Wave Energy Applications

1
Wave Energy Applications

• In Europe and in Portugal

Ana Catarina Guimarães José Pedro Salreta
2
Why Wave Energy?

• Among different types of ocean waves, wind
  generated waves have the highest energy
  concentration. They can travel thousands of kms
  without losses.
• In average, waves have 40-50 kW per meter width
  of oncoming wave.
• Increased wave activity is found between the
  latitudes of 30º and 60º - European Atlantic
  coast.

3
Why Wave Energy?
4
Why Wave Energy?

• The potential worlwide wave energy contribution
  is estimated to be 2 TWh/year, about 10 of the
  world electricity consumption.
• The wave climate along the western coast of
  Europe is highly energetic 16 of worldwide wave
  potential, about 320 GW.

5
Technological Status

• Very large number of concepts for wave energy (in
  contrast with other renewables).
• Large ongoing work, most technologies still in
  their early stage.
• Concepts categorised according to the distance of
  the location of the installation from the shore
  shoreline, near shore and offshore devices

6
Technological StatusShoreline Devices

• Fixed to or embedded in the shoreline, having the
  advantage of easier installation and maintenance.
• Do not require deep-water moorings or long
  lengths of underwater electrical cable.
• Less powerful wave regime, that could be
  compensated by natural energy concentration (hot
  spots).
• The most advanced class of shoreline devices is
  the oscillating water column.
• Examples European Pilot OWC Plant (Azores -
  Portugal), Limpet OWC (Island of Islay - Scotland)

7
Technological StatusShoreline Devices
8
Technological StatusNear Shore Devices

• Deployed at moderate water depths (20-30 m) at
  distances up to 500 m from the shore.
• Nearly the same advantages as shoreline devices,
  being at the same time exposed to higher wave
  power levels.
• Examples OSPREY, Wave Roller (Orkney - Scotland)

9
Technological StatusNear Shore Devices
10
Technological StatusOffshore Devices

• Newest technologies (3rd generation), exploit the
  more powerful wave regimes available in deep
  water (gt40m depth).
• Need to be moored and connected to shore using
  long electrical cables.
• Recent designs concentrate on small, modular
  devices, with high power output when deployed in
  arrays.
• Examples Archimedes Wave Swing (Póvoa do Varzim
  - Portugal), Pelamis (Orkney - Scotland, Peniche
  - Portugal), PowerBuoy, Wavebob, Wave Dragon

11
Technological StatusOffshore Devices
12
Difficulties Ahead

• Irregularities in wave amplitude, phase and
  direction difficulty to obtain maximum
  efficiency of a device over the entire range of
  excitation frequencies.
• The structural loading in the event of extreme
  weather conditions, such as hurricanes, may be as
  high as 100 times the average loading.
• The coupling of the irregular and slow motion
  (0.1 Hz) of a wave to electrical generators
  requires typically 500 times greater frequency.

13
Difficulties Ahead

• New installations have area restrictions
  fishing, leisure, drilling, archeological
  interests, sea routes, military training, other
  offshore platforms and natural reserves.
• Electricity generating costs from wave energy is
  still higher than the average electricity price
  in the EU.

14
Conclusion

• It is very difficult to predict the potential of
  a new technology in such an initial phase, but
  the prospects are encouraging.
• Very low environmental impact, european coast
  with high wave potential, and no land cost.
• Europe needs to reduce external energy dependance
  and has the scientific and technological
  competence to invest in wave energy research.
• There is still 5 to 10 years before technology
  matures.

15
Conclusion

• Risks and investment needed to improve the
  existing technology are still high.
• Hopefully, there will be a progressive cost
  reduction towards electricity generating costs
  from wind energy.

16
Thank you.

• http//www.wave-energy-centre.org/