GB SQSS sub-group of OTEG Illustration of cost benefit analysis - - PowerPoint PPT Presentation

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GB SQSS sub-group of OTEG Illustration of cost benefit analysis - - PowerPoint PPT Presentation

Aug 23, 2022 114 likes •434 views

GB SQSS sub-group of OTEG Illustration of cost benefit analysis reasults 1 Network arrangement examples 33 kV 33 kV 33 kV Windfarm electrical system 132 kV 132 kV 132 kV 33 kV 132 kV/220kV 132 kV 400 kV 132kV/220 kV 400 kV Onshore

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GB SQSS sub-group of OTEG

Illustration of cost benefit analysis reasults

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Network arrangement examples

132kV/220 kV 33 kV Onshore network 132 kV/220kV

Windfarm electrical system

132 kV 33 kV 400 kV 132 kV Onshore network 400 kV 132 kV 33 kV 132 kV 33 kV

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Platform design: Number of transformers 1 SGT or 2 SGTs

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One, two or three transformers (MTTR 3 months)

5 10 15 20 25 30 35 40 45 50 1 2 1 2 1 2 1 2 1 2 1 2 1 2 3 t. 3 t. 2 t. 3 t. 2 t. 2 t. 1 t. 120 MW t. 150 MW t. 180 MW t. 240 MW t. 300 MW t. 360 MW t. Cost (m£) Platform & plant cost (m£) EEC cost (m£) Losses cost (m£) Mainenance cost (m£) Test 1 Technology AC Voltage (kV) (All) Wind generation (MW) 400 MW Transformer rating (MW) Number of transformers Wind profile index Data

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5 10 15 20 25 30 35 40 45 50 1 2 1 2 1 2 1 2 1 2 1 2 1 2 3 t. 3 t. 2 t. 3 t. 2 t. 2 t. 1 t. 120 MW t. 150 MW t. 180 MW t. 240 MW t. 300 MW t. 360 MW t. Cost (m£) Platform & plant cost (m£) EEC cost (m£) Losses cost (m£) Mainenance cost (m£) Test 1 Technology AC Voltage (kV) (All) Wind generation (MW) 400 MW Transformer rating (MW) Number of transformers Wind profile index Data

One, two or three transformers (MTTR 4.5 months)

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10 20 30 40 50 60 70 1 2 1 2 1 2 1 2 1 2 1 2 1 2 3 t. 3 t. 2 t. 3 t. 2 t. 2 t. 1 t. 120 MW t. 150 MW t. 180 MW t. 240 MW t. 300 MW t. 360 MW t. Cost (m£) Platform & plant cost (m£) EEC cost (m£) Losses cost (m£) Mainenance cost (m£) Test 1 Technology AC Voltage (kV) (All) Wind generation (MW) 400 MW Transformer rating (MW) Number of transformers Wind profile index Data

One, two or three transformers (MTTR 15.5 months)

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Break-even MTTR for Transformers

MTTR (months) Energy cost (£/MWh) Substation solution 50 75 100 1x360 MW < 6.5 < 4.5 < 3.2 2x180 MW < 15.5 < 10.5 < 8 2x240 MW < 23.5 < 15.5 < 11.5 3x150 MW < 34 < 23 < 17.5 3x180 MW

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Conclusion

  • For cost (value) of wind energy of

£75/MWh and MTTR above 4.5 months (£100/MWh and 3.2 months), N-1 justified for AC solutions

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Cable system design: Number of cables

1 or 2 cables

MTTR and cost of energy that favour N-1 over N-0

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20 40 60 80 100 120 140 160 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 c. 2 c. 1 c. 2 c. 1 c. 2 c. 1 c. 2 c. 278 MW 278 MW 274 MW 266 MW 500 mm² 500 mm² 500 mm² 500 mm² 25 km 50 km 75 km 100 km Cost (m£) Platform & plant cost (m£) Cables cost (m£) MVArs cost (m£) EEC cost (m£) Losses cost (m£) Mainenance cost (m£) Test 1 Technology AC Voltage (kV) 220 kV Wind generation (MW) 280 MW Transformer rating (MW) 135 MW t. Number of transformers 2 t. Cable length (km) Cable size (mm²) Cable capability (MW) Number of cables Wind profile index Data

