Cyclone Gabrielle: Future of flood-hit Redclyffe substation remains undecided

The Redclyffe substation, a month after Cyclone Gabrielle. Photo / NZME

Transpower is still assessing the future of the flood-hit Redclyffe substation.

Water from the Tutaekuri River submerged parts of the substation - including its control room - during Cyclone Gabrielle, cutting power to Napier for several days.

Now, almost 10 months on from that weather event, Transpower is still trying to determine whether the site of the Redclyffe substation, near Taradale, is too vulnerable to future flooding or if that prospect can be guarded against.

Transpower, who operates the national electricity grid, told Hawke’s Bay Today in March that it was contemplating those two options.

A decision has yet to be made.

“We have already done a huge amount of work since Cyclone Gabrielle to restore our electricity transmission grid in Hawke’s Bay to its pre-cyclone level of security and reliability,” Transpower general manager of grid delivery Mark Ryall said.

“With Redclyffe substation now back to its pre-Gabrielle state we are continuing to consider options for either strengthening its resilience or relocating it to a new site.”

Put simply, a number of related parties and factors combine to dictate this is not a decision Transpower is able to make quickly or lightly, about a substation first built in 1927.

“We have been working with [lines company] Unison and local stakeholders to better understand the region’s long-term electricity needs,” said Ryall.

“Key to this is ensuring that any decisions we make now can allow for future load growth in line with increased electrification while balancing reliability and affordability for local communities.

The Redclyffe substation. Photo / NZME

“To help us decide which option best serves the community’s needs we have commissioned updated flood modelling and investigated possible engineering interventions.

“Key considerations include the timescales involved in relocating Redclyffe, compared with increasing resilience at the current site, costs, logistical challenges and making sure we have sufficient resilience in place now in case another major event happens.”

In March, Transpower told Hawke’s Bay Today that an upgrade of the Redclyffe substation in the 1970s determined that the surrounding stopbanks were sufficient to withstand a one-in-100-year flood.

Transpower says it now builds substations to one-in-450-year flood specifications.

Hamish Bidwell joined Hawke’s Bay Today in 2022 and works out of the Hastings newsroom.