An Taisce has said the two power plants in Lanesborough in Co Longford and Shannonbridge in Co Offaly should never have been built.
It is after the ESB announced both power stations will close next year.
ESB announced the closures last week saying it was a matter of significant regret, and it very much appreciates the commitment of staff.
Up to 90 workers are believed to be affected.
An Taisce said there were political decisions made that were wrong adding that scrapping a plan to ship in biomass from countries like Australia is welcome.
Spokesperson Ian Lumley said the Government ignored advice at the time they were built.
"The technical advice to Government was that this was an ill-advised investment that would require massive subsidy, which was allowed by the European Union, to an amount of hundreds of millions as well as a capital cost," said Mr Lumley.
"That was a waste. That investment and that subsidy could better have been put into energy efficiency."