Mercury hydro generation hits 4th lowest since 1980

Mercury's total generation for FY25 was 7,906GWh, an 11% decrease from the prior year, primarily due to lower hydro generation of 3,410GWh (17% lower). This marks the fourth lowest generation from the Waikato scheme since 1980, attributed to low catchment inflows and Lake Taupō starting levels.

Mercury anticipates average annual hydro generation will increase to 4,140GWh from FY26, driven by the Karāpiro Rehabilitation Project. The third generating unit at Karāpiro is expected to be completed in September 2025, adding 16.5MW of capacity and an estimated 32GWh of additional generation.