Water from the Sun

windmill on skyline
A windmill on the edge of Hughenden in Western Queensland

Much of Western Queensland has always depended on underground water and for years a windmill on the horizon was a traveller’s first sign of the next homestead. That’s gradually changing now, however.

Free, non-polluting, renewable energy from the wind was first challenged by diesel pumps decades ago; they were cheaper to install and easier to maintain but had the disadvantage that they needed regular refuelling at a significant cost in dollars and (unless the pump was near the house) time. Then there were mains-powered electric pumps – so long as the bore was close enough to a power-line that running a wire to it was feasible. Now solar power is taking over from all three. It has the advantages of windmills – endless free power, anywhere – and it has quite recently become cost-competitive with all three older technologies.

When relatives built a house on Hervey’s Range thirty-odd years ago the only bore was half a kilometre away and they chose to run a power line through the scrub to an electric pump. It served the house well until cyclone Yasi came along and knocked over a few of the termite-weakened power poles. Replacing the line wasn’t an automatic decision since a new one would be expensive and would still be vulnerable to termites and storms, while the pump itself was old enough that replacing it was on the horizon anyway. The family chose to run the pump from a portable petrol generator – taking it to the pump every time the tanks needed filling – while investigating other possibilities.

In the end, a new overhead power line was going to cost about as much as a whole new solar pump system while an underground power line was prohibitively expensive so solar it was! A complete kit was ordered: panels, mounting frame, pump, and controller. Batteries and inverter? No and no: the pump simply runs when the sun shines and stops when it doesn’t so there’s no need for any storage. (More correctly, there’s no need to store electricity because the water tank above the house stores the pumped water instead.)

Installation was straightforward and was all done by unskilled family members. A couple of us dug a post-hole and cemented a steel pole in place, then returned a week later to remove the old pump, assemble the kit according to the instruction booklet and connect the new pump to the existing pipeline.  It all took less than a day.

solar panels on pole
The completed solar pump set-up
control box under solar panels
The whole of the control gear.

The black box up on the H-frame is the isolator switch and the bigger one on the post is the control box – and that’s all there is. The only other component is the pump, six metres down the bore at the foot of the post.

This is very early days in our experience of the new system but so far, so good. It pumps for four or more hours per day and when the panels are getting full sun it pumps enough water to run four sprinklers up at the house. It costs nothing to leave it running so that’s what we’ve been doing, making up for a long spell when the garden got less water than it needed.

This installation is only one small example, of course, but it points to two larger trends – one positive, one a little sad. The good one is that solar power is now a genuine alternative to fossil fuels in yet another application. The sadder one is  that all over inland Queensland, windmills are going the way of the blacksmith’s forge.

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