Sep 9, 2025
Farmers Weekly
Media
The big, beautiful batteries that store energy on farm

In Farmer’s Weekly, Phil Weir outlines his vision for farms - and Mike Casey and Rewiring Aotearoa get a special mention.

Mike Casey’s Rewiring Aotearoa comes to mind first. His team have brought electrification to the fore – powering everything from cherry orchards to pump sheds. Banks are following, lining up with green-lending incentives for solar rollout. 

But the real lightbulb moment for me wasn’t the panels – it was the battery behind them.

And it doesn’t have to be lithium-ion. Think of hot-water cylinders and chilled-water tanks as thermal batteries. On dairy farms, they store heat for wash-downs or cold for milk chilling – two assets you already need. 

Add a modest 30 kW solar array, feed surplus power into those vessels, and you cut peak-grid draw. Slip an electric UTV (or even Elon’s Cybertruck) into the yard, reconfigure water tanks and you’re shifting more load off the grid.

Like the tradie with his van of DeWalt, you do have to stump up upfront. You’ll spend $60-100k on panels, inverters and storage. But payback typically lands well inside a 10-year warranty. 

Better still, thermal batteries smooth spikes, trim energy bills and sidestep network outages. Given the fragility of the national grid, that’s a solid example of energy self-sufficiency.

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