ALG advises Coolglass Wind Farm Limited in successful Supreme Court defence.

In a unanimous decision, the Supreme Court has upheld the High Court’s decision and found An Coimisiún Pleanala failed in its obligations under s. 15 of the Climate Action and Low Carbon Development Act 2015 (as amended), but on different and narrower grounds than those underpinning the High Court’s decision.

The Supreme Court appeal related to a decision of the High Court in early 2025 which quashed a decision of An Coimiusiún Pleanála (ACP) to refuse to grant Coolglass Wind Farm Limited planning permission for the construction of a proposed 13-turbine wind farm in County Laois. The High Court decision was appealed by ACP. As noted by the Supreme Court, “the significance of the appeal cannot be overstated, since it presents this Court with its first opportunity to consider the implications of s.15(1) of the [2015 Act]”.

In its decision, the Court confirmed that s. 15(1) of the Climate Action and Low Carbon Development Act 2015, as amended in 2021, strengthens the obligations imposed upon bodies (including ACP) to make the performance of their functions consistent with climate objectives, in so far as is practicable. It is a question of law – reviewable by the Court – whether public bodies have discharged this obligation in any particular case. This obligation is outcomes-oriented, legally enforceable, and intended to have real effect. It is not a mere “have regard to” obligation.

In relation to Coolglass specifically, the Court found ACP failed to consider (in accordance with section 15) whether “the climate benefits of the project required or justified the grant of permission notwithstanding the material contravention of the development plan”. That legal error required the decision to refuse permission to be quashed.

The Supreme Court was careful to acknowledge that while the language of section 15 creates an outcome-based obligation, there is also a degree of tolerance in the way that might be achieved. That tolerance is further qualified by the words “in so far as is practicable”. In other words, there will generally be a spectrum of possible outcomes that could be said to be consistent with section 15 in any given scenario.  The application of section 15(1) in future will therefore be highly dependent on the specific functions of the relevant body and the matters to which they are obliged to have regard. And the Court noted there will be circumstances where it is not “practicable” for the relevant body to perform its functions in a manner consistent with s.15(1) at all.

The Court was also clear that establishing consistency with s15 should in many cases be straightforward, particularly where it can be shown that the individual action is consistent with a plan or strategy that itself was also subject to s.15(1). For individual planning decisions, this will mean ACP can presume compliance with s.15(1) will have already been achieved at the national level and in local development plans. But this is a rebuttable presumption. For example, a development plan may no longer be consistent with s15 where a climate action plan has introduced policies that are not provided for in that development plan. It will be therefore on developers to raise their concerns where they believe the higher-order documents no longer meet climate objectives, particularly where the Government has set specific and quantifiable measures to achieve those objectives.  

What must ACP / Planning Authorities now do in order to comply with their obligations under s15 when determining planning applications?

• ACP must comply with section 15 of the Climate Act and clearly demonstrate (i.e. provide reasons as to) how its decision to grant or refuse permission aligns with national climate plans and objectives referred to in that section, as far as is practicable.
• Climate considerations are woven into the planning system to a significant degree (both at national level and at local level through County Development Plans).  Therefore, ACP can start from the presumption that compliance with the Development Plan will itself be compliant with its section 15 duty.  
• However, ACP must properly consider any submissions that credibly allege the Development Plan does not align with Ireland’s climate change goals and targets. The Court gives the example of where a Development Plan may be out of date and drafted by reference to earlier iterations of national climate action plans. In this context ACP must still explain why its decision (or refusal to grant permission) is compliant with climate targets.

The judgment will be welcome news for renewable energy operators, who have raised increasing concerns over the past three years that insufficient planning permissions are being granted to onshore wind farms, with the consequence being that Ireland will not meet its CAP target of 9 GW of onshore wind capacity by 2030. The planning application has now been remitted back to An Coimiusiún Pleanála, whose redetermination is awaited.

For further information in relation to this topic, please contact  Alan Roberts, partner, Brendan Curran, senior associate, Marika Williams, lawyer, or your usual ALG Environmental & Planning contact.

Date published: 19 March 2026