Despite the market volatility in South Australia and Victoria providing some distraction over the past few days as we put the final touches on the report, we’re pleased to announce that today we’ve released the latest edition of our annual Generator Statistical Digest — the GSD2025.

Background

As with each of the past six editions of the GSD, the GSD2025 is collaborative effort from us at Global-Roam Pty Ltd (the company behind WattClarity), and the team at Greenview Strategic Consulting (now an AZZO company).

The GSD brings together a decade of detailed operational data for every registered generator and load in the NEM, presenting a consistent, unit-level view of operational and financial performance of each unit. The GSD has grown into an annual reference document used by analysts, market participants and policymakers alike.

The GSD2025 is broken into four parts:

• Section #1: FCAS Bidding Profiles. This section covers all operating units in the NEM registered to deliver at least one FCAS service. For each service, this section presents charts showing month-to-month FCAS volumes bid across ten price bands from 2016 to 2025, alongside total monthly enablement volumes. A table detailing each unit’s registered FCAS capacity is also included.
• Section #2: Semi-Scheduled Output Profiles and Availability Source. For each operating semi-scheduled solar and wind unit, this section displays a chart of time-of-day output and availability for each month of the 2025 calendar year. A table of monthly details on UIGF source and self-forecast suppression status are also displayed
• Section #3: FCAS Causer Pays Portfolio. As the FCAS Causer Pays scheme was assessed at a portfolio level up until June 8th 2025 (before being replaced by the new Frequency Performance Payments scheme), this section reports estimated total FCAS Causer Pays costs for each portfolio, with a breakdown of each unit’s contribution to the total up until June 2025.
• Section #4: Unit Profiles. The core of the report. For every operating unit in the NEM, an A and B page is provided. The A page summarises ten years (2016 to 2025) of monthly spot and FCAS revenues, capacity and availability factors, and bid volumes across fourteen price bands, together with tabulated information on unit starts, price setting involvement and other relevant operational and market data. The B page focuses on the 2025 calendar year only and covers spot and FCAS revenues, FCAS costs, average prices, rebid frequency, rebid reasons, top 5 constraints, unit price capture, temperature performance, and more.

What enhancements have we made this year?

In addition to incorporating newly computed data for the 2025 calendar year, we’ve made a number of practical enhancements since the GSD2024 to improve coverage and consistency across the report.

Addition of FPP revenues and costs

To reflect the commencement of the Frequency Performance Payment (FPP) scheme from June 8th 2025, the GSD2025 now includes explicit reporting of FPP revenues and costs for all units. This allows FPP outcomes to be viewed alongside energy and FCAS revenues, providing a more complete picture of how different assets are being remunerated under this new market arrangements.

FPP Revenues and Costs for the John Butters Hydro Power Station in Tasmania for 2025: We’ve added in FPP revenues and costs for all units, to provide a better understanding of the financial impacts of this scheme.

Time-of-day availability and output profiles for Semi-Scheduled wind and solar farms

We’ve also expanded visualisation into semi-scheduled solar and wind farms by adding time-of-day availability and output profiles for each unit, helping to illustrate how diurnal performance varies across the seasons. While curtailment is not shown explicitly in these charts, differences between the availability and output profiles provide a clear indication of when curtailment is occurring at each unit.

Each chart presents average time-of-day profiles at a 30-minute granularity, with months loosely colour-coded by season: summer (red), autumn (yellow), winter (blue) and spring (green).

The availability and output profile for Cherry Tree Wind Farm in Victoria for 2025: For every semi-scheduled solar and wind unit in the NEM, we show the average time-of-day availability and output in 2025 — in order to understand diurnal and seasonal operational patterns.

Tidy up of historical data of battery units following the 2024 IESS rule changes

Prior to the Integrating Energy Storage Systems (IESS) rule changes that came into effect in 2024, battery units were typically assigned two dispatchable unit identifiers (DUIDs), representing the charging and discharging sides of the same physical asset. Once the IESS changes came into affect, and these two DUIDs were merged into a single bi-directional DUID. The change in DUID structure complicated longitudinal analysis, particularly when comparing unit performance across multiple years.

In the GSD2025, we’ve cleaned up the historical treatment of battery units by consolidating DUID histories for bi-directional units into a single, continuous unit record. This improves continuity across the dataset and allows for more consistent, easier, like-for-like comparisons of battery performance through time.

The unit profile for the Hornsdale Power Reserve in South Australia for 2016 to 2025 (left) and 2025 (right): We’ve consolidated the DUID histories for bi-directional units prior to the IESS 2024 changes, to allow for a single continuous unit record for each battery unit’s operational and financial performance.

Network and Economic Curtailment metrics for Scheduled units

Finally, network and economic curtailment metrics have been moved into the main unit section of the report (Section 4). This means these measures are now presented consistently for scheduled units — including coal, gas, hydro and batteries — rather than being confined to just semi-scheduled units as in past editions.

Summary statistics for production, network curtailment, economic curtailment, availability and unavailability for Kareeya Hydro Power Station Unit 1 in Queensland for 2025: By moving our summary production statistics to the main section of the report, readers can now see network and economic curtailment figures for scheduled units.

How to order and more information

Alongside the enhancements outlined above, we’ve also introduced a new online ordering system for WattClarity Deeper Insights publications, replacing the manual order forms used in previous years.

Further information, including ordering options for the GSD2025 (with or without the accompanying data extract), is available via the links below:

• Generator Statistical Digest 2025 Report Only — $950 exGST
• Generator Statistical Digest 2025 with Data Extract — $3,950 exGST

Over the coming weeks and months, we’ll also be sharing selected snippets and insights from the report here on WattClarity.