Diving deeper into Embodied Carbon
Embodied carbon, which accounts for nearly 11% of global greenhouse gas emissions, is the next frontier in sustainable construction. While significant strides have been made in reducing operational energy in buildings, the carbon intensity of building materials and processes remains a critical challenge. This guide offers practical insights to help you understand and measure embodied carbon, ensuring your projects contribute to a greener future.
Table of contents
- What are Embodied Carbon and Operational Carbon?
- How are Embodied Carbon Emissions Measured?
- Key Points for Assessing the Quality of Data from EPD or LCA
- Need for Transparency
- Why Embodied Carbon is a Focus in Construction
- Features of a Good Embodied Carbon Report
- Reference Steps to Consider While Calculating Embodied Carbon of a Structure
- Conclusion
- FAQs
What is Embodied Carbon and Operational Carbon?
Embodied Carbon
Embodied carbon refers to the total greenhouse gas emissions produced during the entire lifecycle of a building’s materials and construction process. This includes emissions from:
- Material Extraction: The energy and emissions associated with mining, harvesting, or extracting raw materials.
- Manufacturing: The processes involved in converting raw materials into finished building products, such as concrete, steel, and glass.
- Transportation: The emissions from transporting raw materials to manufacturing sites and finished products to construction sites.
- Construction: The energy and emissions produced during the actual construction of the building, including the use of machinery and vehicles.
- Maintenance and Repairs: The emissions from ongoing maintenance and repair activities over the building’s lifespan.
- End-of-Life Disposal: The emissions from the demolition of the building and the disposal or recycling of its materials.
Embodied carbon is concerned with “cradle-to-grave” emissions, meaning it takes into account all the emissions from the initial extraction of materials to the final disposal or recycling of the building materials.
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Operational Carbon
In contrast, operational carbon refers to the greenhouse gas emissions produced from the energy consumed during the building’s operational phase. This includes:
- Heating and Cooling: The energy used to heat and cool the building to maintain comfortable indoor temperatures.
- Lighting: The electricity consumed to illuminate the building.
- Electrical Equipment: The energy used by appliances and electronic devices within the building.
- Ventilation and Air Conditioning: The emissions associated with maintaining air quality and comfortable humidity levels.
Reducing operational carbon involves implementing energy-efficient systems and practices, such as:
- Energy-Efficient HVAC Systems: Using advanced heating, ventilation, and air conditioning systems that consume less energy.
- LED Lighting: Replacing traditional lighting with energy-efficient LED bulbs.
- Renewable Energy Sources: Incorporating solar panels, wind turbines, or other renewable energy sources to power the building.
- Building Automation Systems: Utilising smart technologies to optimise energy use based on occupancy and usage patterns.
Both embodied and operational carbon are critical components of a building’s overall carbon footprint. While operational carbon has been the primary focus for reducing emissions in buildings, embodied carbon is becoming increasingly important as the construction industry seeks to achieve comprehensive sustainability goals.
Credits: Ciaran Malik
How are Embodied Carbon Emissions Measured?
To measure embodied carbon, a comprehensive Life Cycle Assessment (LCA) is conducted. This process evaluates the total greenhouse gas emissions associated with all stages of a building’s lifecycle, including:
- Material Extraction and Processing: Analysing the energy and emissions from extracting raw materials and processing them into usable products.
- Manufacturing and Transportation: Assessing the emissions from manufacturing building materials and transporting them to the construction site.
- Construction and Installation: Evaluating the emissions generated during the construction and installation phases, including the use of machinery and energy consumption.
- Maintenance: Considering the emissions from the ongoing maintenance and repair activities over the building’s lifespan.
- End-of-Life Disposal: Measuring the emissions from the demolition of the building and the disposal or recycling of its materials.
Standardising the system boundaries is crucial to ensure consistency and comparability in the LCA. This involves defining which processes and stages are included in the assessment.
Data Collection: Recognized methodologies are used to collect and quantify the embodied emissions. These methodologies include:
- Product Lifecycle Accounting and Reporting Standard
- PAS 2050 (Publicly Available Specification for the assessment of the life cycle greenhouse gas emissions of goods and services)
- ISO 14040-44/14067 (International Standards for Life Cycle Assessment)
Tools: Various tools help streamline the complex process of LCA, such as:
- One Click LCA: A cloud-based software that facilitates LCA and environmental impact assessment.
- GaBi: A robust tool for performing life cycle assessments and environmental product declarations.
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Environmental Product Declarations (EPDs)
EPDs are standardised documents that provide transparent and comparable data about the environmental impacts of products, based on LCAs. They are prepared using Product Category Rules (PCR), which are specific to different product categories. The most reliable EPDs are verified by specialised environmentalists and can be specific to an organization or represent average data for the industry.
Key Points for Assessing the Quality of Data from EPD or LCA
- Publication Date: How recently the EPD was published, as newer data is generally more accurate.
- Location Specificity: Whether the data adheres to the specific location mentioned in the EPD.
- Process Inclusion: Ensuring all relevant processes are included in the assessment.
- Unit of Measurement: Consistency in the units of measurement used.
- Data Precision: The exactness of the data and the degree of variation.
- Installation Specificity: Whether the data considers specific installations or averages.
- Technology Specificity: Whether the data is specific to the technology used in the product.
Need for Transparency
To make EPDs reliable, it is important to maintain transparency and consistency, especially if there is a high rate of fluctuation in the industry. However, there are many challenges that a business has to face:
- Lack of clear and standardised information, which makes it difficult to make correct differentiation between two units.
- Lack of transparency hampers an understanding of environmental impacts associated with the design, processes, and materials.
- There is a good chance of misinterpretation of true sustainability performance, which can lead to misguided decision-making.
