Guide to Biodiversity Net Gain in Ireland
Table of Contents
Biodiversity Net Gain (BNG) is transforming how developments interact with nature, ensuring that biodiversity is left in a measurably better state than before construction begins. While BNG is not yet a legal requirement in Ireland, it is increasingly becoming a de facto policy standard.
Local authorities, state bodies, and private companies are actively incorporating BNG principles into planning and development strategies.
For developers and project managers, understanding and implementing BNG can streamline planning approvals, especially in forward-thinking counties like Dublin City, Fingal and Dún Laoghaire-Rathdown, and Sligo.
Understanding Biodiversity Net Gain
The first step in achieving BNG is to assess your site’s existing ecological value, known as the ecological baseline. An ecologist will evaluate your site, overlay the projected impact of your development, and determine the number of biodiversity units required to offset this loss while creating additional net gain on site and if it is not achievebale onsite that an offsite option is available.
To secure planning approval, you may need to present a Biodiversity Net Gain Plan outlining how you will meet these requirements.
While Ireland currently lacks national BNG legislation, a wide range of planning authorities and semi-state bodies have already embedded BNG in policy:
- Sligo County Development Plan (2024–2030) – Policy BD7 requires developments on sites ≥0.5 ha to demonstrate a site-specific BNG.
- Dublin City Development Plan (2022–2028) – Policy GI16 encourages net gain opportunities in all new developments.
- Fingal, Dún Laoghaire-Rathdown, and Dublin City Councils – All have committed to developing BNG guidance as part of their biodiversity action plans.
- Office of Public Works (OPW) – Action 3.9 of their Biodiversity Action Plan (2022–2026) includes BNG as a policy principle in flood schemes.
- Irish Water – Commits to “no net loss” and actively seeks BNG in its projects using an in-house biodiversity metric.
BNG follows a mitigation hierarchy:
- Avoid biodiversity loss where possible.
- Minimise impacts with sensitive design.
- Offset unavoidable loss through offsite rewilding or habitat enhancement.
- If not possible to improve biodiversity on site then purchase Biodiversity Net Gain units.
According to the BNG Briefing Paper (Aug 2024) from the Irish Business and Biodiversity Platform:
“BNG represents current planning policy in several local authorities and is expected to be promoted more widely in future development plans.”
Engineers Ireland also backs this direction, stating in its 2021 issues paper:
“Aiming for Biodiversity Net Gain should form the basis of all engineering projects.”
Chartered Institute of Ecology and Environmental Management (CIEMM) Briefing Paper – Biodiversity Net Gain 2024 –
‘There is now a pressing need for national guidance on Biodiversity Net Gain in the Republic of Ireland and Northern Ireland. In this Briefing Paper we have reviewed the options available for this process, and set out some key considerations on its implementation in an Irish context. We hope that this will be considered by national bodies responsible for the development of BNG policy in the Republic of Ireland and Northern Ireland, as part of a broader national debate’.
Need to calculate your impact? Use the UK’s Biodiversity Metric 4.0 to assess before-and-after biodiversity values.
Benefits of Purchasing Quality Offsite BNG
BNG can be implemented onsite or offsite. Offsite BNG offers several advantages:
- Greater Ecological Impact: Larger, carefully managed restoration sites deliver broader environmental value.
- Planning Flexibility: Especially helpful when onsite biodiversity enhancements are unfeasible.
- Streamlined Approvals: Demonstrating offsite BNG may improve your chances with local authorities already supporting it.
The Irish Green Building Council’s ‘Home Performance Index’ rewards developers with points under Category EN5 for achieving measurable BNG, assessed by an independent ecologist.
SSE Renewables now requires BNG on all large onshore projects by 2025, adapting UK frameworks in the absence of Irish national guidance.
Factors to Consider Before Purchasing BNG Units
To ensure you get the best from your investment, consider:
- Feasibility Reports: Understand the ecological impact of your development early on.
- Right Habitat Match: Offset your loss with similar or higher distinctiveness habitat types.
- Long-Term Management: Ensure a multi-year habitat plan is in place.
The Briefing Paper stresses:
“A long-term stewardship period of at least 30 years is a key condition for high-integrity BNG delivery.”
Understanding Habitat Types
Ireland currently lacks a standard biodiversity metric, so UK metrics and habitat categories are widely used.
Offsite BNG Planning and Monitoring
Dunsany Estate offers a fully managed BNG solution, including:
- A custom Habitat Management and Monitoring Plan (HMMP)
- Third-party ecological reviews, reporting and gathered on a multi-access platform.
- Biodiversity metrics adapted from the UK standard
Natural England have published a HMMP template and accompanying tools and released a video explaining the HMMP template.
The Purchasing Process for Offsite BNG at Dunsany Estate
- Calculate Your Biodiversity Metric
Work with an ecologist to assess loss and offset requirements.
Use the UK Biodiversity Metric - Select a BNG Provider
Prioritise habitat types that match your development’s ecological impact. - Legal Agreement
Secure your units through a biodiversity contract with multi-year oversight. - BNG Plan Submission
Submit your offsite BNG strategy to the planning authority. - Record and Certify
Overcoming Challenges in Purchasing BNG
- Lack of National Irish Framework: Currently, each council or agency can interpret BNG differently.
- Inconsistent Metrics: Most use the UK’s Defra metric so all parties are talking in the same currency— however Irish standardisation is urgently needed.
- Market Pricing Uncertainty: With more councils embracing BNG, demand for high-quality offsite solutions is expected to rise.
In the 2023 CIEEM BNG conference, more than half of Irish practitioners reported using UK BNG methods, highlighting the growing momentum despite the policy gap.
Final Thoughts on Biodiversity Net Gain
BNG is no longer a concept waiting on legislation. It’s already becoming very real as several County Councils, engineers, and environmental leaders adopt it’s value and methodology.
Developers who proactively adopt BNG will gain faster planning approvals, stronger community support, and a genuine legacy of environmental restoration.
At Dunsany Estate, we provide verified, fully managed offsite BNG solutions, tailored for Irish Businesses and Developers navigating this exciting new standard.
