I’ve not been posting about this type of frequency disruption in recent months (focused elsewhere) but worth a short note because of a 295MW drop in output from Loy Yang A3 just prior to 14:06 (NEM time) on Tuesday 20th May 2025:
Here’s a quick look at the live frequency trace for the mainland over the past hour:
Paul was one of the founders of Global-Roam in February 2000. He is currently the CEO of the company and the principal author of WattClarity. Writing for WattClarity has become a natural extension of his work in understanding the electricity market, enabling him to lead the team in developing better software for clients.
Before co-founding the company, Paul worked as a Mechanical Engineer for the Queensland Electricity Commission in the early 1990s. He also gained international experience in Japan, the United States, Canada, the UK, and Argentina as part of his ES Cornwall Memorial Scholarship.
Like was the case on 4th July 2013, the cause of this large Aggregate Raw Off-Target result (across all Semi-Scheduled Generators) was a single unit trip.
An animation of 90 minutes this morning where the price gyrated wildly in response to a trip at Yallourn, and numerous subsequent reactions by market participants and the AEMO.
If the NEM at the time was about 21GW then yes, the bump is about right for the loss of 300MW odd. Interesting the relatively slow recovery. Must be about the deadband setting. I thought the magic batteries were bidding in for small signal raise????
If the NEM at the time was about 21GW then yes, the bump is about right for the loss of 300MW odd. Interesting the relatively slow recovery. Must be about the deadband setting. I thought the magic batteries were bidding in for small signal raise????