CQUniversity professor says coal dust or hydrogen leak may have caused Callide Power Station explosion

The fire occurred in the Turbine Hall for Callide C4 at the Biloela Power station on Tuesday afternoon and subsequently both Callide C units and 1 Callide B unit tripped and came offline.

The site was evacuated with all 236 personnel accounted for with no injuries.

Related: Investigations underway into the fire and explosion at Callide Power Station on Tuesday

CQUniversity's Professor in Mechanical Engineering, Mohammad Rasul, who is the founder of the Clean Energy Academy at the University recently provided an insight into how power outages like this occur.

Professor Rasul said the power station fire and power outage could have happened from coal dust ignition.

"According to CS Energy the recent power outage happened at Callide Power Station because of fire and an explosion in one of the plant's four turbines hall," he said.

"At the Callide Power Station, the outage was due to an explosion which can happen from coal dust ignition.

"When a fire ignites, oxygen, fuel, and heat is merged into the fire triangle which is a cause of explosion. This is triggered because of dispersion of confined dust."

Professor Rasul said another possible cause could be a hydrogen leak from the generator.

"There are many power stations that use hydrogen cooled generators. About 99.9 per cent hydrogen purity is needed to not to have an explosion," he said.

"If a mechanical break happens in a turbine blade (due to a crack), that can cause mechanical failure because it has high pressure and temperature.

"Turbine and generator relate to the shaft that can impact generator rotor breakage and subsequently hydrogen leak.

"When leaked hydrogen mixes with oxygen an explosion can happen through ignition."

Work has started on restoring the remaining three generating units at the Callide Power Station, following the major failure of the Callide C4 unit.

CS Energy has informed the Australian Energy Market Operator (AEMO) that three generating units will be returned to service sequentially from the 5 June and anticipate all three units being online by 9 June, while Unit C4 will be available in 12 months.

CS Energy CEO Andrew Bills said work had begun on establishing an investigation into what caused the failure on the Callide C4 unit.

"It is too early to speculate as to the cause of the incident and we need to undertake a thorough and comprehensive investigation working with all authorities and regulators to determine the cause of this failure," he said.

"It is not helpful to speculate at this early stage on what the cause was. CS Energy will work closely with our JV partner InterGen as part of the investigation process."