Fife Trades Union Council has called for a halt to plans for fracking and Underground Coal Gasification (UCG).
The move came in a motion to the STUC conference and also asked the congress to call on the government for investment into “real and sustainable industry”.
Tam Kirby, who moved the motion, said: “The timing of the closure of Longannet Power Station coupled with the fact the new contract went to a gas-powered station, and when the Scottish Government are planning on building a new gas-powered plant in central Scotland is astounding”.
He added: “What brilliant timing this all is for the proponents of fracking and UCG. It all stinks of methane and the burning of underground coal.
“Fracking and UCG are under continual attack from local communities and environmental groups. What is proposed in Fife at the moment underground coal gasification is not even covered by the Scottish Government’s moratorium. Campaigning groups continue to push the Scottish Government to include UCG.”
The motion was accepted by the STUC congress.
Scottish Energy Minister Fergus Ewing this week called for a national debate on fracking.
In January Mr Ewing announced a moratorium “on the granting of planning consents for all unconventional oil and gas developments, including fracking.
In a BBC documentary on Wednesday night, however, Mr Ewing suggested fracking could be allowed in Scotland once the moratorium on the controversial process comes to an end.
Scotland’s energy minister insisted that the Scottish government has not yet taken a definite view on the issue, and that a “national debate” had to take place before ministers made up their minds.
Environmental campaigners said that local groups would be alarmed at the remarks, while pro-fracking industrialists have welcomed the debate.