Solar takes to the high seas

Many countries are turning to solar technology and renewable energy because of a need for alternative energy sources and environmental concerns. To help meet these needs, DNV has developed SUNdy, a large-scale offshore solar field concept.

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 4200 solar panels, forms a solar island the size of a large football stadium, capable of generating 2 MW of power. Multiple islands connected together make up a solar field of 50 MW or more, producing enough electricity for 30,000 people.

“The renewable energy market is rapidly changing due in main part to climate change, soaring global demand for electricity, and scarcity of fossil fuels. For DNV, technological innovation is a key element in our strategy to help address these concerns and SUNdy, as an example of our research work, can help illustrate future applications for solar as a truly sustainable resource,” says Bjørn Tore Markussen, Chief Operational Officer for DNV KEMA Energy & Sustainability Asia. “Indeed, renewable energy is becoming increasingly important in nations across the globe, including Asia, and with such a readily available and abundant source that is rapidly approaching grid parity levels, it’s solar power that’s attracting a lot of interest in this part of the world.”

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. “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 Dr 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,” adds Kevin Smith, Global Segment Director for DNV KEMA’s Renewable Energy Services. “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 (2MVA 480/34.5kV). From the offshore solar farm’s central island, 30 kV electrical transmission lines connect, tying other islands in series to form a close loop and continue to the electrical substation 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. While the EU again dominated the global market, markets are expanding in other regions, and China has rapidly emerged as the dominant player in Asia. Emerging markets, such as South-East Asia, are also aiming to grow their renewable energy production with an increased presence in the solar sector.

“Many countries are turning to solar technology and renewable energy because of a need for alternative energy sources and environmental concerns,” says Markussen and adds, “This is particularly so in highly populated countries which need more and more energy to supply their booming economies. We firmly believe the SUNdy floating solar field concept offers sound and sustainable development prospects, particularly in Asia and the congested coastal megacities where there’s limited opportunity for rooftop solar power and urban areas which command premium prices for large-scale mounted solar production.”