Energy Data Hub

SOURCES & DEFINITIONS

Gas methods

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Monthly historical prices

Calculated from the retained user-uploaded AEMO historical workbooks, imported 2026-10-03. Unit: nominal AUD/GJ. This series is separate from the QED quarterly comparison below and does not extend it by interpolation.

Price definitions

VIC DWGM: take the row with Hour = 6 for each Gas_Date in the Prices sheet. AEMO identifies this as the beginning-of-day price and the reference for current ASX Victorian Wholesale Gas Futures. The month’s figure is the arithmetic mean of those daily prices. It is not a volume-weighted or intraday settlement price. Other schedule prices and demand columns are not blended into this series.

STTM: use each hub’s daily exante_price column. Ex-post, imbalance and deviation prices remain separate source fields and are not blended in. Calendar months follow the workbook’s gas-date labels; no conversion to UTC or electricity trading intervals is performed.

Calculation and completeness

Monthly mean = sum of daily selected-basis prices ÷ number of calendar-month gas dates. One valid value is required for every gas date. Missing days, duplicates, nonnumeric prices and changed headers stop or exclude publication, rather than being filled or interpolated. An incomplete month is excluded and recorded in the offline audit. All 796 published market-months have complete daily coverage. Means are calculated using decimal arithmetic and rounded half-up to six decimal places for storage/CSV. The chart and table display cents per GJ.

The DWGM file contains 19 daily 6am dates in December 2022 as DD/MM/YYYY text. These were explicitly parsed rather than skipped. Two missing non-6am schedule rows were detected (10am on 4 February 2013; 10pm on 16 November 2015); neither affects the complete 6am series. This does not establish completeness of every unused workbook field.

Latest means the final month in the selected range. Year-on-year compares that month with the same month one year earlier from the full snapshot, even if it lies outside the selected range. A missing baseline is unavailable; a non-positive baseline uses an absolute AUD/GJ change instead of a percentage. The table is paginated at 24 rows; the graph and CSV always cover the entire selected range.

Original files and version

Checksums identify the uploaded file bytes; no fresh server download or latest-revision verification is claimed. Workbooks remain in the project’s offline sources with a source-row audit. Future source revisions require review before replacing published values. Method gas-monthly-daily-mean-v1; dataset 01c253943113ffaf7174f988838ef84ee89e7b57e40e0dfa5ea3881616ba197b.

Scope and limitations

No national gas aggregate, demand-weighted price, customer bill, hedge payoff or forecast is calculated. GSH has no monthly series in this release. The additional Sydney CLP workbook records historical change in linepack in MJ, not AUD/GJ; it was retained but not used in prices. Its overlapping sheets and missing dates would need a separate reviewed method before use.

Underlying source data © AEMO; AEMO source permissions apply. The monthly summary is an Energy Data Hub calculation, not an official AEMO published monthly index. No live Gas refresh is connected.

Scope

Five reported market series, six continuous quarters from Q1 2025 to Q2 2026. Victoria is the Declared Wholesale Gas Market (DWGM). Adelaide, Brisbane and Sydney are the Short Term Trading Market (STTM) hubs. Gas Supply Hub (GSH) retains the report’s label: this snapshot does not isolate Wallumbilla delivery products. Western Australia, Northern Territory and bilateral gas contract prices are not included.

Price basis

Values reproduce AEMO QED’s “Average east coast gas prices – quarterly comparison” tables. Unit: nominal Australian dollars per gigajoule (AUD/GJ). We preserve two-decimal published precision. We do not reconstruct daily prices, verify the underlying scheduling/volume weights, infer individual GSH products, or assert that the report uses the same definitions as another publisher’s series. In particular, these are not independently calculated beginning-of-day DWGM, STTM ex post, or all-product GSH prices.

Market structures differ. Comparing reported levels provides context, not a tradable location spread after transportation, product and timing adjustments. No combined national average is computed. Tax treatment and additional delivery/network/retail charges are not inferred from the table; these figures are not final invoiced costs.

Calculations and filters

Latest means the last quarter in the selected range. Year-on-year change = (that quarter’s price ÷ the prior-year same-quarter price − 1) × 100; the comparison quarter can fall outside the selected range but must exist in this snapshot. Where absent, the page shows unavailable. A non-positive comparison baseline uses an absolute AUD/GJ change. No annual average or monthly estimate is interpolated from quarterly observations. Lines connect quarterly points only.

The table, chart and selected CSV use the same filtered rows. Static market and all-market downloads remain available without JavaScript. CSVs retain report URL, publication date, page, table, verification date, method and dataset ID.

Versions and checks

Q1 2025 and Q4 2025 use the Q1 2026 comparison table; Q2 2025, Q1 2026 and Q2 2026 use Q2 2026; Q3 2025 uses Q4 2025. Overlapping values were cross-checked between adjacent reports. Report vintages can revise past figures, so a future update requires review. Source table text was transcribed and checked against PDF page screenshots on 2026-10-02. Original PDF binaries were not downloaded; no original-file hash is claimed. The dataset hash identifies our transcription.

Sources and reuse

Underlying figures © AEMO. The reports direct reuse to AEMO’s copyright permissions; this page retains attribution and precise source links. We do not reproduce third-party LNG/commodity data from other sections of the reports. This independent project is not affiliated with or endorsed by AEMO. General information only.

Official historical files

AEMO publishes the DWGM historical prices and demand workbook and the STTM historical prices and withdrawals workbook. These are potential sources for a separate monthly series, not the source of this quarterly chart. A separate monthly dataset has now been imported from retained workbook copies; see the monthly method above. We will not reconstruct monthly prices from quarterly averages.

Update status

This is a fixed reviewed snapshot through June 2026. The separate monthly historical dataset runs through August 2026 and uses the definitions above. There is no live Gas API or automated refresh in this release.

Dataset afe49dbd0e14fb764e47b476f593474bdcbbec22be3bdf067b28f5a8dc19e739