A city leader has apologised for the "Bristol Energy disaster" which cost residents tens of millions of pounds.
The troubled council-run supplier's residential customer base was sold for £14m - far less than the £36.5m Bristol City Council had invested since 2015.
Labour Deputy Mayor Craig Cheney said it "didn't achieve the ambitions" the founders had envisaged it making.
But the Conservatives said "no amount of political spin... can hide the true scale of this financial failure".
Conservative group leader Mark Weston said local taxpayers would "be glad to see the curtain finally fall on this misadventure".
"It is just a pity this action was not done much sooner as we had advised the mayor [Marvin Rees] before Bristol Energy was allowed to rack up such huge losses.
"However, I urge people not to be taken in or fooled by these sale figures".
Mr Cheney, who is also cabinet member for finance, governance and performance, defended the series of decisions by the Labour administration over the past four years to sink more and more money into the company despite Bristol Energy posting total losses of £32.5m.
'Not abject failure'
"The alternative was to let the company wind into administration and make all the staff redundant," he said.
"We still received advice that said if we continued to invest, we would have an energy company that was profitable."
But he denied it had been an "abject failure".
"The energy market is very challenging. The council has very little experience of being involved in it."
He added the exact amount Bristol City Council had lost was not yet certain.
The company was put up for sale in June and its 4,000 business customer accounts were sold to Nottingham-based supplier Yü Energy for £1.34m in August.