On the solarcoaster: Fifteen years, five solar systems


Jeff Knowles is a self-confessed solar enthusiast, and his rooftop bears that out with a higher-than-average number of solar upgrades that reflect changing installation standards. He explains the motivations for each iteration here—and the next chapter to come!

My partner Chrissy and I live in a purpose-built passive solar home in Jerrabomberra, NSW, near Queanbeyan and just over the border from Canberra. When you see that Canberra has had a run of 12 °C days, you might be tempted to think “ugh, that’s cold!”—mostly, though, we get a lot of sun with that 12 degrees and, surprisingly, winter can be a time when we generate more per day than Sydney or Brisbane using a similar-sized PV array.

Being a solar enthusiast, I have always been interested in how much we can generate on our roof. Our PV system has been an ongoing ‘project’ as the technology and our knowledge has improved. In fact, since 2003, we have had five iterations of our solar system—Solace #1 to Solace #5—using a variety of panels, inverters and optimisers—perhaps something of a record!

Solace #1: 2003
Solace #1 in 2003 used 12 x 150 W BP panels mounted almost flat on the roof. The installer hailed from Victoria and came up for the two-day install (as there were no local installers in the ACT in 2003, and the Victorian installer offered the best price and timeframe). The system was sized on paper—we calculated energy use in our all-electric home and what a panel could produce in a year in our region­—thereby arriving at 12 panels. It cost $20,000, before the $8000 government grant.

The system failed in its aim to produce as much as we used in a year, partly because of the way we installed it, with a long piece of steel to mount the panels. The steel got really hot in summer, and so did the panels. Hot panels are less efficient; keeping panels cool is ideal for maximum production of DC electricity. We finished up having to move them because, ironically, while the install was designed to produce the most in summer (they were only 12 degrees to horizontal), they were getting too hot to do so.

Read the full article in ReNew 144.

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