Offshore Wind 101 - mainefishermensforum.org
Transcript of Offshore Wind 101 - mainefishermensforum.org
Offshore Wind 101Fishermen’s Forum
March 5, 2020
Richard Akers
Maine Marine Composites LLC
2 Portland Fish Pier, Suite 211
Portland, Maine 04101
Parts of an Offshore Wind Farm
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Certification of Wind Farms
(DNV-GL, 2014)
• Wind farms north of Cape Cod will be floating,
not fixed
o Floating can be more economical than fixed
because FOWT is constructed shoreside
• Growth Rate: 10MW prototype 50MW
test field 300MW to 500MW wind farm
• Floating
(Hall, 2020)
Scale Factors
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• ����� = � �
�⁄ � � ��
• Goes up by the square of the rotor diameter
• Goes up by the cube of the air speed (clean, high speed wind is good!)
• GE Haliade-X 12 MW turbine: Each blade longer than football field
Offshore Wind Turbine Foundations
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Fixed Foundations:
• Monopile
• Tripod/jacket
Floating Foundations:
• Tension Leg
Platform (TLP)
• Semi-submersible
(Semi-sub)
• Spar Buoy (Spar).
0-100 feet 80-150 feet >150 feet >400 feet
Jacket foundations for Block Island
Wind Farm (Providence Journal,
2015)
EWEA (2013)
Source: Principle Power
Parts of an Offshore Wind Farm
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San Jose Mercury News (2015)
DolWin2 high voltage direct current (HVDC)
transmission link between 3 offshore wind
farms and Germany’s mainland (ABB, 2017)
Mooring Components
Sound & Sea
Technology (2009)
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Mooring Materials: Chain, Wire & Synthetic Rope
Source: API RP 2SK
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Stud Link Chain Properties (Paduca, 2020)
High Tensile
UHMWPE Rope
12 Strand
Mooring Rope,
ROPENET
GROUP CO.,
LTD, China
Tidal Anchor, 3”
studlink chain (MMC)
0
50
100
150
200
250
0
20
40
60
80
100
120
0 1 2 3 4
We
igh
t o
f Li
nk (
lb.)
Len
gth
of
6 L
inks
(in
.)
Wire Size (inches)
Anchor Types
Sound & Sea Technology (2009)
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Gryphon, 35 tonne refurbished Stevpris Anchors
Source : Toal et al. (2014)
Drilled and
grouted
micropiles
(Robertson,
2018)
Drag/Embedment Anchors
• Lots of drag anchor choices
– Vryhof Stevpris, Stevmanta shown
• Uplift in anchor/mooring design?
– Depends on how deep the anchor is imbedded
– Inverse catenary of mooring line (E) allows for uplift
up to 20 degrees before anchor loads change
• Proof load test
required
– 50% of breaking
load of chain
Anchor Manual
2010, “The Guide to
Anchoring,” Vryhof
Anchors.
(Vryhof , 2014)
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Suction Pile Anchor
Sound & Sea Technology, "Advanced Anchoring and
Mooring Study," November 30, 2009
Source:
API RP 2SK
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Mooring System
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Pieces of a Mooring Line
Top: Entire line including synth.
Rope and bottom chain
Left: Anchor yoke, crown line
(to retrieve anchor)
Source: MMC
What is a Wind Turbine’s Footprint?
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Anchor
Safety
Zone
Chain on
Seabed
Pull on Wind Turbine
until mooring line load
limit. Trace chain
locations
What is a Wind Turbine’s Footprint?
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Anchor
Safety
Zone
Chain on
Seabed
Pull mooring lines
out of line until
nylon breaking load
What is a Wind Turbine’s Footprint?
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Extreme Footprint:
Circle around all anchors
What is a Wind Turbine’s Footprint?
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Triangular Footprint:
Around all anchors
What is a Wind Turbine’s Footprint?
• Maine Aqua Ventus Projecto Demonstration project at UMaine Deepwater Offshore Wind Test Site off
Monhegan Island
• Blog entry (March 27, 2018, Josh Plourde)– “…no plans for exclusion zones or setbacks for fishing around the two
turbines [now one turbine] once installed off Monhegan Island.”
– “MAV will work with fishermen that fish around the two turbines to determine an acceptable standoff distance for safe operations near the floating hulls, mooring chains, anchors and electrical cables.
