Harvey Seim   Coastal Wind Study
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Harvey Seim Coastal Wind Study

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  • Wind speeds at 30 m can be converted to wind power class and is depicted here. Continuous shading is from Truewind, circles are power-law extrapolated values, and squares measured (NCSOW). See that wind class 4+ is only found over water. We estimate class 6+ for much of the offshore waters, though Truewind appears to over-estimate winds in SE NC. Eastern Pamlico Sound experiences wind class 5.
  • Hand-contoured map of capacity factor in eastern NC. Greatest values exceed 40% and are found well offshore, from mid-Onslow Bay to north of Cape Hatteras. A small section of Pamlico Sound appears to have capacity factors > 35%. The depiction is relatively poorly constrained in offshore waters due to a lack of observations.
  • Limited quantitative information exists on bird and bat use of airspace over the sounds and the coastal ocean. In addition to review of the relevant literature, 59 interviews were conducted with a variety of experts. Conservation concerns for certain groups were combined with information on their use of the airspace to project potential risks, and how they might vary geographically over the water bodies.
  • Risk of impacts to birds and bats cannot be inferred based on abundance and spatial patterns of use alone because certain avoidance behaviors can limit risk whereas others may elevate risk. Only a few impact studies exist for large bodies of salt water, all were conducted in Europe.
  • Radar studies off the coast of New Jersey identified bird species flying in the altitude range typically swept by wind turbine rotors, but these may not be indicative because Scandinavian studies have revealed avoidance behavior by ducks and geese. The illustration on the right above shows this avoidance behavior.
  • After compiling all the information on distribution and behavior of birds and bats, this map was constructed indicating likely areas of high risk (red), moderate risk (yellow), and low risk (green). A buffer zone of 2 miles along all sound and ocean shorelines is merited to protect passerine birds who rest and feed on land during the day, and to protect shorebirds and bats. Other species including ducks, swans, loons, cormorants, and grebes frequently move from one foraging location to another on the sounds and at sea, and many fly low to the water, potentially enhancing the risk. Prime overwintering and foraging grounds are designated red as well as bird and wildlife sanctuaries.
  • Fish, fisheries, and marine habitats were identified by literature review, maps based on NC Division of Marine Fisheries GIS data, input from Marine Fisheries management and field biologists, and guidance from commercial and recreational fisherman. This slide lists the types of areas that were considered to have unacceptable levels of conflict. Each of the three main capes possess regions of high biological productivity and intense fishing. Similarly, any area within the Gulf Stream, especially its western wall, has high importance as pelagic fish and wildlife habitat.
  • The information gathered was used to create a map with the same three areas – red is unacceptable, yellow is some appreciable level of conflict but where tradeoffs among uses may still lead to approval of wind farms, and green where wind farms would not substantially compromise fish habitat, fishing uses, or transportation by fishing boats.
  • A map of navigation corridors, cultural resources, reef habitats also was prepared. This map includes marked navigation channels, the Intracoastal Waterway, and inlets between the sound and ocean as well as artificial oyster reef sanctuaries, oyster cultch planting areas, shell bottom, live bottom, and wreck habitats. Cultural resources of value, specifically shipwrecks, are included, including the NOAA Monitor Sanctuary, and German U-boats sunk during the Second World War, which are important cultural sites and targets of divers.
  • The map shows artificial reefs as red triangles, shipwrecks as red crosses, and oyster sanctuaries as green circles.
  • The addition of hard structure rising from the bottom in an otherwise unstructured plain of mobile sediments and from impacts on the wind fields in the wake of turbines and how they affect mixing of surface waters can create positive environmental effects, depending upon the location. These include establishment of oyster reefs in saline sounds, creation of additional rocky hard-bottom reefs in the coastal ocean, facilitating off-shore mariculture, enhancing local upwelling and thereby mixing oxygen into seasonally oxygen depleted sound waters, and enhancing local upwelling in the coastal ocean with potential impacts of enhancing food web production.
  • Several pre-existing uses by military aircraft and/or vessels are incompatible with the establishment of wind farms. Information on these areas was provided by the US Navy in Virginia Beach and the US Marine Corps in Jacksonville. Restricted areas were established to avoid interference with low-altitude flights, heavy military boat traffic, and radar signals. Many areas of closed airspace extend across Pamlico Sound. There are also other areas of military and civlian air space that preempt wind farm development, such as heavily instrumented research facilities, amphibious training areas, and bombing support of landing operations.
