Ambitious plans to wean Western Australia entirely off coal within seven years are coming under increasing pressure from across the energy divide amid claims the state's main power system may not be able to cope.
Under plans announced in June, the McGowan government has vowed to close the two remaining state-owned coal plants by 2029 and spend $3.8 billion on wind and storage capacity needed for the transition.
It emerged over the weekend the Australian Energy Market Operator was also assuming that WA's only privately owned coal-fired generator, the 440MW Bluewaters south of Perth, would retire by the same time.
The shock suggestion prompted the body that represents WA's domestic gas users to warn the gas system would simply not be able to replace all of the state's coal-fired generation capacity by 2030.
Backing the claim was advocacy group Sustainable Energy Now, which argued WA was fast running out of time to build the new wind farms, transmission lines and backup power urgently needed to keep the lights on.
"There are no free lunches here, that's the big thing," Ian Porter from Sustainable Energy Now said.
Gas system 'under huge strain'
The DomGas Alliance, which represents big industrial users including Wesfarmers, Alcoa and Yara, said WA's gas system was already strained because of a crisis affecting the state's coal industry.
Chairman Richard Harris said some gas-fired plants that were designed to provide backup services to the grid were having to run around the clock.
He suggested the trend was likely to get worse as gas-fired generators were called on to pick up the slack left by retiring coal plants while riding the ever greater ups and downs of intermittent renewable energy output.
"We don't usually get involved in coal issues," Mr Harris said.
"But we've actually been talking to the government and saying 'guys, don't get rid of the coal plant so quickly because you're going to put enormous strain on the gas market by doing that'.
"From a couple of points of view – gas supply and infrastructure supply – we just don't think there's enough gas available to come into the market to compensate for losing all that coal plant."
In its assessment of WA's gas market for the next 10 years, AEMO in December warned of a growing shortfall in supplies from the end of this decade, thanks partly to the increased demand for gas-fired power.
Mr Harris said on top of the shortage in fuel supplies, there was also likely to be insufficient capacity in the state's main gas pipeline, the 1600km Dampier to Bunbury trunk, at peak demand times.
Pressure for backup builds
He said the pipeline was already stretched periodically and did not have the capacity to handle a big increase in demand for gas-fired power.
"There are a couple of times during the last six months where [the Damper to Bunbury pipeline] has actually gone beyond capacity," he said.
"The gas system is already stretching at the moment just to put gas in gas-fired power stations.
"You drop the coal out and I don't think it can cope."
Mr Porter said a central plank of the government's plan, albeit largely unspoken, was the need to build more gas-fired generation capacity.
He said that even if WA could build enough wind and solar farms to fill most of the void left by coal, the state was still going to be reliant on gas for years to come.
According to Mr Porter, this was because renewable energy would struggle to affordably meet all of the demand throughout the year and there were few other options that could provide backup power for days at a time.
"For this, batteries really don't cut it because they're short-duration," he said.
"They're considered for four hours.
"I'm talking about 100 hours or something like that, several days … where there's insufficient sun or wind.
"So the backup generation must be in place.
"But what we would like to see is the generation goes in but they don't use it very often – only in those [renewable energy drought] times."
'Need to be ahead of the game'
Mr Porter argued there was a pressing need in WA for more wind power, which he said generated far greater amounts of energy over a year compared with solar panels for every megawatt installed.
As well as this, he said the government had to urgently build new or upgraded transmission lines to enable a three- to four-fold increase in the amount of wind power in the state's main grid.
He said whether the government liked it or not, WA was in a global race for the workers and the materials required for the energy transition and it risked being caught flat-footed.
"If we have the will we can do this, no question," he said.
"But we need to be ahead of the game.
"And at the moment, we are not ahead of the game. We are very much reacting."
A spokesman said the government was working hard to bring on the required new green energy and storage projects while managing the decline of the state's coal industry.
The spokesman said much of the effort was aimed to smoothing the way for project approvals.
However, he said gas would be "crucial" to the transition, helping to accommodate the growing volumes of renewable energy and keeping the grid stable.
"The state government has recognised the need to expedite development of renewable energy generation and storage projects," the spokesman said.
