Innovative Foundation Installation Techniques for Offshore Renewables Projects Michael McSherry Marine Renewables Manager E: michael.mcsherry@mclh.co.uk Damian Callan Technical Ops Manager E: damian.callan@mclh.co.uk
McLaughlin & Harvey Offshore
Company Credentials 150 years of Civil and Marine Construction Proven Track Record in Tidal Deployments Practical Experience of Actual Installations Demonstrable Problem Solving Capabilities Staff levels of over 700 Continued annual turnover in excess of 400M
Marine Renewables Activities since 2005 Piled Foundation Installation Design / Methodology Development Gravity Base Deployment Specialist Advice Operation and Maintenance Research and Development
Types of Foundation
Types of Foundation Several different foundation types commonly used in the wave and tidal sector, including: Gravity Large Piled Moored Modular, i.e. multiple ballast Tension anchors Common foundation failure mechanisms are settlement / bearing, fatigue, corrosion induced (steel), bending, sliding and overturning
Types of Foundation Large Gravity Installed as one large mass Significant amounts of material required Typically 1MW device can require around 1000t (sat) Reliance on heavy lift equipment Relatively straightforward design Installation methods well developed and very quick on site
Types of Foundation Modular Gravity Mass provided in smaller interlocking parts More deployments required Opens up possibilities for using smaller equipment and vessels Foundation weight can be added to less conservative design
Types of Foundation Piled Single (monopile) or multi-piled foundations Drilled piles predominantly used for wave and tidal Grouting around the pile annulus required Expensive to install
Types of Foundation Moored Utilise mooring lines from the device to the seabed foundation Seabed foundation may take various forms Wave / tidal device must be buoyant Mooring lines can only act in tension and are often catenary
Types of Foundation Tension Piles Essentially replaces how vertical reaction is generated, from compression in the case of gravity to tension in anchor Application used for many structures, generally to counteract uplift Small diameter drilling, anchor diameter < 200mm Requires bespoke drilling equipment, though relatively lightweight allows for more cost effective marine spread Tension piles have poor performance in bending, therefore shear needs to be dealt using other methods
McLaughlin & Harvey Techniques
Experience. Piled test platform at EMEC for Open Hydro
Installation Works In Harsh Conditions
Gravity Base Deployment Devised the method Designed and commissioned the plant and equipment Installation of gravity base turbines
250t Gravity Base - EMEC Installation of 6m dia. turbine and gravity base at EMEC in Orkney, Scotland
450t Gravity Base Bay Of Fundy 10m dia. 1MW Rated Tidal Turbine deployment In The Bay Of Fundy, Nova Scotia, Canada
Tight timescale - 3 weeks from appointment to completion Delivered early and on budget Collaborated with many UK and NI Companies
SR2000 Foundation Project Gravity solution for main northern and southern foundations considered most appropriate by Scotrenewables Several foundation options considered at concept stage: Floating gravity Large gravity Modular gravity
Gravity Concept Development Modular gravity concept advanced based on: System best suited to the use of Scotrenewables own Multicat vessel, Orcadia II Iterative design optimising block weight relative to vessel s capabilities (and local quayside crane availability) Flexibility to increase foundation weight beyond designed case, as commissioning confirms design load cases Image from Damen website, http://products.damen.com/en/ra nges/multi-cat/multi-cat- 2613/deliveries/muc-2613- orcadia-ii
Modular Gravity Final Design Optimised modular blocks Steel stoppers and chain Onshore and offshore lifting equipment
Modular Gravity - Design Development of system in conjunction with discussions with vessel skippers Use of chain rather than semi-rigid train easier to install given vessel constraints, i.e. size, crane reach, etc Steel stopper arrangement provides larger bearing on side of blocks
Modular Gravity - Design Block weight optimised at 62t (dry wt); volume approx. 27m 3 Innovative use of fibres to minimise quantities of rebar Design optimised for tidal deployment
Modular Gravity Installation Blocks on seabed
Foundation Choices LCOE biggest challenge in terms of foundations Many solutions have been tried thus far, particularly gravity for single device installations Gravity is not a scalable solution for arrays
Our Unique Proposal. and a deployment barge. A with An Deployment/Recovery Foundation Installation/Drilling matching Structure geometry Frame
System Benefits Commercially viable Uses proven technologies Small diameter drilling Low environment impact Universal to most wave and tidal energy generators Anchors tested in-situ / reduced fatigue Serviceable and easily decommissioned UK patent approved, published this month
Research and Development Objectives Phase 1 Complete To design and prove on land and subsea the drilling and self levelling technology for implementation into the overall installation methodology and to market that solution in the industry to secure future installation work.
Stage 1 Drill Rig MK1 Design and Fabrication
Stage 2 - Dry Testing Phase
Stage 3 - Friction Resistance Verification Testing the passive and frictional resistance of the foot / rock interface Results have proven the ground anchor concept Coefficients of friction of up to 0.7 0.8 were recorded Full Life cyclic loading
Stage 4 - Wet Testing Phase
Research and Development Objectives Phase 2 Complete To further the rock anchor concept by applying the drilling technology in a non-controlled offshore environment. Accommodation of larger rock anchors is also part of this novel anchors with working load capacities of up to 400t are being utilised.
Drill Rig MK2 Design & Land Commissioning Part of the collaborative MRCF project with Invest NI and The Carbon Trust Design of MK2 Rig to install Ischebeck Titan 196 / 129 tension anchors (400t SLS) Land commissioning to test drilling systems taking place in NI with Quinn Piling
Land Commissioning recent site photos
Land Commissioning drilling
Drill Rig MK2 Design & Land Commissioning Outcomes Full scale rig designed and fabricated System commissioned and verified Successfully drilled Ischebeck 400t working load capacity 196/129 anchor Drilling methodologies successfully proven Penetration rates verified Future adaptation of rig for site investigation, currently under design