  • This map shows all military conflict areas in red.
  • Generally speaking, offshore wind turbines can be located at water depths from approximately 6 meters to 40-50 meters. Current turbine installations are at depths of around 35-38 meters, but offshore wind farms located at depths exceeding 50 meters and 100 kilometers offshore are being planned today.
  • There are 2 foundation alternatives for wind turbines – monopile and gravity based. Monopile foundations are suitable in clayey and sandy soil types. They can be used in softer rock and shale-like soil but localized drilling may be required. In hard, rocky soil a drive-drill-drive approach can be used but increases the cost by 100%. Gravity based structures are used where the seabed consists of rock too hard to apply piled foundations. These structures rely on mass, including ballast material, to withstand the axial and lateral forces and the overturning moment generated by the local environment and the turbine. Ballast material is typically sand but can also be iron ore or concrete.
  • Transportation and installation of foundations and turbines is done using specially adapted vessels, or by employing a combination of barges and jack-up platforms. Many heavy lift vessels require a draft of 4.5 meters. Another solution could be combining two or more barges fitted with heavy lifting equipment. The limiting factor in this situation would be the draft of the tugs needed to maneuver the equipment. Areas less than 4 meters in depth were eliminated from consideration for wind farms based on these installation requirements.
  • The North Carolina coastal system is large, complex, and consists of over 3,100 square miles of brackish-water estuaries with more than 5,000 miles of estuarine shoreline dominated by marshes, swamp forests, and low to high sediment banks.
  • This map aggregates the information from the prior geologic maps and provides a composite map for the entire coastline shows areas suitable for wind turbine foundations.
  • The utility transmission infrastructure was evaluated at a high level. Transmission providers regulated by the Federal Energy Regulatory Commission adhere to formal procedures for providing information on transmission interconnection impacts. It is difficult to obtain substantial information regarding specific transmission impacts outside of this formal study process. Generation and transmission interconnection requests were not filed with the various utilities as part of this study for cost and timeliness reasons. The analysis relies on assessment of information contained in transmission providers’ Open Access Transmission Tariffs, discussions with local transmission planners, and transmission planning documents. An especially helpful document is a December 2008 report by the North Carolina Transmission Planning Collaborative on 2008-2010 collaborative transmission plans. This report examines the feasibility of interconnecting several hypothetical wind farms on the central part of the North Carolina coast.
  • The North Carolina coast is served by two investor owned utilities, Dominion North Carolina Power (labeled Virginia Electric and Power Company on this map) and Progress Energy (labeled Carolina Power and Light Company on this map), and several electric cooperatives, which belong to the North Carolina Electric Membership Corporation. This map, from Platts Energy Advantage, identifies the service territories of these utilities.
  • This map shows the location of 6 potential interconnection points. These are Dominion Power’s Kitty Hawk substation, the Bayboro, Beaufort, and North River substations owned by Electric Membership Corporation utilities, and Morehead City and Southport substations owned by Progress Energy.
  • The information from the individual groups was integrated into a geographic information system. All the areas identified by the various groups as no-go, or red, were then eliminated, and the wind resource was colored coded for the areas remaining.
  • The result showed that State waters with potential for wind turbine development are limited to the eastern half of Pamlico Sound. Offshore, large areas are potentially well suited. About 190 federal MMS lease blocks were identified that have a wind capacity factor in excess of 35% and do not overlap at all with any eliminated area. About 101 of these with capacity factors above 40% are only found in outer Raleigh and Onslow Bays, an average of 24 miles from the coastline and in water depths of 22 meters or greater. About 60% of the lease blocks are suitable for monopile foundations, with about 28% suitable for gravity based foundations. Since much of this area lies in waters greater than 30 meters in depth, constraints posed by conflict with birds and marine species have not been documented and are not resolved.
  • This map shows the eliminated areas in gray, with the wind capacity in the remaining areas colored by capacity factor. The most promising areas are in Raleigh and Onslow Bays, although wind measurements in Raleigh Bay are lacking. It also is of note that very few actual wind measurements were available along the northeast coast, and this area is deserving of more wind data collection to determine whether additional measurements would result in an increase in the estimated capacity factor.
