Perth, Western Australia is a sunny place, as any local will confirm. Combined with subsidised buyback tariffs for electricity returned into the grid, this has resulted in many local households now having an array of solar panels on their roof.

What most will intuitively understand is the production of these panels varying over the year. That's a combination of the differences in average cloud cover on the one hand, and on the other hand the amount of energy that falls down on the panel from the sun varying over the year due to the tilted axis of the earth.

Combined, this results in significantly different levels of energy available on our roofs throughout the year.

Perth solar exposure variation

Figure 1: Perth solar exposure variation

Table: Average solar exposure per m<sup>2</sup> in Kings Park, Perth Jan 2017 to Jun 2023.

Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
MJ/m<sup>2</sup> 949,152 741,432 642,187 484,428 362,085 280,690 297,863 411,215 548,154 718,831 831,845 958,651

Right now in June, we're at the low point for the year in expected yield from a solar panel, with just about a third of the energy being generated that we can expect to get in Dec.