State-owned West Australian power provider Synergy is facing questions about whether it paid millions of dollars to import the wrong type of coal as it scrambles to keep the lights on this summer.
Later this month, Synergy will take delivery of the first of two 50,000-tonne shipments of New South Wales coal, believed to be costing the utility tens of millions of dollars.
Synergy was left scrambling for the imports in October when it emerged that a deepening crisis in the coal mining and power generation hub of Collie, south of Perth, would leave it short of supplies.
At the time, Premier Mark McGowan blamed a wettish winter and operating difficulties at one of the town's two coal mines for the unprecedented decision, which Energy Minister Bill Johnston also said was "not ideal".
There are growing fears about the security of the state's biggest electricity grid heading into what is forecast to be a scorching summer.
Major coal supply shortages have combined with a gas crunch caused by last week's leak at a critical offshore well and outages at several big plants to put pressure on the system.
Coal unsuitable due to high ash content
In a further blow, it is believed the coal due to arrive at Bunbury port next week is unsuited for use in Synergy's coal plants at Collie because of its high ash content.
A Synergy spokesman insisted the utility had known about and accounted for the content of ash in the coal and planned to "blend" imported product with local supplies, which typically have far lower levels.
But Synergy's former chief engineer has cast doubt over those claims, saying the ash content of the NSW coal was likely to be a major problem at the company's Muja and Collie power stations.
Andrew Wearmouth, also a former manager at Muja, said Synergy's plants were designed to run on coal with an ash content of between six and eight per cent but could "reasonably" handle up to 10 per cent.
However, he said the imported NSW coal was likely to have an ash content of about 20 per cent, which he argued would pose big headaches for power station operators.
Imported coal may not be usable: expert
For starters, Mr Wearmouth said Synergy may not have the "milling capacity" to blend the imported coal at sufficient rates, there was a risk of "emissions breaches" if it was used in large quantities, and it could also cause "erosion" and "fouling" problems.
He said the upshot was that much of the coal may not be usable and, even if it if it was, Synergy may cause other problems that could jeopardise the reliability of plants during summer.
"Coal ain't coal and boilers at Collie and Muja are specifically designed around local sub-bituminous coal, not NSW bituminous rank coals," Mr Wearmouth said.
"I am not aware of any blended fuels that have ever been fed to these boilers.
"Even blends from different coal seams in Collie have been known to cause furnace fouling issues."
Forced outages could add to energy headaches over summer
Mr Wearmouth queried the extent to which Synergy had sought to understand the chemical and technical suitability of the NSW coal before ordering the two shipments.
He said any assumptions that local coal supplies could be used to blend the imported stocks was dangerous given the sharp decline in production at Collie amid growing commercial troubles at the two privately owned mines.
"I would expect Synergy has undertaken this work prior to embarking on this strategy," he said.
"Forced outages caused by fouling or excessive mill wear are not going to help if they occur in summer."
Synergy suggested the government-controlled entity was comfortable with the type of coal it was importing.
"Synergy has ensured the imported coal is suitable for use in its generation facilities and can be blended with its existing supplies," a spokesman said.
"Coal blending is standard practice, even with local supply."
In state parliament last Tuesday, Energy Minister Bill Johnston said the government was also aware of the "higher ash content" contained in coal imported from the east coast, and the need for it to be blended.
"So the coal cannot just go into the power station; it has to be mixed with existing coal from Premier because, otherwise, it cannot be burnt in the power station," he said.
"There is a range of reasons for that, including regulatory reasons."
