Fairbank Farms – battery-backed dairy

Dairy farmers Michael Farmer and Chris Stewart didn’t even realise the grid was down during their last power outage. As other neighbouring operations ground to a halt, Fairbank Farms kept operating at full capacity thanks to their solar and battery setup.

Watch their video and read on to find out more about their solar and battery system, the resilience benefits it offers their farming operation, and what they’ve learned along the way.

Solar and battery for resilience 

Based in Southland, Fairbank Farms' solar system has been operational since August 2025. In that time, it’s already passed several outage tests — which is a major reason why the two equity partners invested in solar.  

“Risk mitigation is massive in dairy farming. You do need to be able to milk cows seven days a week through the season, so there has to be a way of doing that if the power goes out,” says Stewart.  

The $175,000 solar and battery system was installed alongside a chiller upgrade. EECA provided $75,000 co-funding support toward the chiller and battery components, through the Technology Demonstration Fund. The realised payback period of this system will likely be shorter than what is projected below, taking this support into account.

Adapting energy to the milking schedule 

Fairbank Farms haven’t adjusted any of their daily operations around the introduction of solar and battery technology. Instead, they’ve made sure that the technology has been set up to work around their normal ways of working. 

Afternoon milking runs directly off solar, while morning milking runs off the batteries. These are charged either by surplus solar after the previous afternoon’s milking - long Southland summer days help - or overnight from the grid if the weather has been poor.  

“We can run everything on the farm simultaneously — milk chilling, effluent pumping, irrigating, fencing units — everything's going,” says Farmer.  

Powering their operation is a 75 kWp Panasonic system, coupled with a 100 kW inverter and 2 x 100 kWh batteries for storage. With their large battery system, they have enough capacity to power all their equipment at once. Importantly, everything runs off a single ICP, which was factored into the solar design.  

The farm remains connected to the grid for support during peak loads, and to take advantage of cheaper night-rate power to charge the batteries. 

Resilience improvements

Like many rural operations, Fairbank Farms faces a number of power outages each year, from lines down due to overloading, through to accidents or major weather events. 

Being at the end of the line means restoring power to farms can take longer, while rising electricity demand, driven by increasingly powerful farm equipment, is adding further pressure to local networks. 

Their initial objective was simple — to have enough solar and battery capacity to run at least one milking a day for their 800 cows if the grid went down. That goal meant a battery was vital to any system they adopted. Without one, solar panels shut down when the grid fails, as they rely on a power supply to operate. 

“If you don't have a battery, you don't have any resilience because with solar only, you need the grid for them to work,” says Stewart. “As soon as the grid goes out, solar has no value.”  

Instead, they are able to carry on the whole operation as usual, which would not be possible with a generator alone.  

“Generators are pretty hard to power every single thing you've got on-farm,” says Farmer.

System passes major storm test 

The resilience of their system was seriously tested in October 2025, when a severe storm left hundreds of southern farmers dumping milk or searching across the region, and beyond, for generators. 

“When it became more than a one-day event, that's when the seriousness of it all hit. There was a lot of stress out there and a lot of people panicking to get cows milked,” says Farmer. 

While their battery system wasn’t as large as it is now, they were able to work out what was using the most power and manage their load to continue operating. That meant they didn’t need an external generator, which other farmers were struggling to source.  

Instead, solar allowed them not only to keep milking twice a day, but also to keep milk chilled and supplied to Fonterra.  

Just as importantly, cows remained on their normal milking routine, avoiding unnecessary animal distress, health risks, and production losses that can follow prolonged disruption.

“Cows are creatures of habit so even on a day where they're out for an hour or two it just completely throws them out of rhythm.”

Getting the most from the system 

Getting full value from the system has taken time and testing, but delivered benefits beyond generation alone. Initially operating with a 50kW inverter and one battery, the system would overload when their operation was at full demand.  

Analysis of the live data showed short, sharp power spikes well above what they had assumed. That insight led them to double the inverter and battery capacity – ensuring the system could handle peak loads rather than just average consumption. 

More importantly, the detailed energy monitoring provided a level of visibility they had not previously had. Working with their supplier, they identified which pieces of equipment were driving demand spikes and adjusted operations to smooth loads. That included staggering start times, installing automatic timers, and adding variable speed drives. 

The ability to analyse real-time performance also enabled practical refinements, such as force-charging the batteries from the grid if an outage was anticipated. 

As part of their close partnership with Panasonic, they have been able to continue refining in collaboration with the installer team. 

“We’ve been able to work with the Panasonic guys and tinker and change around the settings and really maximize our investment ... We’ve been learning about the system, they’ve been learning about dairy farming,” says Stewart.