America's First offshore wind project
The now-completed first offshore wind project in the U.S., the 30-MW Block Island Wind Farm, in waters off Rhode Island, represents a huge milestone, which heralds the start of a whole new source of renewable energy for the U.S.
By Vicky Boyd
At 30 megawatts, the Block Island Wind Farm is not the largest offshore wind-driven energy generation facility by any means, but it represents a huge milestone as the first of its type in the United States.
The five-turbine project, located three miles off the shore of Rhode Island's Block Island, is actually a demonstration-scale project designed to serve Block Island's energy needs while demonstrating that the technology is economically and logistically feasible in the U.S. Offshore wind farms also face U.S. regulatory and environmental scrutiny since they may not fit the same policy framework as onshore wind development.
"It's really difficult for a utility to say, 'We'd like to see you build a couple of hundred megawatts' if no one has even been successful building one megawatt offshore," said Jeff Grybowski, CEO of the project's developer, Deepwater Wind. "Utilities have seen the success of the Block Island project. That makes them comfortable with this new resource."
But the Block Island Wind Farm is just the tip of the iceberg for the firm. In 2008, Deepwater Wind, which is based in Providence, Rhode Island, was selected by Rhode Island as its preferred offshore wind developer for a project site dubbed Deepwater ONE that eventually could yield up to 1.3 million megawatt hours (MWh) annually.
Offshore wind farms are nothing new. In the European Union, where they account for 11 gigawatts (GW) of generation capacity, they have a 25-year track record, according to Brussels, Belgium-based Wind Europe.
The National Renewable Energy Laboratory estimates the United States has 4,200 GW of developable offshore wind potential compared to an estimated 11,000 GW of onshore wind potential.
The Block Island Wind Farm indirectly had its birth in 2005, when then-Gov. Donald Carcieri, with the support of the Rhode Island General Assembly, established the state Office of Energy Resources. The agency was responsible for engaging stakeholders and the scientific community, creating a framework for viable wind farm proposals, and choosing the best offshore wind project developer for the state.
A panel of experts assembled by Carcieri spent months reviewing detailed proposals submitted by seven developers, and in 2008, Deepwater Wind was selected as the state's preferred offshore wind developer.
This marked a major step toward bringing wind power to Rhode Island and reaching the goal of at least 15 percent of the state's electricity being renewable energy, Carcieri said in a statement, at the time. "Of the many forms of renewable energy alternatives available, wind is the proven leader. Wind power is clean, green power that is not subject to variations and increases in fuel price. Rhode Island is uniquely positioned to lead the nation with the development of this country's first offshore wind farm."
One year later, in 2009, the Rhode Island General Assembly passed historic long-term contracting legislation that set conditions for the 20-year power purchase agreement between National Grid and Deepwater Wind for the Block Island generation.
In 2013, the U.S. Department of the Interior set a precedent with its first-ever auction of two offshore wind energy sites. Deepwater Wind was the high bidder for both sites. The lease area covers about 256 square miles in the Atlantic Ocean about 30 miles east of Montauk, N.Y., and about 17 miles south of Rhode Island between Block Island and Martha's Vineyard, Massachusetts.
Each lease also carries terms and timeframes that the lessee must follow in developing wind projects. After a construction and operations plan is approved, the lessee will have an operations term of 25 years.
Construction of the first phase of the Deepwater ONE site, which is expected to produce enough energy to power about 120,000 homes, could begin as early as 2019, with commercial operations by 2022.
Because of its potential environmental impacts, the Block Island Wind Farm had to undergo lengthy review by 11 federal and state agencies, including the U.S. Army Corps of Engineers, U.S. Coast Guard, U.S. Fish and Wildlife Service, National Oceanic and Atmospheric Administration, and National Marine Fisheries Service.
Deepwater Wind also agreed to implement additional protections for endangered North Atlantic right whales and other marine animals. They include enhanced real-time human monitoring for whale activity in the site area, restricting pile driving activities to daylight hours when whales can be spotted, using noise-reducing tools and technologies, and using a lower speed limit for vessels during the spring, when right whales frequent Rhode Island Sound.
"We take our responsibility to be a national leader in responsible offshore wind development very seriously, and ensuring marine animals are protected is just one way we're fulfilling our commitment," Grybowski said.
In September 2014, the Army Corps, acting as the lead permitting agency, granted project approval.
Meanwhile, Deepwater Wind selected French turbine supplier Alstom (which has since been acquired by GE Power) to supply the five six-MW Haliade 150 offshore wind turbines, as well as the 15 tower sections. As part of the agreement, GE will provide long-term service and maintenance for the turbines.
|Unlike land-based turbines, where components are assembled near the foundation and lifted in place with cranes, offshore components are assembled onshore. Then the pieces are ferried out to the offshore location for final installation.|
Under the contract, Deepwater Wind made an initial multi-million-dollar payment to Alstom in December 2013 that allowed Alstom to have its subcontractor, LM Wind Power, begin manufacturing the turbine blades in Denmark.