N-1 versus N-0 (MTTR 2 months)

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20 40 60 80 100 120 140 160 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 c. 2 c. 1 c. 2 c. 1 c. 2 c. 1 c. 2 c. 278 MW 278 MW 274 MW 266 MW 500 mm² 500 mm² 500 mm² 500 mm² 25 km 50 km 75 km 100 km Cost (m£) Platform & plant cost (m£) Cables cost (m£) MVArs cost (m£) EEC cost (m£) Losses cost (m£) Mainenance cost (m£) Test 1 Technology AC Voltage (kV) 220 kV Wind generation (MW) 280 MW Transformer rating (MW) 135 MW t. Number of transformers 2 t. Cable length (km) Cable size (mm²) Cable capability (MW) Number of cables Wind profile index Data

N-1 versus N-0 (MTTR 8.5 months)

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20 40 60 80 100 120 140 160 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 c. 2 c. 1 c. 2 c. 1 c. 2 c. 1 c. 2 c. 278 MW 278 MW 274 MW 266 MW 500 mm² 500 mm² 500 mm² 500 mm² 25 km 50 km 75 km 100 km Cost (m£) Platform & plant cost (m£) Cables cost (m£) MVArs cost (m£) EEC cost (m£) Losses cost (m£) Mainenance cost (m£) Test 1 Technology AC Voltage (kV) 220 kV Wind generation (MW) 280 MW Transformer rating (MW) 135 MW t. Number of transformers 2 t. Cable length (km) Cable size (mm²) Cable capability (MW) Number of cables Wind profile index Data

N-1 versus N-0 (MTTR 9 months)

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20 40 60 80 100 120 140 160 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 c. 2 c. 1 c. 2 c. 1 c. 2 c. 1 c. 2 c. 278 MW 278 MW 274 MW 266 MW 500 mm² 500 mm² 500 mm² 500 mm² 25 km 50 km 75 km 100 km Cost (m£) Platform & plant cost (m£) Cables cost (m£) MVArs cost (m£) EEC cost (m£) Losses cost (m£) Mainenance cost (m£) Test 1 Technology AC Voltage (kV) 220 kV Wind generation (MW) 280 MW Transformer rating (MW) 135 MW t. Number of transformers 2 t. Cable length (km) Cable size (mm²) Cable capability (MW) Number of cables Wind profile index Data

N-1 versus N-0 (MTTR 9.5 months)

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20 40 60 80 100 120 140 160 180 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 c. 2 c. 1 c. 2 c. 1 c. 2 c. 1 c. 2 c. 278 MW 278 MW 274 MW 266 MW 500 mm² 500 mm² 500 mm² 500 mm² 25 km 50 km 75 km 100 km Cost (m£) Platform & plant cost (m£) Cables cost (m£) MVArs cost (m£) EEC cost (m£) Losses cost (m£) Mainenance cost (m£) Test 1 Technology AC Voltage (kV) 220 kV Wind generation (MW) 280 MW Transformer rating (MW) 135 MW t. Number of transformers 2 t. Cable length (km) Cable size (mm²) Cable capability (MW) Number of cables Wind profile index Data

N-1 v. N-0 (MTTR 10 months)

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20 40 60 80 100 120 140 160 180 200 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 c. 2 c. 1 c. 2 c. 1 c. 2 c. 1 c. 2 c. 278 MW 278 MW 274 MW 266 MW 500 mm² 500 mm² 500 mm² 500 mm² 25 km 50 km 75 km 100 km Cost (m£) Platform & plant cost (m£) Cables cost (m£) MVArs cost (m£) EEC cost (m£) Losses cost (m£) Mainenance cost (m£) Test 1 Technology AC Voltage (kV) 220 kV Wind generation (MW) 280 MW Transformer rating (MW) 135 MW t. Number of transformers 2 t. Cable length (km) Cable size (mm²) Cable capability (MW) Number of cables Wind profile index Data

N-1 versus N-0 (energy cost 230£/MWh)

