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 Renewable energy is energy which comes from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable.  Climate change concerns, high oil prices, and increasing government support, accelerates the growth of this sector.  In 2008, about 19% of global final energy consumption came from renewable sources.  With nations pledging to reduce the carbon emission to counter global warming, the need for systems that generate renewable energy has been on a rise. 2

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 Wind power is the conversion of wind energy into a useful form of energy, such as  wind turbines to make electricity,  wind mills for mechanical power,  wind pumps for pumping water or drainage,  sails to propel ships 5

 Wind energy has been the world’s fastest growing source of electricity during the past decade, with over 20% annual growth  Energy production from wind was 340 TWh, which is about 2% of worldwide electricity usage. 6

 A wind turbine is a rotary device that extracts energy from the wind.  If the mechanical energy is used directly by machinery the machine is called a windmill.  If the mechanical energy is instead converted to electricity, the machine is called a wind generator.  A wind farm is a group of wind turbines in the same location used for production of electric power.  Wind farms and wind turbines are built onshore as well as offshore. 7

 A floating wind turbine is an offshore wind turbine mounted on a floating structure.  As of December 2009, there have been two operational floating wind turbines  BLUE -H 80 kW 21 km off the coast in waters 113 meters deep, southeast of Italy.  HYWIND 2.3 mW 10 km off the coast of Karmoy, Norway in 220-m deep waters. 8

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 Power Output from a wind turbine is proportional to the cube of wind velocity and to the square of the rotor diameter.  The wind can be stronger up to 10 m/sec and steadier over water due to the absence of topographic features.  Existing fixed-bottom wind turbine technology deployments had been limited to water depths of 30-meters.  Worldwide wind resources are abundant over deep-waters.  Wind should be steady and consistent for the smooth working of turbines.  Noise and visual pollution created by fixed turbines near the costal areas are to be avoided. 11

12 Worldwide wind resources are abundant over deep- waters. Wind should be steady and consistent for the smooth working of turbines. Noise and visual pollution created by fixed turbines near the costal areas are to be avoided. Advantages:

Simplified wind turbine model. Maximum Power Constant Power Relative wind velocity [m/s] Power [MW] 13

14 Wind velocity increases from lighter to darker shade. From 1m/s to 10 m/s

 Floating platforms can be classified into.  single-turbine-floater (one wind turbine mounted on a floating structures).  multiple turbine floater (multiple wind turbines mounted on a floating structures)  The electricity generated is sent to shore through undersea HVDC cables.  There are mainly three types of systems used for station keeping for the turbine. Barge System,Spar Buoy System,Tension Leg System 15

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 Barge Systems  Spar Buoy Systems  Tension Leg Systems 17

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 It is the process of fixing the floating structure to the seabed.  Absorb dynamic loads, transfer load to seabed TWO TYPES-  Catenary  Taut leg 21

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23 Hydrodynamic loads Aerodynamic loads Horizontal and Vertical loads Dynamic and static loads

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It has vertical axis turbines mounted in a fence. All the water that passes is forced through the turbines. 25

 Huge initial cost when compared to other renewable energy sources.  The economics of deepwater wind turbines will be determined by the costs of the floating structure and power distribution system when compared to a fixed turbine.  Enough buoyancy to support the weight of the turbine and to restrain pitch, roll and heave motions.  Only at few sites with high wind speeds can compete economically with conventional power production,at present. 26

 Offshore construction is more complicated and it should survive severe marine environments.  Maintainace is high when compared to on-shore turbines.  Complexity of the system. 27

 Blue H has successfully decommissioned the unit as they are planning to build a 38-unit deepwater wind farm at the same location.  The US State of Maine will be soliciting proposals in September 2010 to build the world's first floating, commercial wind farm.  Portugal govt is partnered with Principle Power to install a multi-megawatt full-scale floating wind turbine off the coast of Portugal in  The enormous wind energy resource offshore, covering more than 70% of the Earth’s surface, can be effectively tapped resulting in a cleaner and smarter energy … 28

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30 References:

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