Document Type : Original Article


Chabahar Maritime University, Chabahar, Iran.


The combination of offshore wind turbines and wave energy converters has recently been the focus of researchers. Many types of converters have been installed on the offshore platform in the design step, and the performance of these hybrid systems has been investigated. The oscillating water column converter is one of the most favorite and commercialized systems due to its efficiency and low maintenance cost. In the present study, a new design including the array of the oscillating water column in a circular arrangement around the spar-type platform is considered. The coupled governing equations are solved based on the simplified analytical approach through frequency domain analysis. The results show that the increase in the number of energy converters increases the total generated power, and consequently, the converters capture the vibrational energy of the spar platform. Therefore, the dynamic response of the spar decreases in the case with an array of energy converters which is one of the main objects of this hybrid system.


Main Subjects

[1] A. S. Bahaj, "Generating electricity from the oceans," Renewable and Sustainable Energy Reviews, Vol. 15, pp. 3399-3416, 2011.
[2] G. Iglesias and R. Carballo, "Wave energy potential along the Death Coast (Spain)," Energy, Vol. 34, pp. 1963-1975, 2009.
[3] M. A. A. Farsangi and H. Zohoor, "Acoustic energy harvesting via magnetic shape memory alloys," Journal of Physics D: Applied Physics, Vol. 52, p. 135501, 2019.
[4] H. Sayyaadi, H. Rostami Najafabadi, and M. A. Askari Farsangi, "Modeling and parametric studies of magnetic shape memory alloy-based energy harvester," Journal of Intelligent Material Systems and Structures, Vol. 29, pp. 563-573, 2018.
[5] A. Peiffer, D. Roddier, and A. Aubault, "Design of a point absorber inside the WindFloat structure," in International Conference on Offshore Mechanics and Arctic Engineering, 2011, pp. 247-255.
[6] M. J. Muliawan, M. Karimirad, and T. Moan, "Dynamic response and power performance of a combined spar-type floating wind turbine and coaxial floating wave energy converter," Renewable energy, Vol. 50, pp. 47-57, 2013.
[7] E. E. Bachynski and T. Moan, "Point absorber design for a combined wind and wave energy converter on a tension-leg support structure," in International Conference on Offshore Mechanics and Arctic Engineering, 2013, p. V008T09A025.
[8] J. E. Hanssen, L. Margheritini, K. O'Sullivan, P. Mayorga, I. Martinez, A. Arriaga et al., "Design and performance validation of a hybrid offshore renewable energy platform," in 2015 Tenth International Conference on Ecological Vehicles and Renewable Energies (EVER), 2015, pp. 1-8.
[9] W. Chen, F. Gao, X. Meng, B. Chen, and A. Ren, "W2P: A high-power integrated generation unit for offshore wind power and ocean wave energy," Ocean Engineering, Vol. 128, pp. 41-47, 2016.
[10] M. Karimirad and K. Koushan, "WindWEC: Combining wind and wave energy inspired by hywind and wavestar," in 2016 IEEE International Conference on Renewable Energy Research and Applications (ICRERA), 2016, pp. 96-101.
[11] J. M. Kluger, A. H. Slocum, and T. P. Sapsis, "A first-order dynamics and cost comparison of wave energy converters combined with floating wind turbines," in The 27th International Ocean and Polar Engineering Conference, 2017.
[12] Y. Wang, L. Zhang, C. Michailides, L. Wan, and W. Shi, "Hydrodynamic Response of a Combined Wind–Wave Marine Energy Structure," Journal of Marine Science and Engineering, Vol. 8, p. 253, 2020.
[13] A. H. Patil and D. Karmakar, "Hydrodynamic performance of spar-type wind turbine platform combined with wave energy converter," in Recent Trends in Civil Engineering, ed: Springer, 2021, pp. 115-123.
[14] C. Michailides, "Ηydrodynamic Response and Produced Power of a Combined Structure Consisting of a Spar and Heaving Type Wave Energy Converters," Energies, Vol. 14, p. 225, 2021.
[15] A. Peiffer and D. Roddier, "Design of an oscillating wave surge converter on the windfloat structure," in Proceedings of the 2012 4th International Conference on Ocean Energy (ICOE), Dublin, Ireland, 2012, pp. 17-19.
[16] C. Luan, C. Michailides, Z. Gao, and T. Moan, "Modeling and analysis of a 5 MW semi-submersible wind turbine combined with three flap-type wave energy converters," in International Conference on Offshore Mechanics and Arctic Engineering, 2014, p. V09BT09A028.
[17] A. Aubault, M. Alves, A. n. Sarmento, D. Roddier, and A. Peiffer, "Modeling of an oscillating water column on the floating foundation WindFloat," in International Conference on Offshore Mechanics and Arctic Engineering, 2011, pp. 235-246.
[18] K. P. O'Sullivan, "Feasibility of combined wind-wave energy platforms," 2014.
[19] C. Perez-Collazo, D. Greaves, and G. Iglesias, "Hydrodynamic response of the WEC sub-system of a novel hybrid wind-wave energy converter," Energy Conversion and Management, Vol. 171, pp. 307-325, 2018.
[20] C. Perez and G. Iglesias, "Integration of wave energy converters and offshore windmills," in http://www. icoe-conference. com, 2012.
[21] C. Perez-Collazo, D. Greaves, and G. Iglesias, "A novel hybrid wind-wave energy converter for jacket-frame substructures," Energies, Vol. 11, p. 637, 2018.
[22] A. d. O. Falcão and P. Justino, "OWC wave energy devices with air flow control," Ocean engineering, Vol. 26, pp. 1275-1295, 1999.
[23] A. J. Sarmento and A. d. O. Falcão, "Wave generation by an oscillating surface-pressure and its application in wave-energy extraction," Journal of Fluid Mechanics, Vol. 150, pp. 467-485, 1985.
[24] L. Gato and A. d. O. Falca˜ o, "On the theory of the Wells turbine," 1984.
[25] R. G. Dean and R. A. Dalrymple, Water wave mechanics for engineers and scientists vol. 2: world scientific publishing company, 1991.
[26] S. Nallayarasu and K. Bairathi, "Hydrodynamic response of spar hulls with heave damping plate using simplified approach," Ships and Offshore Structures, Vol. 9, pp. 418-432, 2014.
[27] B. Stappenbelt and P. Cooper, "Mechanical model of a floating oscillating water column wave energy conversion device," 2010.
[28] J. N. Newman, Marine hydrodynamics: The MIT press, 2018.
[29] D. Evans, "The oscillating water column wave-energy device," IMA Journal of Applied Mathematics, Vol. 22, pp. 423-433, 1978.
[30] J. Jonkman, S. Butterfield, W. Musial, and G. Scott, "Definition of a 5-MW reference wind turbine for offshore system development," National Renewable Energy Lab. (NREL), Golden, CO (United States) 2009.
[31] A. F. Falcão, J. C. Henriques, L. M. Gato, and R. P. Gomes, "Air turbine choice and optimization for floating oscillating-water-column wave energy converter," Ocean engineering, Vol. 75, pp. 148-156, 2014.
[32] I. Simonetti, L. Cappietti, H. El Safti, and H. Oumeraci, "Numerical modelling of fixed oscillating water column wave energy conversion devices: Toward geometry hydraulic optimization," in International Conference on Offshore Mechanics and Arctic Engineering, 2015, p. V009T09A031.