Mazao Consulting / Energy Data Analytics
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Mazao Consulting / GB Power Weekly
Week ending Sun 20 Sep 2026 · issued 21 Sep, 07:48 BST

Average day-ahead fell 30.3% on the prior week, to £105.41/MWh, week ending 2026-09-20.

Best 1-hour battery spread of the week was £215.06/MWh, on Sun 20 Sep. Wind share of generation was 50%.

Half-hourly day-ahead and imbalance prices across the week, in pounds per megawatt hour £275 imbalance, Wed 16 Sep SP35 0 50 100 150 200 250 300 £/MWh Mon 14 Tue 15 Wed 16 Thu 17 Fri 18 Sat 19 Sun 20
Day-ahead Imbalance Week high
Average day-ahead
£105.41 /MWh
-30.3% on prior week
Best 1h spread
£215.06 /MWh
30-day median £82.02
Wind share of generation
50%
+11 pts on prior week
Highest imbalance price
£275 /MWh
Wed 16 Sep, SP35

What moved the week

Three drivers, each with the number that matters.

Wind output

MTWTFSS

7.1 GW daily low on Mon 14 Sep, against 15.2 GW on Sat 19 Sep. Wind output ranged from 7.1 GW on Mon 14 Sep to 15.2 GW on Sat 19 Sep.

Peak demand

MTWTFSS

30.8 GW peak on Wed 16 Sep. Peak demand for the week was 30.8 GW, on Wed 16 Sep.

Periods above £100

MTWTFSS

48 settlement periods cleared above £100 on Mon 14 Sep, against 5 on Sat 19 Sep. 48 settlement periods cleared above £100 on Mon 14 Sep, against 5 on Sat 19 Sep.

Best 1-hour spread of the week: £215.06/MWh, on Sun 20 Sep. Wind share of generation was 50% across the week.

Where value sat in the day

Price relative to that day's own average, by settlement period. Blue is below the daily mean, which is when a battery charges. Red is above it.

