Hydro system to be managed to assist Transpower
For immediate release: 10 September 2003
Waitaki hydro system to be managed to assist Transpower maintenance
Meridian Energy is working closely with Transpower over the next week to allow the scheduled maintenance of three 220kV transmission lines that feed Christchurch.
“We will be managing the generation from the eight power stations in the Waitaki hydro system over the coming week to allow Transpower to do its scheduled maintenance,” says Meridian Energy spokesman .
“This work will be completed on Friday 17 October, which means lake and river levels will be back to normal for Labour Weekend, when hundreds of people visit the Mackenzie and Waitaki districts for various recreational events.”
Work on the transmission lines can only be done during daylight hours. To allow this maintenance Meridian Energy will reduce the amount of generation from the Waitaki hydro system during the daylight maintenance periods, which in turn will allow Transpower to isolate and work on the lines scheduled for maintenance.
Transpower spokeswoman Jane Bryden says the maintenance is routine and required to ensure continued security of supply for Christchurch. “We do have to plan the timing very carefully, however, as we only have a few weeks of reduced demand in spring when we can manage this work without affecting residential or agricultural electricity users. Demand in winter is high because of heating needs while demand in summer is high because of irrigation needs,” says Ms Bryden.
Alan Seay says that people will notice more variability in the level of the lower Waitaki River over the coming week as a result of this work. “This reflects the need to reduce generation (and water flow) during the daylight maintenance periods, and increase generation overnight to balance the Waitaki hydro system.”
“No water will be spilled during this period. All actions, including river levels and ramping rates, will be within Meridian Energy’s existing resource consents for the Waitaki hydro system,” says Mr Seay.
The first maintenance period is on Sunday 12 October, and will run from noon to 4pm. The flow rate in the lower Waitaki River will drop to around 180 cumecs over this period, and then return to normal levels overnight.
Monday 13 October, 6am to 6pm maintenance period, flow rate around 180 cumecs. Higher flows overnight.
Tuesday 14 October, 6am to 6pm maintenance period, flow rate around 180 cumecs. Higher flows overnight.
Wednesday 15 October, no maintenance scheduled, normal flow rates (400 cumecs or more).
Thursday 16 October, 7am to 4pm maintenance period, flow rate around 180 cumecs. Higher flows overnight.
Friday 17 October, 7am to 4pm maintenance period, flow rate around 180 cumecs. Higher flows overnight.