At a glance
- Genesis Energy has opened its first grid-scale battery at Huntly Power Station: 100MW, storing 200MWh, enough to power 60,000 homes for two hours.
- The battery is 70 container-sized units of lithium iron phosphate cells from France's Saft, and it cost about NZ$130 million, down from about NZ$150 million when Genesis approved it in August 2024.
- It is New Zealand's third 100MW battery after Meridian's at Ruakākā and Contact's at Glenbrook, and the cheapest of the three per unit of storage on our calculation.
- Transpower counts a two-hour battery as 60 per cent of its size toward winter peaks, because a two-hour battery can run down part-way through a long peak.
- Huntly is in the north Waikato, one of six areas Invest New Zealand has identified as suited to data centres, and a second battery of the same size is due there in 2028.
Genesis Energy has opened the first grid-scale battery at Huntly Power Station, the company said in a media release dated 14 October 2026. The battery can deliver 100MW and store 200MWh, enough to power 60,000 homes for two hours, and it connects to the national grid from the Transpower substation on the Huntly site.
Genesis put the cost at about NZ$130 million, more than NZ$5 million below budget, and says it is the cheapest battery built in New Zealand to date. Huntly is the country's largest power station at 1,200MW, according to Genesis, and the battery is its fastest-starting part.
The battery is 70 shipping containers of cells
Saft, the French battery maker, supplied the battery as 70 of its Intensium Shift+ containers, with the equipment that converts their power for the grid. Each container is the size of a 20-foot shipping container and holds lithium iron phosphate cells, according to Saft's product datasheet. Saft designs the containers to last up to 20 years. Northpower installed them.
A 172-tonne transformer delivered in February steps the battery's voltage up from 33kV to 220kV so it can feed the national grid's high-voltage lines, Genesis said.
Chief operating officer Tracey Hickman said the battery "can be turned on almost immediately, making it the fastest-starting asset at Huntly Power Station and allowing it to respond quickly when extra supply is needed".
The project took just over two years from decision to opening. Genesis approved it in August 2024 at about NZ$150 million, started building on 5 June 2025 and put the cost at NZ$135 million in February 2026. Genesis approved a second battery of the same size in April 2026 at an estimated NZ$106 million, with Saft supplying and servicing it again. Construction begins in late 2026, with full operation due in 2028.
New Zealand now has three 100MW batteries
The Electricity Authority listed six grid-scale batteries operating or on the way in a release on 29 September 2026. Huntly's opening makes it the third at 100MW and 200MWh.
| Battery and owner | Size | In service |
|---|---|---|
| Ruakākā, Meridian Energy | 100MW, 200MWh | May 2025 |
| Glenbrook-Ohurua 1, Contact Energy | 100MW, 200MWh | March 2026 |
| Huntly, Genesis Energy | 100MW, 200MWh | October 2026 |
| Rotohiko, WEL Networks, also in Huntly | 35MW, 35MWh | December 2023 |
| Huntly 2, Genesis Energy | 100MW, 200MWh | Due 2028 |
| Glenbrook-Ohurua 2, Contact Energy | 200MW, 400MWh | Due 2028 |
Source: Electricity Authority, 29 September 2026; Meridian, 23 May 2025; Contact Energy, 21 May 2026; Genesis, 19 April and 14 October 2026.
On our calculation, Huntly cost about NZ$650,000 per megawatt hour of storage, against about NZ$755,000 for Contact's first Glenbrook battery and up to NZ$930,000 for Meridian's. The comparison divides each owner's published cost by its storage. Meridian published a budget ceiling of NZ$186 million, not an exact cost, and the companies may count costs differently. On published figures, each newer project works out cheaper per megawatt hour than the one before it, and Genesis's estimate for its second battery works out at about NZ$530,000.
Contact's second Glenbrook battery, at 200MW and 400MWh, will be the largest on the Electricity Authority's list when it opens in 2028.
