National network operator Transpower announced yesterday it would open up emergency access to additional hydro-lake water in an effort to head off a looming electricity crisis.
Electricity generators and industrial interests said the move should prevent other emergency measures being required for the time being, but the Guardians of Lake Hāwea raised concerns about possible environmental and amenity impacts.
National network operator Transpower said it would bring forward permission to access "contingent storage" to alleviate risks to electricity supply arising from historically low lake levels announced this week.
The decision followed consultation with industry and other stakeholders, and came as controlled hydro storage plunged to just 55% of the average for this time of year — among the lowest in 90 years.
Subject to certain conditions, the extra usage would mean Lake Pūkaki could see an additional 5m drop from usual minimum levels, from 518m to 513m above sea level.
Lake Hāwea could drop from 338m to 336m.
That 2m drop could translate into a 10m horizontal retreat of the Hāwea shoreline, Guardians of Lake Hāwea chairman Geoff Kernick said.
"We understand the lake belongs to everyone, and we understand the necessity entailed by the current situation.
"What’s been frustrating over a period of about 20 years is continual talk about bolstering electricity generation in New Zealand, but no action.
"This is what necessitates knee-jerk reactions like we have now, with all the consequences for residents, wildlife and recreational lake users."
Were Contact Energy to make use of the full additional take, silts would be exposed which had historically caused dust to inundate Lake Hāwea township, he said.
"We’d like to see this lead to proper discussion about other, longer-term measures like roof-top solar generation, to ensure we don’t end up here again."
Major Electricity Users’ Group executive director Karen Boyes said her members supported the Transpower decision.
"Being optimistic, we hope this decision, combined with additional gas access and other measures announced by our members, should get us all through the next few months.
"Although we feel this issue is now receiving the proper attention it requires, it still requires a wider stakeholder response for the long-term, from government, suppliers and users. This is just the start of that discussion."
"Being able to access the contingent storage in Lake Pūkaki more than doubles Meridian’s available hydro storage as of today and offers us a lot more flexibility. Based on our current modelling — after positive weather over the past week — we’re reasonably confident of getting through spring without needing to access that contingent storage, which helps protect storage for next winter."
