Labour energy spokesperson Megan Woods touts fourth Rankine as alternative to LNG
Thursday, 21 May 2026
Installing a fourth “Rankine” turbine at Genesis Energy’s Huntly Power Station to burn carbonised wood waste could be a cheaper and more environmentally-friendly option than importing LNG, Labour energy spokesperson Megan Woods has suggested.
Responding to the idea at a select committee hearing on Thursday, Genesis chief executive Malcolm Johns indicated that — based on 2024 research— a new turbine the size of its existing 240 megawatt units would cost about $800 million.
The Government has signalled an LNG terminal capable of importing 12 petajoules (PJ) of gas could cost about $2 billion to lease and operate over 15 years.
A 240MW turbine could produce about a terawatt-hour (TWh) of electricity over a six-month period, equivalent to about 2.5% of the country’s total annual electricity demand, while it is commonly assumed 12 PJ of gas will produce about 1.8TWh of electricity.
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Genesis’ three existing Rankine units are capable of burning gas, coal or so-called biomass. The company has previously trialled burning charcoal-like pellets produced from wood waste in combination with coal.
The power station also houses two other turbines — one larger and one smaller than the Rankines — that are only capable of burning gas.
Johns said the cost of biomass pellets translated to between $300 and $400 a megawatt hour (MWh), for the electricity they produced, but that price was on a downward curve as manufacturing of the pellets advanced.
That cost compared with about $180/MWh for coal generation, but was “pretty much the same” as the cost of producing electricity from LNG, which he estimated at between $300 and $350 per MWh.
Burning coal and burning biomass releases similar quantities of carbon-dioxide into the atmosphere for the electricity they generate.
But emissions from the latter are generally not counted by climate accountants, on the basis that the wood used to produce pellets is part of the atmospheric carbon cycle and will be replaced by new trees that will draw carbon back out of the atmosphere, as long as they are produced sustainably.
Any charcoal pellets used by a fourth Rankine might only displace pellets that could be used in the existing Rankines, if the supply of pellets was constrained.
Woods told Johns that what she took from his comments to the committee was that biomass was cheaper than LNG, could lock in significant new generation capacity, would have lower emissions and it “seemed like it could be a good deal”.
“Biomass offers an option for New Zealand that gives us fuel security,” she later told The Post. “It's energy that we can make here in New Zealand. It will lead to lower power bills for New Zealand households and businesses. So, it’s a win-win for everybody.”
A downside of banking on biomass over LNG to avoid future winter energy crunches would be if it took longer to put in place.
Johns estimated it could take about five years to commission an additional Rankine, mainly because of the time it would take to have one designed and built from scratch.
That would mean it might not be able to provide cover for a fuel crunch until the winter of 2031, about three years after LNG is projected to be available.
“You’d be wanting to have five years in your mind in terms of the time frame that you were working to. It could be less than that, it could be more than that.
“We haven’t bought a Rankine in New Zealand for over 40 years, so we haven’t reached out to any suppliers. We've done some ‘desktop work’ only,” he said.
Woods insisted the timeframe could be shortened if consent was given quickly to the investment.
“A fourth Rankine would be a ‘greenfields’ development. There would be a consenting element to it. LNG is only quicker because the Government has said it will make it quicker.”
Johns queried the significance of resource consent.
“I don’t think the consent process is the issue; I think it would be the supply-chain process.”
But he confirmed there was a second-hand market for Rankine turbines which might allow one to be sourced sooner.
“We haven’t looked at it, so I can’t categorically say ‘yes or no’. We have all the generation that we need. If the wider market was interested in a fourth Rankine at Huntly, there is a pathway to be able to do that.”