Where you live changes your electricity bill by hundreds of dollars a quarter for identical consumption. Tasmania sits around $250 to $450; South Australia can reach $700.
The reasons are structural and mostly outside your control. What is inside your control is how much grid power you buy, and that is why solar pays differently in different states.
What Drives the Cost of Power?
Four components, and only one of them is about how much electricity you use.
Wholesale generation cost. What it costs to produce the power, varying with fuel prices, demand and weather. States relying on gas generation pay more when gas is expensive.
Network charges. Maintaining the poles, wires, substations and meters that deliver it. This is frequently the largest single component, it is regulated, and it varies enormously by state and even by distribution area within a state. Sparse populations pay more, because the same network cost is spread across fewer customers.
Retailer margin and government schemes. Competition affects the first; environmental and social programs affect the second.
Your climate. Perth air conditioning through February costs more than Hobart air conditioning does. Heating in Melbourne costs more than heating in Brisbane.
Note what that list means: two households consuming identically in different states pay different amounts, and most of the difference has nothing to do with either household.
The States With the Highest Bills
South Australia has historically sat at the expensive end. A dispersed population spreads network costs across fewer customers, and the state relied heavily on gas generation, which is expensive when gas prices spike. The renewable transition has been rapid and grid stability during that transition carries its own costs.
Typical quarterly bills run $400 to $700 depending on usage and retailer.
New South Wales faces different pressures. An enormous network to maintain, high demand from residential and industrial users, and a generation mix still leaning on ageing coal plants, which produces wholesale price volatility as they age and become less reliable.
Quarterly bills commonly land in the $350 to $650 range, higher in regional areas where network charges climb.
The States With the Lowest Bills
Queensland benefits from significant state-owned generation, which dampens wholesale volatility, and from very high rooftop solar penetration that suppresses daytime grid demand. Retail competition in the south-east is genuine.
Quarterly bills often sit around $300 to $550.
Tasmania is the outlier. Almost entirely hydroelectric generation means the state is largely insulated from the fossil fuel price swings that drive mainland wholesale prices. That flows straight through to consumers.
Bills commonly range from $250 to $450 a quarter.
Why the Cheapest States Change the Solar Case
Counter-intuitively, cheap electricity makes solar pay back more slowly.
Your solar savings are measured against the retail rate you avoid paying. In South Australia, avoiding 40-plus cents a kilowatt-hour makes a system pay for itself in three to five years. In Tasmania, avoiding a much lower rate stretches that considerably, and shorter winter days compound it.
That does not mean solar is a poor choice in Tasmania. It means the payback arithmetic differs by state as much as the bills do, and a national average payback figure is close to meaningless.
Solar Works in Every State, for Different Reasons
Network and wholesale charges are outside your control. How many kilowatt-hours you buy is not.
Every unit you generate and consume yourself is a unit you do not buy at your state's retail rate. That saving scales directly with how expensive your state is, which is why South Australia has the highest rooftop penetration in the country and Tasmania has the lowest.
Feed-in tariffs still apply for exported surplus, and they have fallen everywhere to a few cents a kilowatt-hour. Do not size a system around export income. Size it around what you consume.
Battery storage extends the same logic into the evening, storing midday generation for use when grid power is dearest. It pays fastest where the gap between peak retail rates and feed-in tariffs is widest, which again favours South Australia and New South Wales over Tasmania.
The One Thing to Do Regardless
Whatever state you are in, the daily supply charge applies whether you generate or not, typically 90 cents to $1.50 a day. Solar cannot touch it, and for a household that has driven its imports right down it becomes the largest line on the bill.
That means two things. Nobody eliminates their electricity bill entirely, whatever a salesperson says. And a low-consumption solar household should chase a low daily supply charge when comparing plans, and accept a higher usage rate in return, which is the opposite of the advice given to everyone else.
Pull your last four bills, note your imported and exported kilowatt-hours, and run them through Energy Made Easy for your postcode. That comparison is worth more than any state average, because it uses your numbers rather than a typical household's.
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