R&D
Pioneering demonstrations receive US government backing
The Department of Energy in the US is pressing ahead with a series of demonstration projects that it hopes will speed up the deployment of offshore wind energy in the US
IN May, the US Department of Energy (DOE) announced that it had selected three pioneering offshore wind demonstrations to receive up to US$47 million each over the next four years in order to deploy innovative, grid-connected systems in federal and state waters by 2017. So, what will each project entail? And what do the developments mean for the ongoing growth of the US offshore industry? The projects selected for funding include Dominion Virginia Power’s Virginia Offshore Wind Technology Advancement Project (VOWTAP), which will entail the installation of two Alstom 6 megawatt (MW) direct-drive wind turbines 26 miles off the coast of Virginia Beach, Fishermen’s Energy’s Atlantic City windfarm project, which will see five XMEC 5MW direct-drive wind turbines installed in state waters approximately three miles off the coast of Atlantic City, New Jersey, and Principle Power’s WindFloat project, which will install five Siemens 6MW direct-drive turbines approximately 18 miles off the coast of Coos Bay, Oregon. According to Liz Hartman, wind and water power communications lead at the energy efficiency and renewable energy section of the DOE, the selection of the three projects follows a two-year review period during which a total of seven advanced technology demonstration projects received US$4 million from DOE to complete the engineering,
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design, site evaluation and planning phase of their projects. Each of the seven projects were
reviewed to assess progress made towards securing permitting and power off-take agreements as well as being subjected to a technological and economic evaluation and an assessment of their ability to lower the overall cost of energy from offshore wind. “Through this review process, the DOE selected three projects for continued four-year follow-on funding that will support follow-on design, fabrication, construction, and deployment to achieve commercial operation by the end of 2017,” said Mrs Hartman. Each of the selected projects will
feature direct-drive turbine technology from different turbine manufacturers. The Dominion project will install two Alstom 6MW direct-drive turbines, the Principle Power initiative plans to install five Siemens 6MW direct-drive turbines and the Fishermen’s Energy project plans will install five XEMC 5MW direct-drive turbines. “Direct-drive turbines don’t require as many moving parts compared with standard-geared turbines, leading to increased reliability and reduced operating costs,” said Mrs Hartman. Another key technology is the twisted jacket foundation, a variation of the popular jacket foundation, which Mrs Hartman believes is easier to manufacture and install than traditional foundations. “A recent innovation by a US company has resulted in a twisted jacket foundation where three ‘legs’ are twisted around a central column. Both Fishermen’s Energy and Dominion Virginia Power will use twisted jacket foundations incorporating hurricane-resilient design features to ensure that offshore wind facilities placed in hurricane- prone waters are reliable, safe and cost effective,” Mrs Hartman explained. Although the two projects will use the same foundation design, she points out that they will be based at different locations, with different challenges and different wind and wave regimes.
Principle Power will use the WindFloat floating foundation to install five 6MW direct-drive turbines
The Fishermen’s Energy project is in shallow water, extending to depths of just 11m, only three miles from shore in state waters, while Dominion’s project is in water more than twice as deep (25m) and 26 miles from shore in federal waters.
“Demonstrating that the US-designed twisted jacket foundation is applicable and reduces construction and installation costs at both project sites will prove the foundation’s versatility and benefits, speeding its commercial deployment,” said Mrs Hartman. Meanwhile, the Principle Power
project will test the company’s innovative semi-submersible floating foundation. According to Mrs Hartman, floating technology “represents the future of offshore wind”, particularly in view of the fact that more than 60 per cent of the offshore wind resources within 50 nautical miles of US coasts are located in deep water where she says traditional bottom-fixed foundations cannot be used. The Principle Power semi-submersible
WindFloat foundation is shaped like a triangle, with the turbine located on one of the three columns that form the
Offshore Wind Journal I 3rd Quarter 2014 I 23
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