Why "who is cheapest" has no fixed answer
AGL, Origin Energy and EnergyAustralia are the three largest electricity retailers in the National Electricity Market, and between them they supply a large share of Australian households. That scale is why they are the most-compared names in the country, and it is also why the question "which of the three is cheapest" gets answered badly so often. None of them has a single price. Each runs dozens of plans that vary by state, by distribution network, by tariff type, and by whether you arrived through a comparison site, a retention offer or a standing offer.
The honest answer is that the cheapest of the three depends on four things about you: how much power you use, when you use it, whether you export solar, and whether you reliably pay on time. Change any one of those and the ranking between the three can flip. That is not evasion, it is arithmetic. What follows is the structure you need to compare them properly, rather than a headline number that would be wrong for most readers.
If you would rather skip the theory, EnergySorted costs every plan from all three — and every other AER-listed retailer — against your actual usage and ranks them cheapest-first. You can compare the whole market on your real bill, or get a rough figure first with the free electricity bill estimator.
Start with the two numbers, not the brand
Every plan any of the three sells is built the same way: a daily supply charge you pay just for being connected, and a usage rate in cents per kilowatt-hour for the power you draw. The mix between those two decides who wins for you. A plan with a low usage rate and a high daily supply charge suits a heavy user in a large household; the same plan punishes a one-person apartment that barely uses anything, because the fixed daily charge dominates a small bill.
This is the most common reason people switch to a "cheaper" retailer and end up paying more. They compared the advertised cents per kilowatt-hour and never looked at the daily charge, or the reverse. Both numbers are on your bill and both are published for every plan. Comparing one without the other tells you very little about your own bill.
Our guide to how Australian energy retailers set their prices walks through the full structure, including why the same plan can be good value in one postcode and poor value in the next.
Where the three genuinely differ: discounts and benefit periods
The biggest structural difference between the big three is not the raw rate, it is how the rate is dressed. A guaranteed discount is baked into what you pay regardless of what you do. A conditional discount — most often pay-on-time — applies only if you meet the condition, and disappears for any bill you pay late. A large advertised percentage wins the click even when a share of customers never actually earn it.
So when you compare the three, you need to know which kind you are being offered, and whether it applies to the whole bill or only to usage charges. A large pay-on-time discount on usage alone is a materially different product from a smaller guaranteed discount across the bill, even when the advertised percentages look similar. Our how retailers set their prices guide sets out how to read them.
The second structural trap is the benefit period. Competitive plans from all three commonly guarantee a discount or rate for a fixed window, often around twelve months, after which you roll onto ongoing rates that can be materially higher. Nobody is obliged to ring you on the day it ends. A very large share of households who believe they are on a good deal have simply passed their benefit period. This is why a one-off comparison ages badly, and why re-checking matters more than picking the "right" brand once.
Solar changes the ranking completely
If you export solar, the feed-in tariff can matter as much as the usage rate, and it is where the three diverge most. A plan with an attractive feed-in rate often carries a higher usage rate or daily charge to fund it, which is excellent value for a household exporting a lot and poor value for one exporting little. You cannot judge this from the headline feed-in number alone, because it depends on the ratio between what you import and what you export.
The trap is that feed-in rates are advertised prominently precisely because they are easy to compare and hard to evaluate. A household that exports heavily at midday and imports heavily in the evening peak has a completely different optimum from one that self-consumes most of its generation. Our solar feed-in tariff guide explains how to weigh the two, and the free solar savings calculator gives you a starting estimate.
Time-of-use, demand tariffs and the smart meter effect
As smart meters roll out, more customers of all three are being moved onto time-of-use tariffs, where the rate changes by time of day, and in some networks onto demand tariffs, where you also pay for your single highest burst of power draw in a defined window. These make brand-to-brand comparison genuinely hard by hand, because the answer depends on the shape of your usage across the day rather than on a single total.
A household that can shift laundry, dishwashing and car charging into cheaper windows can do very well on time-of-use with any of the three. A household with an inflexible evening peak often does better on a flat rate. Our time-of-use vs single-rate guide explains which suits which pattern, and if you charge an electric car the EV charging cost calculator shows how much the window you choose actually matters.
How to settle it for your own household
The comparison that answers the question is not "AGL vs Origin vs EnergyAustralia" in the abstract. It is every plan all three currently sell in your postcode, costed against your real usage, alongside every plan from every other retailer, with discounts, fees, feed-in rates and tariff type all applied. That is thousands of calculations, which is why it is rarely done properly by hand — or by a site that earns a commission when you pick particular retailers.
EnergySorted does exactly that and takes no retailer commissions, so nothing is boosted for paying to be there. Upload one recent bill and it costs the whole market on your actual usage, ranks the results cheapest-first, and proves the figure against the bill you already paid before recommending anything. It then re-checks nightly, so an expiring benefit period surfaces as an alert rather than as an unpleasant surprise three bills later.
If you want the pairings in more depth, see AGL vs Origin Energy, Origin vs EnergyAustralia and AGL vs EnergyAustralia.
Frequently asked questions
Which is cheapest: AGL, Origin or EnergyAustralia?
There is no fixed answer. All three sell many plans that vary by state, network and tariff type, and the cheapest depends on your usage volume, your usage timing, your solar export and whether you always pay on time. The only reliable method is to cost every plan from all three against your own bill. Compare them on your real usage.
Are the big three more expensive than smaller retailers?
Not automatically. Smaller retailers sometimes lead on headline price and sometimes do not, and scale cuts both ways. What matters is the plan, not the size of the company. Our big retailers vs small retailers guide compares them on what actually differs.
What is a benefit period and why does it matter?
It is the fixed window — often around twelve months — for which a plan guarantees its discount or special rate. When it ends you usually roll onto higher ongoing rates without being contacted. It is one of the most common reasons households quietly start overpaying on a plan they once researched carefully.
Does having solar change which of the three is best?
Substantially. The feed-in tariff interacts with the usage rate and daily supply charge, so the best plan for a heavy exporter is often a poor plan for someone who self-consumes most of their generation. Both sides have to be costed together, on your own import and export figures.
How often should I re-compare the big three?
At least once a year, because benefit periods expire and new plans launch constantly. A tool that re-checks nightly removes the need to remember. See how often you should switch energy plans.