Monday, October 14, 2013

Cape Wind: clearing final hurdles

The hotly debated Cape Wind project is in the process of clearing final hurdles before construction can begin on the 130-turbine project to be located in Nantucket Sound, off the Massachusetts coast in the U.S.
After more than a decade of permitting and appeals, Cape Wind officials expect to overcome the final lingering appeals soon. Cape Wind executives are also in the process of securing final financing for the $2.6bn project, with the Bank of Tokyo serving as the lead arranger of commercial debt.
Cape Wind expects to obtain funding by the end of the year, which would allow it to begin construction this year and benefit from federal production tax credits that may expire Dec. 31. In June it was announced that the Copenhagen Infrastructure I fund, managed by Copenhagen Infrastructure Partners, the pension fund of PensionDanmark, would fund a conditional investment commitment of $200m into the offshore wind farm, which will be the first of its kind in the US.
The first of the 410-foot-high turbines would be connected to the grid approximately 18 months later. The project is expected to produce 468 megawatts of wind power (each wind turbine will produce up to 3.6 megawatts), almost 75 per cent of the 230-megawatt average electricity demand for Cape Cod, a highly populated tourist destination on the Massachusetts coast. Environmentally, the clean wind generation will serve to remove the equivalent of 170,000 cars off the road each year.
Preparing the supply chain
The project has four construction phases, including turbine manufacturing, upland (land) cable, offshore electric cabling and park construction. The park’s 130 turbines will be installed using specially developed offshore equipment and construction techniques. While the park is the first of its kind off American waters, Cape Wind does not expect construction delays.
“If we were commissioned today, Cape Wind would represent the 64th offshore wind farm,” says Mark Rodgers, Communications Director for Cape Wind. “So it’s been done in a lot of places for a long time, it just hasn’t been done here. So we’re not having to re-invent the wheel; we are the beneficiaries of decades of experience.”
Last summer, research vessels were deployed to Nantucket Sound to gather preliminary data prior to beginning construction.
“We conducted a four-stage geotechnical survey, which expanded on the work done years earlier and allowed us to finalize our foundation design,” says Rogers. “The earlier work was related to permitting. This is related to what we need to do as part of the final project design.”
Specifically, the research data, gained from boring samples and sound wave technology, provided Cape Wind with information on sediment characteristics at different depths where the company will be drilling holes and driving foundation pilings.
Before work begins underwater, a local contractor will begin working early next year to bury Cape Wind’s land-based electric cables. Cape Wind awarded a $15m contact to Lawrence-Lynch Corp. in July. The company will also be tasked with providing a conduit for connecting the buried electric cables on land to the submerged ocean submarine cables by using a directional drill from the landfall point to a temporary cofferdam to be constructed in Lewis Bay.
European know-how, local challenges
Cape Wind’s turbines will be supported by towers installed on monopile foundations. Each foundation will be between five and six and a half meters across and will weigh between 250 and 350 tons. Depending on the specific seabed conditions, the foundations will be driven approximately 85 feet into the ocean floor. Once foundations are in place, support towers will be erected, followed by the turbines. When all the turbines are in installed, each one is connected to the local cable grid and is ready to produce energy.
While Cape Wind will rely heavily on technology used in European offshore sites, problems with infrastructure and construction are still be possible. When it comes to burying power cables under the ocean floor, Cape Wind will use a common and environmentally sensitive process called “hydro-plowing” which allows engineers to bury cables six feet under the ocean floor. This process uses high-powered jets to fluidize a pathway in the sea floor. The cables are then laid in the pathway and are buried as the sediment settles around them. This technique, already used commonly in the U.S. for burying utility wires and other infrastructure, is minimally invasive and quickly returns the ocean floor to its original form.
Weather: the big variable
“In general offshore wind is much more technically challenging than building onshore,” says Andy Lubershane, a senior analyst with IHS Emerging Energy Research. “But companies like Siemens have experience in building offshore wind in Europe so it certainly has been done, but it is much more challenging.”
Rodgers believes that weather, and the financial pitfalls caused by weather-related delays, will be the biggest challenge that Cape Wind faces during the construction phase.
“We selected a site that minimises weather risks during construction because Nantucket Sound has a much calmer seascape in terms of wave height, as opposed to being five or six miles offshore in the North Atlantic,” says Rodgers. “But weather is still a big variable. Installation vessels are very expensive especially when you’re paying for them on days when you can’t work because it’s too stormy, but that’s something we don’t have control over. But we have minimized the exposure.”
Feeding demand
According to a recent article in the State House News Service, Independent System Operator New England Vice President of System Planning, Stephen Rourke, said that offshore wind projects off the coasts of Rhode Island and Massachusetts are well placed to provide power to areas that demand more electricity. He also compared the value to the electric grid of Cape Wind connecting into Cape Cod with power projects located in northern New England.
"It's interconnection to the network comes on shore right in the middle of Cape Cod," said Rourke, speaking specifically about Cape Wind. "There's a lot of load there on Cape Cod, especially during the summer. So you can think of power being consumed in the local neighborhood where they interconnect, as opposed to some of the challenges we've been seeing in far northern Maine, northern Vermont, northern New Hampshire, where very few people live there. There's basically no demand or very little demand for the power; the transmission system up there really [is] not built to move large blocks of power."
An ISO New England presentation predicted that if 8,300 megawatts of power production capacity retire by 2020, the region will need more than 6,000 megawatts of "new energy-efficiency resources" with 500 megawatts in southeastern Massachusetts, 400 megawatts in Connecticut and 5,100 megawatts integrated into a "hub" in the western and central Massachusetts area.