Grid batteries are getting cheaper and lasting longer
Lithium iron phosphate made up about 80 per cent of new battery storage worldwide in 2023, up from about 65 per cent in 2022, the International Energy Agency said in an April 2024 report. The IEA puts the shift down to lower costs, longer cycle lives and safety.
Prices for battery packs used in stationary storage fell 45 per cent in 2025 to an average of US$70 per kilowatt hour, research firm BloombergNEF reported in December 2025. That is the price of the pack alone. A finished battery like Huntly also pays for the power equipment, the connection, the site works and the labour.
The world's grid batteries store about two hours of power on average, and the IEA expects that average to reach 2.7 hours by 2030 under current policies. All six New Zealand batteries on the Electricity Authority's list are two hours or less.
How long they last is still being learned. The US national laboratory that publishes regular battery cost forecasts assumes 15 years, which it calls "on the lower end of published values", because "no system has yet reached 15 or more years". It assumes about 85 per cent of the electricity that goes into a battery comes back out.
How a battery earns on the New Zealand grid
A grid battery charges when power is plentiful and cheap and sells it back when power is scarce. Genesis describes the Huntly battery the same way: storing daytime generation for release when demand peaks, often on cold mornings and evenings.
Batteries can also act as standby. Transpower lets them offer instantaneous reserve, whose fastest form must arrive within six seconds if a large power station trips, to stop the grid's frequency falling.
The Electricity Authority is changing its market rules to suit batteries. From 30 October 2026, the grid operator can direct how much power a battery takes when it charges. From 31 March 2028, batteries can trade their full capacity, with the operator able to see how much energy each one holds.
Transpower's 2026 security of supply assessment counts a battery of two hours or less as 60 per cent of its size toward winter peak capacity. Applied to Huntly, that is about 60MW, on our calculation. Transpower said batteries "provide a greater ability to manage peak load periods but do not contribute additional energy".
What the battery means for data centres
The battery covers demand peaks for up to two hours, while data centres typically draw power around the clock. At its full 100MW, it runs through its 200MWh of storage in two hours, so it backs up the grid at peak times rather than supplying a load that runs all day.
Its 100MW equals about half of New Zealand's built data centre capacity, which market researcher Arizton put at about 208MW across 36 facilities in June, but only for those two hours. Transpower is weighing a further gigawatt of data centre connections, and Mercury has said data centre demand will outrun what it can build. That demand needs new generation, and a battery adds no new energy.
We expect the battery to matter most to data centres around Auckland, because it adds fast backup to the grid that serves them. Huntly is about 86km south of central Auckland, where CDC runs three campuses with 98MW between them. That expectation is Data Centres NZ's assessment: Genesis's release describes the battery as support for the electricity system during periods of high demand and makes no mention of data centres.
We know of no data centre in New Zealand or Australia with its own grid-scale battery on site. The nearest New Zealand plan is Contact's: it is exploring a 250MW data centre with CDC at Stratford, alongside 500MW of grid-scale batteries it already holds consent for. The project is at the concept stage. In South Australia, Firmus's power supplier has contracted the planned 200MW, 800MWh Koolunga battery to help firm Firmus's supply, from 2028.
Huntly is in the north Waikato. North Waikato is one of six areas Invest New Zealand, the government agency that coordinates international investment, has identified as suited to data centres. Waikato Regional Council's draft data centre position lists access to the transmission network around Huntly and closeness to Auckland among the region's advantages, and asks developers to fund new generation, storage and network capacity for their own demand.
What to watch
The battery rules. The Electricity Authority's first changes for batteries take effect on 30 October 2026.
Reserve. Whether Genesis offers the Huntly battery as instantaneous reserve; its release does not say.
The council vote. The draft data centre position could return to Waikato Regional Council for possible adoption on 29 October 2026.
The second Huntly battery. Construction is due to start in late 2026, taking Genesis's Huntly site to 200MW and 400MWh in 2028.
Glenbrook. Contact's 200MW second battery is due in 2028.