May 2025
May key points
In the month to 9 June 2025, national hydro storage increased from 88% to 94% of historical average
South Island storage increased to 88% of average and North Island storage increased to 138% of average by 9 June 2025
Meridian's May 2025 monthly total inflows were 106% of historical average
Waiau catchment inflows in May 2025 were 123% of historical average
Meridian's Waitaki catchment water storage at the end of May 2025 was 84% of historical average
Water storage in Meridian's Waiau catchment was 118% of average at the end of May 2025
May 2025 was another warm month, with temperatures well above average for most of the country. Rainfall was mixed across both islands, with much of the South Island below normal levels.
National electricity demand in May 2025 was 6.1% lower than May 2024, which was a notably cold month
New Zealand Aluminium Smelter's average load during May 2025 was 523MW
Meridian's retail sales volumes in May 2025 were 0.7% higher
than May 2024
Compared to May 2024, segment sales in residential were 4.4% lower, small medium business 0.2% higher, large business 10.5% higher, agriculture 8.1% lower and corporate 3.8% higher
Market dataNational electricity demand in May 2025 was 6.1% lower than May 2024, which was a notably cold month
New Zealand Aluminium Smelter's average load during May 2025 was 523MW
May 2025 was another warm month, with temperatures well above average for most of the country. Rainfall was mixed across both islands, with much of the South Island below normal levels.
Demand in the last 12 months was 3.7% lower than the preceding 12 months
12-month average switching rate of customers changing retailers but not moving ("trader" switch) was 5.5% at the end of April 2025
12-month average switching rate of customers moving and changing retailers ("move-in" switch) was 13.4% at the end of April 2025
NATIONAL DEMANDGWh
4,200
4,000
3,800
3,600
3,400
3,200
3,000
2,800
2,600
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Range (2014-2024) 2020 2021 2022 2023 2024 2025
Source: Electricity Authority (reconciled demand)
MARKET ICP SWITCHING (ALL RETAILERS)12 month average
15%
13%
11%
9%
7%
5%
Apr 20 Oct 20 Apr 21 Oct 21 Apr 22 Oct 22 Apr 23 Oct 23 Apr 24 Oct 24 Apr 25 Industry Move-in Switch Industry Trader Switch
Source: Electricity Authority
Market dataWeekly lake storage updates are available on Meridian's website. See comparative lake levels at: https://www.meridianenergy.co.nz/power-stations/lake-levels
NATIONAL HYDRO STORAGE (9 June 2025)GWh
June 2025 saw decreases in the shorter term ASX electricity futures prices
National storage increased from 88% of average on 12 May 2025 to 94% of
average on 9 June 2025
South Island storage increased to 88% of historical average by 9 June 2025 and North Island storage increased to 138% of average
5,000
4,000
3,000
2,000
1,000
0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Average storage (92yr) 1992 2004
2008 2012 2022
2023 2024 2025
OTAHUHU ASX FUTURES SETTLEMENT PRICE$/MWh
400
350
300
250
200
150
100
50
0
BENMORE ASX FUTURES SETTLEMENT PRICE$/MWh
400
350
300
250
200
150
100
50
0
Source: NZX
Q2 Q3
Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
Q2 Q3 Q4 Q1 Q2 Q3 Q4
Q1 Q2
Q3 Q4
Q1 Q2
Q3 Q4
2025 2025 2025 2026 2026 2026 2026 2027 2027 2027 2027 2028 2028 2028 2028
28 June 2024 28 February 2025 31 March 2025
30 April 2025 30 May 2025 11 June 2025 Source: ASX
2025 2025 2025 2026 2026 2026 2026 2027 2027 2027 2027 2028 2028 2028 2028
28 June 2024 28 February 2025 31 March 2025
30 April 2025 30 May 2025 11 June 2025 Source: ASX
Meridian operating information
Meridian retail MERIDIAN'S CUSTOMER CONNECTIONSMeridian's customer connection numbers
ICPs ('000)
400
FY25 Meridian NI
FY25 Meridian SI
FY25 PowershopFY24 Meridian NI FY24 Meridian SI FY24 Powershop
increased 0.4% during May 2025 and have
increased 8.1% since June 2024
Retail sales volumes in May 2025 were
300
119 117 121 118 122 118 124 119 126 120 128 121
132
122
134
136 137
122 122 122
139
120
127
123
121
0.7% higher than May 2024
Compared to May 2024, segment sales in residential were 4.4% lower, small medium business 0.2% higher, large business 10.5% higher, agriculture 8.1% lower and corporate 3.8% higher
200
100
0
127 125 127 125 127 125 128 125 128 126 129 127 129 127 130 127 131 127 132 127 132 126
123 122 124 122 124 122 125 122 125 123 126 124 126 124 127 124 128 124 129 124 129 123
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May June
Source: Meridian
To date this financial year, retail sales
MERIDIAN'S RETAIL SALES VOLUME*volumes are 1.7% lower than the same period last year
Compared to last financial year, segment sales in residential are 0.5% lower, small medium business 0.3% higher, large business 7.8% higher, agricultural 13.2% lower and corporate are flat
GWh
FY24 Large Bus FY24 Corporate
303 334
314 337
336 332 331
318 321 331
326
332
326 338
337 325
303
348
333
367
331 317
61 60
65 61
54
56
56 51
54
53 54
54 53 80 76
57
62 51 52
56
52
59
88 112 116 120 167 150 196 184 133 210 167 186 158
94
59 51
77 104
67
67
60
73
159 154 159 161
137 141 133 134
154 154
130 132 129 127 128 129 127 130 138 134
133
127
201 200 191 201 158 155 144 144
125 124 123 123 122 119 111 112 127 127
138 136 172 180
900
600
300
288
59
*excludes volumes sold to New Zealand Aluminium Smelters Limited and CFDs
0
47 |
144 |
178 |
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May June
Source: Meridian
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Disclaimer
Meridian Energy Limited published this content on June 15, 2025, and is solely responsible for the information contained herein. Distributed via Public Technologies (PUBT), unedited and unaltered, on June 15, 2025 at 20:46 UTC.
