Coal plant reliability hits a new low as unplanned unit outages hit a new high

Australia’s remaining coal power fleet suffered thousands of hours of forced outages over the course of 2022, leaving the grid short of forecast coal generation capacity for nearly one-quarter of the year.

New analysis from Watt Clarity on the remaining 44 still operational coal units nationally – excluding the soon-to-be-fully-closed Liddell – shows a rising level of “unavailability” of registered capacity, most commonly from long term forced outages.

Watt Clarity’s Paul McArdle says the data shows that while coal units are not tripping more frequently than in the past, they are collectively unavailable for a much longer period (or volume of energy) than was the case several years ago.

“At the end of 2022 the 44 remaining coal units (excluding the 3 soon to close at Liddell) have collectively reached 24% aggregate unavailability,” he writes.

McArdle says that of the coal stations assessed in the analysis, just five out of 13 stations were operating with less than 25% unavailability.

A number of the others were found to be significantly in excess of 30% unavailability.

“This is going to increasingly have implications for Reliability Planning into the future,” McArdle says, noting that the data proves that it’s not just the soon-to-retire Liddell that is troubled.

Among the most serious outages experienced across the coal fleet, Watt Clarity points to the 19-month-long (and counting) forced outage of Callide C4 that took the units out for the majority of the year.

Next in line for the longest period of forced outage through calendar 2022 was Loy Yang A2 with 5,233 hours, and Yallourn Unit 4, which was out of action for a total of 3,577 hours.

Less significant through calendar 2022, says McArdle, but dragging into calendar 2023, is the long-term forced outage of Callide C3 following cooling tower failure.