An Bord Pleanala was due to make a decision on the Bord na Móna and the ESB application in recent days. The two are planning the solar farm project across a 494 acre site 6.5km north of the village of Allenwood.
An estimated 150 people are to be employed during the 25-month construction phase and the solar farm will be operational for 35 years if the scheme secures the green light.
However, the appeals board has delayed making a decision on the plan after receiving an objection from Butterfly Conservation Ireland against the scheme.
The organisation was formed 12 years ago in response to the “alarming decline of most of our butterfly species”, which it states has accelerated in recent years.
In the objection drawn up by butterfly expert, Jesmond Harding, he said the solar farm’s site at Drehid is the only known breeding site for the Small Skipper butterfly in Ireland.
He also said that there is a population of Marsh Fritillary butterfly breeding on the embankment on the site of the proposed access road.
Mr Harding said the Government has a legal obligation to protect its breeding sites.
In response to the Butterfly Ireland objection, the board has written to the applicants and told them in the interests of natural justice that they may make submissions on the Butterfly Conservation Ireland objection and they have until April 16th to do so.