Mon 14 SP1: -13 £/MWh vs day mean Mon 14 SP2: -15 £/MWh vs day mean Mon 14 SP3: -13 £/MWh vs day mean Mon 14 SP4: -17 £/MWh vs day mean Mon 14 SP5: -19 £/MWh vs day mean Mon 14 SP6: -17 £/MWh vs day mean Mon 14 SP7: -15 £/MWh vs day mean Mon 14 SP8: -21 £/MWh vs day mean Mon 14 SP9: -14 £/MWh vs day mean Mon 14 SP10: -16 £/MWh vs day mean Mon 14 SP11: +6 £/MWh vs day mean Mon 14 SP12: +11 £/MWh vs day mean Mon 14 SP13: +15 £/MWh vs day mean Mon 14 SP14: +18 £/MWh vs day mean Mon 14 SP15: +29 £/MWh vs day mean Mon 14 SP16: +32 £/MWh vs day mean Mon 14 SP17: +20 £/MWh vs day mean Mon 14 SP18: +22 £/MWh vs day mean Mon 14 SP19: +10 £/MWh vs day mean Mon 14 SP20: -3 £/MWh vs day mean Mon 14 SP21: -5 £/MWh vs day mean Mon 14 SP22: +1 £/MWh vs day mean Mon 14 SP23: +11 £/MWh vs day mean Mon 14 SP24: +4 £/MWh vs day mean Mon 14 SP25: +0 £/MWh vs day mean Mon 14 SP26: -20 £/MWh vs day mean Mon 14 SP27: -25 £/MWh vs day mean Mon 14 SP28: -30 £/MWh vs day mean Mon 14 SP29: -32 £/MWh vs day mean Mon 14 SP30: -34 £/MWh vs day mean Mon 14 SP31: -33 £/MWh vs day mean Mon 14 SP32: -35 £/MWh vs day mean Mon 14 SP33: -34 £/MWh vs day mean Mon 14 SP34: -23 £/MWh vs day mean Mon 14 SP35: +23 £/MWh vs day mean Mon 14 SP36: +19 £/MWh vs day mean Mon 14 SP37: +25 £/MWh vs day mean Mon 14 SP38: +26 £/MWh vs day mean Mon 14 SP39: +39 £/MWh vs day mean Mon 14 SP40: +30 £/MWh vs day mean Mon 14 SP41: +23 £/MWh vs day mean Mon 14 SP42: +19 £/MWh vs day mean Mon 14 SP43: +14 £/MWh vs day mean Mon 14 SP44: +8 £/MWh vs day mean Mon 14 SP45: +5 £/MWh vs day mean Mon 14 SP46: +8 £/MWh vs day mean Mon 14 SP47: +8 £/MWh vs day mean Mon 14 SP48: +6 £/MWh vs day mean Tue 15 SP1: +33 £/MWh vs day mean Tue 15 SP2: +30 £/MWh vs day mean Tue 15 SP3: +17 £/MWh vs day mean Tue 15 SP4: +20 £/MWh vs day mean Tue 15 SP5: +32 £/MWh vs day mean Tue 15 SP6: +20 £/MWh vs day mean Tue 15 SP7: +17 £/MWh vs day mean Tue 15 SP8: +4 £/MWh vs day mean Tue 15 SP9: +22 £/MWh vs day mean Tue 15 SP10: +11 £/MWh vs day mean Tue 15 SP11: +4 £/MWh vs day mean Tue 15 SP12: +13 £/MWh vs day mean Tue 15 SP13: +19 £/MWh vs day mean Tue 15 SP14: +22 £/MWh vs day mean Tue 15 SP15: +20 £/MWh vs day mean Tue 15 SP16: +33 £/MWh vs day mean Tue 15 SP17: +6 £/MWh vs day mean Tue 15 SP18: -5 £/MWh vs day mean Tue 15 SP19: -25 £/MWh vs day mean Tue 15 SP20: -43 £/MWh vs day mean Tue 15 SP21: -73 £/MWh vs day mean Tue 15 SP22: -89 £/MWh vs day mean Tue 15 SP23: -102 £/MWh vs day mean Tue 15 SP24: -100 £/MWh vs day mean Tue 15 SP25: -98 £/MWh vs day mean Tue 15 SP26: -85 £/MWh vs day mean Tue 15 SP27: -70 £/MWh vs day mean Tue 15 SP28: -70 £/MWh vs day mean Tue 15 SP29: -61 £/MWh vs day mean Tue 15 SP30: -54 £/MWh vs day mean Tue 15 SP31: +1 £/MWh vs day mean Tue 15 SP32: +10 £/MWh vs day mean Tue 15 SP33: +33 £/MWh vs day mean Tue 15 SP34: +26 £/MWh vs day mean Tue 15 SP35: +46 £/MWh vs day mean Tue 15 SP36: +53 £/MWh vs day mean Tue 15 SP37: +54 £/MWh vs day mean Tue 15 SP38: +64 £/MWh vs day mean Tue 15 SP39: +57 £/MWh vs day mean Tue 15 SP40: +62 £/MWh vs day mean Tue 