How many offshore windmills are currently generating power on the U.S. East Coast? If you said "One," you're right.

Yale Environment 360 takes a look at wind power in this survey report: ("Will Offshore Wind Finally Take Off on U.S. East Coast?" by Dave Levitan). "In June, after years of offshore wind power projects being thwarted in the United States, the first offshore wind turbine began spinning off the U.S. coast," the online journal reports. "The turbine was not a multi-megawatt, 400-foot behemoth off of Massachusetts, Rhode Island, New Jersey, or Texas—all places where projects had long been proposed. Rather, the turbine was installed in Castine Harbor, Maine, rising only 60 feet in the air and featuring a 20-kilowatt capacity—enough to power only a few homes."

Several projects have made strides in the permitting process, the story reports, including the "Cape Wind" project off Nantucket and Cape Cod, and the "Block Island Wind Farm," about 15 miles off the coast of Rhode Island. But the wind-farm industry is hampered by one inconvenient fact: The power is going to cost more than conventionally produced juice.

Reports Yale Environment 360: "Because of the difficulty of building wind turbines offshore and connecting them to the power grid, the price of electricity generated offshore along the U.S. East Coast is expected to be more than 15 cents per kilowatt hour, or several times the cost of producing electricity with coal or natural gas, according to a 2012 report by the U.S. National Energy Technology Laboratory. Those costs are expected to fall as more offshore wind farms are built and connected by an offshore grid. Another U.S. report says that a reasonable goal for offshore wind prices would be 10 cents per kilowatt hour by 2020 and 7 cents per kilowatt hour by 2030."

That problem leaves wind-power advocates crying for federal subsidies — a hard sell in these tough budgetary times. But advocates say that government support could help the industry develop economies of scale that could make their power cost-competitive. And they say it's worth investing to tap into what could be a huge source of non-polluting energy. Says wind-power expert Matt Heulsenbeck: "The East Coast is the Saudi Arabia of offshore wind, because there is enough energy there to provide the entire U.S. with electricity if it was fully developed."