APPENDIX A Marine Vessels for Construction and Maintenance of Offshore Wind Farms

217 Pages·2010·4.72 MB·English

APPENDIX A

Marine Vessels for Construction and Maintenance of
Offshore Wind Farms

Vessel Requirements for Offshore Wind Farm
Construction and Maintenance

Prepared for
Tetra Tech EC, Inc.
Boston Massachusetts

File No. 09065.01
22 October 2009
Rev. A

BY: _____________________________________ ___________
Charles J. Nordstrom, PE
Signed Original
Project Manager
CHECKED: _______________________________ ___________
oPonrter W. BrFatten ile at Glosten
Project Naval Architect
APPROVED: ______________________________ ___________
Paul S. Smith
Principal-in-Charge
Consulting Engineers Serving the Marine Community
1201 Western Avenue, Suite 200, Seattle, Washington 98101-2921 TEL [phone] FAX [phone] www.glosten.com

Contents
Executive Summary ............................................................................................................................ ii
Section 1 Site Conditions at Ports and Wind Farm Locations ............................................... 1-1
1.1  Conditions at Proposed Wind Farm Sites .............................................................................. 1-1 
1.1.1  Nantucket Sound ...................................................................................................... 1-2 
1.1.2  Rhode Island ............................................................................................................ 1-3 
1.1.3  Delaware Bay ........................................................................................................... 1-4 
1.1.4  Other Areas .............................................................................................................. 1-5 
1.2  Methods of Transport ............................................................................................................ 1-6 
1.2.1 Required Clearances ................................................................................................ 1-6
1.3  Navigational Constraints at Proposed Staging Areas (Ports)................................................. 1-8 
1.3.1 Navigational Constraints – Boston .......................................................................... 1-8
1.3.2 Navigational Constraints – Gloucester .................................................................. 1-11
1.3.3 Navigational Constraints – New Bedford .............................................................. 1-12
1.3.4 Navigational Constraints – Fall River .................................................................... 1-13
1.4  Example Timeline for Foundation & Turbine Installation .................................................. 1-14 
Section 2 Installation and Transport Vessel Requirements .................................................... 2-1
2.1  Flag and Class ........................................................................................................................ 2-1 
2.2  Principal Dimensions ............................................................................................................. 2-1 
2.3  Propulsion .............................................................................................................................. 2-2 
2.4  Crane Requirements ............................................................................................................... 2-2 
2.5  Jacking System Requirements ............................................................................................... 2-3 
2.6  Limiting Weather Conditions for Pile Driving and Crane Operations .................................. 2-3 
2.7  Accommodations ................................................................................................................... 2-3 
2.8  Machinery for Crane and Jacking Systems ............................................................................ 2-3 
2.9  Auxiliary Machinery Systems ............................................................................................... 2-4 
2.10  Deck Load Requirements ....................................................................................................... 2-4 
2.11  Safety Equipment ................................................................................................................... 2-4 
2.12  Vessel Alternative and Future Uses ....................................................................................... 2-4 
2.13  Parametric Cost Estimate ....................................................................................................... 2-4 
Section 3 Import Vessel Requirements ..................................................................................... 3-1
Section 4 Tugboat and Auxiliary Vessel Requirements .......................................................... 4-1
4.1  Tug Boat Requirements ......................................................................................................... 4-1 
4.2  Crew Boat Requirements ....................................................................................................... 4-1 
4.3  Other Auxiliary Vessel Requirements ................................................................................... 4-1 
Section 5 References .................................................................................................................. 5-1

Tetra Tech EC, Inc. The Glosten Associates, Inc.
Wind Farm Vessel Requirements, Rev. A i File No. 09065.01, 22 October 2009
H:\2009\09065_TetraTech-MTCPortsStudy\Ph_1\01 Vessel Requirements\Report\00_Front.doc

Executive Summary
The report evaluates the marine vessel requirements for deploying and maintaining offshore
wind farms along the U.S. East Coast. The findings of this report are intended to be inputs
for a comprehensive evaluation of port infrastructure. Understanding the characteristics of
these vessels is critical in the overall evaluation of a port's suitability as a staging area for
offshore wind farm deployment and maintenance.
Vessel requirements are governed primarily by the following:
 Physical conditions at offshore wind farm sites
(i.e., conditions in which vessels must operate)
 Navigational constraints in port and along transit route to wind farm site
 Size and weight of turbines being transported and installed
 Methodology for transporting and installing turbines
We evaluated physical conditions – including wind speeds, wave regime and water depth –
at proposed offshore wind farm sites along the U.S. East coast. We evaluated navigational
constraints in and near the Ports of New Bedford, Boston, Gloucester, and Fall River. We
summarized the physical properties of large offshore wind turbines (3- to 5-MW), and we
reviewed demonstrated methodologies for transporting and installing these turbines.
Our findings indicate that the Port of New Bedford is well suited as an offshore wind farm
staging area. New Bedford is a particularly promising staging area in the long term, as it
does not have any overhead clearance ("air draft") constraints. Industry trends are moving
toward the deployment of fully erected turbines, which require overhead clearances in
excess of 400 feet. Present industry practice requires overhead clearances of up to 150 feet.
Designated port areas in the Inner Harbor of Boston (i.e,, downriver from the Tobin and
McArdle Bridges) are well suited as staging areas. Sites along the Mystic River and Chelsea
Creek (west of existing Chelsea St. Bridge) are feasible sites for an offshore wind farm
staging area, but bridges impose constraints on air draft and transport methodology.
Approaches to Logan Airport impose an air draft constraint for sites in South Boston, which
is otherwise feasible as a staging area.
The Port of Gloucester is accessible for wind turbine installation vessels (jack up crane
barges or ships), but is not accessible for wind turbine import vessels (ocean-going cargo
ships) due to limited water depth. The Port of Fall River is feasible as a staging site, but is
constrained by the Mt. Hope Bridge, which imposes a maximum air draft of 135 feet.
The principal dimensions of wind turbine installation vessels/barges and import vessels are
summarized below, as are the navigational constraints for all the analyzed ports.
Section 1 of this report describes the physical conditions at proposed wind farm sites, as
well as navigational constraints in and near the subject ports. Section 2 discusses the unique
aspects of wind turbine installation vessels/barges. Section 3 is a brief discussion of cargo
Tetra Tech EC, Inc. 2 The Glosten Associates, Inc.
Wind Farm Vessel Requirements, Rev. AP0File No. 09065.01, 22 October 2009
H:\2009\09065_TetraTech-MTCPortsStudy\Ph_1\01 Vessel Requirements\Report\00_Front.doc
ships used to transport turbine components from overseas. Section 4 discusses auxiliary
vessels, which are readily available on a time-charter basis along the U.S. East Coast.
Principal Dimensions for Turbine Installation Vessels
(Jackup Crane Vessels/Barges)
Length Overall.................................................................300' – 450'
Beam..............................................................................100' to 130'
Navigation Draft.................................................................12' to 16'
Air Draft (legs in up position)............................varies, approx. 150'
Air Draft (tower sections, bunny ears).......................................150'
Air Draft (crane in stowed position).......................................varies

