Researchers at DNV have developed a dynamic floating offshore solar field concept. Dubbed SUNdy, the core feature of the concept is a hexagonal array which floats on the sea surface. A collection of these arrays, totalling 4,200 solar panels, forms a solar island the size of a large football stadium, capable of generating 2.0 MW. Multiple islands connected together make up a solar field of 50 MW or more, producing enough electricity for 30,000 people.
The SUNdy concept is made possible using thin-film 560 W solar panels which are flexible and lighter than the traditional rigid glass-based modules, allowing them to undulate with the ocean’s surface explains Sanjay Kuttan, managing director of the DNV Clean Technology Centre in Singapore, says. “The key to creating an ocean-based structure of this size is the use of a tension-only design. Rather like a spider’s web, this dynamic, compliant structure yields to the waves, yet is capable of withstanding considerable external loads acting upon it.”
According to Kuttan separating the solar arrays into prefabricated sections allows for large scale manufacturing and streamlined assembly offshore. The cable grid provides for maintenance access in the form of floating gangways. Below the surface, the shape of the island is maintained by the tensile forces from the lengthy spread mooring.
“The island has been optimised for solar capability and cabling efficiency,” Kevin Smith, global segment director for DNV KEMA’s Renewable Energy Services, says. “The solar arrays are divided into electrical zones feeding electricity produced into two main switches collecting the power for voltage step up at a central transformer (2.0 MVA 480/34.5kV). From the offshore solar farm’s central island, 30kV electrical transmission lines connect, tying other islands in series to form a close loop and continue to the electrical sub-station onshore for grid connection.”
The unveiling of the SUNdy concept comes at a time when solar photovoltaics (PV) is experiencing extraordinary market growth. Almost 30 GW of operating capacity has been added, increasing total global capacity by 74% to more than 69 GW according to the Renewable Energy Policy Network 2012 report.