Ocean Energy

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

• ocean energy is replenished by the sun and
  through tidal influences of the
• moons and suns 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, although
• technically, only seabreezes are from ocean
  energy

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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
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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

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
Worlds electricity consumption 17,000 TWh/yr
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Source of Ocean Wave Energy
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(No Transcript)
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Wave Energy Extraction Technologies
Oscillating Water Column (Energetech/Oceanlinx)

• Point
• Absorber
• (OPT,
• Finavera)

Overtopping, Wave Dragon
Attenuator, Pelamis WP
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Power From Ocean Waves
kW/m crest length
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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.

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Point absorber buoys most common
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(No Transcript)
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Oscillating Water Column Installations LAND
NOTE Plant Bowen (Georgia Power) operates at
3,200,000 kW
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Oscillating Water Column Installations OCEAN
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Overtopping Wave Energy
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Sea Snake Wave Energy
121m long, 3.5m tall!
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(No Transcript)
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Tidal Energy Conversion
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Ocean Thermal Energy Conversion
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210 kW OTEC test plant, 1993-1998, Hawaii
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Future OTEC plant grow food and fuel?
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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

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Ocean Energy PROS and CONS?