Breeza farmer, Scott Morgan is designing a 85 kilowatt photovoltaic tracking array for an irrigation pump site. Photo: Jon Welsh

Irrigators reduce pump costs with solar energy

Hybrid solar diesel bore pumps for cotton and sugarcane

SOLAR and diesel hybrid bore pumps are saving irrigators money.

Work funded by the cotton and sugarcane industries shows installing micro-grids on pump sites is currently a good choice for irrigators.

Not only does the investment lead to cuts in grid electricity or fuel use, the switch can result in improved irrigation efficiency and reduce greenhouse gas emissions.

AgEcon economists and CottonInfo technical specialists, Jon Welsh and Janine Powell are investigating the feasibility of incorporating renewable energy into pumping systems currently using traditional power sources of grid connected electricity and diesel.

“In cotton ninety per cent of energy use in irrigation is from diesel, the remainder is from grid connected pumps,” Mr Welsh said.

“While in sugarcane ninety per cent of power for pumps is sourced from the grid.”

Mr Welsh said the grid connected farmers have a double benefit of being able to offset on-site consumption and sell excess solar generated power back into the grid.

“We are currently looking at moving to hybrid micro-grid systems, where potentially you have two or more independent energy systems feeding into that a pump source.”

In one case study, conducted on Narromine cotton farmer, Andrew Gill’s business, the switch to solar diesel hybrid bore pumps saved $35 a megalitre.

Mr Welsh and Ms Powell’s modelling suggest this will slash diesel use by between 45,000 and 55,000 litres a year on Mr Gill’s farm.

The model predicted this could equate to a saving of at least one million litres of fuel and a reduction of over 3000 tonnes in carbon emissions, over 25 years.

Mr Welsh said the project at Mr Gill’s would pay for itself in four years. 

“It’s a good use of capital and it is a win-win,” he said.

Mr Welsh said at the moment, the hybrid solar diesel power system was necessary to secure energy supply 24 hours a day.

“Introducing batteries or some kind of storage is the next stage, but pricing is not quite there yet,” he said.

However, Mr Welsh said it was only a matter of time until batteries became an economically viable alternative. 

“An international report has been released on battery prices to 2030,” he said.

“It predicted flow batteries and lithium ion batteries could be 60 per cent reduced in price.”

Mr Welsh said for now, it made sense for irrigators pumping over long time periods to switch to the hybrid system.

“Wherever there is an economic benefit, combined with an environmental benefit, it’s a good investment decision.” 

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