This is the second blog of a two-part series discussing floating foundations in the offshore wind market.
Floating foundations face many challenges that must be overcome in order to become a major factor in the offshore wind industry. At the same time, there are many possible advantages these systems could have over traditional foundation types.
Obstacles to Overcome
Despite the tremendous opportunities floating foundations could provide the offshore wind industry, there are multiple obstacles and challenges that need to be addressed before this technology can be used in large-scale projects. The majority of these challenges can be attributed to the fact that this technology is still in its infancy. Numerical models that analyze and compute structural and aerodynamic behaviors of foundations are relatively advanced for grounded foundation types as a result of an increasing amount of empirical data to draw from. In contrast, there are only a handful of test sites with large turbines installed along with some small-scale experimental projects that can be used to model floating foundations on. More test projects need to be built and tested to improve the accuracy and reliability of these models. Additionally, the interface between these floating platforms and the wind turbines themselves needs to be better understood. These foundations need to be able to account for different tower types and sizes as well as varying rotor diameters and hub heights in order to be fully integrated into the market.
Around 20% of current offshore capital expenditure is in the production and installation of substructures. Thus, it’s important to developers that supply chains and port infrastructures are fully realized prior to the beginning of construction. Floating technology, being as immature as it is, will require time to catch up to the more seasoned foundation types. However, there is evidence to support the notion that construction and installation of floating substructures will be both cheaper and easier than their grounded counterparts.
Monopiles and jacket foundations need to be driven deep into the ocean floor, which requires extensive ocean floor surveys. GBS foundations require a large area on the ocean bottom to rest on, which demands extensive preparation. These grounded foundations also require large vessels and dock storage facilities to hold and transport these large structures. Floating foundations can be constructed and assembled almost entirely onshore prior to being loaded onto transport vessels. This reduces vessel usage fees, port storage fees, and potential lost time due to weather delays.
Outlook for Floating Foundations
Several projects are in the pipeline to test floating foundations in Europe, Asia, and in the United States, particularly on the west coast. Siemens has signed a contract with Statoil to install 5 6 MW turbines off the coast of Scotland that will use the Hywind floating spar foundation. A 30 MW floating project funded by Principle Power is also planned off the coast of Oregon. Additionally, France has launched a tender for floating offshore wind projects using three to five turbines of at least 5 MW. These projects and others will undoubtedly face substantial challenges, but their success could lead to a significant expansion of potential offshore wind sites across the globe.