Queensland government plans to extend the life of the coal-fired Callide Power Station are under renewed attack, after a new report detailed a laundry list of “long-standing unresolved issues” that contributed to a serious explosion at the aged and troubled plant.
State-owned utility CS Energy on Thursday released a report into the “major operational safety event” that struck Unit C3 at the jointly owned Callide C Power Station on April 04, 2025, taking it out of action until June.
The report confirms that the Callide Unit C3 experienced a significant boiler pressure event after a larger-than-usual clinker (piece of hardened ash) fell into the furnace ash system. This event disrupted flame stability, resulting in a delayed unit trip and subsequent re-ignition.
“While no injuries were reported,” it says, “the incident caused notable equipment damage and necessitated an extended outage of approximately two months. The nature of the event carried the potential for serious harm.”
And it’s not the first time. Callide C – whose two units are 50/50 owned by CS Energy and IG Power and operated by CS Energy – is the same facility that suffered a catastrophic explosion in May 2021, that took the C4 units offline for more than three years, until August 2024.
This time around, however, the Callide C explosion came just days before the Queensland LNP government announced it would extend the life of the two ageing Callide B coal units – fully owned by CS Energy – from 2028 to either 2030 or 2031.
This idea was slammed by the industry and green groups at the time – even before the explosion was public knowledge – coming as it did as part of a broader plan from the Crisfaulli government to hit the brakes on Queensland’s shift to renewables.
But the Queensland Conservation Council says plans to “pump hundreds of millions of taxpayer dollars” into keeping old coal plants on life support looks less sensible than ever following the findings of this week’s CS Energy report.
“You can’t flog a dead horse,” QCC campaigner Stephanie Gray said on Thursday. “Queensland’s coal power stations were offline a staggering 78 times over the last summer period because they’re old and keep breaking down.
“If the Crisafulli government keeps pushing these coal clunkers past their scheduled end of life we’re going to see more breakdowns, more outages, and more price spikes for Queensland consumers.
“The practical thing for Queensland’s Energy Minister, David Janetzki, to do now is plan for the replacement of Queensland’s ageing coal power stations with renewable energy backed by storage.”
“Significant weaknesses” exposed
The 146-page report from CS Energy sets out the key findings of the investigation into the April incident, drawn from an internal root cause analysis and an independent external investigation, while also detailing CS Energy’s action plan going forward.
“The incident was triggered by the concurrent failure of several independent controls. A large clinker formed and fell, leading to total flame loss in the furnace, while fuel was not isolated in time,” it says.
“Each failure point had an associated control mechanism; had any single control operated effectively, the event could have been averted.”
The report finds that while the technical root causes of the explosion have been rectified – at an approximate cost of around $5.4 million – several long-standing unresolved issues are still plaguing the ageing power station.
“The C3 clinker incident was a high-risk event that exposed significant weaknesses in CS Energy’s technical controls, operational systems, and leadership oversight,” it says.
“While immediate engineering improvements are being actioned, the investigation found that many of the underlying conditions that enabled the incident to remain present.
“These include unclear accountability across functions, inconsistent application of risk processes, gaps in operator competency, maintenance
discipline, and a safety culture that has not been fully embedded.”
Brian Gillespie, appointed as the new CEO of CS Energy after a comprehensive purging of executive ranks in the aftermath of the explosion, said the report reflects a commitment to transparency and accountability.
“The CS Energy leadership team acknowledges that what happened on Unit C3 was not good enough,” Gillespie said on Thursday.
“We have a new leadership team who is listening and acting. There is no finish line to creating a great safety culture and we are committed to being among the best in the world when it comes to safety.”
Energy production over risk management
But the QCC remains concerned about the transparency and culture of the current state government, the ultimate owner of the ageing coal assets.
And it says the explosion at Callide C is ultimately the result of “prioritising energy production over risk management” and fossil fuels over renewables.
“The state government needs to be upfront about when the state-owned coal-fired power stations will close to provide workers and local communities with certainty, and make sure new opportunities are being created locally to transition the workforce,” Gray says.
“Our research found that keeping Callide B open past 2028, the end of its technical life, would cost up to $420 million a year. Queenslanders can’t afford for the Crisafulli government to put ideology over getting on with the practical transformation of our energy system.
“CS Energy’s annual reports show that Callide B appears to have recorded a real loss of $120 million over the last five years, costing taxpayers an average of $24 million per year.”