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20 40 60 80 100 120 140 160 180 200 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 c. 2 c. 1 c. 2 c. 1 c. 2 c. 1 c. 2 c. 278 MW 278 MW 274 MW 266 MW 500 mm² 500 mm² 500 mm² 500 mm² 25 km 50 km 75 km 100 km Cost (m£) Platform & plant cost (m£) Cables cost (m£) MVArs cost (m£) EEC cost (m£) Losses cost (m£) Mainenance cost (m£) Test 1 Technology AC Voltage (kV) 220 kV Wind generation (MW) 280 MW Transformer rating (MW) 135 MW t. Number of transformers 2 t. Cable length (km) Cable size (mm²) Cable capability (MW) Number of cables Wind profile index Data

N-1 versus N-0 (energy cost 240£/MWh)

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20 40 60 80 100 120 140 160 180 200 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 c. 2 c. 1 c. 2 c. 1 c. 2 c. 1 c. 2 c. 278 MW 278 MW 274 MW 266 MW 500 mm² 500 mm² 500 mm² 500 mm² 25 km 50 km 75 km 100 km Cost (m£) Platform & plant cost (m£) Cables cost (m£) MVArs cost (m£) EEC cost (m£) Losses cost (m£) Mainenance cost (m£) Test 1 Technology AC Voltage (kV) 220 kV Wind generation (MW) 280 MW Transformer rating (MW) 135 MW t. Number of transformers 2 t. Cable length (km) Cable size (mm²) Cable capability (MW) Number of cables Wind profile index Data

N-1 versus N-0 (energy cost 250£/MWh)

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1 or 2 Cables: summary

Length MTTR Energy cost km months £/MWh 25 13 50 50 14.5 50 75 16 50 100 18 50 25 8.5 75 50 9 75 75 9.5 75 100 10 75 25 6 100 50 6 100 75 6.5 100 100 7 100 25 2 230 50 2 240 75 2 240 100 2 250

  • Break-even

parameters are in red

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Cable Redundancy Analysis

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10 20 30 40 50 60 70 80 1 2 1 2 1 2 2 c. 1 c. 2 c. 278 MW 334 MW 500 mm² 800 mm² Cost (m£) Platform & plant cost (m£) Cables cost (m£) MVArs cost (m£) EEC cost (m£) Losses cost (m£) Mainenance cost (m£) Test 1 Technology AC Voltage (kV) 220 kV Wind generation (MW) 350 MW Transformer rating (MW 170 MW t. Number of transformers 2 t. Cable length (km) 25 km Cable size (mm²) Cable capability (MW) Number of cables Wind profile index Data

N-1 versus N-0 (MTTR 2 months)

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10 20 30 40 50 60 70 80 1 2 1 2 1 2 2 c. 1 c. 2 c. 278 MW 334 MW 500 mm² 800 mm² Cost (m£) Platform & plant cost (m£) Cables cost (m£) MVArs cost (m£) EEC cost (m£) Losses cost (m£) Mainenance cost (m£) Test 1 Technology AC Voltage (kV) 220 kV Wind generation (MW) 350 MW Transformer rating (MW 170 MW t. Number of transformers 2 t. Cable length (km) 25 km Cable size (mm²) Cable capability (MW) Number of cables Wind profile index Data

N-1 versus N-0 (MTTR 6.5 months)

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10 20 30 40 50 60 70 80 1 2 1 2 1 2 2 c. 1 c. 2 c. 278 MW 334 MW 500 mm² 800 mm² Cost (m£) Platform & plant cost (m£) Cables cost (m£) MVArs cost (m£) EEC cost (m£) Losses cost (m£) Mainenance cost (m£) Test 1 Technology AC Voltage (kV) 220 kV Wind generation (MW) 350 MW Transformer rating (MW 170 MW t. Number of transformers 2 t. Cable length (km) 25 km Cable size (mm²) Cable capability (MW) Number of cables Wind profile index Data

N-1 versus N-0 (MTTR 7.5 months)

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Case Study 350 MW Wind Farm 1 circuit of 220kV or 2 circuits of 132kV