Unlike land-based turbines, where components are assembled near the foundation and lifted in place with cranes, offshore components are assembled onshore. Then the pieces are ferried out to the offshore location for final installation.
In response, Deepwater Wind and GE established a temporary manufacturing site at the Port of Providence in late 2015 to assemble the turbine components. The operation initially received five 95-foot tower sections, which were offloaded from ships.
During the next six months, GE—aided by 60 local workers—installed electrical, mechanical, and safety equipment in these five bottom tower sections. The remaining tower sections arrived in Rhode Island in spring 2016.
The assembly activities at the Port of Providence complemented construction and staging work at Quonset Point in North Kingstown, Rhode Island. Quonset will also host the project's long-term operations and maintenance facility.
In late 2014, Deepwater Wind selected Gulf Island Fabrication Inc. of Houma, Louisiana, to construct the five steel jacket foundations, which were designed by Mandeville, Louisiana-based Keystone Engineering's Offshore Renewables Division.
The two Louisiana firms were a natural fit for the project because the foundations are similar to those used by the Gulf of Mexico oil industry. Designing the wind farm's foundations required some adjustments, however, such as taking into account the added strain from the steady, repetitive vibration of the spinning turbine.
Fabrication began in early 2015 at Houma, with the structures ready for delivery to the wind farm site in the summer of 2015. It took almost two months to build each jacket; the finished jackets were shipped to Rhode Island by barge.
As part of the agreement, Gulf Island Fabrication subcontracted work to Specialty Diving based at Quonset Point. Trained welders and other local workers fabricated some of the foundation components there.
|The five steel jacket foundations used for the Block Island Wind Project are similar to those used by the Gulf of Mexico oil industry. Designing the wind farm's foundations required some adjustments, however, such as taking into account the added strain from the steady, repetitive vibration of the spinning turbines.|
"We remain committed to hiring as many local workers as possible to support this endeavor, and our fabrication agreement is just the start of our commitment to kick-starting a homegrown economic engine centered here in the Ocean State," Grybowski said.
Before the submarine cables that would transmit power from the turbines to the shore could be laid, the ocean floor had to be cleared of debris, such as old fishing gear.
With a clean floor, the Big Max cable laying vessel, under contract with South Korean LS Cable & Systems Ltd. and its subcontractor, Durocher Marine, installed the cables. Included in the work were four inter-array cables connecting the five wind turbine foundations and the export cable connecting the wind farm to a new substation on Block Island.
Developed by LS Cable, the specially designed 34.5kV submarine transmission cable interconnected to the Block Island offshore wind farm and transports power from Block Island to Narragansett.
In June 2016, stevedores offloaded the 15 blades at the Providence port facility, where they were assembled with the tower sections for boat transport to the wind farm site in August. Using more than a dozen construction and transport barges, tugboats and other vessels, Deepwater Wind began installing the foundations in July 2016. A joint venture between Weeks Marine and Manson Construction served as the offshore foundation installation contractor.
At Block Island Wind Farm, the jackets were attached to the seabed with piles. Each structure is up to 108 feet tall and weighs nearly 380 tons. The platforms add another 50 feet and 340 tons. Once assembled, the turbine's hub is almost 330 feet above the platform, and its blades stretch up to 270 feet long.
Unlike onshore turbine construction, where tall cranes are used to help lift the components in place, Deep-water Wind had to go a different route. It selected Fred. Olsen Windcarrier to provide their jack-up vessel, Bold Tern, for the turbine installation. As the name implies, a jack-up vessel can rise up from the sea floor on leg-like structures. Construction crews installed the last deck platform in late November. Altogether, about 200 workers were involved in the project.
"From the first steel in the water in July to the last deck left in November, we've completed a season of firsts—not only for the Block Island Wind Farm but also for the launch of a new American offshore wind industry," Grybowski said. "We're proud of the work we've accomplished so far, but we've only just begun—and 2016 will be a year to remember."
The project was commissioned in late 2016.
Duke Energy's Renewable Control Center will supply 24-7 monitoring and control services, data acquisition, performance analysis, and reporting. It will also perform energy market and dispatch services for the wind farm, serving as a point of contact with ISO New England, the regional transmission organization.
Shortly after the project's completion, GE Energy Financial Services and global banking company Citi closed tax equity financing on Deepwater Wind's Block Island Wind Farm. The role of the D.E. Shaw group, principal owner of Deepwater Wind, remains unchanged with the addition of the two tax equity investors.