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Offshore Wind in the Great Lakes . NAME Great Lakes Wind Collaborative DATE. Technical Details. Turbine Size. 2.5MW Turbine: 75-100m (246-328ft) hub height 3MW: 100-120m (328-394ft) hub height. Compared to onshore, offshore turbines…. Tend to be larger, but shorter.
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Offshore Wind in the Great Lakes NAME Great Lakes Wind Collaborative DATE
Turbine Size • 2.5MW Turbine: 75-100m (246-328ft) hub height • 3MW: 100-120m (328-394ft) hub height
Compared to onshore, offshore turbines… • Tend to be larger, but shorter. • Require helipads or landings for maintenance activities. • Have a designated area for maintenance workers. • Are built to withstand waves, currents, and ice formation. • Might use Conditional Monitoring Systems. • Might have more redundant systems. • House the transformer in the nacelle.
30 meters wide 130 meters long 48 meter legs can extend 5 meters into the lakebed
Installation Vessels • St. Lawrence • Max draft: 26.5 ft (should be min?) • Max beam: 78 ft • Chicago Sanitary and Ship Canal • Max draft: 7 ft (should be min?) • Max beam: 110 ft
Foundations • 3-30 meters. • Technology based on onshore. • Three kinds: gravity, monopile, suction bucket/caisson • Loadings unique to the offshore environment: • Wave loading • Static and dynamic ice loading • Water currents • Require more analysis and modeling to understand the impact to the foundation
Suction Bucket or Caisson • Tubular steel foundation installed by sealing the top of the steel bucket and creating a vacuum inside. • Hydrostatic pressure difference and the dead weight of the structure cause the bucket to penetrate the soil. • New technology. • Shallow water
Gravity Base Foundations • Steel or concrete foundations • Steel is lighter and normally filled with granular material. • Concrete is heavier – handling can be difficult. • Relies on weight of structure to resist overturning • Ballast added after placement • Shallow water with proper lakebed preparation essential • conical collars (ice cones) • Might be cost prohibitive in 15+ meters
Monopile Foundations • Large, thick-walled, single steel pipe • 4.5 - 6 m diameter steel tube typical • Wall thickness 30 -60 mm • Driven or drilled 25 -30 m embedment • Water depth experience to 25 m • Stiff soils only (e.g. sand) • Most common type, especially in shallow water. • Minimal footprint • Large barges, specialized equipment. • Ice cones • Transition pieces can be steel, concrete, or composite.
Conical collars / ice cones • Conical shaped structures at water level. • Cones cause ice to bend and break up. • Ice thickness: • Nearshore Lake Michigan: 0 to 0.5 meters • Deepwater Lake Michigan: 0 to .15 meters • Lake Superior: .05 to .8 meters • Green Bay: .2 to .7 meters
Transmission • Voltage is stepped up to distribution voltage (25-35 kV) using a transformer at each turbine. • Turbines are then connected to an offshore substation. • Substation steps up to transmission voltage (400-800 kV) • One cable connects to the mainland.
Cables • Can be several medium voltage cables (34.5 kV), or one or more high (100-200 kW) or extra high voltage (>200 kV) cables. • Redundant cables built in in case of failure • Higher voltage cables require insulation • self-contained, fluid-filled (SCFF) cable • Fluid biodegrades in 30-60 days if there is a leek.
Cables • Buried in the lake bed • 6 to 10 feet • Jet plow rolls and fluidizes the lake bottom material in a narrow path. • Sand or clay bottoms. • Laid on the lake bottom • Water jets create a trench and bottom material is allowed to sink back into the trench • Rocky bottoms at deeper depths • Issues to consider: • Overhead lake traffic • ice scouring • Disruption of lakebed and stirring up of pollution • Cable can be covered with concrete mattresses or rock. • Horizontal directional boring to pull the cable to shore.
