From solar orphan to carbon neutral

Seven years ago, Randall Pearce invested in a solar system from a small Melbourne company that went on to deliver very poor service, and an even poorer quality system that slowly began to fail. Eventually, the company closed down in Australia, leaving Randall a solar orphan. Unfortunately, this experience is far too common in Australia. We worked with Randall to find a solar provider that could be trusted to deliver a quality system, quality products and outstanding customer service. Randall describes his experience.

I’ve spent many years planning to extend our system, to produce more power in the morning and in the late afternoon, by observing where most sunlight falls on the different faces of our roof.

We selected DC Optimizers from Solar Edge, which are less susceptible to voltage variations in the mains, and can provide instantaneous on-line monitoring. This allows us to identify how much power we are using, and to ensure all panels are operating correctly, all of the time.

The old panels were sent up the country to be used for dam pumps and we bought an entirely new system from SolarGain, a large Australian-owned Clean Energy Corporation (CEC) accredited installer. I have been very happy with the installation.

We opted for the largest system that our distributor (Jemena) would permit, a 10 kW inverter system, and 11 kW of panels (30 panels at 370 W each), which cost $13,500. There was no government subsidy, since we had already received one for the previous system.

Five panels face and slope towards the north east, to collect the morning sun as it rises above the horizon. These also benefit from substantial reflection of this early morning sun from the adjacent shiny metal deck roof. Another three panels face south-west, collecting more direct solar energy as the sun is about to set. Six panels are set to catch direct north-west sun in winter, when it shines through under some adjacent gum trees, whilst 12 others further south collect sun from above those trees. I had the top of an old chimney dismantled, and moved our TV antenna and whirligig roof vent, to eliminate any shading of the new panels.

On commissioning, the new system generated 9.8 kW at solar noon on a late February day, so it should easily produce its rated power of up to 10 kW in the middle of summer. Currently it begins generating from before 8am, and continues until after 5pm, with enough power to run nearly everything between about 9am and 4pm. The monitoring App helps us to adjust our routines where appropriate to use the bigger power loads (heating, washing, dishwasher, vacuum cleaner, baking) within these times, in order to minimise our energy imports.

Over the last 28 days of March, the energy generation of 850 KWh averaged 30 kWh/day, exactly as predicted by SolarGain. For this period, our total export of energy was 730 kWh (earning credits of $74), self-consumption was 121 kWh and our import of energy was just 80 kWh (less than 3 kWh/day), costing just $18 for 100% green power.

The system produces more than ten times what we have to import out of hours, and ten times what the old system had been producing, so I am very happy with it. My objective was to export enough excess green energy to fully offset our total carbon footprint. Whilst we might struggle to export over some periods in the middle of the year, I anticipate this system should provide enough energy to meet two thirds of our mid-winter heating needs, which average 18 kWh/day.