AEMO’s 2024 Intermittent Generator Forum provides renewed awareness for wind and solar generators

AEMO hosted the Intermittent Generator Forum on December 3, 2024.

These forums typically happen once each year so a large body of information was presented in the 2-hour session this time.

Points of interest

Information spanned the following topics:

  1. Recent improvements to AEMO intermittent generator forecasting systems,
  2. Future improvements underway and proposed,
  3. A weather data initiative,
  4. A guest presentation by AER on “biasing”.
  5. Advice on updating intermittent generator availability, and
  6. Perspectives and updates from the AEMO control room regarding measures, and capabilities, for managing inverters for power system security.

If slides are published by AEMO we’ll endeavour to update this post with a link when available. Until then, we’ve collated the following points from the forum.

Recent improvements to AEMO forecasting systems

The recent improvements to AEMO forecasts were highlighted. These included:

  • Improvements to accuracy performance in 2022 (15% improvement to the dispatch forecast models),

    Enhancement of ASEFS and AWEFS forecasts provided by AEMO – from Wednesday 23th November 2022

  • In 2023, enablement of bid Max Avail for semi-scheduled generators – this equips participants with a way to restrict unit availability for commercial reasons, for dispatch, and acts as a backup for communicating physical availability when SCADA signals are not available.

    Implemented: Enablement of bid energy MaxAvail for semi-scheduled generators

  • Publishing actual SCADA availability data – elements available and the local limit

  • In November 2024, self-forecast submission API upgrades – in response to slow submission times due to volume of submissions, upgrades to the API have drastically improved the speed of self-forecasts to be submitted and accepted into AEMO systems.
  • Other administrative changes, including
    • Managing how TLS certificates are created,
    • Clarity on who can submit an application for participant self-forecasting.

Future improvements underway and proposed

The audience now understands there’s a bunch of improvement work that AEMO is doing to transform the forecasts it produces.

  • Improving the AWEFS/ASEFS dispatch forecast models (the FCST analog, typically used during early stages of onboarding, will no longer be required). Anticipating early 2025.
  • Uplifting systems to support a multi-vendor approach to forecast models used. We anticipate that when multiple models are making forecasts there’ll be a ‘track’ table that indicates which one is eventually used. Anticipating December 2025.
  • Rooftop PV actuals and forecasts are getting a revamp. Particularly the introduction of 5-min forecasts (P5-min) and actuals, alongside 30-min actuals and forecasts. A multi vendor approach to forecasts is also planned. Anticipating December 2025.

The Observation Hub Project

Attendees were introduced to the Observation Hub Project and received the call for collaboration and feedback on the project. The project was announced in the NEM engineering framework roadmap. December 17 2024 is the deadline for feedback to op.foreasting.

The project aims to make enhanced use of weather observation data that is being collected at intermittent generator sites. The weather data can contribute to improved AEMO wind and solar forecasts. It’s also envisaged that appropriate, controlled,  sharing of this data could support specific industries including emergency services.

A guest presentation by AER on “biasing”

We’ve prepared a separate article on this item:

AER sends clear message on self-forecasting behaviours

We’ve noted the following reflections in other media:

Advice on updating intermittent generator availability

It’s always good to reflect upon the inputs AEMO uses for its forecasts. Helpful because the industry in general is undergoing a lot of change  – new market participants coming in, staff changes, and market reforms all happening (seemingly) at the same time making it a challenge to keep up to date with requirements and responsibilities. Yet we must.

Intermittent generator availability information is a key input to AEMO forecasts in the pre-dispatch and ST-PASA timeframes.  There was particular focus in the forum on availability under extreme weather conditions. A degree of understanding is required to effectively submit values for local limits, inverters available, turbines in extreme wind cut-out states, high-temperature impacts on inverters (deratings).

Perspectives and updates from the AEMO control room

The real time operations group at AEMO, as the name implies, operates the power system in real time, principally through the control room.

Attendees at the forum gained an appreciation of potential ambiguity in what it means to turn off a semi-scheduled unit’s inverter.

This was discussed in the context of AEMO needing to have fine-grained control on inverter-based resources for system security. Current approaches involve the control room making phone calls to participants to make the necessary changes to inverter settings when needed.

Even under normal conditions this can result in a large number of phone calls. We gathered that, as more and more semi-scheduled inverter-based VRE enters the market the time needed to make individual calls is becoming a looming barrier to effect timely change at plant inverters.

To turn off an inverter? We understood this can mean stopping it from exporting active power or going further to prevent it from any interaction with the power system. This latter case is needed in situations where the control room needs enhanced control of the power system.

Work is underway to consider whether these power system requirements can be automated to address issues raised with phone calls.  E.g. though constraints.

Yet it appears there is some ambiguity in what it means to ‘turn off’. Categories discussed included “blocked”, “paused”, “disconnected” and discussion indicated that certain words or phrases may mean different things to different people. Further, differences between these categories may require different actions (and time) on behalf of plant operators. And, importantly, there are differences in how the inverter interacts with the power system when in these states.

We look forward to seeing support for AEMO in its efforts to effectively manage the system, and in resolving potential ambiguity around inverter control so that participants respond as necessary when needed.

 


About the Author

Linton Corbet
Linton joined Global-Roam as a software engineer and market analyst in August 2020. Prior to joining us, he worked with the AEMO for 7 years, and before that, as an air quality scientist.

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