Hydro lakes reach five-year high

15:20, May 14 2009

High country lakes may be the highest they have been since 2004 but do not expect your power bill to get any cheaper.

Meridian spokesman Gerald Raymond said yesterday Lake Tekapo was at 710.99 metres, just above the top of its operating range of 702.1 metres to 710.9 metres, and Lake Pukaki was at 532.48 metres, just above the top of its normal operating range of between 518.2 metres and 532 metres above sea level.

"Meridian is generating as much electricity as possible from the Waitaki chain, as well as spilling from the lakes to reduce the levels to the top of the operating range. This is expected to happen by the end of the week. There are no forecast large inflow events for the coming week or so."

In May last year low hydro lake levels were named as a factor by Meridian Energy for increasing residential power prices, but the high lake levels did not equate to a price drop.

"Electricity prices reflect the long-term cost of building new generation and a lack of generating capacity has been putting pressure on prices. Retail prices are fixed for six to 12 months and take into account the variability and risk in the wholesale market, which includes the possibility of prices spiking as a result of a low-rainfall year, transmission constraints, plant outage or other operational issues. Commercial and industrial spot-users, however, will be benefiting this year from lower prices as a result of high levels of hydro storage."

The last time Meridian spilled from Pukaki and Tekapo lakes as a result of high lake levels, apart from January this year, was in March 2004. Lake levels were also very high in February 2007 but no spill was necessary at that time.

"The Waitaki system is currently 32 per cent above average storage which puts Meridian in a very good position to manage demand through the winter months," Mr Raymond said.

Yesterday, large amounts of water were being spilled from the dams 80 cubic metres per second (cumecs) from Lake Tekapo, 80 cumecs from Lake Pukaki, 330 cumecs from Lake Benmore, 370 cumecs from Lake Aviemore, and 205 cumecs from the Upper Waitaki. Spills were expected to continue all week.

The Waitaki River at Kurow was flowing at 674 cumecs yesterday, a dramatic decrease from the 1400 cumecs it was flowing at last Thursday evening which saw tents and campervans near hydro lakes slightly submerged and the boat ramp at Lake Tekapo under water.


The Timaru Herald