  • The result showed that State waters with potential for wind turbine development are limited to the eastern half of Pamlico Sound. Offshore, large areas are potentially well suited. About 190 federal MMS lease blocks were identified that have a wind capacity factor in excess of 35% and do not overlap at all with any eliminated area. About 101 of these with capacity factors above 40% are only found in outer Raleigh and Onslow Bays, an average of 24 miles from the coastline and in water depths of 22 meters or greater. About 60% of the lease blocks are suitable for monopile foundations, with about 28% suitable for gravity based foundations. Since much of this area lies in waters greater than 30 meters in depth, constraints posed by conflict with birds and marine species have not been documented and are not resolved.
  • Generally speaking, offshore wind turbines can be located at water depths from approximately 6 meters to 40-50 meters. Current turbine installations are at depths of around 35-38 meters, but offshore wind farms located at depths exceeding 50 meters and 100 kilometers offshore are being planned today.
  • North Carolina is lagging other states but can catch up. Strategies to be pursued are shown on the 3 following slides. The legislation proposing a pilot turbine project in State waters needs to be passed in this legislative session. The state needs to move to gain access to the existing US Navy platforms off the coast for wind data collection. This would provide a significant time and cost advantage over other states without platforms, where platforms would have to be built before wind data collection equipment could be installed.
  • This is a photo of a 5 MW turbine being erected off the coast of Europe.

Harvey Seim   Coastal Wind Study Harvey Seim Coastal Wind Study Presentation Transcript

  •  
  • Coastal Wind Energy Study
    • Requested by the North Carolina General Assembly
    • University of North Carolina at Chapel Hill designated to conduct the study
      • C. Elfland, Associate Vice Chancellor for Campus Services, project leader
    • Study area
      • Pamlico and Albemarle Sounds
      • Offshore over waters less than 30 meters in depth (wind to 50 meters in depth)
  • Potential wind farm layout Courtesy of G. Hagerman 80 m (265 ft) 45 m (150 ft)
    • Dimensions:
    • 1) ~700 m between turbines*
    • MMS leases are 3 mi by 3 mi
    • 49 turbines per lease block
    View slide
  • Operating Off-Shore Wind Farms National Geographic sustainableninja.com projo.com sustainyc.com govtech.com View slide
  • Coastal Wind Energy Study
    • Study Components (from legislation)
      • Wind resource evaluation
      • Ecological impacts, synergies, use conflicts
      • Foundation concepts
      • Geologic framework
      • Utility transmission infrastructure
      • Utility-related statutory and regulatory barriers
      • Legal framework, issues, and policy concerns
      • Carbon reduction
      • Preliminary economic analysis
  • Wind Resource Evaluation
    • H. Seim (Marine Sciences, UNC Chapel Hill)
    • G. Lackmann (RENCI, NC State)
    • Compare existing wind power estimates from AWS Truewind with available low-level (largely 10 meter) wind observations
    • Extrapolate low level winds to height – use NC SOW meteorological tower data to examine power-law and log layer fits
    • Collect new observations with a sodar wind profiler
    • Initiate archive and evaluation of regional wind models being run by NC Climatology Office and RENCI
  •  
  • Capacity Factor
    • Power generation is dependent on the generator used
    • Simple but realistic approach is to use power curve for common wind turbine to convert wind speed to power
    • Power curves for 3-3.6 MW turbines are all similar – kick-in speed of 3-5 m/s, rated power at 15 m/s, no output above 25 m/s.
    • Capacity factor is simply the average output from a generator divided by its maximum output, expressed as a percentage.
