A report has found that high energy costs are inhibiting water efficient irrigation and undermining agricultural productivity. It calls for a radical rethink of regional electricity distribution under which government would co-fund investment in solar power installed on irrigation farms, coupled with a program addressing all aspects of energy efficient irrigation.
According to ABS data, the amount of irrigation water used by Australia's 41,000 irrigating agricultural businesses in 2012-13 was 11.1 gigalitres, up 32 percent on the amount used the previous year. That's about 11 billion tonnes of water being moved - some of it by gravity but a large proportion of it being pumped, powered by diesel fuel or grid-supplied electricity.
The report, The Water & Energy Nexus: a Multi-factor Productivity Challenge, found that the cost of the energy used in pumping is setting back water-efficiency gains and is a barrier to achieving the objectives of the national water reform process. Farmers have to balance the costs of water and energy. In the face of rising energy prices, however, they are holding back from installing water-efficient systems and, in some cases, are leaving existing pressurised systems idle.
David Eyre, General Manager of R&D at NSW Farmers and a co-author of the report, explains that in general, water-efficient irrigation systems are more energy-intensive. The most potent water-efficiency measures involve moving water from open to closed, pressurised delivery systems - for example, by running bulk water in pipes rather than open channels, or by installing drip or centre pivot systems to replace gravity-fed, flood-irrigation systems.
"A typical irrigation farm in the Murray Darling system could be spending more than $500,000 per annum on diesel or mains electricity for pumping" he tells AgInnovators.
"We see a significant disconnect between national water and energy policy. Increasing water productivity means growing more stuff with less water, but that requires using more energy. It follows that we have to find way to supply that energy more cost-effectively and sustainably. Successive governments have invested in water efficiency programs without first ensuring that farmers can afford the energy needed to operate the systems".
Eyre notes that large Solar PV systems installed on farms could provide all the energy needed but that co-investment by government is needed to cover capital costs.
While solar power has been widely adopted across other sectors of agriculture, the challenge in irrigated cropping is the large amount of energy required for only a few months in the year.
"The farmer may need a 600-kilowatt system to meet peak irrigation load, but won't get sufficient return on the asset without a use for the power off-season," Eyre explains. "We want to see distributors taking some of that energy and co-investing with farmers in solar to help reduce the net costs of regional electricity supply."
The report calls for an engineering and economic study that correlates electricity demand in regional Australia with the costs of mains supply on a geographic basis. This would make it possible to precisely identify farms and irrigation districts where the installation of solar could be co-funded by savings on the distribution side.
He says that in some cases, farmers could go off-grid; in others, they could contribute to smart load-shifting solutions, either by reducing their own loads or by exporting power to other users.
"Users at the ends of networks, particularly those with high and irregular demand, are expensive to supply but there are policy limits on cost recovery," Eyre says. "Instead of subsiding the network charge, which still ends up being more than 60 percent of the bill for some farmers, why not subsidise them to generate all or some of their own power?"
"Today, digital network control technology and solar technology make it possible to rethink electricity distribution in regional Australia, with off-grid, island grid and hybrid grid solutions optimised to local needs," notes Eyre.
"Our report is just scratching the surface of this issue - we are calling for a collaborative effort across government and industry and some lateral thinking around solutions."