ACCESSING THE ACCESSING THE FAR SHORE WIND FARM C. Cockburn S St S. Stevens E. Dudson
ACCESSING THE FAR SHORE WIND FARM ACCESSING THE FAR SHORE WIND FARM SUMMARY SUMMARY • Operation and maintenance of offshore wind farms • Current wind farms are relatively small and positioned close to shore • Round 2 and 3 sites will be significantly further offshore • Rougher seas and longer transits • Requires a change in the current regulations and vessel designs This presentation aims to:- This presentation aims to:- • Assess the likely availability and operability of wind farm support vessels • Assess the likely requirements for future vessels Assess the likely requirements for future vessels • Suggest a forward looking strategy to meet the predetermined service requirements ACCESSING THE FAR SHORE WIND FARM
INTRODUCTION INTRODUCTION • 25% of UK electricity supplied from offshore wind energy by 2020 • Approximately 5,000 offshore units • A large number of vessels will be required required • Finite time and number of ship yards • Current vessels inappropriate for longer transits and increasing wave heights ACCESSING THE FAR SHORE WIND FARM
BACKGROUND BACKGROUND AN EVOLUTION IN VESSEL DESIGN • First vessels were small work boats and fishing boats • Dedicated vessels • Relatively fast • Aluminium • Catamarans • Custom bow fenders • Tailored power installations • Lengths of 15 metres to 20 metres, increasing to 24 metres • • Now bespoke arrangements Now bespoke arrangements ACCESSING THE FAR SHORE WIND FARM
INTRODUCTION INTRODUCTION AN EVOLUTION IN WIND ENERGY INDUSTRY • The UIK has adopted a highly progressive policy of wind energy generation • After Round 1 – UK Total of ~400 Turbines, 1.3GW • After Round 2 – UK Total of ~2000 Turbines, 7.6GW • After Round 3 – UK Total of ~6000 Turbines, 32.2GW • Size of turbines ‘Offshore Wind - Round 3 Zones’ supplied b Th by The Crown Estate C E t t ACCESSING THE FAR SHORE WIND FARM
RELATIVE SIZE AND DISTANCE OFFSHORE OF UK WIND FARMS Transit Time @ 20 kts (hours) 0 1 2 3 4 5 6 2000 ATION LIMIT 1800 Dogger Bank 9.0 GW 1600 EL CERTIFICA Round 1 Zones ‐ Offshore Wind 1400 Norfolk Round 2 Zones ‐ Offshore Wind rbines 7.2 GW Round 3 Zones ‐ Offshore Wind 1200 Round 3 Zone Extents VESSE Number of Tu 60 NM Limit Irish Sea 1000 4.2 GW 800 Hornsea 4 0 GW 4.0 GW 600 Firth of Forth 3.5 GW 400 200 0 0.0 20.0 40.0 60.0 80.0 100.0 120.0 Distance from shoreline (Nautical Miles) ACCESSING THE FAR SHORE WIND FARM
EXISTING FLEET CAPABILITY EXISTING FLEET CAPABILITY DESIGN LIMITATIONS • MCA Small Commercial Vessels MCA Small Commercial Vessels 60 nm 60 nm Code 40 nm • 60 nautical mile limit • 2 hour desirable transit time • Assuming an average transit speed of 20 knots • Restricts the range to 40 nautical miles ACCESSING THE FAR SHORE WIND FARM
ACCESSING THE FAR SHORE WIND FARM 40 nm 60 nm 60 nm
EXISTING FLEET CAPABILITY EXISTING FLEET CAPABILITY VESSEL CAPABILITY VESSEL CAPABILITY • ISO 2361 Limits for 0.5, 1 and 2 hours, 10% MSI • D Double for technicians more used to travelling at sea bl f t h i i d t t lli t • Vertical accelerations averaged over head, bow quartering and beams seas • • Possible to approximate the wave height at which the ISO limits are exceeded Possible to approximate the wave height at which the ISO limits are exceeded 0.60 0.60 0.60 16m 16 16m 16m 20m 20m 0.50 0.50 0.50 20m 24m 24m 24m cal Acceleration (g) cal Acceleration (g) cal Acceleration (g) 0.40 0.40 0.40 0.30 0.30 0.30 Vetic Vetic Vetic 0.20 0.20 0.20 0.5 hours exposure 0.5 hours exposure 0.5 hours exposure 1 hour exposure 1 hour exposure 1 hour exposure 0.10 0.10 0.10 2 hour exposure 2 hour exposure 2 hour exposure 0.00 0.00 0.00 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 Significant Wave Height (metres) Significant Wave Height (metres) Significant Wave Height (metres) Vertical Acceleration Response at 20 Knots V ti l A l ti R t 20 K t V Vertical Acceleration Response at 16 Knots ti l A l ti R t 16 K t V Vertical Acceleration Response at 24 Knots ti l A l ti R t 24 K t ACCESSING THE FAR SHORE WIND FARM
0.60 16m 16 20m 0.50 24m ) ration (g) 0.40 cal Accele 0.30 Vetic 0.20 0.5 hours exposure 1 hour exposure 0 10 0.10 2 hour exposure 0.00 0.00 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 Significant Wave Height (metres) Vertical Acceleration Response at 20 Knots Vertical Acceleration Response at 20 Knots ACCESSING THE FAR SHORE WIND FARM
