Approval for HVDC Pole 1 replacement welcomed

1 August 2008

Transpower welcomes approval for HVDC Pole 1 replacement

Transpower has welcomed the Electricity Commission’s (EC) notice of intention to approve its proposal to replace Pole 1 of the HVDC inter-island link. The proposed project, worth up to $672million, involves replacing the older Pole 1 equipment with a new state of the art thyristor valve unit. Transpower’s analysis shows the benefits of the project significantly outweigh the costs. The project will increase the capacity of the overall HVDC link to 1000 MW from 2012, and 1200 MW from 2014.

Transpower’s Chief Executive Patrick Strange said the final Grid Upgrade Plan followed many months of consultation and engagement with interested parties on the approach, assumptions, methodology and options in investigating the need for a replacement. “Since submitting the plan in May, we have been busy with the planning and procurement for the project, on the assumption that final approval would be received in the future, and are on track to commission the new pole in 2012.

“It is pleasing that the proposal has been recognised by the Electricity Commission as a good investment for the country. Thank you to those industry and community representatives who participated in the consultation stages and helped to shape the solution we presented - and now have interim approval for.”

Additional information The HVDC link, which links Benmore Substation in the South Island and Haywards Substation just north of Wellington, consists of two separate circuits, each with its own major converter system at each end. The converters are called Pole 1 and Pole 2. The current Pole 1 includes equipment that is 43 years old and was stood down late last year. Half of that pole has now been returned to service for use in critical periods. Pole 2, which was fully commissioned in 1992, continues to operate reliably and has been able to carry additional electricity since Pole 1 was stood down.

The HVDC link also includes three undersea cables across the Cook Strait – two connected to Pole 2 and one to Pole 1. These three cables are in good condition. The HVDC inter-island link is a key part of New Zealand’s electricity makeup.

It provides:

• the South Island with access to the North Island’s gas and coal generation, (important for the South Island during dry winter and summer periods).

• the North Island with access to the South Island’s large hydro generation capacity (important for the North Island during peak winter periods).

ENDS

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