Carbon Management at MetroLink

Carbon Management at MetroLink

Delivering a Low Carbon Railway for Ireland 

MetroLink is Ireland's largest public transport infrastructure project and a key part of Project Ireland 2040. Connecting Swords, Dublin Airport and the city centre to Charlemont, MetroLink is designed to provide a high-capacity, reliable and sustainable transport network that supports Ireland's transition to a low-carbon future.  

Climate action is one of MetroLink's core policy objectives. The project aims to deliver a climate-resilient transport system, minimise whole life carbon emissions, and provide low-carbon journeys powered by renewable energy sources. To achieve this, TII requires a robust Carbon Management Plan (CMP) for the overall programme and for individual work packages throughout design, construction and operation. 

Our Carbon Management Approach 

MetroLink's carbon management process is aligned with PAS 2080:2023 – Carbon Management in Buildings and Infrastructure, the internationally recognised framework for managing and reducing whole life carbon emissions across infrastructure programmes. 

Our approach establishes a structured process to: 

• Measure and quantify whole life carbon emissions. 
• Establish carbon baselines and reduction targets. 
• Identify carbon reduction opportunities throughout delivery. 
• Integrate carbon considerations into decision-making. 
• Monitor, report and continuously improve performance. 
• Collaborate across the supply chain to drive innovation and reduce emissions. 

Carbon management is embedded across the project lifecycle, ensuring that carbon reduction is considered alongside cost, programme, quality and operational performance. 

Why Carbon Management Matters 

The MetroLink project supports Ireland's Climate Action Plan and national carbon budgets by: 

• Reducing greenhouse gas emissions from construction and operation. 
• Enabling a significant modal shift from private vehicles to public transport. 
• Supporting Ireland's net zero ambitions. 
• Delivering long-term sustainable transport infrastructure. 
• Creating a resilient asset capable of supporting future generations. 

Early integration of carbon management into design and procurement allows the project team to maximise opportunities for carbon reduction when influence over project outcomes is greatest. 

Current Carbon Baseline 

The current project baseline has been derived from the Environmental Impact Assessment Report (EIAR). 

Total Estimated Embodied Carbon 

1,016,536 tCO₂e 

Key Sources of Embodied Carbon 

The baseline will be reviewed and updated as the Reference Design, Tender Design and subsequent Detailed Design progress, providing increasing levels of accuracy and enabling improved carbon reduction monitoring. 

Carbon Reduction Targets and Commitments 

Through commitments made during the Railway Order process and Oral Hearing submissions, MetroLink has established a number of key carbon reduction requirements. 

Project Commitments 

• Use renewable electricity for 100% of construction-stage power demand, including tunnel boring machine (TBM) operations. 
• Use renewable electricity for 100% of operational power demand. 
• Utilise low-carbon concrete where practicable, typically equivalent to a 50% GGBS replacement. 
• Use Hydrotreated Vegetable Oil (HVO) as an alternative to fossil diesel in construction plant and equipment. 
• Procure from suppliers that demonstrate alignment with Climate Action Plan requirements, including embodied carbon reduction commitments. 

Apply PAS 2080 principles throughout design, procurement and construction activities. 

Indicative Carbon Reduction Outcome 

Analysis undertaken during the project development process identified the potential to achieve approximately: 

51.7% reduction in embodied carbon emissions 

when compared with the original embodied carbon estimate through measures including: 

• Low carbon concrete. 
• Clean energy procurement. 
• Low carbon construction methodologies. 
• Supply chain decarbonisation initiatives. 

The project will update this throughout delivery and development, and targets will be consistently reviewed.  

Carbon Reduction Hierarchy 

MetroLink follows the PAS 2080 Carbon Reduction Hierarchy: 

1. Avoid 

Challenge the need for carbon-intensive activities and seek opportunities to eliminate emissions before they occur. 

Examples include: 

• Design optimisation. 
• Reduced material demand. 
• Efficient asset utilisation. 
• Elimination of unnecessary works. 

2. Switch 

Replace high-carbon solutions with lower-carbon alternatives. 

Examples include: 

• Renewable electricity. 
• Low-carbon concrete. 
• Sustainable construction materials. 
• Alternative fuels and technologies. 

3. Improve 

Increase efficiency and maximise value from resources already required. 

Examples include: 

• Circular economy principles.
• Material reuse and recycling. 
• Efficient construction techniques. 
• Improved asset durability and lifespan. 

Key Carbon Management Activities 

Throughout the programme, MetroLink will: 

Measure 

• Undertake whole life carbon assessments. 
• Develop and maintain carbon baselines. 
• Benchmark project performance. 
• Monitor carbon performance against targets. 

Reduce 

• Identify carbon saving opportunities. 
• Maintain Carbon Opportunity Registers. 
• Evaluate alternative materials and methods.
• Promote low-carbon innovation through the supply chain. 

Manage 

• Integrate carbon requirements into procurement. 
• Monitor contractor performance. 
• Report carbon metrics throughout delivery. 
• Support continual improvement initiatives. 

Collaborate 

• Engage designers, contractors and suppliers early. 
• Share carbon data and lessons learned. 
• Promote innovation across work packages. 
• Enable transparent reporting throughout the value chain. 

Compliance and Governance 

MetroLink's carbon management framework supports compliance with: 

• PAS 2080:2023 Carbon Management in Buildings and Infrastructure.
• Ireland's Climate Action and Low Carbon Development Acts. 
• National Climate Action Plans. 
• Railway Order requirements. 
• Project Sustainability Plan commitments.
• Whole Life Carbon assessment principles. 

The project recognises that compliance with planning approval alone is not sufficient. Carbon management must be demonstrably embedded into project decision-making and delivery to support Ireland's climate objectives. 

Looking Forward 

Carbon management will remain a central component of MetroLink delivery. As design develops and procurement progresses, carbon assessments will be refined, opportunities identified and performance continually monitored against project requirements. 

Through collaboration across the programme, MetroLink aims to deliver a transport system that not only improves connectivity across Dublin but also leaves a lasting legacy in sustainable infrastructure, supporting Ireland's journey towards a low-carbon future.