The presiding judge in the Commercial Court has described the deficit in the ESB pension fund as potentially a "disastrous" situation for the workers.
Mr Justice Peter Kelly made his comments as he admitted an action, against the ESB by four workers, into the fast-track commercial division of the High Court.
The court heard there is a deficit of more than €1.5bn in the pension scheme.
Mr Justice Kelly said workers would be very worried about a potential "doomsday situation" where they would not be eligible for the State pension and not able to receive a pension from the ESB either.
He said the deficit was one of the largest he had seen in the many pension schemes that had come before the court in the past few months.
Four ESB workers; Brian Baitson, William Flavin, Owen Killmurray and Margaret O'Connor, are suing the company over the scheme.
They say there appears to be a wilful and deliberate failure or refusal of the board to address the clear and significant funding deficit in the scheme.
The four workers and most members of the scheme, who joined the company prior to 1995, do not have an entitlement to a State pension.
They say the board has maintained wrongfully that it has no obligation to meet any deficit in the scheme.
They say the board is wrongfully insisting that the scheme is a defined contribution scheme when it is in fact a defined benefit scheme.
They say the proposed special payment of a dividend of €400m out of the scheme to the Exchequer by 2014 further undermines the ability and obligation of the board to address the deficit.
The case is due to be heard by the court in January next year.