Solar in Bargo – numbers

We installed solar at our house in Bargo 2574 (a town in Wollondilly, NSW) in March 2020.

It cost approximately $5k for a 6.5kW system (feeding into a 5kW inverter). Half the panels face west, and half face north.

I’ve always been concerned that people who install solar need to convince the world that it was a good decision, and they often mask the real numbers involved. With that, here’s some real numbers.

A few interesting points, after a week of ownership.

A sunny day in Summer generates >30kW ($9 of electricity). The effective timespan is 8:30am (~1kW) until 6pm (~1kW). From 11am until 4pm the system generates consistently generates between 4-5kW. The highest I’ve seen is just slightly over 5kW, so I assume it maxes out there.

A gloomy day, raining from sunrise to sunset is generating ~5kW max for the day. ($1.50 of electricity)

Our usage (6 person household, 3 x split system air conditioners, tvs left on, 2x fridges, always using a dryer, and a pool) is 30-40kWh/day ($9-12 of electricity per day). This means on the sunny days we’re generating as much power as we’re using.

Unfortunately, the feed-in payment will be 10c/kW (where it costs ~30c/kW to consume) so we expect that even with perfect summer days we will still generate a bill*.

I’m not sure what our day/night consumption is like relative to the solar power generation window of 8:30-6pm, and obviously those goalposts will continue to move after summer. We’re expecting a 30-40% drop on our electricity bills and a 2 year repayment window on the $5k outlay.

*At the moment, our power meter (that is read manually every 3 months) cycles backwards when we are generating excess power. Wish we could leave it that way, it’s effectively 30c/kW feed-in payment too! I have a feeling the energy company won’t waste time fixing that.

I’ll follow this up when we receive our next power bill. The solar system was installed the day after our quarterly bill rolled over, so we should get a very realistic number on what we’ve saved.