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International Symposium on the Protection of Waves Impacts of Wave Energy Projects on Surfing Waves Steve Challinor on beh...
What are Wave Farms? <ul><li>Arrays of wave energy converter devices (WECs) </li></ul><ul><li>Many types of WECs under dev...
Floating WECs <ul><li>Examples: Pelamis (attenuator) and Powerbuoy (point absorber) </li></ul>
Seabed-mounted WECs <ul><li>Example: Oyster (oscillating wave surge converter) </li></ul>
How do WECs affect Waves? <ul><li>WECs change wave characteristics by: </li></ul><ul><li>Absorbing wave energy – reduces w...
Evidence of Impacts <ul><li>Very few WECs deployed, so no evidence from direct measurements </li></ul><ul><li>Most evidenc...
Example 1: Cornwall, SW England <ul><li>‘ Wave Hub’ - proving facility for prototype WECs </li></ul><ul><li>8km 2  sea are...
Halcrow (2006) study <ul><li>‘ Typical layout’ of floating WECs comprising: </li></ul><ul><li>1 x Wave Dragon WEC </li></u...
Wave Hub Array 2 x Fred Olsen FO 3  WECs 1 x Wave Dragon WEC 6 x Pelamis WECs 30 x Powerbuoy WECs
Small Summer Waves (Hs 1m, Tp 7s) Wave height immediately behind WECs reduced by >20% Wave height at shore reduced by 9-11%
Large Autumn Waves (Hs 4m, Tp 16s) Wave height immediately behind WECs reduced by >20% Wave height at shore reduced by 3-5%
Different WECs = Different Effects 1 x Wave Dragon WEC 2 x Fred Olsen FO 3  WECs 30 x Powerbuoy WECs 6 x Pelamis WECs
Example 2: Orkney Islands, Scotland <ul><li>Part of the ‘Pentland Firth’ licensing area for wave farms and tidal farms </l...
Venugopal and Smith (2007) <ul><li>Site off mainland Orkney </li></ul><ul><li>Seabed-mounted WECs = 2km offshore </li></ul...
Porosity Scenarios <ul><li>Porosity = % wave energy transmission through WEC </li></ul><ul><li>Wave energy lost to absorpt...
Wave Height Changes Wave height reduced from 13% (90% porosity) to 67% (50% porosity) immediately behind WECs Porosities 0...
Results <ul><li>For all porosities wave height and wave energy are always reduced downstream of WECs </li></ul><ul><li>Thi...
Threats to Surfing Waves? <ul><li>PMSS (2010) study: </li></ul><ul><li>Present = 20MW (Wave Hub)  </li></ul><ul><li>Future...
Threats to Surfing Waves? <ul><li>West Cornwall </li></ul>
Threats to Surfing Waves? <ul><li>North Cornwall </li></ul>
Threats to Surfing Waves? <ul><li>Marwick Bay, Orkney </li></ul>
Threats to Surfing Waves? <ul><li>Marwick Bay, Orkney </li></ul>Various reef breaks c.500m 10MW array 2MW array
Conclusions <ul><li>Studies suggest: </li></ul><ul><li>Wave farms pose a threat to surfing waves </li></ul><ul><li>Threat ...
More Info – SAS Reports <ul><li>Climate change issues:  Climate Change – A Surfer’s Perspective </li></ul><ul><li>Wave far...
More Info – Cited Studies <ul><li>Halcrow (2006).  Wave Hub.  Development and design phase.  Coastal processes study repor...
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The Potential Effect of Wave Energy Converters on Surfing Waves - Steve CHALLINOR

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The Potential Effect of Wave Energy Converters on Surfing Waves - Steve CHALLINOR

