KEY POINTS:
Lakes Pukaki and Tekapo were at 35 per cent and 40 per cent capacity respectively yesterday. Their historical average for this time of year is about 70 per cent.
The two lakes are responsible for the country's biggest hydro production, Meridian's eight-station scheme using Canterbury's Waitaki River.
Contact Energy's Clutha River scheme's storage lake, Hawea, was yesterday at about 52 per cent of its usual level for this time of year.
Despite the lakes having just half their expected capacity, each one is still comfortably within its normal operating range.
That is not the case for Manapouri, the country's largest hydro power station. Both its storage lakes, Manapouri and Te Anau, are below their normal operating range.
Te Anau dipped below its minimum operating limit in mid-April and has not recovered. Manapouri's level fell below its minimum normal operating range in late May.
Wholesale electricity prices have soared this winter, reaching an all-time high of $441 per MW hour on May 29. That had dropped somewhat to $321 on Tuesday, but is still some four times above the seasonal average price.