Environmental Considerations • Bird & Bat • Fish • Lakebed Alterations • Habitat Alterations • Noise
Bird & Bat • Risk of collision/barotrauma • Short-term habitat loss during construction • Long-term habitat loss due to disturbance by O&M • Habitat fragmentation • Formation of barriers to migration and daily movements
Fisheries Research • Research on aquatic habitat and spawning grounds focused on the nearshore. • less research on the open water. • Most research related to the effects of wind turbines is marine-focused. • Habitat disruption more likely during transmission installation. • Frac-outs: excessive pressure causes the vertical release of drilling mud through fractures. • Most commercial and recreation fishing takes place within 3 miles of shore.
Fisheries Research • Foundations will likely provide additional habitat for some beneficial fishes for possibly food, shelter from predation, nursery areas and spawning. • Lake trout will spawn on artificial reefs within a few months of construction • yellow perch and smallmouth bass were observed using the artificial reefs located within the study area. • Might provide additional recreational fishing opportunities. • Might cause an increase in the species richness, abundance or biomass of the benthic community. Great Lakes Energy Development Task Force. 2008. Great Lakes Wind Energy Center Feasibility Study: Initial Ecological Assessment. Prepared by DLZ. September.
Fisheries Best Practices • If turbines are built in spawning areas, foundation materials should mimic the substrate. • If not in these areas, planners should consider materials that are conductive to spawning. • Construction and maintenance should avoid spawning times. • Fishing activities in general should avoid turbines.
Primary Fish Species of Commercial and Recreational Interest in LakeSuperior and Lake Michigan
Habitat Fragmentation/Disruption • No evidence of any detrimental effects on coastal processes from the Danish experience. • Numerous turbines could affect direction or velocity of currents, plankton, sediment, nutrients, and fish.
Noise • Noise from wind turbines will travel underwater and could disturb aquatic organisms. • Studies from existing offshore turbines note that the noise is very low frequency, and many species are actually unable to hear it. • Noise from construction activities could disrupt organisms in the short-term.
U.S. Federal Involvement • Rivers and Harbors Act, Section 10 • Prohibits the obstruction or alteration of navigable water of the U.S without a permit. • Army Corps of Engineers is the lead permitting agency (MMS is the lead on the Outer Continental Shelf) • Martin v. Waddell • states own navigable and tidal waters and their underlying land for the common use of the people of the state.
U.S. Federal Involvement • Submerged Lands Act • Great Lakes states have jurisdiction up to the international boundaries. • Coastal Zone Management Act • CZM Programs should include “a planning process for energy facilities likely to be located in, or which may significantly affect, the coastal zone, including a process for anticipating the management of the impacts resulting from such facilities.”
Wind Turbine Placement Favorability Analysis MapOhio Coastal Management Program
Ohio Criteria • Shipping lanes, fairways, harbors • Distance from shore • Raptor nests • Important bird areas • Natural heritage observances • Fish habitat and bathymetry • Reefs and shoals • Substrates • Sand and gravel mining • Military zones • Confirmed shipwrecks • Sport fishery effort • Commercial fishery trap net lifts
When? Construction 2012-13
Ontario Criteria • National/Provincial Park • Protected area • Water depth 5 m <X< 30 m • Wind speed > 8.0 m/s • Airports • Radiocommunication Systems • Population density • Distance from shore • Commercial waterway and ferry route • Protected shipwreck • Submerged utility line • Shoreline • Great Lakes coastal wetland • Conservation reserve • Environmental Area of Concern • Important Birding Areas
Michigan Dry Run • Examined Michigan’s current state of readiness to permit large-scale offshore wind facilities • Two different areas of the Great Lakes • nearshore Lake Huron • remote offshore Lake Michigan • Final Report published May 2008 • GLOW Council
Great Lakes Offshore Wind Council • created by Executive Order No. 2009-1 • serves as an advisory body within the Michigan Department of Energy, Labor & Economic Growth (DELEG) • Identify criteria that can be used to review applications for offshore wind development. • Identify criteria for identifying and mapping areas that should be categorically excluded from offshore wind development as well as those areas that are most favorable to such development • September 1, 2009 www.michiganglowcouncil.org/