Mark Ryall (left), Transpower and Jason Larkin, Unison

Transpower announced on Thursday that its ‘preferred option’’ is to improve resilience at the existing Redclyffe substation, rather than move it to a new site.

Flood water from Cyclone Gabrielle inundated the substation, cutting power throughout the region. Here’s what the site looked like at the time.

Various options were looked at to ensure the future resilience of the power supply, with Transpower coming down on the side of a proposed $35 million, three-year project to raise the vulnerable equipment by over 1.7 metres.

Building a new substation at a less flood-prone site was estimated to be a 10-year process that would cost over $200 million. “To be frank, we probably didn’t expect the rebuilding here of Redclyffe would come out on top,’’ Unison Networks general manager commercial and regulation Jason Larkin said to those gathered at the substation on Thursday.

BayBuzz asked Larkin to clarify that statement.

“Look, I think being incident controller during Gabrielle and seeing the impact on the community and the devastation around the surrounding area, but also here at Redclyffe, and the fact we had a major city in the North Island without power for a week, you had to question whether this was the right site for future resilience,’’ said Larkin.

“But we’ve been through a robust exercise that highlights it’s the right location. It’s central to the cities and future growth of the region. Based on the extensive flood modelling that Transpower’s done, the modern design standards that Transpower can build to, there is a resilient solution that can be built at Redclyffe and it can also be done a lot faster than basically moving Redclyffe.

“In fact, you wouldn’t move it, you would have to build a new major interconnection site like this somewhere else … You’d then have to re-route all these huge transmission lines as well as our own distribution feeders to that new site and you’re talking probably up to 10 years, but also talking three or four times that cost and the reality is we’re both regulated electricity businesses and the regulation under the Commerce Commission means those costs flow through to the consumers.’’

Larkin said the $35 million option is likely to mean an additional cost of $10 per household, per annum on top of their current Unison bill. Transpower, who owns and operates the national electricity grid, passes the cost of this work onto lines company Unison, who then bills its customers.

In announcing the preferred option, Transpower executive general manager of grid delivery, Mark Ryall, gave every indication Redclyffe could eventually withstand most of what mother nature can throw at it. He said the substation was already more resilient than it was when Cyclone Gabrielle hit it and, once the remedial work is complete, will be “above a 450-year flood model event.’’

Asked if the substation would be relocated on higher ground than Springfield Road if time and money weren’t a problem, Larkin responded,  Larkin responded, “I guess there’s also an element of taking the world as we find it and it would be a huge exercise to move and we think it’s important that there’s resilience for this region in the shortest time frame. Redclyffe enables that and Redclyffe can be made resilient, so that makes it the right place for the region’s resilient supply.’’

Detailed plans for the resilience work will be released in the coming months, as part of a public consultation programme. Under Commerce Commission regulations, Transpower is required to undertake public consultation for capital expenditure above $20 million.

Once that’s complete, Lyall is hopeful the project will begin in earnest by the end of this year.

Public Interest Journalism funded through NZ On Air

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1 Comment

  1. Why not build a stop bank high enough for future flood events around the perimeter plus an internal pump to handle what falls inside. ??

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