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Total costs

20 40 60 80 100 120 140 160 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 2 c. 1 c. 1 c. 2 c. 1 c. 1 c. 2 c. 1 c. 1 c. 2 c. 1 c. 1 c. 168 MW 334 MW 334 MW 168 MW 334 MW 334 MW 168 MW 328 MW 328 MW 166 MW 319 MW 319 MW 500 mm² 800 mm² 800 mm² 500 mm² 800 mm² 800 mm² 500 mm² 800 mm² 800 mm² 500 mm² 800 mm² 800 mm² 2 t. 1 t. 1 t. 2 t. 1 t. 1 t. 2 t. 1 t. 1 t. 2 t. 1 t. 1 t. 160 MW t. 320 MW t. 320 MW t. 160 MW t. 320 MW t. 320 MW t. 160 MW t. 320 MW t. 320 MW t. 160 MW t. 320 MW t. 320 MW t. 132 kV HC 220 kV LC 220 kV 132 kV HC 220 kV LC 220 kV 132 kV HC 220 kV LC 220 kV 132 kV HC 220 kV LC 220 kV 25 km 50 km 75 km 100 km Cost (m£) Platform & plant cost (m£) Cables cost (m£) MVArs cost (m£) EEC cost (m£) Losses cost (m£) Mainenance cost (m£) Test 1 Technology AC Wind generation (MW) 350 MW Cable length (km) Voltage (kV) Transformer rating (M Number of transforme Cable size (mm²) Cable capability (MWNumber of cables Wind profile index Data

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Sensitivity of failure rate

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Break-even MTTR of Cables

MTTR (months) 1 or 2 cables 2 or 3 cables Energy cost Length Failure rate (1/year.100km) £/MWh km 0.04 0.08 0.12 0.04 0.08 0.12 25 39 19.5 13 45 23 15.5 50 43 21 14.5 48 24.5 16.5 75 47 23.5 16 50 25.5 17 100 52 26.5 18 51 26 17.5 25 24 12.5 8.5 28 14.5 9.5 50 26 13 9 30 15 10 75 28 14 9.5 30 15.5 10.5 100 29 15 10 30 15 10 25 17 9 6 20 10 7 50 18 9.5 6 21 10.5 7 75 19 9.5 6.5 21 10.5 7 100 20 10 7 21 10.5 7 100 75 50

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Break-even Energy Costs

Energy cost (£/MWh) 1 or 2 cables 2 or 3 cables MTTR Length Failure rate (1/year.100km) month s km 0.04 0.08 0.12 0.04 0.08 0.12 25 420 300 230 410 310 250 50 430 300 240 420 320 250 75 430 310 240 420 310 250 100 440 310 250 420 310 250 2

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Summary

  • Cost of wind energy lost (losses + constrained energy) should be valued at

forward price from brown electricity + ROC (BM prices should not be used)

  • Sensitivity approach used: determine critical values of driving parameters

that change the design:

– Parameters analysed:

  • Mean Time to Repair for Transformers
  • Cost of energy lost
  • Mean Time to Repair for Cables
  • Distance from shore

– Cost parameters kept constant

  • Design of platform for AC solution

– For cost of wind energy above 75£/MWh and MTTR greater than 4.5 months (or £100/MWh and 3.2 months) – N-2 not justified for any of the values of the parameters analyzed – N-1 not justified for DC solutions

  • Design of cable networks:

– N-0, minimum number of circuits

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Size limit of a single circuit connection

  • Recommendation: Limit single circuit cable connection

to 1500MW – Loss of 1500MW of offshore wind farm capacity connected to a single cable circuit is infrequent:

  • On average, less than 1 event of 1500MW loss in 25-31

years, per 1500MW wind farm – Failure rates of cables 0.08failures/100km.year – Probability that a wind farm of 1500MW capacity will generate above 1000MW is between 16% and 20%

– Cost of additional response for handling losses above 1320MW of a 1500MW wind farm is 5 times smaller than the cost of additional circuit (cost of response is assumed to be extremely high)

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Probability that the output of a wind farm of a given capacity is above 1000MW level Wind Capacity (MW) Probability

1050

0.00

1160

0.03

1260

0.08

1370

0.12

1470

0.16

1580

0.20

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HVDC singe and double circuit costs (1500MW) (includes both capital and operating cost of the design)

Singe and double circuit HVDC costs (capitalised) and additional annual response costs

Wind farm capacity [MW] Annual additional cost

  • f reserve [m£]

1395 1421 0.04 1447 0.12 1474 0.23 1500 0.43