Challenges

Reducing Costs

Cost reduction can be accomplished by combining installation and maintenance costs of both wind and wave devices and by sharing the undersea transmission costs by using both wind and wave resources [1]. O&M cost for small near-shore sites has been estimated about 25% of the life cycle cost of an offshore wind farm [7], [8].

Furthermore, the fusion of different but collaborated technologies will trigger industry synergies, which is the key for cost reduction, but also for sharing data and experience in order to minimise risk. Industry synergies from completely different fields can be enabled as well. For example, aquaculture [2] can be combined with floating platforms used as Operations and Maintenance (O&M) bases, or platforms could accommodate research facilities or leisure activities [3].

Exploiting Ocean Resources

The significance of wind resources far from shore compared to near-shore resources combined with the enormous wave energy produced in the oceans are the main reasons that motivated renewable energy specialists to explore locations far from shore into deep waters. Strengthening this argument, Wind & Wave Synergy is able to smooth out and stabilize the power output, minimising the impact of variability on the main electric power system and promoting further penetration of renewables into the main grid [1]. It also improves the predictability of the output.

The question may still be asked – why not near to shore?

The majority of the sites close to land that have both adequate wind and wave resources have already been leased, developed, or discarded due to complications such as seabed conditions, social and environmental impacts [4]. This illustrates the need to discover alternative sites to overcome those shortcomings.

Wave Energy Capture

Wave energy has been seen for many years as the “holy grail” of renewable technologies. It is less variable and more predictable than wind or solar, with higher energy density and, for the inventor or engineer, the lure of being the first to market is a strong one. Recent failures of innovative wave energy developers have dissuaded investors and made governments wary; however, as a result of this support packages available via the Contracts for Difference trading scheme are generous at £305/MWh compared to £155/MWh for offshore wind (CfD). It is estimated that up to 70 TWh [5] of wave energy is available for energy extraction – if even a small fraction of this was successfully converted it could provide a significant contribution to the UKs electricity demand, which was 303 TWh in 2014 [6].

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References

  • [1] E. D. Stoutenburg and M. Z. Jacobson, “Reducing Offshore Transmission Requirements by Combining Offshore Wind and Wave Farms,” Journal of Oceanic Engineering, vol. 36, no. 4, pp. 552-561, 2011.

  • [2] L. K. Carlberg and E. D. Christensen, “Go offshore - Combining food and energy production,” DTU Mechanical Engineering, Lyngby, 2015.

  • [3] E. Quevedo, E. Delory, A. Castro, O. Llinás and J. Hernández, “Modular multi-purpose offshore platforms, the TROPOS project approach,” Dublin, 2012.

  • [4] R. James and M. C. Ros, “Floating Offshore Wind: Market and Technology Review,” The Carbon Trust, London, 2015.

  • [5] AMEC Environment & Infrastructure UK Limited, “Carbon Trust - UK Wave Energy Resource,” Carbon Trust, 2012.

  • [6] DECC, “DUKES 2015,” DECC, London, 2015.

  • [7] J. Phillips, O. Fitch-Roy, P. Reynolds and P. Gardner, “GL Garrad Hassan "A Guide to UK Offshore Wind Operations and Maintenance",” Scottish Enterprise and The Crown Estate, 2013.

  • [8] I. Dinwoodie, D. McMillan, M. Revie, I. Lazakis and Y. Dalgic, “Development of a Combined Operational and Strategic Decision Support Model for Offshore Wind,” Energy Procedia, vol. 35, pp. 157-166, 2013.