth of 60 m offshore. • Current U.S. electrical use 11,200 TW-hr • Technologies • Terminators – Perpendicular to waves • Attenuators – Parallel to waves • Point Absorber – Small floating device • Overtopping – Reservoir (above avg. ocean level) filled by waves, turbines
Wave Energy Oscillating Water Column (OWC)
Wave Energy The 500 kW LIMPET OWC, New Zealand
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Wave Energy The 750 kW Pelamis Wave Energy Converter, Portugal
Wave Energy • Environmental Considerations • Visual appearance • Reduction in wave height • Marine habitat • Toxic releases – hydraulic fluids • Conflict with other sea space users – Shipping, fishing, recreational boating • Installation, decommissioning
Wave Energy • Benefits • Waves = Concentrated Solar Energy • Demand in Phase with Availability (Winter) • Low/No Chemical Pollution • Low Visual Pollution (Offshore) • Large Potential Resource • Challenges • Electricity Transmission • Immature Technology • Potential Shipping, Boating Accidents