APPLICATION TO WIND FARMS APPLICATION TO WIND FARMS WAVE ENVIRONMENT WAVE ENVIRONMENT • Based on data from BMT ARGOSS • 53° 00'N, 2° 30'E • Northern end of the Norfolk site 50% 42% 41% 40% nce 30% Occure 20% 13% 10% 3% 0 1% 0% 0% 0 ‐ 1 1 ‐ 2 2 ‐ 3 3 ‐ 4 4 ‐ 5 5 ‐ 6 Wave Height (metres) ACCESSING THE FAR SHORE WIND FARM
APPLICATION TO WIND FARMS APPLICATION TO WIND FARMS WAVE ENVIRONMENT WAVE ENVIRONMENT 100% 90% 90% eeding Hs 80% 70% of Time Exce 60% 50% 40% Percent 30% 20% 10% 0% 0 1 2 3 4 5 Significant Wave Height (m) ACCESSING THE FAR SHORE WIND FARM
APPLICATION TO WIND FARM SITES APPLICATION TO WIND FARM SITES R Round 3 Site - Norfolk d 3 Sit N f lk • 1440 turbines • 30 30 nm average distance offshore di t ff h • Calculated duration based on speed • • Estimated wave height limit for each Estimated wave height limit for each length of vessel at each speed • Seem low but driven by increased duration and use of offshore d ti d f ff h spectrum for entire transit Speed Duration Max Wave Height Kts hrs 16m 20m 24m 16 1.88 0.59 0.70 0.86 20 1.50 0.55 0.65 0.78 24 1.25 0.54 0.63 0.73 ACCESSING THE FAR SHORE WIND FARM
APPLICATION TO WIND FARMS APPLICATION TO WIND FARMS OPERABILITY OPERABILITY Speed Availability (%) • Using the wave statistics and Kts 16m 20m 24m motions analysis motions analysis 16 16 25 25 29 29 36 36 20 23 27 32 • Determine the percentage that 24 22 26 30 the sea state exceeds the derived limits derived limits • Increase in length increases availability • Increase in speed, reduces availability • • Lower speeds will induce higher Lower speeds will induce higher durations and reduce the acceptable ISO limits ACCESSING THE FAR SHORE WIND FARM
APPLICATION TO WIND FARMS APPLICATION TO WIND FARMS MAINTENANCE REGIMES MAINTENANCE REGIMES • Norfolk site – 1440 turbines 16 metre 20 metre 24 metre V Vessel l vessel l vessel l • 1 t 1 turbine takes 3 technicians 5 bi t k 3 t h i i 5 16 knots 21 17 14 days (15 man days) 20 knots 22 19 16 • 12 technicians per boat, 4 turbines 24 knots 22 19 17 per boat • Calculate the required number of vessels based on the availability vessels based on the availability • Unscheduled maintenance not accounted for ACCESSING THE FAR SHORE WIND FARM
APPLICATION TO WIND FARMS APPLICATION TO WIND FARMS IMPROVING OPERABILITY IMPROVING OPERABILITY • Example of the 24 metre @ 20 knots knots • Increase sea keeping ability, increases operability and availability il bilit • Increased availability reduces number of required boats • Reduces number of technicians Wave Height Vessels Technicians Availability • Reduces time of boats and crew (metres) (#) (#) (%) on standby t db 0 78 0.78 16 16 192 192 32 32 1 12 144 42 1.5 8 96 62 2 6 72 83 ACCESSING THE FAR SHORE WIND FARM
IMPROVING OPERABILITY IMPROVING OPERABILITY RIDE CONTROL SYSTEMS RIDE CONTROL SYSTEMS Potentially allow for 20% • increase in wave height increase in wave height • Increase in cost • Control Systems y • Foils • Fins • Gyros • Ballast tanks ACCESSING THE FAR SHORE WIND FARM
IMPROVING OPERABILITY IMPROVING OPERABILITY LONGER VESSELS LONGER VESSELS Increase above 24 metres in length • • Increase construction costs, fuel Increase construction costs, fuel costs, etc. • Require a change in the MCA regulations regulations • Potentially could take more technicians • More technicians would service more turbines per boat reducing the required number of boats further BMT Nigel Gee MODCat 50m Crewboat ACCESSING THE FAR SHORE WIND FARM
IMPROVING OPERABILITY IMPROVING OPERABILITY SMALL WATER PLANE AREA TWIN HULL (SWATH) HULL FORMS SMALL WATER-PLANE AREA TWIN HULL (SWATH) HULL FORMS • Significant reduction in ship motions • Much more costly to build and operate • Considerable increase in availability would significantly reduce the number of vessels required significantly reduce the number of vessels required ACCESSING THE FAR SHORE WIND FARM
Mothership Technology Mothership Technology P Purpose : Determine a suitable Hull Form for Offshore Accommodation Module D t i it bl H ll F f Off h A d ti M d l • Define Requirements • C Concept Design t D i • 80-100m OSV • 50-70m SWATH • Regulatory Review • Seakeeping Calculations • Launch and Recovery Discussions
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