Meridian Energy welcomes rain in the Waitaki
For immediate release Friday December 7 2001
Meridian Energy welcomes
rain in the Waitaki
Heavy rainfall in the Waitaki catchment in the last week has seen hydro storage lakes return to levels close to normal for the time of year.
Meridian Energy spokesman Alan Seay says the rain has filled Lake Ohau, with water now spilling over a weir structure and into the Ohau River.
“While Lake Ohau is not really significant in terms of its storage capacity, it is a sign of just how much things have changed in only a short time. However it is far too early yet to be able to say how the country will fare next winter as far as electricity is concerned.”
The two major storage lakes in the Waitaki system, lakes Pukaki and Tekapo were today at 45% and 65% full respectively after receiving large inflows over the past week, with more rain forecast in the next few days.
The two lakes between them account for some 60% of New Zealand’s total hydro storage capacity.
Mr Seay says lake storage is only part of the picture in looking at overall hydro electricity supplies.
- Waitaki River system
The Upper Waitaki system begins at Lake Tekapo, a storage lake with about 800 GWh of storage capacity, which represents about 22 percent of the country’s hydro storage.
Water passes through the Tekapo A power station and is diverted by a purpose-built hydro canal to Tekapo B station on the shores of Lake Pukaki.
Lake Pukaki has some 1600 GWh of storage capacity – about 44 percent of New Zealand’s total. Water is drawn by canal from both Lakes Pukaki and Ohau to supply Ohau A , B and C power stations, before being discharged into Lake Benmore.
After passing through the Benmore power station, the water flows down the Waitaki River through the Aviemore and Waitaki stations.
- Manapouri/Te Anau system
The combined storage of Lakes Te Anau and Manapouri is 380 GWh. The Manapouri power station lies 178m underground on the western shore of Lake Manapouri, and is accessed via a 2km road tunnel.
After passing through the station the water flows into Doubtful Sound via a 10km-long tailrace tunnel.
All of the stations are designed to be remote controlled from a control centre at Twizel.
Meridian Energy Australia Ltd
owns hydro generation facilities at five small dams in New
South Wales and Victoria, generating a total of 62 MW.
“The other key part of the equation is inflows. These were the lowest on record for the first six months of this year which was the major cause of the problems we had this winter.
“We will have to see what inflows are like in the early part of next year and what our storage situation is in March-April, before we can say with any degree of certainty how things will go over winter.
“However we are very pleased indeed to have increased storage in Pukaki and Tekapo over the last few days to the extent that we have.”
Mr Seay says the eight hydro stations on the Waitaki system have been generating “flat out” to make use of the inflows.
He says despite this, with the Ahuriri and Ohau rivers in flood and more rain forecast, there is a possibility the company may have to spill water past the three lower power stations in the chain, Benmore, Aviemore and Waitaki.
Principal, Communications & External Relations
Ph (04) 381-1243
Meridian Energy at a glance
Meridian Energy is the largest of the three state-owned enterprises formed from the split of ECNZ on March 31 1999.
With a total New Zealand capacity of 2323 MW, it has some 30 percent of the country’s total electricity generation.
In addition to the eight hydro power stations based on the Waitaki River system, Meridian Energy owns and operates New Zealand’s largest hydro station at Manapouri, and the Wellington wind turbine. It also owns five small hydro stations in Australia.
The company supplies energy to the country’s single biggest electricity customer, the Comalco aluminium smelter at Bluff, while at the other end of the customer scale it serves householders and businesses nationwide from a purpose-built retail operations centre in downtown Christchurch.
Meridian Energy has interests in South Island hydro development opportunities, research and development investments in superconductor and fuel cell technologies and wind generation opportunities.
It employs about 150 people at offices in Christchurch, Wellington, Twizel and Sydney.