Island in maintenance strategy Siebe Rooseboom de Vries, Tengfei Sun, Sander Smit, Anouk Dijkman 25-01-2018 31/01/2018 1
Why is this case study performed? The energy transition Lack of space to build wind farms closer to shore 31/01/2018 2
Animation of the vision of Tennet 31/01/2018 3
The North Sea Wind Power Hub Doggerbank, North Sea Artificial island 30 GW wind farm 30 clusters of 1 GW, consisting of 100 10MW turbines 27 sub transformer stations around the island Estimated investment costs for wind farm: 70,5 billion euro 31/01/2018 4
Maintenance Equipment Transportation Access systems Rope Access Heavy lifting Safety 31/01/2018 5
Transportation CTV 20 kn 10-15 crew 2m & 15 m/s SOV 15 kn 40 60 crew 3m & 17 m/s Helicopter 120 km/h 6 crew 20 m/s 31/01/2018 6
Access systems Helideck Tower access Gangways (Motion compensated) Rope access 31/01/2018 7
The jack-up vessel 31/01/2018 8
Maintenance visions Corrective Run to failure Maximum lifetime usage Preventive Inspect, Detect, React Higher costs and maint. hours Predictive Experience / Testing Data storage Strategic Opportunity based Correlation 31/01/2018 9
Offshore wind farm maintenance Scheduled maintenance Inspection Components replacement Minor repair Unscheduled maintenance Major replacement Major repair Minor repair Remotely repair 31/01/2018 10
Offshore wind farm maintenance Scheduled maintenance Once per year 3 technicians work onsite for 2 days (12-14 hours) No crane or heavy equipment need Scheduled maintenance yearly Daily Technicians 60 60 Down time (hour) 108,000 296 Crane 0 0 Heavy equipment 0 0 31/01/2018 11
Offshore wind farm maintenance Unscheduled maintenance is not ideal, it will increase Loss of production Logistic cost Spare part inventory Number of vessel & equipment Number of technician 31/01/2018 12
Simulation model Input Output Failure rate per failure category for offshore wind turbine Whether data Equipment specification Technician salary information Number of defect in failure category Total downtime Number of technician needed Logistics distance 31/01/2018 13
Simulation model 31/01/2018 14
Simulation model Unscheduled maintenance Theoretical (Yearly) Simulated (Yearly) Simulated (Daily) Major replacement 795 858 2.35 Major repair 3186 3201 8.77 Minor repair 17342 17564 48.12 Non-cost repair 2304 2364 6.48 Technicians - - 158.14 Repair time (hour) - 279643.4 766.15 Crane 879 953 2.61 Heavy components 1293 2241 6.14 31/01/2018 15
Simulation model Logistic distance Total logistic distance year KM 594632.5 daily logistic distance KM 3258.260274 average logistic distance KM 13.75 Chance of defect at same cluster 3% Logistics time (One way) CTV-small (Minutes) 22.2972973 CTV-large (minutes) 17.83783784 SOV (Minutes) 44.59459459 Crane (Minutes) 60 helichopter (minutes) 6.875 prepair time crane (minutes) 83 prepair time (minutes) 30 31/01/2018 16
Simulated strategy Use mature technology and equipment Keep redundant equipment as less as possible 24/7 always ready technician team High flexibility for further development 31/01/2018 17
Simulated strategy More vs less Trade-off Crew numbers reduced downtime (hour/day) energy profit/year (million Euro) cost/year (million Euro) net profit (million Euro) Crane 0.5 0.059704875 10.95-10.89029513 CTV-small 0.743243243 0.08875049 1.4395-1.35074951 CTV-XL 0.743243243 0.08875049 3.39625-3.30749951 SOV 3.716216216 0.443752449 20.12125-19.67749755 Helichopter 0.859375 0.102617754 7.665-7.562382246 31/01/2018 18
Simulated strategy Just enough Strategy 31/01/2018 19
Simulation model Minimum number of equipment require Crane 2.610958904 Heavy components 6.139726027 vessels 56.63013699 The number of defect can a vessel Amoun Availabili handle per day t ty CTV-small 4 53% CTV-large 5 53% SOV 10 75% Helicopter 15 93% Crane 1 75% 31/01/2018 20
Simulated strategy Just enough Strategy Equipment Amount remarks Crew numbers 660 180 scheduled maintenance. 480 unscheduled maintenance. Crane CTV-small CTV-XL SOV Helicopter 3 One additional crane is advised 7 53% of the unscheduled maintenance workload 5 3 for 22% unscheduled maintenance work. 2 for 100% of scheduled maintenance work. 1 18% of the unscheduled workload 1 The rest unscheduled maintenance work 31/01/2018 21
Simulated strategy Just enough Strategy Maximum profit High availability Low maintenance cost High flexibility Equipment Total 72.07 million Euro Total personal cost 29.08 million euro Total material cost per year Total maintenance cost per year 175.05 Million Euro 276.21 Million Euro 31/01/2018 22
Defining the best maintenance strategy(1) The Just enough strategy The bigger is better strategy The small and quick strategy The high tech strategy 31/01/2018 23
Simulated strategy (just enough strategy) The Just enough strategy The bigger is better strategy The small and quick strategy The high tech strategy 31/01/2018 24
Defining the best maintenance strategy(2) Criteria Weight factor 1. Just Enough 2. Bigger is 3. Small and 4. High tech Better Quick Scaling 1 and up 1 to 5 1 to 5 1 to 5 1 to 5 Logistic hours 1,3 2 5 4 4 Logistic availability 1,6 1 4 5 4 Total downtime 1,8 2 2 3 4 Technical difficulty 1 5 4 4 1 Technicians 1 2 2 3 5 required Crew comfort 1 1 4 3 4 Environment 1,1 2 3 2 5 Initial investment 1 4 1 2 1 Safety 1,5 2 4 2 4 Total score 21 29 28 32 Total score including wf 25 36,8 35,8 41,3 31/01/2018 25
The high tech strategy Logistics Inspection & repair Condition monitoring (Big Data) The island 31/01/2018 26
Conclusion 31/01/2018 27