Many U.S. coastal regions have both large population centers and strong offshore wind resources, making offshore wind energy an attractive solution for meeting the energy needs of coastal communities. However, the biggest barrier to realizing the potential benefits of offshore wind is its cost, particularly in deep-water environments—and nearly 60% of U.S. offshore wind resources are located in water deeper than 60 meters (197 feet).
Funded by DOE’s Wind Energy Technologies Office, Sandia National Laboratories’ floating offshore vertical-axis wind turbine (VAWT) research project focuses on demonstrating technical and economic feasibility by developing innovative VAWT rotor designs that enable reliable, cost-effective, and easily manufactured rotor systems for deep-water offshore machines. In deep water, VAWTs potentially offer several advantages over horizontal-axis wind turbines (HAWTs), as shown in the graphic. One such advantage is placement of the drivetrain at the base of the VAWT tower, which significantly lowers the vertical center of gravity and improves accessibility of drivetrain components. This innovation reduces costs not only for installation, but also for operation and maintenance, all of which are major cost drivers.
“We’re motivated by the vast deep-water U.S. offshore wind resource that can provide cost-effective and reliable clean electricity to a large number of consumers,” said Todd Griffith, the technical lead for Sandia’s Offshore Wind program. “To maximize this resource, Sandia has been engineering a system-level design to evaluate the overall feasibility of a floating VAWT system and develop this new technology.”
Sandia’s wind program began working on VAWT development in the 1970s. The laboratory’s current VAWT research and development work includes a system design study focused on multiple rotor configurations and multiple floating system types, particularly large-scale, multimegawatt systems. This study has provided a better understanding of a floating VAWT’s optimal configuration and how this system compares with a floating HAWT.
Sandia researchers have partnered with colleagues from academia and industry to investigate several novel innovations to improve VAWT technology and reduce costs. These include VAWT-specific airfoils, floating foundations for VAWT rotors, aeroelastic stability (flutter) analysis for large-scale VAWTs, tower resonance mitigation, rotor-platform dynamic stability, rotor manufacturing technology, and storm survival and load alleviation. Sandia’s research has also been featured at several recent international conferences including the Euromech VAWT Colloquium in Delft, the Netherlands, and the Science of Making Torque from Wind Conference in Munich, Germany.
For more information, visit Sandia’s website.