15 SP41: +54 £/MWh vs day mean Tue 15 SP42: +43 £/MWh vs day mean Tue 15 SP43: +22 £/MWh vs day mean Tue 15 SP44: +16 £/MWh vs day mean Tue 15 SP45: +8 £/MWh vs day mean Tue 15 SP46: +11 £/MWh vs day mean Tue 15 SP47: -4 £/MWh vs day mean Tue 15 SP48: -4 £/MWh vs day mean Wed 16 SP1: -31 £/MWh vs day mean Wed 16 SP2: -32 £/MWh vs day mean Wed 16 SP3: -22 £/MWh vs day mean Wed 16 SP4: -27 £/MWh vs day mean Wed 16 SP5: -37 £/MWh vs day mean Wed 16 SP6: -32 £/MWh vs day mean Wed 16 SP7: -19 £/MWh vs day mean Wed 16 SP8: -28 £/MWh vs day mean Wed 16 SP9: -23 £/MWh vs day mean Wed 16 SP10: -29 £/MWh vs day mean Wed 16 SP11: -11 £/MWh vs day mean Wed 16 SP12: -24 £/MWh vs day mean Wed 16 SP13: +2 £/MWh vs day mean Wed 16 SP14: +16 £/MWh vs day mean Wed 16 SP15: +20 £/MWh vs day mean Wed 16 SP16: +35 £/MWh vs day mean Wed 16 SP17: +20 £/MWh vs day mean Wed 16 SP18: +6 £/MWh vs day mean Wed 16 SP19: -4 £/MWh vs day mean Wed 16 SP20: -12 £/MWh vs day mean Wed 16 SP21: -11 £/MWh vs day mean Wed 16 SP22: -17 £/MWh vs day mean Wed 16 SP23: -10 £/MWh vs day mean Wed 16 SP24: -18 £/MWh vs day mean Wed 16 SP25: -16 £/MWh vs day mean Wed 16 SP26: -7 £/MWh vs day mean Wed 16 SP27: +2 £/MWh vs day mean Wed 16 SP28: +2 £/MWh vs day mean Wed 16 SP29: +6 £/MWh vs day mean Wed 16 SP30: +1 £/MWh vs day mean Wed 16 SP31: +5 £/MWh vs day mean Wed 16 SP32: +1 £/MWh vs day mean Wed 16 SP33: +7 £/MWh vs day mean Wed 16 SP34: +31 £/MWh vs day mean Wed 16 SP35: +39 £/MWh vs day mean Wed 16 SP36: +52 £/MWh vs day mean Wed 16 SP37: +50 £/MWh vs day mean Wed 16 SP38: +41 £/MWh vs day mean Wed 16 SP39: +37 £/MWh vs day mean Wed 16 SP40: +31 £/MWh vs day mean Wed 16 SP41: +30 £/MWh vs day mean Wed 16 SP42: +20 £/MWh vs day mean Wed 16 SP43: +3 £/MWh vs day mean Wed 16 SP44: -8 £/MWh vs day mean Wed 16 SP45: -3 £/MWh vs day mean Wed 16 SP46: -6 £/MWh vs day mean Wed 16 SP47: -10 £/MWh vs day mean Wed 16 SP48: -23 £/MWh vs day mean Thu 17 SP1: +39 £/MWh vs day mean Thu 17 SP2: +37 £/MWh vs day mean Thu 17 SP3: +23 £/MWh vs day mean Thu 17 SP4: +13 £/MWh vs day mean Thu 17 SP5: +17 £/MWh vs day mean Thu 17 SP6: +30 £/MWh vs day mean Thu 17 SP7: +14 £/MWh vs day mean Thu 17 SP8: +21 £/MWh vs day mean Thu 17 SP9: +18 £/MWh vs day mean Thu 17 SP10: +22 £/MWh vs day mean Thu 17 SP11: +23 £/MWh vs day mean Thu 17 SP12: +28 £/MWh vs day mean Thu 17 SP13: +31 £/MWh vs day mean Thu 17 SP14: +40 £/MWh vs day mean Thu 17 SP15: +41 £/MWh vs day mean Thu 17 SP16: +62 £/MWh vs day mean Thu 17 SP17: +45 £/MWh vs day mean Thu 17 SP18: +18 £/MWh vs day mean Thu 17 SP19: -45 £/MWh vs day mean Thu 17 SP20: -83 £/MWh vs day mean Thu 17 SP21: -90 £/MWh vs day mean Thu 17 SP22: -97 £/MWh vs day mean Thu 17 SP23: -101 £/MWh vs day mean Thu 17 SP24: -100 £/MWh vs day mean Thu 17 SP25: -101 £/MWh vs day mean Thu 17 SP26: -102 £/MWh vs day mean Thu 17 SP27: -85 £/MWh vs day mean Thu 17 SP28: -93 £/MWh vs day mean Thu 17 SP29: -91 £/MWh vs day mean Thu 17 SP30: -84 £/MWh vs day mean Thu 17 SP31: -53 £/MWh vs day mean Thu 17 SP32: -41 £/MWh vs day mean Thu 17 SP33: -21 £/MWh vs day mean Thu 17 SP34: +8 £/MWh vs day mean Thu 17 SP35: +43 £/MWh vs day mean Thu 17 SP36: +55 £/MWh vs day mean Thu 17 SP37: +65 £/MWh vs day mean Thu 17 SP38: +69 £/MWh vs day mean Thu 17 SP39: +77 £/MWh vs day mean Thu 17 SP40: +71 £/MWh vs day mean Thu 17 SP41: +62 £/MWh vs day mean Thu 17 SP42: +50 £/MWh vs day mean Thu 17 SP43: +35 £/MWh vs day mean Thu 17 SP44: +21 £/MWh vs day mean Thu 17 SP45: +23 £/MWh vs day mean Thu 17 SP46: +23 £/MWh vs day mean Thu 17 SP47: +33 £/MWh vs day mean Thu 17 SP48: +31 £/MWh vs day mean Fri 18 SP1: +43 £/MWh vs day mean Fri 18 SP2: +44 £/MWh vs day mean Fri 18 SP3: +42 £/MWh vs day mean Fri 18 SP4: +40 £/MWh vs day mean Fri 18 SP5: +39 £/MWh vs day mean Fri 18 SP6: +42 £/MWh vs day mean Fri 18 SP7: +36 £/MWh vs day mean Fri 18 SP8: +38 £/MWh vs day mean Fri 18 SP9: +43 £/MWh vs day mean Fri 18 SP10: +45 £/MWh vs day mean Fri 18 SP11: +51 £/MWh vs day mean Fri 18 SP12: +62 £/MWh vs day mean Fri 18 SP13: +68 £/MWh vs day mean Fri 18 SP14: +87 £/MWh vs day mean Fri 18 SP15: +89 £/MWh vs day mean Fri 18 SP16: +84 £/MWh vs day mean Fri 18 SP17: +57 £/MWh vs day mean Fri 18 SP18: +45 £/MWh vs day mean Fri 18 SP19: +24 £/MWh vs day mean Fri 18 SP20: +10 £/MWh vs day mean Fri 18 SP21: -18 £/MWh vs day mean Fri 18 SP22: -28 £/MWh vs day mean Fri 18 SP23: -63 £/MWh vs day mean Fri 18 SP24: -71 £/MWh vs day mean Fri 18 SP25: -69 £/MWh vs day mean Fri 18 SP26: -70 £/MWh vs day mean Fri 18 SP27: -69 £/MWh vs day mean Fri 18 SP28: -68 £/MWh vs day mean Fri 18 SP29: -67 £/MWh vs day mean Fri 18 SP30: -71 £/MWh vs day mean Fri 18 SP31: -55 £/MWh vs day mean Fri 18 SP32: -48 £/MWh vs day mean Fri 18 SP33: -34 £/MWh vs day mean Fri 18 SP34: -31 £/MWh vs day mean Fri 18 SP35: +39 £/MWh vs day mean Fri 18 SP36: +36 £/MWh vs day mean Fri 18 SP37: +45 £/MWh vs day mean Fri 18 SP38: +39 £/MWh vs day mean Fri 18 SP39: +18 £/MWh vs day mean Fri 18 SP40: +7 £/MWh vs day mean Fri 18 SP41: -4 £/MWh vs day mean Fri 18 SP42: -22 £/MWh vs day mean Fri 18 SP43: -43 £/MWh vs day mean Fri 18 SP44: -56 £/MWh vs day mean Fri 18 SP45: -63 £/MWh vs day mean Fri 18 SP46: -66 £/MWh vs day mean Fri 18 SP47: -79 £/MWh vs day mean Fri 18 SP48: -79 £/MWh vs day mean Sat 19 SP1: -29 £/MWh vs day mean Sat 19 SP2: -28 £/MWh vs day mean Sat 19 SP3: -26 £/MWh vs day mean Sat 19 SP4: -28 £/MWh vs day mean Sat 19 SP5: -26 £/MWh vs day mean Sat 19 SP6: -26 £/MWh vs day mean Sat 19 SP7: -25 £/MWh vs day mean Sat 19 SP8: -23 £/MWh vs day mean Sat 19 SP9: -25 £/MWh vs day mean Sat 19 SP10: -22 £/MWh vs day mean Sat 19 SP11: -24 £/MWh vs day mean Sat 19 SP12: -22 £/MWh vs day mean Sat 19 SP13: -19 £/MWh vs day mean Sat 19 SP14: -19 £/MWh vs day mean Sat 19 SP15: -15 £/MWh vs day mean Sat 19 SP16: -11 £/MWh vs day mean Sat 19 SP17: -15 £/MWh vs day mean Sat 19 SP18: -13 £/MWh vs day mean Sat 19 SP19: -17 £/MWh vs day mean Sat 19 SP20: -20 £/MWh vs day mean Sat 19 SP21: -20 £/MWh vs day mean Sat 19 SP22: -22 £/MWh vs day mean Sat 19 SP23: -23 £/MWh vs day mean Sat 19 SP24: -25 £/MWh vs day mean Sat 