– “Experience from Europe’s first floating farm is a 150 ft safety setback from the hulls.”
http://maineaquaventus.com/index.php/2018/03/27/project-update-zone-d-zone-e-license-holders/
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Power Lines to Shore
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AC Line from
other Turbines
(typ. 34.5 kV)
HVDC (or HVDV)
Line to shore
Approx. 5.5” diameter 34.5 kV, three
conductors with fiber-optic
communications cable (Plourde, 2017).
Electrical Connection
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(Baring-Gould, 2014)
Protecting the Power Cable• Cables are trenched and laid in place
– Jet the trench, then drop cable in behind jet
– 6' underground (2M)
– Use mechanical plow to minimize impact in
sensitive areas
• If trenching not feasible (or near shore)
use cast iron armor, 10" to 12" diameter
– Small anchors won’t catch, heavy anchors
won’t damage
• Use polyurethane bend restrictors for
dynamic cable
• Trenches allow lobstering
– Only precludes fixed gear trawlers
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Cast iron,
articulated
bend restrictor.
(PCS Italiana,
2017)
Polyurethane Vertebrae
Bend Restrictor (ABCO
Subsea, 2020)
Articulated
concrete
mat.
(Kokosing,
2018)
Trenching the Power Cable
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Jet plow on Town Beach in preparation
for connecting Block Island to Wind Farm.
Photo by K. Curtis (Shuman, 2016)
Van den Berghe (2008)
Block Island Cable Installation (Henrikson, 2017)
QUESTIONS?
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References
• ABB Power Grids. ABB delivers DolWin2 wind connection. June 2017. https://i.ytimg.com/vi/SYwDHH4rN2w/maxresdefault.jpg
• ABCO Subsea. Polyurethane Vertebrae Bend Restrictor. 2020. (https://www.abcosubsea.com/products/bend-limiters)
• American Petroleum Institute (API). Design and Analysis of Stationkeeping Systems for Floating Structures. API Recommended Practice 2SK Third Edition, Washington DC, 2005.
• Baring-Gould, Ian (NREL). Offshore Wind Plant Electrical Systems. BOEM Offshore Renewable Energy Workshop. July 29-30, 2014.
• DNV-GL SERVICE SPECIFICATION: Project certification of wind farms according to IEC 61400-22. DNVGL-SE-0073, December 2014. https://rules.dnvgl.com/docs/pdf/DNVGL/SE/2014-12/DNVGL-SE-0073.pdf
• European Wind Energy Association (EWEA): Deep Water: The Next Step for Offshore Wind Energy. Brussels, Belgium, 2013. https://windeurope.org/fileadmin/files/library/publications/reports/Deep_Water.pdf
• Hall, Dick. SGC (private conversation with author, 3/2020).
• Henrikson, Mark. Ocean News. Subsea Cable Installation For the Block island Wind Farm. August 2017.
• Kokosing Industrial. Cable Protection. Oct. 2018. https://kokosingindustrial.com/marine/special-cable-installation-handling-equipment/.
• Paduca Rigging. Stud Link. https://www.paducahrigging.com/product/stud-link/, accessed Mar., 2020.
• PCS Italiana srl. Articulated Protection Shell. 2017. http://www.pcsitaly.it/index_htm_files/Ariculated%20Protection%20Shell.pdf
• Plourde, Josh. Electrical Engineering Overview,St. George, Maine. Aqua Ventus Maine.November 27, 2017.
• Providence Journal, Jacket foundations for Block Island Wind Farm, July, 2015. (source: https://www.providencejournal.com/storyimage/PJ/20150629/NEWS/150629272/AR/0/AR-150629272.jpg)
• San Jose Mercury News. California’s first offshore wind farm proposed near Hearst Castle. 2015. (source: https://www.mercurynews.com/2015/11/07/californias-first-offshore-wind-farm-proposed-near-hearst-castle/)
• Shuman, C. Deepwater Wind connects its cable at Fred Benson Town Beach. Block Island Times. 05/20/2016 https://www.blockislandtimes.com/article/deepwater-wind-connects-its-cable/46346
• Sound & Sea Technology. Advanced Anchoring and Mooring Study. November 30, 2009 (source: https://tethys.pnnl.gov/sites/default/files/publications/Advanced_Anchoring_and_Mooring_Study.pdf)
• Toal et al. Gryphon Alpha FPSO – Experience gained during moorings replacement and hook-up. OTC-25322, Houston, Texas, May 5-8, 2014.
• Van den Berghe, J. Jet-Induced Trenching Operations: Mechanisms Involved. Offshore Technology Conference, OTC-19441-MS, Houston, TX. 2008
• Vryhof Anchors, Source: http://www.vryhof.com/products.html, Accessed July 15, 2014
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