Meridian Energy monthly operating report for May 2026
15/06/2026 08:30 NZST, MKTUPDTEP
Meridian Energy Limited has released its monthly operating report for the month of May 2026 (attached).
“Consistent inflows and careful management of the southern hydro lakes have removed any risk of significant drought this winter,” says Meridian CEO Mike Roan.
“These conditions have also allowed Meridian to maintain solid momentum as we close in on the end of the financial year.”
Key points this month include:
In the month to 11 May 2026, national hydro storage increased from 106% to 119% of historical average.
In the month to 8 June 2026, national hydro storage increased from 119% to 125% of historical average.
South Island storage increased to 120% of average and North Island storage decreased to 160% of average by 8 June 2026.
Meridian’s May 2026 monthly total inflows were 82% of historical average.
To date this financial year, total inflows are 118% of historical average, the highest financial year to date inflows since 1998.
Meridian’s Waitaki catchment water storage at the end of May 2026 was 106% of historical average.
Water storage in Meridian’s Waiau catchment was 48% of average at the end of May 2026.
May was a record dry month for many regions, dominated by high pressure and settled weather. This resulted in a warm month with temperatures above average for much of New Zealand. Rainfall was below normal for much of both islands.
National electricity demand in May 2026 was 1.7% higher than May 2025. Excluding New Zealand Aluminium Smelters Ltd (NZAS), demand is 0.6% higher than May 2025.
NZAS average load during May 2026 was 576MW, compared with 523MW a year ago, when Meridian and NZAS had agreed a 50MW demand response reduction from March 2025 to August 2025.
Meridian’s retail sales volumes in May 2026 were 7.8% higher than May 2025.
Compared to May 2025, segment sales in residential were 20.4% higher, small medium business 6.7% higher, large business 8.3% higher, agriculture 9.7% higher and corporate 1.2% higher.
Weekly lake storage updates are available on Meridian’s website. See comparative lake levels at: www.meridianenergy.co.nz/power-stations/lake-levels