Tuesday, October 16, 2012

Comparing Solar

With both our solar arrays connected, it was only a matter of time before we started to compare the two. Over the last few weeks, we’ve had some beautiful sunny days (in amongst the throwback to winter *sigh*), so we’ve started noting down what each array was doing.

We have 1kw array of flat panels on our roof.

And a 1kw solar tracker.

Our block is oriented east to west (not the best), so our flat panels receive most of their sun in the afternoon from the west. Our solar tracker obviously tracks the sun from whenever the sun first hits the panels (8.45am) until sundown.

On our best day last week, our flat panels generated 4.69 kwh. BUT our solar tracker generated 8kwh. I was very chuffed to say the least. First of all, because we generated nearly 13kwh that day and we only use 6kwh on our worst days. I’m not that much into feeding back into the grid (though Mr B is). In my mind, as long as we make more than we use, I’m happy :-)

But secondly, because the solar tracker was so much more effective than the flat panels. And now this is where I must divulge that Mr B has been working in solar & sustainability measures for the last 8 years. He was so enamoured by different solar farms that he saw in Germany and Spain about 4 years ago, that he came to Australia with the dream of building solar trackers.

And so it began, working in our garage and in our study. He has mainly worked rurally in Victoria getting his dream up off the ground. Working with farmers, vineyards and small city councils. The biggest solar tracker he built has been for Wangaratta City Council.

So we have always wanted one in our own yard but with all our housing issues over the last few years, it just hasn’t been possible. But now we have one in all its glory (yes I’m biased LOL) and I am so proud of my dear hubby that it lives up to all its promise.


  1. LOVE your solar tracker.

    We'll be installing solar panels on the ground (rather than roof) at our little farm - because our house will likely be small and we have plenty of paddock space.

    I'm planing to price fixed vs tracking. Do you (or Mr B) know whether its worthwhile getting tracking panels even if we have plenty of full sun paddock space? Is tracking considerably more expensive? Any advice appreciated :-)

  2. Hi Tricia,

    From Mr B:

    Thanks for the compliments :-)

    Compared with equivalent quality ground mount frames (compliant to 140km/h winds etc) the trackers are generally about $1000 extra per 2kW. This of course depends on the frame, but a quality frame and foundation is essential.

    These trackers only follow the sun by moving east to west. This makes them really inexpensive compared with a “proper” two axis tracker, yet they make almost as much power. They generate approx 25% more power than ground mount flat panel.

    Trackers are good because they catch the day’s “shoulder” – i.e. they start making power early and stop making power late. This does not happen as much with fixed arrays and you need them bigger to “bank” electricity into the grid.

    With these machines, each tracker can carry up to 2kW of panels, although I only had one spare kW lying around… :-)

    From Mrs B:

    PS Tricia, I've sent you a graph via email which shows the difference between trackers and ground mount capturing the sun.

  3. Great work Mr & Mrs B. So cool to be able to install PV tracking in your very own backyard.

    Do you get much of a feed-in tariff over there? I was fortunate to get locked into a 66c/kWh tariff when the Vic Labor gov was in power. It is now down to 8c/kWh which is really ripping off homeowners and lining the pockets of Big energy retailers.


    1. Hi Gav,

      We got locked in with the 25c/kWh tariff from the Vic Govt plus we get a bonus from our electricity provider which increases it to a 33c/kWh tariff.

      Couldnt agree with you more about the decrease to 8c. So ripping off homeowners and such a blow to renewable energies in Australia!!