Auction Units Report

The Auction Units Report details the financial outcomes of the AEMO’s Settlement Residue Auctions (SRA’s).

Australia’s National Electricity Market (NEM) trades electricity across states to take advantages of differences in supply, demand, and cost.

The scope of the NEM state interconnections are:

NSW <–> QLD
VIC <–> SA
VIC <–> NSW

If a region experiences excess power production and a neighboring region experiences high demand it can trade the excess electricity to meet the demand. This temporal diversity allows regions to support each other.

Insight potential

Data Source

Current files: https://nemweb.com.au/Reports/CURRENT/Auction_Units_Reports/

AUCUNITS_20250629.R009 Download

Published weekly in a CSV format and 12 months of rolling historic data can be sourced from the AEMO data repository.

Description of Report Field Names

Field	Description	Unit
AUCTION_UNITS	Fixed value. “AUCTION_UNITS”	—
1	Fixed value. “1” Probably kept for legacy reasons.	—
CONTRACTYEAR	The year the auction contract applies to (e.g. 2024, 2025).	Year (YYYY)
WEEKNO	Calendar year week number of the auction period (1–52)	Integer
BILLRUNNO	Internal reference billing run identifier	Integer
STARTDATE	Start of the auction week	DateTime (DD/MM/YYYY HH:MM)
ENDDATE	End of the auction week	DateTime (DD/MM/YYYY HH:MM)
BILLRUNTYPE	Type of billing run (PRELIMINARY, REVISION [1,2] or FINAL)	Text
RESIDUEYEAR	Year the settlement residue applies to (usually same as contract year)	Year
QUARTER	Calendar year quarter (1–4)	Integer
INTERCONNECTORID	– Transmission link between regions (e.g. VIC1-NSW1) – Unique code identifying the transmission link (interconnector) between two regions.	Text
FROMREGIONID	– Region on one side of the interconnector (e.g. VIC1, NSW1) – Identifier of the region from which auctioned capacity is being exported or dispatched.	Text
PURCHASEDUNITS	– Number of auction units purchased for that region – Total quantity of capacity (in megawatts) successfully awarded in the auction for the given direction and period	Units
TOTALSURPLUS	– Total settlement residue generated across the interconnector ($). – Aggregate economic surplus created by the auction: the sum of (bid price – clearing price) × awarded units across all bids.	AUD
DISTRIBUTEDSURPLUS	– Portion of surplus distributed to unit holders ($). – Portion of the Total Surplus actually allocated back to participants as payments or credits.	AUD
AUCTIONFEES	– Fees deducted by AEMO (usually zero) ($). – Total fees collected by the market operator for running the auction, deducted from participants’ payouts.	AUD
NETPAYMENT	– Final payment to unit holders after fees ($). – Net amount participants receive (or pay) after fees: Distributed Surplus – Auction Fees.	AUD
NETPAYMENTPERUNIT	– Net payment divided by purchased units – Average net payment per megawatt: Net Payment ÷ Purchased Units, expressed in AUD/MW.	AUD/unit
ACCUMULATEDNETPAYMENT	– Total net payments received by that region over time ($). – Cumulative sum of Net Payment across multiple auction periods (e.g., running total over weeks).	AUD
ACCUMULATEDNETPAYMENTPERUNIT	– Cumulative earnings per unit ($) – Running average net payment per unit: Accumulated Net Payment ÷ total Purchased Units to date.	AUD/unit

Data Analysis

Query #1 – “direction-based_earning_comparison.sql”
- Purpose – Identify which interconnector and direction, based on the historical data is earning the most revenue.

-- Filename: direction-based_earning_comparison.sql
-- Version: 1.0
-- Purpose: Analyze which side ("from region") of each interconnector tends to earn more
-- Focuses on three key interconnectors: NSW1-QLD1, V-SA, VIC1-NSW1

SELECT
  interconnector_id,              -- e.g. NSW1-QLD1, V-SA, VIC1-NSW1
  from_region_id,                 -- the region on one end of the interconnector (e.g. QLD1, SA1, VIC1)
  
  -- Sum up all net payments for that region+interconnector combination over the time period
  -- Also round to two decimal points
  ROUND(SUM(net_payment), 2) AS total_net_payment,
  
  -- Calculate average net payment per auction unit to measure per-unit profitability
  -- Also round to two decimal points
  ROUND(AVG(net_payment_per_unit), 2) AS avg_net_payment_per_unit

FROM auction_units

-- Limit to only the three interconnectors of interest for focused comparison
WHERE interconnector_id IN ('NSW1-QLD1', 'V-SA', 'VIC1-NSW1')

-- Group by both interconnector and region to isolate directional earnings
GROUP BY interconnector_id, from_region_id

-- Sort so you can easily compare which region on each interconnector earned the most per unit
ORDER BY interconnector_id, avg_net_payment_per_unit DESC
;

Output

 $ ./runsql.sh direction-based_earning_comparison.sql
 interconnector_id | from_region_id | total_net_payment | avg_net_payment_per_unit
-------------------+----------------+-------------------+--------------------------
 NSW1-QLD1         | QLD1           |      900253113.32 |                  3202.62
 NSW1-QLD1         | NSW1           |      103699992.29 |                   796.60
 VIC1-NSW1         | VIC1           |      524390222.78 |                  1501.12
 VIC1-NSW1         | NSW1           |      143050435.81 |                   478.43
 V-SA              | VIC1           |      329301950.83 |                  1627.68
 V-SA              | SA1            |       96223574.57 |                   536.16
(6 rows)

$

Interpretation of results

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