Principal Dimensions for Turbine Import Vessels
(Cargo Ships)
Length Overall.................................................................330' – 470'
Beam....................................................................................66' – 75'
Draft.....................................................................................22' – 32'

Summary of Navigational Constraints

Controlling Feasible
Potential Lateral Overhead Water Turbine Jackup
Staging Port Obstructions Clearance Clearance Depth Load-Outs Feasible?
Hurricane no
New Bedford 150' 30' all yes
Barrier constraints
water depth, no fore-aft marginal
Gloucester 200 – 250' 15.5 – 19'
channel width constraints bunny ear (water depth)
Mt. Hope marginal
Fall River 400' 135' 40' star
Bridge (air draft)
Logan report air
South Boston over 500' 40' all yes
Airport draft to
Charlestown / airport
Logan
East Boston over 500' traffic 40' all yes
Airport
(inner harbor) control
Tobin
marginal
Mystic River Memorial over 500' 135' 25-35' star
(air draft)
Bridge
Chelsea River Andrew
no fore-aft
(west of Chelsea McArdle 175' 29-40' yes
constraints bunny ear
St. Bridge) Bridge
Chelsea River
Chelsea St. rotor
(east of Chelsea 93' 83' 29-40' no
Bridge disassembled
St. Bridge)
This report was prepared for Tetra Tech and the Massachusetts Clean Energy Center in
support of the Massachusetts Ports and Infrastructure Study. Information in this report is
derived from interviews with offshore wind farm developers, specifications from turbine
Tetra Tech EC, Inc. 3 The Glosten Associates, Inc.
Wind Farm Vessel Requirements, Rev. AP0File No. 09065.01, 22 October 2009
H:\2009\09065_TetraTech-MTCPortsStudy\Ph_1\01 Vessel Requirements\Report\00_Front.doc
manufacturers, and publicly available data sources such as technical papers, conference
proceedings, NOAA buoys1, and corporate literature

1 NOAA is the National Oceanographic and Atmospheric Administration. NOAA deploys and maintains
buoys throughout the coastal waters of the United States. Data from these buoys are analyzed and archived,
providing publicly available databases from which long-term climatology statistics can be derived.
Tetra Tech EC, Inc. 4 The Glosten Associates, Inc.
Wind Farm Vessel Requirements, Rev. AP0File No. 09065.01, 22 October 2009
H:\2009\09065_TetraTech-MTCPortsStudy\Ph_1\01 Vessel Requirements\Report\00_Front.doc
Section 1 Site Conditions at Ports and Wind Farm
Locations
1.1 Conditions at Proposed Wind Farm Sites
Wave height and wind speed impose limitations on at-sea construction operations. The
following sub-sections describe sea states, wind conditions, and water depths at proposed
wind farm sites along the U.S. East Coast. Transit distances1 between proposed wind farm
sites and potential staging ports are listed.
Sea states are typically characterized by the significant wave height H , which is the average
S
of the 1/3 largest waves. H correlates very well to the sea state as observed by mariners.
S
Wind is characterized by the 10-minute average wind speed V .
W
The base line transit routes are around the east end of Cape Cod. Alternative routes are via
the Cape Cod Canal. Air draft in the Cape Cod Canal is limited to 135 feet. In practice, this
means vessels or barges transporting 5-MW turbines in the “bunny ear” configuration
probably cannot transit the Cape Cod Canal. Alternative turbine load-out configurations
(e.g., “star” configuration) and/or smaller turbines (e.g., 3.6-MW turbines) in the “bunny
ear” configuration can probably utilize the Cape Cod Canal.

1 Transit distances are in nautical miles (nm) and are based on typical shipping routes.
Tetra Tech EC, Inc. The Glosten Associates, Inc.
Wind Farm Vessel Requirements, Rev. A 1-1 File No. 09065.01, 22 October 2009