Sustainable Marine Structures

Current Status and Future Trends for Mooring Systems of Floating Offshore Wind Turbines

Ruyan Yang

Institute for Ocean Engineering, Tsinghua University Shenzhen International Graduate School, Guangdong, China

Xiangyuan Zheng

Institute for Ocean Engineering, Tsinghua University Shenzhen International Graduate School, Guangdong, China

Jinlu Chen

Institute for Ocean Engineering, Tsinghua University Shenzhen International Graduate School, Guangdong, China

Yufei Wu

Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering, Shenzhen University, Shenzhen,518060, China

DOI: https://doi.org/10.36956/sms.v4i2.617

---

Abstract

With the increasing demand of energy and the limitation of bottom-fixed wind turbines in moderate and deep waters, floating offshore wind turbines are doomed to be the right technical choice and they are bound to enter a new era of rapid development. The mooring system is a vital system of a floating wind turbine for station-keeping under harsh environmental conditions. In terms of existing floating wind turbine projects, this paper is devoted to discussing the current status of mooring systems and mooring equipment. This paper also presents the mooring analysis methods and points out the technical difficulties and challenges in mooring design, installation, operation and maintenance stages. Finally, the developing trends of the mooring system are summarized, aiming to provide a reference for future mooring research.

Keywords: Mooring system; Mooring equipment; Mooring analysis; Floating offshore wind turbines; Mooring line; Anchor

---

References

[1] Manwell, J.F., Mccowan, J.G., Rogers, A.L., 2006. Wind Energy Explained: theory, design and application. Wind Engineering. 30(2), 169-170.

[2] Williams, R., Zhao, F., Lee, J., 2022. GWEC. Global Wind Report 2022. Global Wind Energy Council. Brussels, Belgium.

[3] Henderson, A.R., Witcher, D., 2010. Floating offshore wind energy—a review of the current status and an assessment of the prospects. Wind Engineering. 34(1), 1-16.

[4] Campanile, A., Piscopo, V., Scamardella, A., 2018. Mooring design and selection for floating offshore wind turbines on intermediate and deep water depths. Ocean Engineering. 148, 349-360.

[5] González, S.F., Diaz-Casas, V., 2016. Present and future of floating offshore wind. Floating offshore wind farms. Springer, Cham. 1-22.

[6] Lerch, M., De-Prada-Gil, M., Molins, C., et al., 2018. Sensitivity analysis on the levelized cost of energy for floating offshore wind farms. Sustainable Energy Technologies and Assessments. 30, 77-90.

[7] Ma, K.T., Luo, Y., Kwan, C.T.T., et al., 2019. Mooring system engineering for offshore structures. Gulf Professional Publishing.

[8] Zhao, J.R., Feng, W., Li, X.K., 2013. Development status of multipoint mooring system in deep water. Oil Field Equipment. 42, 1-7.

[9] Anchors, V., 2015. Anchor manual 2015–the guide to anchoring. Rotterdam: Vryhof Anchors.

[10] Equinor. Equinor - the world’s leading floating offshore wind developer. (2022-07-31). https://www.equinor.com/energy/floating-wind.

[11] Equinor. Statoil to build the world’s first floating wind farm: Hywind scotland. (2022-07-31).https://www.equinor.com/energy/hywind-scotland.

[12] Hole, K.B., 2018. Design of Mooring Systems for Large Floating Wind Turbines in Shallow Water. NTNU.

[13] Sanxia Energy. Sanxia Yinling: China’s first floating offshore wind turbine. (2021-08-13) [2022-07-31]. http://www.cnenergynews.cn/zhuanti/2021/12/16/detail_20211216113637.html.

[14] Jefferys, E.R., Patel, M.H., 1982. On the dynamics of taut mooring systems. Engineering Structures. 4(1), 37-43.

[15] Qiao, D., Haider, R., Yan, J., et al., 2020. Review of wave energy converter and design of mooring system. Sustainability. 12(19), 8251.

[16] Pham, H.D., Schoefs, F., Cartraud, P., et al., 2019. Methodology for modeling and service life monitoring of mooring lines of floating wind turbines. Ocean Engineering. 193, 106603.

