The Department of the Interior (DOI) today gave its approval to the first U.S. offshore wind farm, a long-disputed and much-delayed project on federal submerged lands in Nantucket Sound. The approval comes with conditions, however, including requiring the developer of the $1 billion wind farm to agree to additional binding measures to minimize the potential adverse impact of construction and operation of the facility.
“After careful consideration of all the concerns expressed during the lengthy review and consultation process and thorough analyses of the many factors involved, I find that the public benefits weigh in favor of approving the Cape Wind project at the Horseshoe Shoal location,” Secretary of the Interior Ken Salazar said today at the State House in Boston.
The first wind farm on the U.S. Outer Continental Shelf, Cape Wind has been thought capable of generating enough power to meet 75% of the electricity demand for Cape Cod, Martha’s Vineyard, and Nantucket Island combined. The facility would occupy a 25-square-mile section of Nantucket Sound and generate a maximum electric output of 468 MW with an average anticipated output of 182 MW. The project includes a 66.5-mile buried submarine transmission cable system, an electric service platform and two 115-kV lines connecting to the mainland power grid.
Salazar said that the department has taken extraordinary steps to fully evaluate Cape Wind’s potential impacts on traditional cultural resources and historic properties, including government-to-government consultations with the Wampanoag Tribe of Gay Head (Aquinnah) and the Mashpee Wampanoag Tribe, and that he was “mindful of our unique relationship with the Tribes and carefully considered their views and concerns.”
Because of concerns expressed during the consultations, DOI said it has required the developer to change the design and configuration of the wind turbine farm to diminish the visual effects of the project and to conduct additional seabed surveys to ensure that any submerged archaeological resources are protected prior to bottom-disturbing activities.
Under these revisions, the number of turbines has been reduced from 170 to 130, eliminating turbines to reduce the visual impacts from the Kennedy Compound National Historic Landmark; reconfiguring the array to move it farther away from Nantucket Island; and reducing its breadth to mitigate visibility from the Nantucket Historic District. Regarding possible seabed cultural and historic resources, a “Chance Finds Clause” in the lease requires the developer to halt operations and notify Interior of any unanticipated archaeological find.
Salazar said he understood and respected the views of the Tribes and the Advisory Council on Historic Preservation, but noted that as Secretary of the Interior, he must balance broad, national public interest priorities in his decisions. “The need to preserve the environmental resources and rich cultural heritage of Nantucket Sound must be weighed in the balance with the importance of developing new renewable energy sources and strengthening our Nation’s energy security while battling climate change and creating jobs,” Salazar said.
“After almost a decade of exhaustive study and analyses, I believe that this undertaking can be developed responsibly and with consideration to the historic and cultural resources in the project area,” Salazar said. “Impacts to the historic properties can and will be minimized and mitigated and we will ensure that cultural resources will not be harmed or destroyed during the construction, maintenance, and decommissioning of the project.”
He pointed out that Nantucket Sound and its environs are a working landscape with many historical and modern uses and changing technologies. These include significant commercial, recreational and other resource-intensive activities, such as fishing, aviation, marine transport and boating, which have daily visual and physical impacts, and have long coexisted with the cultural and historic attributes of the area and its people.
A number of tall structures, including broadcast towers, cellular base station towers, local public safety communications towers, and towers for industrial and business uses are located around the area. Three submarine transmission cable systems already traverse the seabed to connect mainland energy sources to Martha’s Vineyard and Nantucket Island. Visual and physical impacts associated with Nantucket Sound and its associated shorelines abound; it is not an untouched landscape.
Salazar disagreed with the Advisory Council’s conclusion that visual impacts from the proposed wind farm, which will be situated between and at substantial distance from Cape Cod, Nantucket Island, and Martha’s Vineyard, provide a rationale for rejecting the siting of the project. The viewshed effects are not direct or destructive to onshore traditional cultural properties. In no case does the turbine array dominate the viewshed. The project site is about 5.2 miles from the mainland shoreline, 13.8 miles from Nantucket Island and 9 miles from Martha’s Vineyard.
Nevertheless, Interior has required the developer to reduce the number of turbines and reconfigure the array to diminish its visual effects. Moreover, the developer will be required to paint the turbines off-white to reduce contrast with the sea and sky yet remain visible to birds.
No daytime Federal Aviation Administration lighting will be on the turbines, unless the U.S. Coast Guard requires some “day beacons” to ensure navigation safety. FAA nighttime lighting requirements have been reduced, lessening potential nighttime visual impacts. The upland cable transmission route was located entirely below ground within paved roads and existing utility rights of way to avoid visual impacts and potential impacts to unidentified archeological or historic resources.
These mitigation measures, coupled with the overall distance from which the turbine array will be viewed at any location, will reduce the visual impacts of the project. Lease terms also require the developer to decommission the facility when the project has completed its useful service life, deconstructing the turbines and towers and removing them from the site.
The secretary also disagreed that it is not possible to mitigate the impacts associated with installation of piers for wind turbines in the seabed, noting that piers for bridges, transmission lines and other purposes are routinely built in relatively shallow waters consistent with those found in Horseshoe Shoals. A number of marine archaeological studies have indicated that there is low probability that the project area contains submerged archaeological resources. Most of the area has been extensively reworked and disturbed by marine activities and geological processes.
Nonetheless, DOI will require additional and detailed marine archaeological surveys and other protective measures in the project area. A full suite of remote sensing tools will be used to ensure seafloor coverage out to 1000 feet beyond the Area of Potential Effect. More predictive modeling and settlement pattern analyses also will be conducted as well as geotechnical coring and analyses to aid in the identification of intact landforms that could contain archaeological materials. Moreover, the Chance Finds Clause in the lease will not only halt operations if cultural resources or indicators suggesting the possibility of cultural habitation are found but also allow the tribes to participate in reviewing and analyzing such potential finds.
The advisory council’s regulations provide that DOI must take into account the council’s comments on particular projects. DOI, as the decision-making authority, is required to consider the council’s comments but is not legally bound to follow its recommendations or conclusions.