The road from potential to actual is often long, winding and windy. Add controversial, and you have the path taken by offshore wind to becoming a viable source of electricity for America’s energy markets.

While still in its relative infancy as a significant contributor to the renewable-power revolution, offshore wind has faced, and continues to face, no small amount of politics, feasibility and bureaucracy.

A recent study by the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) should bolster the efforts of proponents. The study, “Assessment of Offshore Wind Energy Resources for the United States,” summarizes the offshore wind-resource potential for the contiguous United States and Hawaii. More specifically, it measured the national combined total capacity for electrical-power generation from offshore wind in all the states with coastal boundaries for the 2009 calendar year.

Using geographic information system techniques, the study compiled a database of various wind-resource characteristics, such as average wind speeds, water depths and distance from shore, to assess the total generating capacity of the resource, which was then plotted on maps. Wind-power generating capacity was categorized according to annual average wind speeds at 90 meters above the surface and up to 50 nautical miles offshore.

One of the most compelling findings of the study is the total capacity of potential U.S. wind-turbine generation, calculated at 4,150 gigawatts. That is more than four times the national total of generating capacity from all energy sources, measured at approximately 1,010 gigawatts in 2008 by the U.S. Energy Information Administration.

Hawaii and California were leaders in the NREL study, with 127,477 gigawatts and 117,555 gigawatts of generating capacity, respectively. The next highest state was Michigan with 96,642 gigawatts of capacity.

Of course, the study does not measure technical feasibility, political opposition or other intangibles that could slow the path to more development. But there is no denying the raw capacity of the resource. As the study asserts, “Offshore wind energy development promises to be a significant domestic renewable-energy source.”