What is the Environmental Impact of Offshore Wind on Block Island Sound?

By FRANK CARINI/ecoRI News staff

KINGSTON — Sticking massive turbines through the water column and into the seafloor will undoubtedly impact the environment. Deepwater Wind will soon be pile-driving five wind turbines and laying cable in Block Island Sound. There will be an impact on habitat and marine life, but it’s a matter of what areas to avoid and minimizing that impact as much as possible, Jonathan Stone said during last week’s Rhode Island Foundation-sponsored community forum entitled “The Future of Offshore Wind Energy in Rhode Island.” “There are areas of special environmental value above the water, in the water column and on the seafloor,” the executive director of Save The Bay said. “It’s a major challenge. All sources of energy have an environmental impact. You have to determine the true cost of these sources."

The Block Island Wind Farm is a 30-megawatt, demonstration-scale offshore wind farm to be sited 3 miles southeast of Block Island. The wind farm will be located entirely in Rhode Island state waters, will generate more 100,000 megawatt-hours annually and will supply most of Block Island’s electricity needs, according to Deepwater Wind. Excess power will be exported to the mainland via the bi-directional Block Island transmission system. The cable will be buried about 6 feet beneath the seafloor and will connect the island to the mainland. Deepwater Wind plans to begin site preparation in late 2012 and start commercial operations in 2013. This small-scale project could lead to the development of a 200-turbine project in state and federal waters that would provide power to Rhode Island, Long Island and other areas in the Northeast.

The sitting of turbines for the Block Island project and for any other future offshore wind-energy development will be in environmentally sensitive ocean waters. It’s an issue that has been addressed thoroughly in the state’s Ocean Special Area Management Plan (SAMP), according to the speakers at last week’s forum.

 “We know where the environmentally sensitive areas are,” said Jeffrey Grybowski, senior vice president for strategy and external affairs for Deepwater Wind. “Environmental concerns are part of the discussion, but there are trade-offs. The construction of the Block Island Wind Farm will for the most part shut down one of the dirtiest forms of energy we have — diesel.” Diesel-powered generators supply Block Island with most of its energy. However, trading in fossil-fuel sources for cleaner wind energy isn’t without its environmental concerns. The challenging part will be to avoid leaving a major scar, as building and maintaining an offshore wind farm will impact marine life and its habitat.

The Ocean SAMP area is an ecologically unique region that contains an interesting biodiversity that is a mix of northern, cold-water species and southern, warm-water species. Any offshore renewable energy development could result in temporary or permanent habitat displacement or modification during the construction, operation or decommissioning of a facility, according to the document.

Water quality around an offshore renewable energy facility may potentially be impacted if illegal dumping or accidental spills occurs from vessels or equipment. Birds may potentially be displaced from offshore feeding, nesting, migratory staging or resting areas.

Juvenile fish and eggs in the Ocean SAMP area are rich and varied, and show strong seasonality for many species, which is most often linked to reproduction. The adult fish community in Ocean SAMP waters is dynamic and diverse, but has undergone a major change during the past several decades. Bottom-dwelling fish such as winter flounder were once dominant. Since the mid-1970s, however, there has been a shift towards pelagic fish species dominance, with a corresponding increase in bottom-dwelling invertebrates such as crabs and lobster. The dominant fish species are now bluefish, butterfish and sea robins. Marine mammals — whales, dolphins, porpoises and seals — appear in the Ocean SAMP area, but sparsely and generally on a seasonal basis. But the impact of offshore wind farms on marine mammals and fish are relatively new, and in most cases still under development, according to the Ocean SAMP.

Among the high-priority concerns regarding the construction and operation of a wind farm — whether it’s the five-turbine one off Block Island or a potential commercial-scale operation — is the impact on North Atlantic right whales. The right whale is the most endangered great whale, with fewer than 300 in the North Atlantic, according to the Woods Hole Oceanographic Institution. Despite federal protection, these whales have had no recovery during the past 60 years.

Rhode Island’s Ocean SAMP area overlaps with right whale migratory routes. In April 2010, nearly 100 right whales were spotted feeding in Rhode Island Sound. Right whales winter in the waters off Florida and migrate as far north as Nantucket Sound in the spring and summer. “Right whales are a critical species in this area and their migratory patterns are a concern to us,” Grybowski said.

He said Deepwater Wind will monitor work areas during the construction of the Block Island Wind Farm and if any right whales or other marine mammals are spotted, work will be stopped and all sonar turned off. Marine mammals have highly developed acoustic sensory systems, which enable individuals to communicate, navigate, orient, avoid predators and forage in an environment where sound propagates far more efficiently than light, according to the Ocean SAMP.

Underwater noise will likely be generated during all stages of an offshore renewable energy facility, including during pre-construction, construction and operation. The strength and duration of the noise will vary depending on the activity, from pile-driving, which will result in short periods of intense noise, to the long-term, low-level noise associated with operational activities. To help mitigate potential impacts on marine mammals, especially to large whales such as right, humpback and fin, pile-driving will be done above the water column, Grybowski said.

Stone commended the Ocean SAMP research, but also noted that it doesn’t take the place of a formal wind farm environmental impact statement, which will need to be completed before any offshore large-scale commercial wind farm is built. He also said the environmental costs of installing wind farms must be compared with the true costs of continuing to use fossil fuels.

“We understand that renewable energy is critical to our future, and we think there are ways to minimize the environmental impacts,” Stone said.

Source: http://www.ecori.org/renewable-energy/2011/9/12/what-is-the-environmental-impact-of-offshore-wind.html