The proposed Cape Wind rates, now under review by state regulators, are in stark contrast to the lower prices for land-based wind power now available from turbines in Maine, New York and Canada.

At a recent state regulatory hearing, TransCanada Energy, which owns 44 wind turbines in Maine, said it could sell its wind electricity to National Grid for less than 11 cents per kilowatt hour, or 41 percent lower than the 18.7 cents per kilowatt hour that the offshore Cape Wind will cost in its first year in 2013.