19 SP25: -24 £/MWh vs day mean Sat 19 SP26: -25 £/MWh vs day mean Sat 19 SP27: -26 £/MWh vs day mean Sat 19 SP28: -28 £/MWh vs day mean Sat 19 SP29: -27 £/MWh vs day mean Sat 19 SP30: -27 £/MWh vs day mean Sat 19 SP31: -24 £/MWh vs day mean Sat 19 SP32: -18 £/MWh vs day mean Sat 19 SP33: +6 £/MWh vs day mean Sat 19 SP34: +24 £/MWh vs day mean Sat 19 SP35: +42 £/MWh vs day mean Sat 19 SP36: +58 £/MWh vs day mean Sat 19 SP37: +83 £/MWh vs day mean Sat 19 SP38: +95 £/MWh vs day mean Sat 19 SP39: +103 £/MWh vs day mean Sat 19 SP40: +112 £/MWh vs day mean Sat 19 SP41: +77 £/MWh vs day mean Sat 19 SP42: +50 £/MWh vs day mean Sat 19 SP43: +60 £/MWh vs day mean Sat 19 SP44: +24 £/MWh vs day mean Sat 19 SP45: +10 £/MWh vs day mean Sat 19 SP46: +7 £/MWh vs day mean Sat 19 SP47: -14 £/MWh vs day mean Sat 19 SP48: -19 £/MWh vs day mean Sun 20 SP1: -47 £/MWh vs day mean Sun 20 SP2: -50 £/MWh vs day mean Sun 20 SP3: -52 £/MWh vs day mean Sun 20 SP4: -53 £/MWh vs day mean Sun 20 SP5: -53 £/MWh vs day mean Sun 20 SP6: -51 £/MWh vs day mean Sun 20 SP7: -52 £/MWh vs day mean Sun 20 SP8: -52 £/MWh vs day mean Sun 20 SP9: -52 £/MWh vs day mean Sun 20 SP10: -51 £/MWh vs day mean Sun 20 SP11: -41 £/MWh vs day mean Sun 20 SP12: -31 £/MWh vs day mean Sun 20 SP13: -40 £/MWh vs day mean Sun 20 SP14: -41 £/MWh vs day mean Sun 20 SP15: -43 £/MWh vs day mean Sun 20 SP16: -42 £/MWh vs day mean Sun 20 SP17: -43 £/MWh vs day mean Sun 20 SP18: -38 £/MWh vs day mean Sun 20 SP19: -48 £/MWh vs day mean Sun 20 SP20: -50 £/MWh vs day mean Sun 20 SP21: -51 £/MWh vs day mean Sun 20 SP22: -52 £/MWh vs day mean Sun 20 SP23: -54 £/MWh vs day mean Sun 20 SP24: -54 £/MWh vs day mean Sun 20 SP25: -55 £/MWh vs day mean Sun 20 SP26: -56 £/MWh vs day mean Sun 20 SP27: -54 £/MWh vs day mean Sun 20 SP28: -56 £/MWh vs day mean Sun 20 SP29: -58 £/MWh vs day mean Sun 20 SP30: -63 £/MWh vs day mean Sun 20 SP31: -68 £/MWh vs day mean Sun 20 SP32: -63 £/MWh vs day mean Sun 20 SP33: -70 £/MWh vs day mean Sun 20 SP34: -13 £/MWh vs day mean Sun 20 SP35: +52 £/MWh vs day mean Sun 20 SP36: +83 £/MWh vs day mean Sun 20 SP37: +124 £/MWh vs day mean Sun 20 SP38: +128 £/MWh vs day mean Sun 20 SP39: +136 £/MWh vs day mean Sun 20 SP40: +144 £/MWh vs day mean Sun 20 SP41: +146 £/MWh vs day mean Sun 20 SP42: +144 £/MWh vs day mean Sun 20 SP43: +147 £/MWh vs day mean Sun 20 SP44: +142 £/MWh vs day mean Sun 20 SP45: +129 £/MWh vs day mean Sun 20 SP46: +110 £/MWh vs day mean Sun 20 SP47: +111 £/MWh vs day mean Sun 20 SP48: +100 £/MWh vs day mean Mon Tue Wed Thu Fri Sat Sun 1 8 16 24 32 40 48 Settlement period
−150 £/MWh Day mean +150 £/MWh

Day by day

Day-ahead prices and best 1-hour battery spread, £/MWh
DayAverage PeakTroughBest 1h spread Wind share
Mon 14 Sep 179.76218.31145.18 69.5529%
Tue 15 Sep 148.80212.3946.33 164.0150%
Wed 16 Sep 154.33206.12117.77 85.3235%
Thu 17 Sep 99.32176.18-2.25 175.0357%
Fri 18 Sep 78.70167.78-0.50 167.0460%
Sat 19 Sep 25.70137.30-3.26 135.9863%
Sun 20 Sep 51.23197.83-19.03 215.0655%

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