Loy Yang B power station may be shut down on Friday unless the union and the station's owners can resolve negotiations over a new pay deal.
Meanwhile, union members at another Victorian coal power station have been forced by a court to cease go-slow industrial action because it was not the same as a ban on work, which had been approved by the Fair Work Commission.
Yallourn and Loy Yang B stations are now operating at full capacity, 24 hours a day. The output at Loy Yang B station had been cut by 20 per cent for 12 hours a day since early February, and Yallourn station cut by about 35 per cent for two hours a day since mid-February. Both actions were organised by the Construction, Forestry, Mining and Energy Union in protest during negotiations for new pay rates. Yallourn is owned by EnergyAustralia, while Loy Yang B is owned by GDF Suez.
A CFMEU spokesman confirmed workers at Loy Yang B were planning a 24-hour stoppage on Friday, March 22, effectively shutting the station down, unless negotiations were successful.
Neither action has had an impact Victoria's electricity supply. A spokeswoman for the Australian Energy Market Operator said Victoria would still have enough electricity if both stations turned off completely, but could not "tolerate any other failures".
The industrial action at Yallourn stopped on Thursday morning after Justice Elizabeth Hollingworth of the Victorian Supreme Court agreed to grant EnergyAustralia an injunction.
Justice Hollingworth found that the action was not "a ban" on work so did not fall within the protected industrial action.
"I agree with EnergyAustralia that the word 'ban' contemplates a prohibition on work, rather than a prescription to perform work in a certain way or to achieve a certain result," she said.
CFMEU members had been using a manual override to reduce output at four Yallourn generators between 4pm and 6pm every afternoon since March 1, cutting output by up to 38 per cent.
Justice Hollingworth ordered CFMEU members to stop using the manual override or from taking any further action unless it was authorised by EnergyAustralia.
Her decision impacted the action at Loy Yang, where the CFMEU stopped the go-slow order on Friday afternoon.