Using solar energy to save on diesel costs

Karin and Jon, a fourth-generation farmer, live on a 2,500 hectare farm near Narromine in New South Wales. The property is used for farming cotton, barley and wheat. “We used to spend 300,000 dollars on diesel to run our irrigation bores. It is one of the biggest costs on our farm. That’s why we decided to switch to a solar diesel hybrid pumping system,” Karin explains.

180,000 litres of diesel

They installed Australia’s biggest solar-diesel hybrid pumping system on their farm, a hybrid 500kW solar-diesel irrigation system, which is helping to reduce their diesel costs by 45%. “This means the systems has a payback period of five years”, Karin says. “We use solar energy during daytime hours and diesel overnight.”

The farm saves 180,000 litres of diesel per year using solar energy. Karin emphasises that there is a huge potential for renewables on farms to save on costs and reduce emissions. “We’re reducing 500 ton of carbon emissions through it. That’s something we’re really excited about as well.”

7 megalitres of water pumped per day by solar energy

The 1,550 solar panels cover one hectare of land. Karin and Jon invested about AUS $ 900,000 (US $ 630,620) in the system. “We were able to use a low interest loan of AUS $ 250,000 (US $ 175,170) through the Rural Assistance Authority of the NSW government”, Karin says. “The rest was paid in the hope that it will pay for itself in five years.”

A diesel generator was also installed and with the addition of an automated control panel, it blends generator power with the available solar power, enabling the pump to run day and night. With three quarters of the farm’s water coming from bores, the system will pump 15 megalitres of water per day, with up to 7 megalitres of water pumped per day by solar alone. The 1,550 solar panels have a 25-year warranted life.

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Problems

Combining solar and diesel on this scale has its problems, Karin says. “The system isn’t as reliable as we had hoped. The generator is not meant to trickle in a little bit of diesel on a cloudy day for example. When a cloud comes over, you start to lose some power from solar. And the diesel generator doesn’t start up quick enough to provide the lost power from the solar.”

Our system has become a bit of a research and development project

Karin says the technology of solar and diesel were not made to be blended. “Our system has become a bit of a research and development project”, she says. “A battery would be the perfect solution, but batteries are very expensive. It would be at least AUS $ 400,000 (US $ 280,270) for our system.”

Solar energy a strong business case

Karin would still advise farmers to use solar power on their farms. “The cost of solar panels has come down so much in the last ten years. The use of solar energy can be a strong business case. I would definitely advise farmers to have a look at it. They need to first look at reducing energy across the farm, and understand where they are using it and if they are using it efficiently. Then they can look at how renewables can help save on those costs. And they have to try to use the energy before if goes to the grid, because that’s where they will save money.”

The use of batteries will be worth it in some scenarios, Karin says. “There are different types of battery technology that suit different operations. A lithium-ion battery might be better for a pumping system and a thermal battery could be better for dairies.”

Solar energy also provides a secondary guaranteed income

According to Karin more farmers in Australia are starting to see the benefits of being able to convert some of their energy over to solar. “It’s becoming more and more common and I expect it to increase further. Australia has some of the best solar and wind resources in the world. Also, for hosting large scale renewable projects, as we transition to a low carbon economy. And farmers have the land to host solar and wind developments to go into the grid. That also provides a secondary guaranteed income. It means that even during a drought farmers can make money. We’ve just been through yet another drought and the worsening climate crisis will undoubtedly see more on the way.”

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Competitive edge

Karin explains that farmers that invest in these projects will also spend money in towns on contractors and small businesses. “It can really help regional economies. And with the global trend to decarbonise and import low carbon products, reducing emissions through the use of on farm renewables will ensure Australian agriculture maintains its competitive edge.”

She points out that 70% of Australian agricultural products are exported. “If farmers want to continue their export, they have to keep in mind that a lot of countries have net zero emission targets. They are likely to introduce tariffs in the future. If we are not demonstrating that we are decarbonising and using renewables, it will be harder for us to export to those markets. And consumers also want green products.”

Farm Renewables Consulting

Karin runs her own business, Farm Renewables Consulting. It aims to create change through sharing stories, connecting people and facilitating opportunities for increasing cheaper, low emission technologies in agriculture. “It’s all about sharing knowledge”, she says. “It is an exciting space to be working in, with so many opportunities that are yet to be realised. I can’t wait to see how farmers may be able to produce their own green hydrogen and even create their own ammonia and urea for use directly on the farm.”