Huntly power unit may stay operational until 2035, Genesis confirms

Genesis Energy says talks are continuing with the aim of enhancing power security. Photo / NZME

Genesis Energy says talks are continuing with market participants about keeping a third coal- and gas-powered Rankine at Huntly going until 2035.

The third is currently scheduled for retirement in January 2026, and the other two in the early 2030s.

In February, the big four power companies teamed up to look at ways of extending the life of the Rankines at Huntly to improve the security of the power supply.

Genesis, in its latest third-quarter report, said preparations for this winter remained a key focus because of below-average hydrology and the continued decline in the national gas supply.

Huntly’s Rankines, which use boiler and steam turbine technology to generate electricity, were commissioned between 1982 and 1985.

Genesis said Unit 1 is scheduled to return from service in June, which would enable the three units to be available for this winter.

The company also said its coal stockpile at Huntly, which ran low during last year’s dry spell, had been rebuilt to 474 kilotonnes (kt) by the end of the quarter.

A further 735kt of future-dated coal is expected to arrive between April 17 and the end of August 2025, with an option to order an additional 35kt.

“Negotiations with industry participants to maintain a third Huntly Rankine Unit out to around 2035, supported by long-dated HFOs [Huntly firming options], are continuing,” Genesis chief executive Malcolm Johns said.

“These discussions include jointly funding a coal reserve for dry years to support national energy security,” Johns said.

Forsyth Barr said wholesale market conditions were challenging for Genesis in the third quarter as it had to run high-cost thermal generation to support its retail book, impacting its electricity gross margin and offsetting gains in retail.

“On the positive side, it is well-positioned to provide the country’s back-up generation through winter 2025 if conditions remain dry, with plenty of coal arriving before the end of August 2025,” the broker said.

“If dry conditions persist, they should support a strong finish to 2025 and on balance, we have lifted our ebitdaf [earnings before interest, tax, depreciation, amortisation and financial instruments] forecast.

“Beyond 2025, we are more cautious,” the broker said, adding it had assigned a “neutral” recommendation on the stock.

Genesis said the activation of power purchase agreements (PPAs) for geothermal energy from the Tauhara project and solar power from Lauriston, in Canterbury, saw electricity supply from PPAs increase to 229 gigawatt hours in the quarter.

The first site works for the first stage of the company’s battery project at Huntly Power Station were successfully completed.

Construction of the first 100MW/200MWh (Megawatt/Megawatt hour) stage will start shortly, it said.

The company said it was advancing negotiations with Carbona and Foresta for biomass supply, as an alternative to coal, at Huntly.

Genesis and the other power generators have talked about New Zealand’s “energy trilemma” – the need to balance affordability, security and sustainability of electricity supply.

As it stands, there are about $4 billion worth of renewable projects in the pipeline by various companies in the form of new wind and solar farms and geothermal plants.

Huntly and Contact Energy’s gas-fired Taranaki combined cycle plant and fast-start gas peakers back up the system when the weather dictates.

A fourth Rankine unit at Huntly was permanently taken out of commission in 2015. At the time, Genesis had planned to retire the remaining Rankine units by 2018.

Jamie Gray is an Auckland-based journalist, covering the financial markets, the primary sector and energy. He joined the Herald in 2011.