STTR Phase I: Preliminary Design and Manufacturing of Mooring Line Connections for 3D Concrete Printed Floating Wind Turbine Anchors

The broader impact of this Small Technology Transfer Research (STTR) Phase I project opens pathways to large-scale domestic manufacturing of low-cost energy infrastructure needed to facilitate the clean energy transition in the United States. The United States has a vast offshore wind energy resource that is nearly four times the nation's current electricity use. This enormous potential presents an opportunity to deliver clean and reliable electricity to the country’s largest population centers while creating hundreds of thousands of jobs to manufacture and service the wind plants. However, approximately 60% of the offshore wind energy resource is in deep waters that require floating wind turbines moored to seafloor anchors. With an installed cost of approximately $1 M each, lower-cost anchor solutions are needed to accelerate the deployment of wind energy. This Phase I project uses advanced additive manufacturing methods to cut the installed costs of wind turbine anchors. The additive manufacturing technology also has strong future market potential in diverse renewable energy technologies beyond anchors, including fixed-bottom offshore substructures, floating wind platforms, wave energy devices, on-shore wind turbine towers, small hydropower, and pumped hydro electric energy storage. This project combines four cost-reducing innovations to create a low cost additively manufactured anchor that will cut installed anchor costs by up to 80% compared to conventional steel suction anchors – saving approximately $3M per floating wind turbine. The proposed project advances the following innovations: (1) the first-ever application of 3D concrete printing to floating wind turbines, (2) an innovative concrete reinforcement system, (3) integrated buoyancy chambers that aid transport and installation of the anchor, and (4) a new mooring line connection method, the development of which is the primary focus of the project. The project goal is to pave the way for the first-ever seafloor embedment of the innovative concrete anchor by de-risking key aspects of a mooring line connection solution capable of resisting extreme mooring line forces of approximately 1,700 metric tons. The Phase I project scope includes comparison and down-selection of mooring line connection concepts, preliminary design of the selected design, fabrication of a section of the concrete anchor using additive manufacturing at a scale of up to 2.5 meters in diameter, and analysis of the cost effectiveness and production rates of the innovative anchor and additive manufacturing process. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.