Tall towers and foundations for modern offshore and land-based wind turbines are too large to transport over roads or rail due to their extremely large dimensions. Existing âone-offâ on-site construction methods are too expensive, and are too slow for manufacturing foundations and towers in the large numbers needed, especially for offshore components manufactured in ports with limited lay-down space. Innovative on-site manufacturing technologies and processes are needed to increase the production rate and reduce the capital cost of very large foundations and towers for offshore and land-based wind plants. This project will develop and assess the feasibility of an innovative concrete additive manufacturing process for building a variety of offshore and land-based wind turbine tower and foundation configurations on-site. The advanced manufacturing method reduces the capital cost of an offshore substructure and tower compared to conventional methods by up to 80% using low-cost regionally sourced concrete without expensive formwork, and increases production speed up to 20 times using an automated production-line approach. The initial target application of the additive manufacturing process is a 160-m tall gravity-based foundation and concrete tower for an offshore 10-MW turbine installed in 40-m of water. The STTR Phase I scope of work entails the first-ever conceptual design and techno-economic assessment of an additively manufactured concrete offshore wind turbine foundation and tower. The team will (1) design a concrete printer that can be used for a variety of tower and foundation designs, (2) develop a conceptual design for an offshore gravity-based foundation and tower, (3) assess the feasibility and production speed of additively manufactured concrete foundations and towers, and (4) perform an initial assessment of an a tripod substructure concept. Phase I maximizes the impact of project funding by using a recently published, federally funded study as the framework with which to assess the proposed technology for an existing East Coast port, and by adapting concrete additive manufacturing technologies initially developed for manufacturing of buildings. A follow-on Phase II will leverage national laboratory facilities to manufacture and test a sub-scale component or assembly if award
