Floating offshore wind turbines (FOWTs) are poised to expand wind energy capture in the United States, especially in regions where magnitudes of sustained wind velocities support the deployment of high-capacity wind turbines (15 MW or higher). Although advances have been made in recent years to improve the maturity of new and existing designs, dynamic responses resulting from wave and wind loads remain some of the main drivers of cost in FOWTs, threatening the economic viability of projects. 

For projects to be successful, the levelized cost of energy (LCOE), which encompasses capital expenditure (CAPEX) and operational expenditure (OPEX) associated with an FOWT project (among other factors such as installation and assembly methods/options, etc.), must be kept below the project threshold estimated to be < 60 $/MWh.

Our approach to meeting the challenge of providing safe and cost-effective FOWTs for deployment in offshore wind projects entails the Front-End Engineering Design (FEED) of two passively controlled platforms—a Tension Leg Platform, and an Inclined-Frame Semi-submersible, suitable for relatively shallow- and deep-water deployments, respectively.

Each of the platforms is designed with passive controls to minimize the impact of dynamic loads on the platform motions, nacelle accelerations, tower reactions, and mooring line tensions. FEED design includes model testing of each unit at scale 1:30 to adequately de-risk the design at all interface points. The impact of these reduced responses is expected to lead to a significant reduction in the CAPEX and OPEX of the platform facility.

Our team is led by Kent Houston Offshore Engineering, whose scope includes the design of the floating platforms and manages the entire project. Our partners and their respective contributions to the project are: National Aeronautics and Space Administration (NASA) – designing and testing the passive control systems, which will be integrated into the platforms; National Renewable Energy Laboratories (NREL) – improving and customizing analysis tools which will be implemented in platform / turbine analysis and design; Linc Research Inc. – optimizing the performance of NASA’s passive control systems; American Bureau of Shipping (ABS) – independent third party review and classification of the FOWT technologies; Maritime Research Institute Netherlands (MARIN) – conducting wave basin model testing of the integrated platform and passive control systems.

Achieving safe FOWT designs that satisfy LCOE of < 60 $/MWh requires novel technologies; in our project, these are the integrated systems of efficient platform configurations which are passively controlled to mitigate impacts of dynamics. The ARPA-E SCALEUP project presents a unique opportunity for our team to design and test these technologies at an adequate scale. The success of this project will positively impact the advancement of the floating wind industry towards viable commercial applications.