[17] Alexandre, A., Percher, Y., Choisnet, T., et al., 2018. Coupled analysis and numerical model verification for the 2MW Floatgen demonstrator project with IDEOL platform. International Conference on Offshore Mechanics and Arctic Engineering. American Society of Mechanical Engineers. 51975, V001T01A032.

[18] Floatgen, France’s First Offshore Wind Turbine. (2022-07-31). https://www.weamec.fr/en/synthesis/floatgen/.

[19] Bach-Gansmo, M.T., Garvik, S.K., Thomsen, J.B., et al., 2020. Parametric study of a taut compliant mooring system for a FOWT compared to a catenary mooring. Journal of Marine Science and Engineering. 8(6), 431.

[20] Tomasicchio, G.R., Armenio, E., D’Alessandro, F., et al., 2012. Design of a 3D physical and numerical experiment on floating off-shore wind turbines. Coastal Engineering Proceedings. 1, 67.

[21] Bea, R.G., Cornell, C.A., Vinnem, J.E., et al., 1994. Comparative risk assessment of alternative TLP systems: Structure and foundation aspects.

[22] Kim, C.H., Zhao, C., Zou, J., 1995. Springing and ringing due to nonlinear waves on a coupled TLP. The Fifth International Offshore and Polar Engineering Conference. OnePetro.

[23] Adam, F., Steinke, C., Dahlhaus, F., et al., 2013. GICON®-TLP for wind turbines–validation of calculated results. The Twenty-Third International Offshore and Polar Engineering Conference. OnePetro.

[24] Adam, F., Myland, T., Dahlhaus, F., et al., 2014. Gicon®-TLP for wind turbines—the path of development. The 1st International Conference on Renewable Energies Offshore (RENEW). 24-26.

[25] GICON-SOF. Development of A Floating Foundation for Third Generation Wind Turbines with The University Of Rostock. (2022-07-31). http://www.gicon-sof.de/en/sof1.html.

[26] GICON & GLOSTEN n.d. Glosten and Gicon partnership. glosten.com: Glosten. (2022-07-31)

[27] Eolink Cost-effective Floting Wind Farms. Proven shipyard technologies. (2022-07-31).https://www.eolink.fr/en/concept.

[28] Guyot, M., De Mourgues, C., Le Bihan, G., et al., 2019. Experimental offshore floating wind turbine prototype and numerical analysis during harsh and production events. International Conference on Offshore Mechanics and Arctic Engineering. American Society of Mechanical Engineers. 59353, V001T02A004.

[29] DNV. GL. DNVGL-OS-E302: Offshore mooring chain. 2015.

[30] Lunde, T.H., 2021. Roksvaag T B, Solheim S. Mooring of Floating Offshore Wind Turbines. NTNU.

[31] Chakrabarti, S., 2005. Handbook of Offshore Engineering (2-volume set). Elsevier.

[32] Petruska, D.J., Kelly, P., Stone, B., et al., 2010. SS: Fiber Moorings, Recent Experiences and Research: Updating API RP 2SM on Synthetic Fiber Rope for Offshore Moorings. Offshore Technology Conference. OnePetro.

[33] Song, B.T., Jiang, R.X., Li, T., 2021. Application and development status of synthetic fiber cables for marine engineering at home and abroad. Technical Textiles. 1, 77-79.

[34] Zimmerman, E.H., Smith, M., Shelton, J.T., 2009.Efficient gravity installed anchor for deepwater mooring. Offshore technology conference. OnePetro.

[35] Zhao, Y., Liu, H., 2016. Numerical implementation of the installation/mooring line and application to analyzing comprehensive anchor behaviors. Applied Ocean Research. 54, 101-114.

[36] Drilling Formulas. Suction Anchor Calculation. (2022-07-31) https://www.drillingformulas.com/suction-anchor-calculation/:DrillingFormulas.

[37] Kwan, C.T., Bruen, F.J., 1991. Mooring line dynamics: comparison of time domain, frequency domain, and quasi-static analyses. Offshore Technology Conference. OnePetro.

