successful test of a stealth wind turbine blade mitigating radar reflection problems for aviation. In December 2010 Vestas were developing the V164 7 MW offshore turbine, with a 164 m rotor diameter. Prototypes of it were manufactured at Lindø (the former Maersk shipyard) due to size, crane and port access requirements. Series production of nacelles for the 32 turbines (256 MW) extension of the 90 MW Burbo Bank Offshore Wind Farm occurs at Lindø, while blades are made at Vestas' Isle of Wight facilities in England. DONG Energy tested a prototype in the sea off Frederikshavn in 2013, at a cost of DKK 240 million. A V164 was installed for testing in Østerild Wind Turbine Test Field in 2014, later uprated to more power. In June 2011, the Vestas supercomputer Firestorm was number 53 on the TOP500-list of the world's most powerful computers calculating worldwide weather in a 3x3 km grid, and it delivers daily weather reports to the newspaper Ekstra Bladet and similar purposes. In 2012, Vestas donated the older 1344-core supercomputer from 2008 to Aalborg University. In October 2011, Vestas participated in the deployment of a floating wind turbine offshore of Portugal. Vestas supplied a v80 2.0 MW offshore turbine to Windplus, S.A. (a joint-venture company including Energias de Portugal, Repsol, Principle Power, A. Silva Matos, Inovcapital and Portugal Ventures). The system, known as the WindFloat, consists of a semi-submersible type floating foundation, a conventional catenary mooring, and the wind turbine. The successful deployment represents the first offshore multi-megawatt wind turbine to be installed without the use of any heavy-lift or specialized offshore construction equipment. In 2012, Vestas scaled back and closed some of its R&D offices in Houston, Marlborough, Louisville, China, Singapore and Denmark. In August 2013, Vestas started operating its 20 MW test bench for nacelles in Aarhus. On 5 September 2013, Chris Spruce, Vestas Senior Product Engineer, served as member of the Scientific Advisory Board (SAB) for the kite-energy-systems project ERC HIGHWIND, a project at KU Leuven dedicated to the research and development of tethered airfoils dedicated to generating energy by airborne wind energy (AWE). In April 2016, Vestas installed a 900 kW quadrotor test wind turbine at Risø, made from 4 recycled 225 kW V29 turbines. The first three months of testing confirmed theoretical models. Vestas has no immediate plans of commercializing the prototype. Test results were published in 2019, indicating lower costs. As