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www.sname.org/sname/mt October 2012 of soil conditions, and the platform can be placed in almost any water depth above 40 m, which provides signi cant exibility in nding suitable sites. Similar roots In the oil and gas industry, the move to deeper water occurred because of better resources (oil reserves). e wind industry is following a similar trend. e biggest dif- ference is that in the wind industry, 50 m is considered deep water. It is interesting to see that similar types of oaters have made their way to oating wind concepts. We see spars, such as the Hywind, designed by Technip for StatoilHydro; tension leg platforms such as Blue H; the Glosten Associates concept; and many types of semi-submersibles, most of them having three circular columns. Unlike the oil and gas industry, where significant efforts are placed on dry tree applications and focus on very low-heave motions, oating turbines must emphasize the minimization of the pitch rotation for the turbine to operate properly. e design of the oater must take this into consideration. A comparison of revenue with the oil and gas industry shows that a platform producing 40,000 barrels of oil per day makes, on aver- age, $4 million per day at $100 per barrel; while a wind farm of 300 MW (composed of 50 6-MW turbines) at 15c/kwh, with a capac- ity factor of 30%, will make $325,000 per day, less than a factor of 10. It is therefore of the utmost importance for the offshore wind industry to leverage any and all cost savings opportunities that present themselves. Figure 1 represents the decision point to move from one technology to the next, which depends, among other factors, on water depth. Seabed and metocean condi- tions are also important factors. Beginning with monopiles, as the water depth gets deeper, so too does the depth, diameter, and thickness of the monopile. At a certain point, the installation vessels become too large, the steel plate thicknesses too thick, and the rollers too expensive, which requires very specialized machinery. is is when the jacket becomes cost competitive against the monopiles. Similarly, the same issues arise for the jackets at deeper depths and the oater solution emerges as the most eco- nomical. We note that for a oater, there is no drastic in ection point in cost, as the moor- ing hardware is the only thing that changes Figure 1: O shore wind turbine support concepts. GOOD OFFSHORE WIND SITES ?THOSE WITH PROXIMITY TO THE GRID, NO SIGNIFICANT RESTRICTIONS, AND SHALLOW WATER?ARE BECOMING DIFFICULT TO FIND. DEMONSTRATING FLOATING WIND POWER