  1. 1. International Symposium on the Protection of Waves Impacts of Wave Energy Projects on Surfing Waves Steve Challinor on behalf of Surfers Against Sewage
  2. 2. What are Wave Farms? <ul><li>Arrays of wave energy converter devices (WECs) </li></ul><ul><li>Many types of WECs under development </li></ul><ul><li>WECs generate electricity by harnessing power from waves </li></ul><ul><li>Located in shallow (seabed-mounted WECs) and deep water (floating WECs) </li></ul>
  3. 3. Floating WECs <ul><li>Examples: Pelamis (attenuator) and Powerbuoy (point absorber) </li></ul>
  4. 4. Seabed-mounted WECs <ul><li>Example: Oyster (oscillating wave surge converter) </li></ul>
  5. 5. How do WECs affect Waves? <ul><li>WECs change wave characteristics by: </li></ul><ul><li>Absorbing wave energy – reduces wave energy and wave height </li></ul><ul><li>Interfering with wave energy (reflecting and blocking waves) – changes wave height and wave direction </li></ul><ul><li>Changes to waves can cause changes to shoreline bathymetry, particularly at breaks with mobile sediment (e.g. sand bars) </li></ul>
  6. 6. Evidence of Impacts <ul><li>Very few WECs deployed, so no evidence from direct measurements </li></ul><ul><li>Most evidence gained from numerical modeling / computer simulations </li></ul><ul><li>Examples from Cornwall, SW England and Orkney Islands, Scotland </li></ul><ul><li>Evidence = threats to surfing waves? </li></ul>
  7. 7. Example 1: Cornwall, SW England <ul><li>‘ Wave Hub’ - proving facility for prototype WECs </li></ul><ul><li>8km 2 sea area (4km x 2km) </li></ul><ul><li>Floating WECs = 20+km offshore </li></ul><ul><li>20MW generating capacity (1MW = 400 houses) </li></ul>
  8. 8. Halcrow (2006) study <ul><li>‘ Typical layout’ of floating WECs comprising: </li></ul><ul><li>1 x Wave Dragon WEC </li></ul><ul><li>2 x Fred Olsen FO 3 WECs </li></ul><ul><li>30 x Powerbuoy WECs </li></ul><ul><li>6 Pelamis WECs </li></ul><ul><li>2 wave scenarios: </li></ul><ul><li>small summer waves (Hs 1m, Tp 7s) </li></ul><ul><li>large autumn waves (Hs 4m, Tp 16s) </li></ul>
  9. 9. Wave Hub Array 2 x Fred Olsen FO 3 WECs 1 x Wave Dragon WEC 6 x Pelamis WECs 30 x Powerbuoy WECs
  10. 10. Small Summer Waves (Hs 1m, Tp 7s) Wave height immediately behind WECs reduced by >20% Wave height at shore reduced by 9-11%
  11. 11. Large Autumn Waves (Hs 4m, Tp 16s) Wave height immediately behind WECs reduced by >20% Wave height at shore reduced by 3-5%
  12. 12. Different WECs = Different Effects 1 x Wave Dragon WEC 2 x Fred Olsen FO 3 WECs 30 x Powerbuoy WECs 6 x Pelamis WECs
  13. 13. Example 2: Orkney Islands, Scotland <ul><li>Part of the ‘Pentland Firth’ licensing area for wave farms and tidal farms </li></ul><ul><li>Up to 1,600MW generating capacity </li></ul>Orkney Islands Thurso
  14. 14. Venugopal and Smith (2007) <ul><li>Site off mainland Orkney </li></ul><ul><li>Seabed-mounted WECs = 2km offshore </li></ul><ul><li>1 layout scenario of 5 WECs </li></ul><ul><li>1 wave scenario (Hs = 4m, Tp = 10s) </li></ul>
  15. 15. Porosity Scenarios <ul><li>Porosity = % wave energy transmission through WEC </li></ul><ul><li>Wave energy lost to absorption and reflection </li></ul><ul><li>Porosities = 0%, 50%, 60%, 70%, 80% and 90% </li></ul>5 WECs in line Downstream wave climate
  16. 16. Wave Height Changes Wave height reduced from 13% (90% porosity) to 67% (50% porosity) immediately behind WECs Porosities 0% to 90% Wave height reduced by >20% 1000m behind WECs Wave height increased in front of WECs due to wave reflection Wave height reduced by c.10% 500m behind WECs
  17. 17. Results <ul><li>For all porosities wave height and wave energy are always reduced downstream of WECs </li></ul><ul><li>This could affect sedimentation processes and wave climate near the shore </li></ul><ul><li>Lower porosity = lower energy absorption + higher energy reflection = lower wave transmission = more impact on wave height </li></ul><ul><li>Potential for second row of WECs behind first row </li></ul>
  18. 18. Threats to Surfing Waves? <ul><li>PMSS (2010) study: </li></ul><ul><li>Present = 20MW (Wave Hub) </li></ul><ul><li>Future = 1200MW </li></ul>
  19. 19. Threats to Surfing Waves? <ul><li>West Cornwall </li></ul>
  20. 20. Threats to Surfing Waves? <ul><li>North Cornwall </li></ul>
  21. 21. Threats to Surfing Waves? <ul><li>Marwick Bay, Orkney </li></ul>
  22. 22. Threats to Surfing Waves? <ul><li>Marwick Bay, Orkney </li></ul>Various reef breaks c.500m 10MW array 2MW array
  23. 23. Conclusions <ul><li>Studies suggest: </li></ul><ul><li>Wave farms pose a threat to surfing waves </li></ul><ul><li>Threat related to wave farm characteristics </li></ul><ul><li>Different WECs = different effects on waves </li></ul><ul><li>Seabed mounted WECs = shallower water / closer to shore = greater threat? </li></ul><ul><li>Floating WECs = deeper water / further offshore = smaller threat? </li></ul>
  24. 24. More Info – SAS Reports <ul><li>Climate change issues: Climate Change – A Surfer’s Perspective </li></ul><ul><li>Wave farms and WECs: The WAR Report – Waves Are Resources </li></ul><ul><li>Impacts on surfing waves: Guidance on Environmental Impact Assessment of Offshore Renewable Energy Development on Surfing Resources and Recreation </li></ul>
  25. 25. More Info – Cited Studies <ul><li>Halcrow (2006). Wave Hub. Development and design phase. Coastal processes study report. South West of England Regional Development Agency, June 2006. </li></ul><ul><li>Venugopal, V and Smith, G. (2007). Wave climate investigation for an array of wave power devices. Proceedings of the 7th European Wave and Tidal Energy Conference, Porto, Portugal, 2007. </li></ul><ul><li>PMSS (2010) Offshore Renewables Resource Assessment and Development (ORRAD) Project – Technical Report. Report prepared for South West Regional Development Agency. </li></ul>

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