Renewable energy made big national headlines October 12 as a group of investors, including search engine giant Google, announced plans to build a 560-kilometer offshore wind power transmission "backbone" off the U.S. eastern seaboard. The developers of the plan say it will make wind power more economical and enhance the reliability of the existing grid.

The proposed high-voltage direct current (HVDC) cable, dubbed the Atlantic Wind Connection (AWC), would run from southern Virginia to northern New Jersey, occupying shallow trenches on the seabed of federal waters some 15-20 miles off the shore. The line would connect with the mainland at four points—southern Virginia, Delaware, and southern and northern New Jersey. And if all goes according to plan, it would have a whopping 6,000-megawatt (MW) capacity—roughly equal to that of five large nuclear reactors and capable of powering some 1.9 million homes.


Trans-Elect, the Maryland-based transmission line company heading up the plan, expects the project to cost $5 billion in total, not including financing and permit fees. It hopes to begin construction in 2013, and estimates the first phase—a $1.8 billion, 240-kilometer stretch—could be completed by 2016. The entire project will not be complete until 2021 at the earliest. Google's initial stake is 37.5 percent of the equity portion of the project.

Certain details of the plan were at least in part inspired by research led by Willett Kempton, a professor of marine science policy at the University of Delaware. In a paper published April 5 in Proceedings of the National Academy of Sciences, Kempton's group described offshore wind data collected over a five-year period along a 2,500-kilometer stretch of the U.S. eastern seaboard. The researchers used a mathematical model to show that, thanks to ocean wind patterns, a system of turbines placed strategically and wired together could be counted on to produce a steady supply of power—unlike land-based systems which can be hindered by intermittent winds. In an email, Kempton told Scientific American that the AWC developers contacted him several times for information related to the PNAS paper, and also asked him to speak with investors as they analyzed the plan.

Several undersea HVDC cables already exist off the Atlantic Coast for long-distance transport of electricity generated on land. But these lines simply carry electrons from one point to another, with no power-generating inputs in between. In the case of the AWC, generating stations along the line would add electricity to the system, a process that will require newer, more cutting-edge technology, says Kempton.

Practically, the biggest obstacles to the plan's implementation are more administrative than technological, several experts, including Kempton, told The New York Times. For one thing, it will face a complicated permitting process—the same one that took almost a decade for a proposed wind farm in near-shore waters off Cape Cod, Mass, which was finally approved by the Department of Interior in April.

Symbolically, though, the AWC plan is a big step. "This shows that there is confidence that the offshore wind industry is going to take off in the U.S. as it is already in Northern Europe," Kempton says.

See also the links at series "Beyond Fossil Fuels," part of a survey conducted by Scientific American of executives at companies engaged in developing and implementing non–fossil fuel energy technologies.

Image credit: Flickr/ PEBondestad