Disruptive technologies are like the weather: Lots of talk and little action. But Principle Power has a disruptive floating wind turbine technology and a prototype in the water generating electricity.
It's a “paradigm shift in the approach to offshore wind,” said Principle Power Chief Business Development Officer Craig Andrus, “because it opens up a footprint that right now is not available.”
Incumbent offshore wind technology is limited to fixed platforms and 50-meter depths, while it faces increased opposition because of environmental impacts. Principle Power’s WindFloat, Andrus said, resolves the depth limitation and “mitigates many of the issues and some of the risks.”
Because it is “structurally decoupled from the sea floor,” Andrus explained, “there are significantly reduced environmental impacts during deployment, little harm to the seabed, and, because of siting flexibility, negative visual impact can be eliminated.”
WindFloat, Andrus claimed, potentially opens up rich new markets in waters previously thought inaccessibly deep, such as those off the U.S. Pacific Coast, across the Mediterranean, along the coast of Japan and in the British Isles’ deeper waters.
Principle Power was formed in 2007 to guide renewable technologies from the lab to the marketplace. “Very early on,” Andrus recounted, “we were presented with this opportunity” of Marine Innovation & Technology’s semi-submersible floating platform. Designed for marginal oil field exploration, MI&T’s concept turned out to be “optimally suited to offshore wind deployment.”
In November 2011, a WindFloat bearing a two-megawatt Vestas wind turbine was towed out to sea by a standard, anchor-handling tugboat and positioned with a catenary mooring configuration using chain and drag embedment anchors.
Stability comes from WindFloat’s three submerged ballast columns attached by a triangle of beams. The turbine tower sits atop a column that contains relatively little water ballast. The other two columns have more ballast, enough to steady the approximately 400- to 800-ton turbine.
Broad flat heave plates at the bottom of each ballast column add stability. Balancing is passive as the WindFloat system seeks equilibrium.
The paradigm shift comes from the many advantages of a floating, deep water system, the first being cost.
“We see this being commercialized with large turbines,” Andrus said, because “cost per megawatt is reduced.” Going “from a two-megawatt to a five-megawatt turbine,” Andrus said, “increases power two-and-a-half times but increases foundation size by only 20 percent to 30 percent.” WindFloat, Andrus explained, “will be optimal for existing five-plus-megawatt turbines in development today and for the even larger turbines envisioned for the near future.”
Andrus provided no specifics about WindFloat costs, implying such details are both proprietary and premature. Economies of scale, he predicted, will eventually change cost considerations completely. “This business is all about scale,” he said, though an independent GL GH study, he added, found the WindFloat “very cost competitive” with jacket foundations.
The prototype now in service off the coast of Portugal was towed from the dry dock south of Lisbon where it and its Vestas turbine were readied for an ocean energy test site some 350 kilometers to the north, off the coast of Aguçadoura.
Because it was assembled quay-side and towed by a standard tug, Andrus explained, it eliminated two significant limitations of existing offshore wind technologies. There was no need for either costly ocean construction or the cranes and equipment needed to do that work.
The system was linked to Portugal’s grid via a subsea cable originally installed for Pelamis Wave Energy converters in September 2008 in the world’s first utility-scale wave energy trial. The harsh ocean environment and vigorous waves ended that trial early.
“We’re fortunate to have our first trial in a challenging environment,” Andrus said. “It would have been easier to be in a lake with few waves but I’m not sure what that would prove.” In answer to a question about what has been learned in WindFloat’s first two months, Andrus would only say, “So far, so good.”
The other utility-scale floating wind technology is Statoil’s Hywind. “They were in the water ahead of us,” Andrus said of the project that drew on the Norwegian national oil company’s experience in deep water oil platform design and has been successfully generating electricity since mid-2009. “It’s a spar technology with a Siemens 2.3-megawatt turbine,” Andrus added.
Andrus was unconcerned about the competition. “If you think of the footprint that floating wind opens up, I’m not too worried.” Like the several oil and gas platform technologies currently in use, he said, “There are applications that will favor one technology over the other.”
Principle Power’s partners in the WindPlus Joint Venture WindFloat trial include Portuguese mega-utility Energias de Portugal, A. Silva Matos, Vestas Wind Systems A/S, InovCapital, Fundo de Apoio a Inovacao, and 60+ European vendors.
The current two-year trial is the first of three WindFloat development phases. The next “pre-commerical” phase will involve five larger turbines. Its timing depends on funding that may come from a European Commission grant program.
WindFloat, Andrus noted, has drawn the interest of developers in the U.K. Crown Estate’s Round Three program and has had interest from the German offshore industry, as well, where dramatic expansion is imminent following the Merkel government’s decision to abandon nuclear power.
"We’re also excited about the U.S.," Andrus said. “It is hard to know when that will take off, but when it does, we want to be a part of it.”