Electricity providers return to coal-fired power as natural gas export revenue soars

Updated

The rising international price of natural gas is causing electricity providers to return to coal-fired power, with Queensland among the first to make the move.

Power companies are taking advantage of the export gas price, making more money by selling their gas rather than burning it.

Stanwell, one of Queensland's government-owned electricity companies, will bring a coal-fired generator at its Tarong power station back into service this month, after taking it offline in 2012.

It will bring another back online next year, returning the Tarong complex, near Nanango, to its former position as the state's largest power station.

"It's the first time anyone's ever returned a unit like ours from cold storage," site manager Dennis Franklin said.

"It's the first time we've ever done a weld repair on a turbine the way we have and it really is a first for this site with anything of this ilk.

How a coal-fired power station works Heat is created

Coal is finely pulverised, mixed with hot air and blown into the firebox of the boiler.

Coal is finely pulverised, mixed with hot air and blown into the firebox of the boiler. Water turns to steam

Water contained in pipes inside the boiler is turned into steam by the heat.

Water contained in pipes inside the boiler is turned into steam by the heat. Steam turns the turbine

The enormous pressure of the steam pushing against a series of turbine blades turns the turbine shaft. The turbine shaft is connected to the shaft of the generator, where magnets spin within wire coils to produce electricity.

The enormous pressure of the steam pushing against a series of turbine blades turns the turbine shaft. The turbine shaft is connected to the shaft of the generator, where magnets spin within wire coils to produce electricity. Steam turns back into water

After doing its work in the turbine, the steam is drawn into a condenser containing very large amounts of cool water. This converts the steam back into water that can be used over and over again in the plant. Source: Stanwell Source: Stanwell

"I'd like to think it's the last time we do it, but as you know, we're in a very interesting market with the way we're influenced by the overseas demand for gas."

The unique recommissioning task has taken 20,000 hours and required an Australian-first in the repair of the unit's 50-tonne turbine rotor - the part that heated steam spins to generate electricity.

"We're using cameras, video cameras, to put down pipework. We also have visual inspections, ultrasonic thickness measuring much like you might have a pregnant lady undergo," Tarong's services manager David Barram said.

"Things like that that are certainly new for us and in new areas."

Stanwell announced the move earlier this year, when it foreshadowed the mothballing of its Swanbank E gas generator at Ipswich, with the loss of about 30 jobs.

Rising price will push other companies to follow suit: expert

University of Queensland energy analyst Dr Liam Wagner says the rising price will push other power companies to make similar decisions.

"Gas-fired electricity is becoming more expensive; gas in Australia is going to become more expensive with exports," he said.

"In the future we're going to have less gas because it'll be far more expensive to burn it here and the gas producers will be able to make more money overseas."

Mr Franklin says that means power stations like Tarong will be able to do what they were built for: providing so-called "baseload" power, the bulk amount currently being partially generated by gas.

"That means that gas generation in Queensland becomes limited and coal again resumes its rightful place as the cheapest generator of electricity," he said.

"Coal, at the end of the day, is the cheapest way of producing energy in this country."

Burning coal emits more carbon than burning gas and the trend could have repercussions for Australia's overall carbon emissions.

Dr Wagner says that will depend on whether companies adopt cleaner coal technologies, and on renewable energy policy.

"This is all dependent upon what happens with the renewable energy target and whether those renewables are able to compete and also whether we maintain a carbon price," he said.

The carbon price repeal legislation is soon to go before the Senate, and Government backbenchers have recently raised concerns about the renewable energy target.

It seems likely Tarong's recommissioned generators will stay in service for some time.

Topics: coal, electricity-energy-and-utilities, oil-and-gas, industry, tarong-4615, qld, nanango-4615

First posted