The Coast Guard’s Navigation Safety Mission

Striking a balance between mariner routes and alternative offshore energy plans

By J.R. Wilson - September 15, 2012

Whales and ships share the waters of Boston’s shipping lanes. Agencies such as the Fish and Wildlife Service and the National Marine Fisheries Service are advising the Bureau of Ocean Energy Management to ensure living marine resources and their migration routes and habitats are a part of the discussion on the impact of wind farms. Marine life, cargo tankers, U.S. naval ships, and commercial vessels will increasingly share the same marine routes. Unlike any port access route study before it, the Atlantic Coast Port Access Route Study will include an assessment of the coast-wise shipping routes and near-coastal users of the western Atlantic Ocean between the coastal ports and the approaches to coastal ports within the exclusive economic zone. Photo courtesy of WCNE and SBNMS

The U.S. Coast Guard’s responsibilities for navigation safety, easy access to the nation’s ports and harbors, and protection of the marine environment all come together as part of a standard Port Access Route Study (PARS).

A PARS is a normal part of the service’s effort to ensure maritime navigation ease and safety, usually looking at one specific port, and is required whenever it might be necessary to establish a new routing measure or change an old one. Once a routing measure is established, by law, navigation and maritime traffic have precedence over everything else in that particular area of the water.

“So a PARS is the Coast Guard doing due diligence to ensure the routing is balanced against all other needs for the water,” said Dana Goward, director of the Coast Guard’s Marine Transportation Systems Directorate.

The current ongoing Atlantic Coast PARS (ACPARS), however, has been expanded to focus on the impact of an ancient technology with a new twist – windmills morphing into maritime wind farm turbines.

The Atlantic Coast Port Access Route Study is necessary to determine if new routing measures or changes to existing routing measures are necessary to balance the multiple uses of the waterway such as proposed wind farms, offshore energy platforms, or other structures, while ensuring the safety of navigation. Photo courtesy of Andy S-D

“A traditional windmill is to one of these wind farm turbines as the Wright Flyer would be to a 747,” according to Goward. “They produce DC power, so they are similar in a remote way, but way distant in terms of capability.”

While the United States has no offshore wind farms, several already are in place in Europe.

“We have a manual [from Europe] on how to do navigation safety risk assessments, which is an expanded version of what we already had developed,” he said. “So we’re taking a lot of lessons learned from rules they have developed for buffer distances and appropriate risk levels. It’s disappointing that in the U.S., we have a wealth of AIS [Automatic Identification System] data to do these assessments, but we have yet to develop the tools to effectively use that data.”

Although the European experience is a significant help, the Coast Guard also must consider the differences, from rerouting traffic to increased vessel traffic density, and proximity to shipping lanes, just to name a few.

“In Europe, how close together the [generator towers] are placed depends on the size of the turbine and their output – 3.5 to 10 MW – because the bigger they are, the bigger the blades, which means they could affect each other,” George Detweiler, acting Navigation Standards Division chief, explained. “It also depends on how much sea bottom the developers lease for their wind turbine generators. BOEM [Bureau of Ocean Energy Management, Department of the Interior] is the caretaker of the OCS [outer continental shelf] and leases the sea bottom for a variety of purposes, including wind farms.”

The Coast Guard’s study of the impact of wind farms ranges from the Canadian maritime border to Florida and east to the end of the OCS, which begins about 3 miles offshore and extends to the end of the U.S. exclusive economic zone (EEZ) – about 200 miles.

Areas under consideration for wind energy. DHS image

BOEM currently is looking at wind energy areas offshore out to about 30 miles, some of which are based on the potential length of transmission lines, where the technology currently stands, and how they are placed – bored into the sea bottom. But technology is moving very rapidly, so there could be wind farms even farther offshore in the future. The Coast Guard concern is the potential impact of wind farms on vessels transiting to, from, and in between U.S. ports. So it is working with BOEM, as one of many cooperating agencies, to ensure the maritime industry has port access with navigation and safety maintained.

“We are studying current vessel routing, volume, density, and, eventually, a hypothetical farm and what to do with traffic that currently moves through where the wind farm would be, what are the impacts involved and safety issues,” Detweiler added. “For example, is it worth routing those ships around the wind farm? We hope to have a risk analysis tool and model to accomplish that, but we’re not there yet. We’ve been able to do some initial work, looking at AIS in relation to potential wind energy areas. But we can’t go much beyond that at this point.”

The Coast Guard quickly saw that the areas being studied by BOEM would impact navigation along the entire Atlantic Coast – not only in the areas actually occupied by wind farms, but also resulting in increased or significantly altered maritime traffic and routes in adjacent waters. Cumulative impacts were important to look at so rather than pursue multiple little PARS, the decision was made to conduct a single study of the entire Eastern Seaboard.