    • Used measured-over-water wind records to estimate capacity factor
  •  
  • Ecological impacts, synergies, use conflicts
    • C. Peterson (Marine Sciences, UNC Chapel Hill)
    • S. Fegley (Marine Sciences, UNC Chapel Hill)
    • J. Meiners (Marine Sciences, UNC Chapel Hill)
    • Risk to birds, bats, and butterflies and the loss or fragmentation of their terrestrial habitat
    • Risk to marine mammals, sea turtles, fish, and bottom-dwelling invertebrates
    • Synergies with other ecosystem services
    • Conflicts with military, mining, cultural, and ocean dumping uses
  • Procedure for estimating risk Estimation of risk: - examine accumulated information for patterns and specific concerns - use general ecological data and paradigms to reduce uncertainty - consult with experts again on preliminary assessments Interview experts, managers, bird watchers, fishermen, and duck hunters: - 54 in-person interviews - 5 phone interviews Review relevant literature: - 21 environmental assessments - 21 government reports - 40 peer-reviewed articles - 14 unpublished manuscripts Accumulate and organize pertinent information: - distributions and temporal patterns of organisms - possible presence of endangered, threatened, or species of concern - specific behavioral responses to structures, noises, and visual cues - distribution of fishery habitat and fishing activities
  • Bird and Bat Risk Distribution
    • Risk assessment – combines abundance and behavior
      • Mortality risk from encounter with blades
      • Turbine avoidance increases fitness risks from loss of foraging habitat or by inducing longer flight paths (especially for overwintering ducks)
    Scott Hecker, National Audubon Al Perry
  • Compilation of radar tracks for common eiders and geese flying near and through an offshore, Danish wind mill farm (individual mills are represented by red dots – Desholm and Kahlert 2005). These results are controversial; the wind mills interfere with the radar used to document flight paths. Behavioral responses (an example) Aerial photograph of a flock (a “raft”) of 20,000 common eiders – photograph by Simon Perkins, Mass Audubon
  •  
  • Measures to Reduce Risk to Birds and Bats
    • Do not use continuous lighting
    • Reduce or eliminate perches
    • Avoid white colors. Paint wind mill vanes in high contrast patterns
    • Pilot studies and impact studies after installation and operation of the first wind farm will demonstrate whether other mitigation procedures are needed
  • Critical Fish Habitats and Fishing Uses
    • Primary, secondary nurseries, migration paths, strategic habitats, submerged aquatic vegetation, shell bottom, oyster reefs (sounds), and live reefs (ocean)
    • Larval fish and blue crab migration corridors (may require seasonal constraint on construction)
    • Intense fishing uses
      • Trawling (shrimp, crabs, flounder)
      • Dredging (scallops, oysters)
      • Long hauling (various fishes)
    • High productivity regions
      • Gulf Stream, three Capes, all inlets, the “Point”
      • All inlets with 5 mile radius from centerpoint
  •  
  • Navigation Corridors, Cultural Resources, Reef Habitats
    • All marked navigation channels (ferries, shipping, intercoastal waterway), 1 km buffer on each side
    • Shipwrecks, including Monitor National Marine Sanctuary
    • Artificial reefs, live bottom and oyster sanctuaries
    • Dumping sites
    • Areas of National Park Service sensitivity to viewscape impacts (e.g., near lighthouses)
  •  
  • Synergies – Positive Interactions
    • A stone, scour apron surrounds the monopile base (12-m radius with stones rising 2-3 m above bottom)
      • Excellent foundation for artificial oyster reef in Sounds
      • Excellent foundation for live-bottom reef in coastal ocean
    • Wind farms may induce upwelling downstream
      • Could mitigate seasonal hypoxia and anoxia events in Sounds
      • In the coastal ocean could enhance local primary production
    Thieler et al. 1995 NOAA
  • Military Conflicts
    • Special use airspace
    • Training routes
    • Radar vector areas
    • USMC firing ranges
  •  
  • Foundation Concepts
    • J. Schuett (Affiliated Engineers, Chapel Hill)
    • S. Petersen (Ramboll Wind, Denmark)
    • K. Jensen, (Ramboll Wind, Denmark)
    • Structural systems
    • Appropriateness for sound and coastal ocean bottom geology
  • Foundation Alternatives Open gravity-based structure without ballast and at water depth of approximately 20 meters. The design shown includes an ice deflection cone. 2000-5000 tons Monopile foundation with transition piece and scour protection. Flange height above sea level approximately 20 meters. 200-300 tons
  • Foundation Alternatives
    • Installation vessels need at least 4 meters water depth
  • Geology
    • S. Riggs (Geological Sciences, East Carolina)
    • D. Ames (Geologic Sciences, East Carolina)
    • Sound and ocean bottom geology
    • Suitability for various types of wind turbine foundations
  • RIGGS AND AMES, 2009
  • Utility Transmission Infrastructure
    • K. Higgins, Energy Strategies, Salt Lake City
    • Caitlin Collins, Energy Strategies, Salt Lake City
    • Assessment of the transmission infrastructure along the coast of North Carolina
    • Ability of transmission infrastructure to absorb large-scale offshore wind projects
  • Electric Services Territories
  • Transmission Lines and Substations
  • Synthesis
    • Methodology (Marine Spatial Planning)
    • Information from the individual groups was integrated into a geographic information system
    • Emphasis was placed on identifying severe constraints likely to preclude any wind energy development
    • Areas identified as no-build (e.g. too shallow, reserved for use by the military) and areas identified as having high ecological impact or low suitability for foundation construction were eliminated
    • Each constraint equally weighted and an equal degree of certainty as to their extents assumed
    • Provides a conservative and introductory look at what areas remain viable for wind power development.
