The UK will soon import more gas and oil than it exports and delegates at the TUC conference will be warned the UK could be at the mercy of international events unless other resources are established.
"The sources of gas and oil will be from some of the world's most unstable countries where security of supply and price will be out of our hands," said the union's Welsh general secretary Felicity Williams.
At the same time, she said demand for energy was "likely to double over the next 50 years".
She added: "There is increasing doubt about whether renewable energy generation such as wind farms can meet our future energy needs.
BBC
