The High Court’s decision to overturn planning permission for the continued operation of Bord Na Móna’s (BNM) Edenderry plant represents a major setback for the company with possible implications for its other turf-burning plants in the midlands.

The ruling, which came on foot of a legal challenge by An Taisce to an earlier decision by An Bord Pleanála (ABP) to uphold planning permission, places up to 180 jobs at risk, with unions warning the company must not seek compulsory redundancies.

Mr Justice Michael White ruled ABP's original assessment of the environmental impact of the continued operation of the plant was too narrow.

An Taisce had in its proceedings challenged the board's permission for the continued use and operation of a electricity generating power plant at Clonbullogue, Co Offaly.

It argued the environmental effects of extracting the peat as a fuel source for the plant had not been properly assessed in accordance with an EU environmental impact assessment directive.

Mr Justice White granted a six-month stay on the order, until the end of April, to allow time for ABP to decide on a new planning application involving a wider environmental impact assessment.

The decision poses a threat to BNM’s two other turf-burning power plants in the midlands on which planning permission runs out in 2019.

Siptu organiser and BNM group of unions secretary John Regan said the High Court decision was "concerning". However, he said the union expected a second planning application to be approved next year.

“The success of this planning application should secure all the jobs in Edenderry Power and its surrounding operations,” Mr Regan said.

If the second application was rejected, he said, the position of the BNM group of unions remained that no compulsory redundancies would be accepted at the semi-State company.

Unite's Colm Quinlan called on BNM to seek a stay on the ruling beyond next April to make space for "very difficult negotiations".

The Green Party welcomed the court decision. Leader Eamon Ryan said the ruling "gives us a chance to change tack and to turn away from this most polluting form of power generation for good".

He added: “The Government has made a shameful decision to extend the life of our peat- fired power stations for the next 15 years. That approach will make us one of the worst offenders when it comes to tackling climate change.”

Mr Ryan claimed burning peat was costing every household at least €70 a year in subsidies.