How we work out the numbers

What the reference price is

In most of the country the federal regulator, the AER, sets a yearly benchmark called the Default Market Offer, or DMO. In Victoria the state regulator, the Essential Services Commission, sets the equivalent: the Victorian Default Offer, or VDO. Both are the reference price every retailer has to quote their plans against. We use it as our benchmark because it is set by a regulator, not by a retailer, and it is the one yardstick the whole market shares.

The cheapest plan we track

We deliberately exclude plans whose headline rate is not what a typical customer pays. That means wholesale passthrough plans, where the rate follows the spot market and the published price is an estimate; plans requiring a paid membership, mandatory direct debit, bill smoothing, or a bundle; plans open only to new customers or closed to existing ones; and time of use and demand tariffs, which cannot be costed on a single rate. Those plans remain among the plans we track and in our plan counts. They cannot be the cheapest plan we publish.

For each distribution zone we take every plan we track and work out its estimated annual cost at that zone’s benchmark usage. The lowest is the cheapest-tracked figure. The gap between that figure and the reference price is the saving we publish. We compare the plans we track, not every plan in the market, and we say so plainly: where we write “the cheapest plan we track”, that is exactly what we mean. The comparison covers fixed-price plans; wholesale passthrough products, where your rate varies with the spot market, are excluded because their published rates are estimates rather than a set price.

We also match the unconditional basis of the reference price itself: the cheapest-tracked figure reflects plans a typical customer can actually obtain without strings attached. Plans that gate their headline rate behind conditions — mandatory direct debit or bill smoothing, membership or bundling requirements, or offers open to new customers only or closed to existing ones — are noted separately and left out of the headline cheapest, because the regulated benchmark assumes no such conditions. Those plans still appear among the plans we track and in our plan counts.

The usage benchmark

Annual cost is worked out at the representative residential usage the AER or ESC sets for each zone, on a single-rate tariff, with no controlled load and no solar export assumed. We show the usage figure we used for each zone so you can check our working. Your own bill depends on how much power you actually use, so treat these as a like-for-like comparison, not a quote.

What we cover

The index covers the ten distribution zones that sit under the DMO and VDO: Ausgrid, Endeavour Energy and Essential Energy in New South Wales, Energex in south-east Queensland, SA Power Networks in South Australia, and CitiPower, Powercor, United Energy, Jemena and AusNet in Victoria. Western Australia, the ACT, Tasmania and the Northern Territory price their energy outside the DMO and VDO framework, so they are not in this index.

How often it updates

Plan data refreshes nightly from the Consumer Data Right, the government open-data feed every energy retailer is required to publish to. Reference prices update when the AER and the ESC release new determinations, usually once a year on 1 July. The “updated” date you see on the index is the real date the underlying data last changed, not a fixed label.

Current period: DMO 8, effective 1 July 2026.

What the index does and doesn’t tell you

It tells you, at a glance, how far the best available deal sits below the regulated reference price in your zone. It is a like-for-like comparison at a standard usage level. It is not a personal quote: conditional discounts, solar feed-in, time-of-use tariffs and your real usage will all move your actual bill. Use the index to see the size of the prize, then compare on your own postcode and usage to get your number.

Our sources

• AER Default Market Offer (DMO 8)
• ESC Victorian Default Offer (VDO)
• Consumer Data Right energy product data

Version and changelog

Methodology version 1.0, effective 9 July 2026. We version this methodology so that if a published figure ever changes we can show when the method changed and why.

• 8 July 2026 — Excluded time-of-use and demand tariffs from the cheapest-plan selection: they cannot be costed on a single-rate basis.
• 8 July 2026 — Excluded eligibility-restricted plans (paid membership, mandatory direct debit or bill smoothing, bundling, and new-customer-only or closed-to-existing offers), matching the unconditional basis of the reference price.
• July 2026 — Excluded wholesale passthrough plans, where the rate follows the spot market and the published price is an estimate rather than a set price.

Spot an error?

Energy data moves, and we would rather hear about a mistake than leave it standing. Email support@energyplans.com.au and we’ll check it.