Sunday, March 3, 2024

Much to gain with battery-powered on-farm energy

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Advances in battery technology and significant drops in their cost means more farmers can opt to go off the grid to source their farm’s energy supply, and even position themselves to become micro-power generators during their farm’s off-peak periods. Richard Rennie reports.
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Come the third quarter of this year, Auckland-based company Lightforce intends to start providing farmers with Huawei battery technology capable of affordably powering high-energy dairy farm operations.

The company has been supplying solar energy panels and systems for the past five years, including to some dairy goat, beef and dairy cow properties.

The capabilities of those properties and others to not only generate their electricity but also store it is set for a boost with the batteries that come in a modular 8kWh form, and can be progressively built up depending upon energy needs.

“This particular battery has been built with agricultural and farm applications in mind,” Lightforce chief executive Luke Nutting said.

It contrasts with the more well-known Tesla batteries, which are typically used more in residential applications.

The options to hook into existing solar power systems will include being able to link onto the national grid, selling electricity over and above that needed back onto the grid. Dairy farms in particular are well-suited for such configurations.

“Farms milk in the morning, then their demand drops off and during the day the solar panels will charge the battery and then send power back onto the grid, with the battery providing power for the afternoon milking and the early part of the morning milking before being picked up by solar,” he said.

Milking plants typically have a high and intense energy demand, pumping milk, cooling it and heating water, consuming about 80kW at their peak demand.

“Often the power pricing on these farms is extremely high and usually farms face other charges, including lines, distribution and capacity charges, whether you use the power or not,” he said.

Nutting is claiming a significant drop in the battery cost, thanks to a global ramping up of lithium-ion battery production, with China’s demand for electric vehicles providing much of the horsepower for that increase.

“We have seen battery costs halve, dropping from about US$250 per kWh to US$125,” he said.

This comes alongside a 50% reduction in recent years on solar panel costs, again driven by China, to the extent that panels are very close to an all-time low.

The impact of the cheaper battery technology is to halve the period for return on investment, from about 10 years to five.

Extraction of lithium-ion for battery production has also increased significantly.This includes here in NZ, where a Taupo-based firm Geo40 has proven it can extract lithium to a commercial scale from geothermal waste in a sustainable manner.

It has recently secured $7.5 million of investment through venture capital company Pacific Channel.

Nutting says the company’s existing solar panel client farms were obvious first candidates for the battery technology.

Drying off the dairy herd over winter can provide an opportunity for farmers to monetise their battery investment, selling the battery’s surplus and unused solar generated power back onto the grid.

Lightforce has VPP (virtual power plant) software technology to manage the battery and optimise the returns it is capable of generating. 

VPPs represent a disruptive energy technology that does away with centralised hub and spoke electricity generation and supply models. They instead combine small independent producers, often generating power from a variety of sources, including wind, solar and small-scale hydro.

Nutting maintains NZ’s cloudy conditions are not overly detrimental to the solar system-battery technology, with charge possible even on a Waikato client’s frequently foggy goat farm.

“The tipping point for many farmers looking at this sort of system is when they do the maths and see they can finance the system for less than they are paying for electricity. This is really possible now because the cost of capital is so cheap,” he said.

For farmers facing significant upfront costs to install utility poles or underground cable to hook onto the grid, the battery technology can now offer a more cost efficient alternative.

“You can create your own mini-grid and keep adding to the battery pack – the ability to increase the energy is really only limited by the number of solar panels you can put on the roof,” he said.

One of the company’s most recent and largest clients is South Waikato-based Trinity Lands, one of the country’s largest dairy and kiwifruit growers.

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