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By Henrik Stiesdal, Chief Technology Offi cer, Siemens Wind Power
Hywind: The world’s fi rst fl oating MW-scale wind turbine
O
ne of the future possibilities for offshore wind development is fl oating turbines, which would make deeper waters potential wind farm sites. Norwegian energy company StatoilHydro has placed a fl oating wind turbine off the west coast of Norway. The project consists of a 2.3 MW Siemens turbine fi xed to a fl oating slender cylin-der which is also ud by the oil and gas industry. Traditionally, offshore wind farms are installed in relatively shallow waters. Nominally, Europe has very large areas of abed with a suitable water depth and a fl oor. However, shipping lanes, fi sh-ing banks, bird migration zones, defence testing grounds and recreational interests all tend to limit the area potentially available for offshore wind farms. Taking the limitations into account, a number of European countries including Norway, Portugal and Spain simply do not have suffi cient shallow water areas for large-scale offshore
wind farms using traditional turbine foundations.
魔方高级公式Furthermore, in the United States, China, and
Japan, most of the offshore wind resource poten-tial is available in water deeper than 30m. All of the existing European offshore wind turbines are fi xed-bottom substructures, mostly installed in water s
hallower than 20m by driv-ing monopiles into the abed or by relying on conventional concrete gravity bas. The
technologies are not economically or technically feasible in deeper water. Many alternative solu-tions have been suggested, including tripods and jacket platforms, amongst others. Some have been tested, but the general perception is that the foundation costs become prohibitive at water depths of 50m or more.
A solution to this is to replace the traditional, fi xed foundation with a fl oating platform, teth-ered with mooring lines to the abed. Since the 1970s, various concepts for fl oating wind turbines have been investigated. The Spar-buoy concept us ballast to lower the centre of gravity below the centre of buoyancy to make the structure
stable. It can be moored by catenary or taut lines. A Tension Leg Platform us mooring line tension and excess buoyancy in the tank to make the structure stable. The barge concept is stabilid through its water plane area and is generally
moored by catenary lines. Hybrid concepts, which u features from all three class, have also been considered.
In 2007 StatoilHydro approached Siemens with a proposal to jointly develop the concept for StatoilHydro’s Hywind fl oating wind turbine into a full-scale, proof-of-concept turbine.
For veral years StatoilHydro investigated fl oating wind turbines in order to develop offshore wind power, drawing on its offshore experti gained from the oil and gas industry. At an early stage, a slender cylinder concept was lected, mainly due to its simplicity. This solution is simi-lar to production platforms and offshore loading buoys. A 3m scale model was successfully tested in SINTEF Marintek’s wave simulator in Trondheim, Norway, to qualify the basic technology.
水草怎么养
StatoilHydro and Siemens entered a technol-ogy development agreement, and over the next two years the project was taken from a concept stage to a full-blown proof-of-concept installa-
tion using a modern MW-class wind turbine, the
The Hywind turbine being towed out to a.
家雀Photo: Statoil Hydro
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诺福克海军基地Siemens SWT-2.3-82. This turbine type has a long track record offshore, being ud in the
Samsoe (2002) and Nysted (2003) projects. The larger variant of this type - with a rotor diameter of 93 m – is employed at the Lillgrund (2007) and Horns Rev 2 (2009) projects.
The attractive simplicity of the slender cylinder concept comes at a price. Even though it is teth-ered, and sits on a large fl oating foundation, the wind caus the tower to sway. Such swaying adds to the structure’s fatigue load. Finding solutions to the slender cylinder concept’s disadvantage has been one of the core elements of the Hywind tech-nology development. An advanced adaptive regula-tion has been developed, using the pitch system of the rotor blades to stabili the movements. This improves both power production and mini-mis the loads on the blades and the tower. The software controlling this process is able to meas-ure the success of previous changes to the rotor angle and u that information to fi ne-tune future attempts to dampen wave-induced movement. The proof-of-concept turbine was asmbled in Åmøyfjorden near Stavanger during the summer of 2009. It was then towed to its fi nal location, 12km out to a off Karmøy on the western
coast of Norway. The wind turbine itlf was sup-plied and installed on a fl oater built by Tecnip of Finland. The cylinder is a 117m long steel cylin-der, weighing 3,000 tonnes in ballasted condition. The anchoring system enables Hywind technology to be ud at depths from about 120m to 700m or maybe even more.
海底世界游戏The proof-of-concept turbine was formally inau-gurated on 8 September 2009, and at the time of writing it is passing the commissioning tests. Ahead waits two years of operational testing. Both Siemens and StatoilHydro are well aware that fl oating wind power is in its infancy, and that the road to commercialisation and large-scale development is long. In addition to the need for reduction in infrastructure costs, challenges include establishing an effi cient arrangement for rvice operations.
Service operations on fl oating offshore wind turbines are likely to require new technologies. Not only are conditions by defi nition likely to be more vere, becau fl oating turbines will be installed further offshore and in deeper waters,
but the fl oater’s movements also brings its own challenges. For major rvice operations on fi xed-foundation offshore wind turbines, jack-up vesls are ud, creating a situation where both the crane and the target are fi xed. This will not be possible with fl oating wind turbines; neither the cran
e nor the target is fi xed. Unless one accepts that crane operations can only be carried out during very calm conditions, which may not occur during the entire winter ason, new technologies will need to be developed for the replacement of main components.
Notwithstanding the challenges, both StatoilHydro and Siemens are hopeful that fl oat-ing wind power will become a genuine commercial alternative. For fi xed offshore wind turbines, it took nine years to move from the world’s fi rst offshore wind turbine demonstration project built at Vindeby in 1991 to the fi rst large-scale project with multi-megawatt turbines at Middelgrunden in 2000. But then the expansion really took off. The prospects of commercial fl oating wind power will benefi t not only from the experience already gained with offshore wind power, but also from the development of much larger wind tur-bines. Indications are that the infrastructure costs do not increa proportionally to the energy gen-eration potential of large turbines. Depending on the outcome of the Hywind demonstration project, Siemens and StatoilHydro expect that fl oating
wind turbines may be commercially viable for large wind turbines within a time frame of 5-10 years.
英语高考满分作文
The slender turbine is tethered to the abed.
Photo: Statoil Hydro季节的英语单词
“Commercial fl oating wind power will benefi t from the experience already gained with offshore wind power and from the development of much larger wind turbines.”
