Stormy times lies head for New Zealand's electricity market if an agreement cannot be reached with NZ Aluminium Smelters to extend the period of its closure beyond August next year.
That's the view of Contact Energy chief executive Mike Fuge as he presented his outlook during the company's full-year profit announcement.
The exit from Tiwai - which uses 13 per cent of New Zealand's power supply - combined with the economic impact of the Covid-19 pandemic made for what he said was a "black swan event" for the electricity market.
Fuge earlier announced an 11 per cent decline in Contact's earnings before interest, tax, depreciation, amortisation and financial instruments, to $451m. Market consensus was for $459m.
As promised, the company stuck to its 39 cents per share total dividend payout.
Tiwai's main supplier, Meridian Energy, earlier confirmed that it had put a confidential proposal to NZ Aluminium Smelters to close down the smelter over a longer period of time - up to four years.
Fuge said that with Contact's generation portfolio and its retail business was in good shape, and the company was well-positioned to come through the likely period of market disruption in a much stronger position.
"That being said, it (Tiwai) is a disorderly exit and it is going to impact," Fuge added.
The smelter closing, and with Refining NZ and NZ Steel both looking at changing the way they operate, would all have an impact on the electricity market.
"We do need joined-up thinking. It does require everyone understanding the risk of a disorderly exit," Fuge said.
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"We do need a short-term contract (with NZAS) to be negotiated to facilitate a staged exit - we think five years is the ideal timeframe," he said.
"Combined with the economic uncertainty created by Covid-19, I think it's fair to say that the market is looking at a black swan event."
Once Tiwai closes, the electricity market structure would fundamentally change.
"There will be disruption and there will be winners and losers," he said.
"In that, baseload-inflexible thermal generation will be profoundly challenged as well as wind generation, particularly in the central North Island."
Grant Swanepoel, director of equity research at Jarden, said the fact that Contact maintained its dividend at 39c reflected a level of confidence by the board that the balance sheet was in good shape to face a potential Tiwai exit.
"We are at that point where it is very hard to predict earnings," Swanepoel said.
"If Tiwai does exit as of next year then thermal (generation) has to come out of the market," he said.
"The positioning of their thermal generation is not too bad relative to what is in the market," he said.
Despite the uncertainties, the sharemarket appeared to be bullish on the electricity sector.
"I suggest that there is a level of expectation that the big five gentailers will find a way to manage their way through whatever the outcome is," Swanepoel said.
"If Tiwai exits on a hard closure, then you would have to assume that there will be a rational exit of thermal, and a timely one."
"Is the market pricing in all the risk of this? I'm not sure that it is.
"Right now it's a matter of planning for all the uncertainties and dealing to them when they occur," he said.
Contact said the 11 per cent fall in its Ebitdaf was to a combination of lower renewable generation, lower wholesale prices and the impact of rising costs of thermal generation and restricted gas supply.
Fuge said income from electricity market making was also down $10m on the prior year following "volatile swings" in the wholesale market during the large inter-island transmission outage early in 2020.
Market "headwinds" were partially offset by strong cost control with fixed costs down by $13m.
Fuge said the increasing cost of gas and carbon was "accelerating the case" for the substitution of Contact's Taranaki Combined Cycle thermal plant at Stratford with new renewables.
About 80 to 85 per cent of Contact's electricity comes from renewable hydro and geothermal stations. Its natural gas and diesel-fired power stations kick in when renewable sources like hydro and wind plant can not operate.
The company's shares last traded at $6.18, up 8 cents from Friday's close.