Electricity demand reaches record levels
Friday 24 September 2004
Electricity demand reaches record levels over cold winter months
High electricity demand over the winter has been met by very strong hydro power generation as a result of greater than average inflows into the big hydro storage lakes.
“The winter weather, although cold, provided plenty of water for hydro generation,” says Alan Seay, spokesman for Meridian Energy.
As a result, Meridian’s eight Waitaki power stations and the Manapouri power station have been generating hard since the first big inflow in early May, which was followed by more water in late June and early July.
National demand growth this year, however, has surged higher again following the conservation campaigns of 2001 and 2003 and is running at 5% year-on-year. Weekly demand peaked at a record 842 GWh during the week ended 31 August, capping a series of weekly demand records set over the cold winter months. Warmer spring weather has since caused a drop in demand in September.
“Meridian was able
to help meet this increased winter demand because of the
high lake levels. Hydro lake storage of at times more than
130% of normal will not happen every year, and helped to
mask the very strong ongoing growth in demand,” says Alan
Generating Assets 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 two 10km-long tailrace tunnels.
All of the stations are designed to be remote controlled from a control centre at Twizel.
Meridian Energy Australia Ltd owns the Southern Hydro power stations in Victoria.
The ten stations have a total generating capacity of 540MW, with about 940 GWh of output.
company also owns hydro generation facilities at five small
dams in New South Wales and Victoria, generating a total of
“Demand growth, according to official forecasts, is supposed to average around 1.2% a year, equivalent to adding a city the size of Hamilton or Dunedin every year, but we haven’t seen a rate that low for some time. The current rate of around 5% means that New Zealand’s energy ‘day of reckoning’, when generation struggles to meet demand, is going to happen earlier than forecast,” says Alan Seay.
Meridian’s strategies to address this situation include the development of new generation capacity, including wind generation, as well as initiatives for managing and reducing energy demand.
“If supply is unable to meet demand, it will have serious economic and social implications for New Zealand,” concludes Alan Seay.