8 May 2002
Wholesale electricity prices increased significantly during April, due predominantly to the Taranaki Combined Cycle
(TCC) plant being out of operation for most of the month.
TCC's planned outage began on 5 April and, in the days following, average prices jumped from between 5-7c/kWh to between
7-10.5c/kWh. However, prices gradually eased as other generators increased their output in response to the outage.
During April the North Island continued to send electricity southward during morning and late night periods. This is a
reverse of the usual trend where the South Island supplies the North Island with additional generation.
The average half-hour wholesale electricity price for the South Island reference point, Benmore, was 6.93 c/kWh in
April, a significant increase on 4.26 c/kWh the previous month. Haywards, the North Island reference point recorded 7.07
c/kWh, up considerably from 4.43 c/kWh in March. Otahuhu, often used as an indicator of upper North Island prices,
recorded an increase to 6.92 c/kWh, up from 4.66 c/kWh in March.
Inflows into the main hydro lakes remained consistently below average for much of April, causing national storage to
decline steadily. However, welcome rainfall toward the end of the month saw storage levels increase slightly. National
storage was at 93% of average, or 2,784 GWh, at the month's end. Lakes Tekapo and Pukaki were down significantly to 71%
and 73% full respectively at the end of the month, while Lake Taupo's storage had decreased to 61% full.
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