Here is a link to the executive sumary of the US Dept. of Energy’s National Renewable Energy Laboratory’s September 2010 report titled “Large-Scale Offshore Wind Power in the US.” There is a link to the full report at the end of the summary.
Here is one of the quotes cited in the report, taken from an earlier DoE report:
Under conservative assumptions about transmission, fossil fuel supply, and supply chain availability, the United States could feasibly build 54 GW of offshore wind power by 2030.
— 20% Wind Energy by 2030, U.S. Department of Energy,
Put this report together with the offshore backbone, and what do you get? No PATH.