World’s First Floating Offshore Wind Farm Achieves 65% Capacity Factor After 3 Months
Statoil recently announced that its pioneering offshore floating wind farm, Hywind Scotland, achieved an astounding 65 percent capacity factor from November through January. Not only does this far surpass onshore wind farms the United States’ wind fleet enjoyed an average capacity factor of about 37 percent last year it bests America’s thermal power generators. EIA data suggests coal and natural-gas combined-cycle power plants will end 2017 with capacity factors in the 54 percent to 55 percent range.
The Norwegian energy firm plans to deploy an onshore 1 megawatt-hour lithium-ion battery system in late 2018, to evaluate the potential for energy storage to complement the offshore wind technology.
Located about 20 miles off the coast of the eastern tip of the Scottish mainland, Hywind Scotland Pilot Park consists of five 6-megawatt wind turbines with blade tips that reach more than twice the height of the Statue of Liberty. Each turbine sits atop a 90-meter-high substructure, itself ballasted with 5,000 tons of iron ore. Each substructure in turn is moored to three 15-meter-high suction piles anchored into the seabed at a depth of about 100 meters.
The design of the floating wind turbine platforms can be traced to Statoil’s decades of experience as the world’s largest offshore oil and gas platform operator. Given that 80 percent of the world’s offshore wind resources are in waters too deep for anchored wind turbines, and that oil platforms have been successfully deployed in waters almost 2,500 metres deep, it’s unsurprising in retrospect that an oil major has committed to the sector.
Scotland’s healthy winds and proximity to Norway made it a natural site for Statoil’s first floating offshore wind farm. Policy support, including a goal to generate 100 percent of Scotland’s electricity from renewables by 2020, also helped.
The small size of the wind farm made the project easier to develop, by capping the financial risk. (By coincidence, the United States’ first offshore wind farm, Block Island, also consisted of five 6-megawatt turbines.)
Statoil built its first floating wind turbine off the Norwegian coast in 2009, a reminder of the long time scales that can be required to vet, validate and verify newly developed capital intensive technologies. In its more than eight years of operation, the Hywind Demo has endured Category 1 hurricane speeds of 40 m/s and 62-foot waves, while achieving annual capacity factors of up to 50 percent.
With wind turbines becoming larger by the year, Hywind Demo’s then-typical 2.3 megawatts is minuscule compared to today’s towers; it will seem positively quaint by 2030. Larger turbines facilitated a two-thirds cost reduction for Hywind Scotland; as the waterfall chart below shows, Statoil continues to pursue cost reductions on all fronts.
Source : Green Tech Media