pre systems floating wind turbines - first marine …€laid mooring systems for floating wind...
TRANSCRIPT
Pre‐Laid Mooring Systems for Floating Wind Turbines
We Will:
• Save Time by Pre‐laying the Mooring System (Foundations)
• Save money by providing and utilising Anchor Handling Vessels AHV’s instead of expensive Construction Vessels
• Improve Safety by reducing risk and reducing exposure time
• Provide a long term rental solution No Capex Requirements
What We Can OfferDesign, Installation and Maintenance of a Mooring System for Floating Wind Turbines
• A Pre‐laid Mooring System is simply one that has been installed, load tested & buoyed‐off prior to Turbine arrival
• Pre‐lay Moorings can be installed in water depths of up to 500m+
Introduction to Pre‐LayWhat is a Pre‐laid Mooring System?
• Designed using standard components
• Installation is completed outside of the critical path
• Lower Installation costs by using AHV’s
• Short weather window requirements during pre‐lay operations
Introduction to Pre‐LayAdvantages of Pre‐laid Moorings
• Ball and taper connection: male mandrel/female receptacle
• Female receptacle pre‐installed on pile
• Flexible two stage mooring system deployment
• Catenary and taut mooring configurations
• Self aligning, self activating mechanical connection
• Quick installation, typically 9 minutes from deployment
Mooring Connectors
Top Tendon Connector
Bottom Tendon Connector
Location Environment Data
• Meteorological Site Data Analysis
• Wind Waves, Currents
Mooring Analysis
• Simulation of Environmental loads
on the Mooring System
Soil Analysis
• Anchor Selection
• Drag Anchor Analysis Sample Design Code Requirements
DNV‐OS‐J103 Design of Floating Wind Turbine Structures DNV‐OS‐J301 Wind Turbine Installation Units
Scope of Work ‐ Design
• Pre‐lay of mooring system
• Towing of Turbine from Shore to site
• Hook‐up of moorings with Turbine
• Maintenance and Inspection
• Disconnect (Temporary)
• Disconnect (Final Decommissioning)
Also
• Project Management
• Drawings and Method Statement
• Vessel Suitability Assessment
• Equipment and Personnel
Scope of Work ‐ InstallationProcedures
Mooring Installation & Turbine Hook‐up carried out using AHT’s
• No requirement for Construction Vessel
Significantly reduced costs
• AHT typically 20% cost of Construction Vessel
Fast Installation time
• Typically 24 hours per mooring system
Reduced downtime due to weather
• Shorter weather windows required
Vessels – Pre Lay & Hook UpAdvantages of using AHT’s over Construction Vessels
Monitoring
• Real time line tension monitoring
Maintenance
• Planned maintenance & inspection of the mooring system to DNV Standards
• Scheduled to coincide with planned maintenance of Turbine every 5 years
• Mooring lines reinstated prior to Turbine return – no loos of time
Disconnection
• Procedures for the disconnect shall be prepared to allow for removal of the turbine maintenance
Post Installation – Monitoring & Maintenance
Final Disconnect
• Disconnection and removal of Turbine
• Full recovery of Mooring Systems
Seabed Condition• Assessment of seabed condition to ensure no long term damage
Upgrade
• Opportunity to replace Turbines with improved models as technology develops by modifying the design of the mooring system
Decommissioning
• No upfront capital expenditure
• 3 Turbines = Circa £2 million + interest
• Long term rental can spread that cost over 5 to 20 years
• Benefits of no initial outlay, economical monthly payments, expense deductible
• 5 yearly Maintenance included in rental costs
• Ease of connect and disconnect
Capex Vs Opex
• Installation capex costs 4MW class turbine is £611k per MW
• Foundation installation vessel DP £220k/day
• Jack‐up Vessel £150k/day
Vs
• Anchor Handling Vessel £25k/day circa 3 days installation
• Conventional moorings £521k – 3 Anchor line spread
• Circa £3.1m versus £596k – SAVING circa £2.5million
Comparative Costs
Qty Purchase for one Turbine unitYear 1
1 Unit (£) 3 Units (£) 5 Units (£) 10 Units (£)
3 15mT Bruce FFTS Anchor 179,622 538,866 898,110 1,796,220
3 200m x 76mm R4 Grade Studlink Chain 223,800 671,400 1,119,000 2,238,000
3 84mm Trident Anchor Shackle (Anchor‐Chain Connection) 8,385 25,155 41,925 83,850
3 76mm Kenter (Chain‐Turbine Connection) 3,381 10,143 16,905 33,810
Purchase Total 415,188 1,245,564 2,075,940 4,151,880
Cost of Capital 75,945 187,392 367,281 734,745
Shipping Costs 105,000 315,000 525,000 1,050,000
TOTAL 596,133 1,767,956 2,968,221 5,936,625
Comparative Costs
Standard rental costs – 3 lines/unit Per day (£) Per month (£) Per annum (£) 3 Units (£) 5 Units (£) 10 Units (£)
15mT Bruce FFS Anchor 160 4,950 59,400 178,200 297,000 594,000
200m x 76mm R4 Grade StudlinkChain 216 6,480 77,760 233,280 388,800 777,600
84mm Trident Anchor Shackle (Anchor‐Chain Connection) 18 540 6,480 6,480 32,400 64,800
76mm Kenter (Chain‐Turbine Connection) 9 270 3,240 3,240 16,200 32,400
Year 1 408 12,240 146,880 440,640 734,400 1,468,800
Year 2 Year on Year 10% disc 132,192 394,576 660,960 1,321,920
Year 3 Year on Year 15% disc 112,363.20 337,089.60 561,816 1,123,632
Year 4 Year on Year 20% disc 89,890.56 269,61.68 449,452.80 898,905.60
Year 5 Year on Year 25% disc 67,417.92 202,253.76 337,089.60 674,179.20
548,743.68 1,646,231.04 2,743,718.40 5,487.,436.80
Rental Foundations
• Reduced costs through elimination of requirement for construction vessel
• Siting of Turbines in deeper water without significant increases in overall costs
• Short weather windows reduce downtime and risk to the project
• Additional ‘Trigger Stop Points’ built in meaning a safer operation
• Speedy disconnect for maintenance onshore maintenance of turbine, reducing costs
• Complete removal of mooring system during decommissioning
Advantages of Pre‐Lay Design & Installation
Questions?