Seite - 127 - in Water, Energy, and Environment - A Primer

by84%toarriveat the2058GWfigure.Toput this latternumber into context, total installed US electricity generating capacity today is just over 1000MW. TheglobalOSWmarket is projected to continuegrowing at a 16%annual rate, reachingacumulative installed capacityof115 GWin2030but slowingdown thereafter. It is important tonote thatmuchof theglobalOSWresource is located in areas where the water is so deep that conventional turbine support structures – large steel piles or lattice structures attached to the seabed– cannot be used. This has stimulated the development of floating offshore wind platforms, building on the floating technology developed for the oil and natural gas industries. These platforms, tethered to the sea floor, provide the top-heavy turbines with enough stability to operate effectively. Installation of test and demonstration projects, which began in 2007, employs the ‘tow-out’ concept in which the support structure and turbine are constructed in port and then towed out to the anchor site. Statoil built its first floating wind turbine off theNorwegian coast in 2009, and this 2.3MW turbine, Hywind, is still operating today and has endured category 1hurricanes and 62 ft waves while achieving annual capacity factors of up to 50%. Statoil has also reported that its five-turbine, 30MW wind farm Hywind Scotland (the first commercial floatingwind farm in operation), installed 20miles off the Scottish coast in 2017, has achieved a 65% capacity factor. To put this in context, the US onshore wind fleet’s average capacity factor is 37%. Many other floatingwind farms exist today (seeWikipedia’s ‘List of offshorewind farms’).As of February 2018 theLondon Array in theUK is the largest offshore wind farm in theworld at 630 MW. Other large OSW farms in operation include the GeminiWind Farm in the Netherlands (600MW), CodeWind in Germany (582 MW), Gwynt y Mor in the UK (576 MW), RaceBank in theUK (573MW), andmany others in the range 200–504 MW. Quite a few other OSW farms with nameplate Renewableenergy 127