I was recently in Glenbrook, south of Auckland, for the opening of Contact’s first grid-scale battery, which can power the equivalent of around 44,000 homes for up to two hours.
The ceremony had a distinctly different feel to other openings and groundbreakings I’ve been to over the years. Not because batteries like this are new, but because they solve a distinctly different problem to other infrastructure like power stations or transmission lines.
Batteries (also known as Battery Energy Storage Systems, or BESS) provide flexible capacity in New Zealand’s energy market by storing excess energy during periods of high output, which can then be used when generation is low.
Contact CEO Mike Fuge described batteries as ‘a bit like the Swiss Army Knife of the electricity system’, which is a nod to batteries’ flexibility and responsiveness. In fact, in a New Zealand context, it becomes clear they have the potential to completely reshape our energy profile.
A battery revolution?
Battery storage is the fastest growing power technology in the world today, with costs falling fast. BESS capacity in New Zealand has increased by over 300% since 2023, and more projects are being planned, consented, and built.
Some of these projects include Meridian’s battery in Ruakākā, Genesis’ Huntly battery currently under construction, and Contact is lining up a second battery at Glenbrook.
Batteries’ modular design and relatively small physical footprint mean they are far quicker to build and deploy than most other grid assets. The Glenbrook battery was built in just 18 months – and was delivered on time and under budget.
This makes them scalable, which is why commercial users and industrial sites such as Wellington’s CentrePort are investing in the technology. This is a positive development as it helps build a more resilient energy system – I hope we see more supermarkets, food processors, manufacturers, and agriculture companies exploring their own large-scale battery projects in coming years.
So why batteries and why now? As New Zealand’s electricity system becomes more renewable, we naturally see more variation in supply and demand over the course of a day. That can lead to greater price volatility at certain times, particularly during peaks. Batteries help smooth that out – they store energy when it’s abundant and release it when it’s needed. And importantly, the falling cost of battery technology makes them an increasingly practical part of the solution.
A tale of two islands
New Zealand has a unique energy profile, and batteries are playing their own role in reshaping our energy geography.
A big chunk of our electricity is generated in the South Island, largely because that’s where our biggest lakes are. Most of our electricity is consumed in the North Island, largely due to its bigger population. So, it’s no coincidence that the largest grid-scale batteries are being planned or built in the top half of the North Island.
When you throw into the mix the billions of dollars being invested in new wind, geothermal, and solar projects throughout the country – including in Taupō, Manawatū, and the Waikato – we’re seeing a boom in energy infrastructure in the North Island.
It’s all about energy independence
When the Prime Minister officially opened Glenbrook, he declared that energy independence must be treated as an immediate national security interest.
Energy has always been closely intertwined with geopolitics, but such a statement underlines how events overseas are reshaping the discussion about energy at home. We know how exposed our economy is to overseas energy shocks – and any infrastructure that helps offset these shocks is worth investing in.
Grid scale batteries help keep the lights on, often over winter when demand is at its highest. They can charge up overnight while power use is low and then discharge the following evening when people are warming their homes and cooking dinner, which improves the overall efficiency and reliability of the electricity system.
Batteries are also incredibly responsive and able to respond to a change in demand or a power outage within milliseconds.
Part of the solution, but not the whole answer
Of course, batteries have their limitations.
In a New Zealand context, they can inject energy into the grid when it’s most needed, but their contribution doesn’t compare to that of a full lake, which is often described as the biggest battery of all. In other words, they provide energy for minutes or hours, not weeks or months.
There’s no silver bullet for New Zealand’s energy challenges – but there is a clear need for sustained investment in the technologies that deliver affordable, reliable outcomes for consumers. Batteries will play an important role, alongside a broader mix of firm and flexible solutions, in building a resilient, self-sufficient energy system.