[38] Wang, H.W., 2011. Research on truncation technology of deepwater mooring system in model test. HEU.

[39] API R P. 2SK. Recommended practice for design and analysis of stationkeeping systems for floating structures, 2005.

[40] Ormberg, H., Larsen, K., 1998. Coupled analysis of floater motion and mooring dynamics for a turret-moored ship. Applied Ocean Research. 20(1-2), 55-67.

[41] Ormberg, H., Fylling, I.J., Larsen, K., et al., 1997. Coupled analysis of vessel motions and mooring and riser system dynamics. Proceedings of the international conference on offshore mechanics and arctic engineering. American Society of Mechanical Engineers. 91-100.

[42] AS D N V G L. Position mooring. DNVGL-OS-E301, 2015.

[43] Xu, K., Larsen, K., Shao, Y., et al., 2021. Design and comparative analysis of alternative mooring systems for floating wind turbines in shallow water with emphasis on ultimate limit state design. Ocean Engineering. 219, 108377.

[44] Dan, D., Chen, Z., Yan, X., 2014. Closed-form formula of the transverse dynamic stiffness of a shallowly inclined taut cable. Shock and Vibration.

[45] Berlioz, A., Lamarque, C.H., 2005. A non-linear model for the dynamics of an inclined cable. Journal of Sound and vibration. 279(3-5), 619-639.

[46] Jiang, K.H., 2005. Study on buoy mooring system. Tianjin University.

[47] Liu, H., Huang, W., Lian, Y., et al., 2014. An experimental investigation on nonlinear behaviors of synthetic fiber ropes for deepwater moorings under cyclic loading. Applied Ocean Research. 45, 22-32.

[48] Luongo, A., Zulli, D., 2012. Dynamic instability of inclined cables under combined wind flow and support motion. Nonlinear Dynamics. 67(1), 71-87.

[49] Huang, W., Liu, H., Lian, Y., et al., 2013. Modeling nonlinear creep and recovery behaviors of synthetic fiber ropes for deepwater moorings. Applied Ocean Research. 39, 113-120.

[50] Bhattacharjee, S., 2015. Design and Installation Challenges for Deepwater Mooring Systems. 2015.

[51] Elman, P., Bramande, J., Elletson, E., et al., 2013. Reducing uncertainty through the use of mooring line monitoring. OTC Brasil. OnePetro.

[52] Siréta, F.X., Zhang, D., 2018. Smart mooring monitoring system for line break detection from motion sensors. The Thirteenth ISOPE Pacific/Asia Offshore Mechanics Symposium. OnePetro.

[53] Bayati, I., Efthimiou, L., 2021. Challenges and opportunities of major maintenance for floating offshore wind. World Forum Offshore Wind eV.

[54] Yuan, Z.M., Incecik, A., Ji, C., 2014. Numerical study on a hybrid mooring system with clump weights and buoys. Ocean Engineering. 88, 1-11.

[55] Xu, S., Wang, S., Soares, C.G., 2020. Experimental investigation on hybrid mooring systems for wave energy converters. Renewable Energy. 158, 130-153.

[56] Lian, Y., Liu, H., Hu, L., 2015. Feasibility analysis of a new hybrid mooring system applied for deep waters. The Twenty-fifth International Ocean and Polar Engineering Conference. OnePetro.

[57] Benassai, G., Campanile, A., Piscopo, V., et al., 2014. Mooring control of semi-submersible structures for wind turbines. Procedia Engineering. 70, 132-141.

[58] Campanile, A., Piscopo, V., Scamardella, A., 2018. Mooring design and selection for floating offshore wind turbines on intermediate and deep water depths. Ocean Engineering. 148, 349-360.

[59] Flory, J.F., Banfield, S.J., Berryman, C., 2007. Polyester mooring lines on platforms and MODUs in deep water. Offshore Technology Conference. OnePetro.

[60] Davies, P., Weller, S.D., Johanning, L., et al., 2014. A review of synthetic fiber moorings for marine energy applications. 5th International Conference on Ocean Energy (ICOE 2014), 4th-6th November 2014, Halifax.