Biogenic Carbon in Buildings: A Critical Overview of LCA Methods

The article Biogenic Carbon in Buildings: A Critical Overview of LCA Methods provides an in-depth analysis of the various life-cycle assessment (LCA) methods used to evaluate biogenic carbon in buildings. By reviewing common approaches and comparing them through a case study of a timber building, the study identifies significant inconsistencies between the different methods. The review highlights the limitations of existing LCA methods in capturing land-use changes, carbon storage, and timing of carbon release, which are crucial for accurately assessing the impact of bio-based construction materials. The dynamic LCA method is recommended as the most robust approach for future biogenic carbon assessments.

Key Takeaways

• LCA Method Discrepancies: Existing methods, such as the 0/0 and –1/+1 approaches, fail to adequately capture carbon storage and land-use change, leading to up to 200% variation in carbon emissions results.
• Dynamic LCA Advantage: The dynamic approach provides a more accurate assessment by considering the timing of carbon sequestration and release throughout a building’s lifecycle.
• Timber Case Study: The comparison of LCA methods on a timber building showed that the dynamic approach is more reliable and transparent, offering a 29% higher global warming score than static methods.

How It Can Help You

This report is useful for LCA practitioners, construction industry professionals, and policymakers looking to:

• Choose the most reliable LCA method for evaluating biogenic carbon in building materials.
• Understand the impact of bio-based materials, such as timber, on carbon emissions reduction.
• Inform decision-making for sustainable building projects based on dynamic LCA insights.

Key Learnings

1. Biogenic Carbon Complexity: LCA methods must capture the full complexity of biogenic carbon, including land-use change, carbon storage, and timing of emissions, to provide accurate environmental assessments.
2. Importance of the Dynamic Approach: The dynamic method is recommended for future bio-based building assessments, offering the most accurate and transparent results by considering the timing of carbon cycles.
3. Misleading Results: Static approaches can lead to inaccurate conclusions, particularly when the system boundary is limited to the product stage, neglecting the lifecycle impacts of materials.

Date: August 2020