  • Synthesis
    • Results
    • Limited portion of State waters, restricted to the eastern half of Pamlico Sound, appears feasible for further study
    • Large areas offshore are potentially well-suited for wind energy development.
  •  
  •  
  • Findings
    • Large areas offshore
      • 2800 square miles (311 MMS lease blocks)
        • less than 50 m deep, within 50 miles of the coastline
        • Raleigh and Onslow Bay appear most promising
        • Over the shelf north of Cape Hatteras does not appear as favorable, but lack data
      • If all developed, could support 55,000 MW nameplate capacity (average output 130% of total NC use in 2007)
      • Developing 45 MMS blocks= 20% of total NC power demand in 2007
  • Benefits to North Carolina
    • National Renewable Energy Laboratory
    • 20% of the nation’s electricity from wind by 2030
    • Economic benefit
    • Environmental benefit
  • NREL Wind Powering America , Year 2030
    • Construction Phase
    • 24,500 new jobs
    • $2,9 B to local economies
    Direct Impacts Indirect and Induced Impacts Totals (construction + 20 years)
    • Construction Phase
    • 24,500 new jobs
    • $2.9 B to local economies
    • Operational Phase
    • 5,600 new long term jobs
    • $535 M/yr to local economies
    • Construction Phase
    • 20,500 new jobs
    • $1.9 billion to local economies
    • Operational Phase
    • 3,500 local jobs
    • $335 M/yr to local economies
    Construction Phase = 1-2 years Operational Phase = 20+ years Total economic benefit = $22.2 billion New local jobs during construction = 45,000 New local long-term jobs = 9,100
  • Environmental Impact 10,440 MW New Offshore Development
    • Cumulative Impact through 2030
    NREL Wind Powering America , Year 2030 Water Savings Carbon Savings 74.7 billion gallons 135 million tons
  • Strategic Direction
    • Support additional wind research
    • Support additional utility transmission research
    • Establish state policy toward utility-scale wind farm development
    • Leverage the expertise of the public universities
    • Develop demonstration turbines
      • No water-based wind turbine pilot projects ongoing in the US at this time
      • Area in the Pamlico Sound identified as potentially suitable
  • Possible Turbine Demonstration Site In Eastern Pamlico Sound 3 square mile area to host 1-3 turbines 16-20 ft deep 7-10 miles from Outer Banks Each 3.6 MW turbine will power about 1000 homes Each turbine will cost $12-15 million (installed) Avon Hatteras Buxton
  • Possible Turbine Demonstration Site In Eastern Pamlico Sound 3 square mile area to host 1-3 turbines 16-20 ft deep 7-10 miles from Outer Banks Each 3.6 MW turbine will power about 1000 homes Each turbine will cost $12-15 million (installed) Avon Hatteras Buxton
  • Photo simulation of wind farms 6.8 miles SE of Tybee Island, GA
  • Photo simulation of wind farms 10.4 miles SE of Tybee Island, GA
  • Example Pilot Study Topics
    • Study actual mortality of birds and bats in the presence of the turbines, test mitigation strategies
    • Measure power generation capacity and the influence of varying winds, wind shear and turbulence on it
    • Ability of the turbines to withstand storm-force winds
    • Enhancement of oyster and mussel growth and water quality from the turbine foundations
    • Study of visual impacts and their acceptability, especially National Park Service visitors and local Outer Banks residents
  • Questions