A case for desalination in agriculture

Leader

Challenge

Historically desalination has been viewed as too expensive to use for producing water for agricultural use in Australia. However, utilising recent technological advances and faced with a future of increased climate variability and more intense droughts, the efficient use of desalinated water may be the difference between a marginal and a sustainable, profitable farming industry. Desalination might also provide opportunities to expand production of high-value agriculture using water-efficient production techniques or sustain production in parts of Australia affected by seasonal rainfall and limited water storage capacity. The potential for using desalinated water in agriculture had not been assessed in a holistic or comprehensive manner in Australia.

Investigation

Conduct the first national holistic and comprehensive assessment of the potential to deploy desalination technologies. Specifically, identify regions and industries which could gain the most benefit from desalinated water, whilst considering the current circumstances of the agricultural sector as well as its potential future developments. This will involve detailed individual case-studies of integrated water and food production in Myalup and Carnarvon in Western Australia and Sundrop farm in South Australia and a hypothetical case study of desalinated water use in Dalby in Queensland. A comparison between Australian and Spanish vegetable production in greenhouses will also be undertaken.

Outcomes

It was found that the cost of desalinated water is generally more expensive than the cost of water from other sources used in agriculture but that there are circumstances when the cost is comparable. This includes water sourced from a highly productive groundwater resource located in close proximity to the agricultural users or when it is characterised by low salinity and requires minimum pre-treatment. Brackish and saline groundwater resources occur extensively in Australia with a national sustainable yield of over 5,800GL per year. However, the requirement for brine disposal significantly increases the cost of water production, with disposal to the ocean found to be cost effective if the desalination plant is located within 50km from the coast.

With the use of state of the art technologies, desalination is likely to be cost effective in a tightly controlled environment, using agricultural practices with effective water use and crops with high productivity. Such conditions are often associated with greenhouses and the production of high-value irrigated crops, where the cost of water is small compared to the infrastructure investment, i.e. glasshouses and hydroponics. High value crops such as eggplants and feedlots would also benefit from the use of desalinated water as they use water more efficiently and have the highest gross value of irrigated agricultural production. Blending desalinated water with fresh water would also increase the profitability of a number of different crops.

The adaptation of desalination technologies to agriculture that uses surface irrigation for low value crops, which represents 68% of the irrigated area in Australia, is not economically feasible at this time but it would increase the amount of available brackish water resources for irrigation. With the cost of conventional water supplies rising and the cost of desalination technologies decreasing, it is considered only a matter of time before desalinated water becomes a competitive option for irrigation.

Future Direction 

Following a national assessment of the feasibility of utilising desalination technologies to supplement water supplies to agriculture, it was identified that desalination can provide a cost–effective alternative to conventional water supply sources. This is provided that both water use efficiency and agricultural productivity increase as a result of desalination deployment. Having identified the most prospective circumstances for the profitable use of desalinated water in agriculture, strategic trials would be the next step. The three main activities (groundwater characterisation, desalination technologies selection and design and advancement in agricultural productivity due to “designed” water use) are suggested to demonstrate technical and economic viability of supplying water for selected high value agricultural activities. Consideration should also be given to food production in peri-urban areas. Myalup agricultural region in Western Australia would be an ideal experimental trial site.

Partners

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Total Value: $989,074 (cash and in-kind contributions)

Principal Investigator: Dr Olga Barron

Title: Opportunities for desalination in Australian agriculture

Length: 17 months

Personnel: 13 collaborators contributing 2.5 FTE

Further Information

FR4 CSIRO Agriculture Summary Poster small

Project Summary Project – desalination in agriculture

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