Saltwater Greenhouse

Australia is the world’s driest inhabited continent, and in the past decade farmers have struggled with severe drought and unpredictable weather. Water is an essential commodity in the agricultural process, yet only 2.75 per cent of the earth’s water is fresh, and 0.7 per cent is unfrozen – 97 per cent is seawater. In some regions energy and water costs represent up to 70 per cent of total farm expenses, and in traditional greenhouse agriculture, vast amounts of energy and fossil fuels are used for climate control.

A small company in south Australia called Sundrop Farms has become the world’s first commercial greenhouse to use seawater and solar energy to heat, cool, power and irrigate, using technology that could help address the world’s water crisis and transform farming.

Unlike traditional greenhouses which need large amounts of fresh water and electricity, or land-based horticulture which relies on fertile soil and predictable rainfall and sunlight, Sundrop Farms provides a holistic system of horticulture that makes use of the arid land, the sunny climate and abundant seawater. Located in low, hot, humid Port Augusta, just four kilometres from the Spencer Gulf, the efficient system delivers year-round crop production.

The sun’s energy is used to desalinate seawater for irrigation, produce electricity to power the greenhouse, and provide energy for heating and cooling. Eighty-five per cent of all energy needs are covered by solar power – only during prolonged periods of reduced sunlight is additional power required. The seawater ventilation also cleans and sterilises the air, making it possible to grow crops without chemical pesticides. And the results are impressive – the crop yield is 15-30 times higher per hectare than conventional field production. The system is so successful that Sundrop Farms plan to build a new eight hectare greenhouse – 40 times bigger than the current greenhouse.

Juliette Pearce travels to Port Augusta to visit Sundrop Farms, now in their second successful season of tomatoes and capsicums.

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