Who has all the rooftop solar in Australia?


Last week, we looked at rooftop solar units by postcode and found patterns based on location. I.e. Where is all the rooftop solar in Australia? (TLDR: Rural and regional areas generally have more per capita).

Today, we're looking at other characteristics that define those postcodes. I.e. Who has all the rooftop solar?

Let's take a look.

Primer

The charts below are scatter charts that compare two or more variables. Each dot represents a postcode in Australia.

The y-axis is the same on all charts, showing rooftop solar units per 10,000 residents.* The x-axis changes for each chart to show a different characteristic.

Houses vs Apartments

There are a couple of necessary ingredients for rooftop solar. One of them is a roof.

Let's compare solar uptake with the proportion of homes that are standalone houses.

See how the two variables increase together, showing postcodes with more standalone houses tend to have more solar units.

Below is the inverse. This chart compares solar with the proportion of homes that are apartments.

Rooftop solar is dramatically skewed against apartment living.

Homeowners vs Renters

Let's look at home ownership.

The chart below shows that postcodes with more homeowners tend to have more solar units. (Includes homes owned outright or with a mortgage).

In contrast, renters are far less likely to have rooftop solar.

It's clear that someone living in a standalone house and who owns their home is more likely to install rooftop solar.

If you're thinking, 'duh', there's one more thing. Let's add income to the mix.

Money Matters

The chart below shows homeowners again. But this time, we've added average household income, in the form of colour.

Darker dots mean a higher average income. Lighter dots mean a lower average income.

See how the shade changes from dark to light, as it moves upwards.

Where home ownership rates are roughly equal, postcodes with lower average incomes have more rooftop solar.

Below, we've isolated income as a variable. See the fall in uptake as average weekly income grows.

Upshot: The conditions of roof- and homeownership need to be right. But when they are, lower-income households are more likely to install rooftop solar, than those with higher incomes. It seems solar panels are a financial choice, as much as they're an environmental choice. But the financial benefits aren't generally available to renters or apartment-dwellers.

Data notes

  • Rooftop solar is a proxy for ‘small’ generation units, means under 100kW in capacity
  • 1 x unit = entire rooftop solar system installed at a home or business
  • Postcodes with fewer than 500 residents excluded

Credits

  • Data sources: Clean Energy Regulator, Australian Bureau of Statistics
  • Climate data briefing by Juliette O’Brien OAM (Words and Data), James Wagner (Data), and Anthony Macali OAM (Data)

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