Offshore wind farms could also have the advantage of being close to big cities, unlike wind farms in remote areas, which require significant power grid upgrades to transport the power to places where it's needed. Making the technology cheap enough to be feasible will not be easy. "You've got to push all the buttons to get the costs down," Lyons says. Using a combination of far-offshore and land-based farms, however, one day it may be possible to provide 20 percent of U.S. energy from wind, he says.
the article was describing plans for 95m tall towers and 140m rotors. So 300+ ft tall for the 3.6MW version. the diagram of wind towers.
The 5MW plan has tower height of 120m. Or almost 400 feet. The tip of the rotor would reach 180m. A 10 MW version planned for 2015 will probably be 200m tall for the tower which is an over 650 feet tall tower.