Bright ideas

A frequent topic of discussion at Foodqube (largely because we have differing opinions and Rob refuses to concede until I write a blog) is the use of solar cells to deliver electrical power to pumps and heaters used in aquaponics systems. I come down squarely on the side of ‘don’t bother’ where you are looking to build a solar setup solely for your kit.

When Rob and I were first getting in to aquaponics, one of the pumps he bought was a tiny 6W pump with an in-built solar panel. The life of this pump was measured in days and even when it did work it was hardly a robust solution as I have seen Rob do a better job of dribbling than this pump could. Whilst I acknowledge that this example is at the flimsy end of the spectrum as to what is available and that wanting a sun-powered fish-powered planter is a noble aim, a dedicated solar system just to run an aquaponics kit at this stage is both uneconomic and impractical.

The key to keeping your kit healthy is a reliable flow of water throughout the system. To get the reliability necessary from a solar setup you need to have battery back-up which substantially increases the cost of the installation. Dependent on where you are, the cost of this only goes up as the likelihood of extended periods without sunshine. If you don’t happen to live in Mareeba with 300 days of sunshine a year, you could be looking at installing 50Ah worth of batteries just to be comfortable that your kit won’t stop running after a glum week of overcast skies.

If waves of guilt course about your being as you realise your aquaponics kit is too dependent on coal for it’s survival, I would suggest going the whole hog and getting roof-top solar of a suitable size for your entire house’s consumption (or lobbying your landlord to install one). Keeping your kit grid connected means it will have a reliable supply of electricity and you may end up not paying for another power bill ever again. If you can jump through the hoops to allow you to sell your excess capacity you can actually end up making money out of it.

This of course means a substantial outlay initially but even without generous subsidy (such as the incredible 44c feed-in tariff that Queensland instituted at one stage) solar power makes sense. The devil is in the detail but if you shop around and spend time researching the rebates and subsidies available in your particular state and also the various offers available from electricity retailers, there’s no reason why most householders can’t make the leap.

If you’re looking for information that isn’t too pushy from a commercial point of view, check out the information on the federal Department of Industry website

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