Management

Solar can slash bills by 75 per cent

By Rick Bayne

SOME DAIRY farmers are looking at alternative supply options as power bills continue to soar with no relief in sight.

WestVic Dairy’s Dairy Innovation Day, held in Warrnambool last month, heard how solar-powered farms could cut 75 per cent from grid power bills.

Raj Subramanian from Crystal Solar Energy showed how farmers could save nearly $75 000 a year with the solar system.

Profiling Bill and Wendy Couch’s Nullawarre farm, where they milk 700 cows, as a test case, Mr Subramanian said it was the largest solar PV installation in Victoria using eArche lightweight solar panels.

A total of 279 solar panels were installed on the farm, with a mix of 270 and 325-watt capacity. The panels weigh 70 per cent less than conventional solar panels, negating the need to strengthen the existing shed structure.

Solar power could provide 27 per cent of the farm’s energy needs; leading to a potential reduction in grid power bills of $74 393 a year.

The case study showed a potential return on investment of 23.7 per cent, based on a $425 708 investment.

Based on a projected 17-year lifespan of the solar product, it could save the farm $180/MWh.

A review of the site found the changes could reduce temperature in the shed by up to 9 degrees in summer.

Mr Subramanian said farmers could pay back their investment in about four and a half years.

“As dairy farmers get their power bills, we’re getting more and more coming back to us to ask about solar,” he said.

After eight months of monitoring and performance review, battery storage is now recommended as the next step for the farm’s energy conversion. The 85 kW solar PV could charge a 150 kWh battery storage and still provide 100 kWh for self-consumption.

The battery storage would provide power for morning and evening milking with surplus solar power used during the day to charge the battery.

The farm’s assistant manager, Reece Taylor, said the system had been working well since its introduction in December 2017.

“On a normal good winter’s day with a bit of sun about, we’re using no power during the day, though that’s with no irrigation running,” he said.

“Summer will be the next test,” he added.

The possibility of adding battery storage could potentially make the farm virtually free from grid power.

“We’re looking into the battery side of it,” Mr Taylor said. “We use about 25–30 kWh during milking time, which is three hours, but we’d run them off the battery storage which would mean we’d pretty much won’t use grid power.”

This would require a separate solar system and Mr Taylor said a decision would be made after more data was collated and costs confirmed.

As part of its changes, the farm aims to avoid a demand charge for access to a 219 kW transformer for three phase power.

“We’re trying to lower our peak demand so we don’t have to pay that extra monthly service charge,” Mr Taylor said.