- A lack of details can lead to uncertainty and variance in interpretation.
Why Embodied Carbon is a Focus in Construction
Embodied carbon represents a significant portion of the construction industry’s total greenhouse gas emissions, estimated to account for about 11% of global emissions. This figure is expected to increase as operational emissions decrease due to advancements in energy efficiency and renewable energy use. By 2050, embodied carbon could constitute nearly 50% of the total emissions from new buildings, underscoring the urgent need to address this issue to achieve comprehensive sustainability in construction.
Global Impact and Industry Contribution
The construction industry is a major contributor to global carbon emissions, especially from energy-intensive processes like steel and concrete production. As urbanisation and infrastructure development continue to accelerate, reducing embodied carbon is crucial for mitigating the environmental impact of buildings.
World Green Building Council’s Targets
The World Green Building Council (WGBC) aims to reduce embodied carbon in new buildings by 40% by 2030 and achieve net-zero embodied carbon by 2050. These ambitious targets align with global climate initiatives and highlight the importance of addressing embodied carbon early in the building lifecycle.
Environmental and Economic Benefits
Focusing on embodied carbon helps reduce greenhouse gas emissions and encourages the use of sustainable materials and innovative construction techniques. This emphasis can drive demand for low-carbon materials, enhance supply chain transparency, and promote circular economy practices, such as recycling and reusing materials.
Regulatory and Market Drivers
Increasingly, regulatory frameworks are addressing embodied carbon. The European Union’s Level(s) framework provides a common language for assessing the sustainability performance of buildings, including embodied carbon. In the UK, the Royal Institute of British Architects (RIBA) has integrated embodied carbon targets into their 2030 Climate Challenge. These regulations, coupled with growing market demand for sustainable practices, drive industry changes.
Holistic Approach to Sustainability
Addressing embodied carbon requires collaboration across the entire supply chain, from material producers to architects, engineers, and contractors. Integrating these considerations into design, procurement, and construction practices is essential for achieving net-zero carbon buildings and supporting global climate goals.
Features of a Good Embodied Carbon Report
There needs to be a good practice of incorporating quality report writing, based on the specifications and guidelines mentioned below:
- A clear statement of the emission factors and quantities undertaken in the assessment.
- The type and source of data need to be mentioned.
- Key assumptions in the report should be made clear.
- The data should be reviewed and consistent.
- A third-party verification by an independent expert can ensure a high-quality report.
- The report should highlight the main areas of high emission intensity.
Reference Steps to Consider While Calculating Embodied Carbon of a Structure
Pre-design Stage
Setting Goals: Establish clear objectives for reducing carbon emissions at the outset of the project. This involves setting targets for embodied carbon reduction and identifying potential strategies to achieve these goals.
Formulating Strategies: Develop plans to minimise carbon emissions through innovative design, material selection, and construction techniques. This may include specifying the use of low-carbon materials or prefabrication methods to reduce waste.
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Design Stage
Incorporating Low-Carbon Materials: Select materials with low embodied carbon footprints. Use Environmental Product Declarations (EPDs) to compare the carbon impacts of different materials and choose those with the least environmental impact.
Design for Efficiency: Design structures to be resource-efficient. This can involve optimising material use, reducing waste, and incorporating modular construction techniques that allow for easier disassembly and reuse of materials.
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Construction
Sustainable Processes: Ensure that construction processes are sustainable and resourceful. This includes using energy-efficient machinery, reducing on-site waste, and sourcing materials locally to reduce transportation emissions.
Monitoring: Continuously monitor the construction process to ensure compliance with sustainability goals. This can involve regular site audits and tracking the carbon footprint of construction activities.
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Post-Construction
Data Compilation: Collect all relevant data relating to embodied carbon throughout the project lifecycle. This includes data on material use, transportation, construction activities, and waste management.
Reporting Results: Compile the data into a comprehensive report that outlines the embodied carbon of the structure. This report should detail the emission factors, quantities, and lifecycle stages considered, and provide recommendations for future projects.
Conclusion
With building operations accounting for nearly 28% of global CO₂ emissions, and embodied carbon contributing up to 50% of the total emissions over a building’s lifecycle, it is imperative to focus on reducing these impacts from the outset.
FAQs
What is embodied carbon?
Embodied carbon refers to the total greenhouse gas emissions associated with the production, construction, and end-of-life of building materials and structures. It includes emissions from material extraction, manufacturing, transportation, construction, and disposal.
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Why is reducing embodied carbon important?
Reducing embodied carbon is crucial because it accounts for a significant portion of a building’s total carbon footprint, often up to 50% over its lifecycle. Lowering embodied carbon helps mitigate climate change and supports sustainable building practices.
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How can embodied carbon be measured?
Embodied carbon is measured through Life Cycle Assessment (LCA), which evaluates the environmental impact of materials and construction methods throughout their lifecycle. Standardised LCA methodologies ensure accurate and consistent measurement of embodied carbon.
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What are some strategies to reduce embodied carbon?
Strategies to reduce embodied carbon include using low-carbon materials, optimising design for material efficiency, adopting sustainable construction practices, and selecting energy-efficient building systems. Additionally, implementing recycling and reuse practices can further lower embodied carbon.
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How can investors support embodied carbon reduction?
Investors can support embodied carbon reduction by aligning their portfolios with projects that demonstrate low embodied carbon through LCA findings. Investing in sustainable construction and low-carbon technologies promotes environmentally responsible development.
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What role does data standardisation play in reducing embodied carbon?
Data standardisation is essential for accurate and consistent measurement of embodied carbon. By implementing uniform standards for LCA data, stakeholders can compare and assess carbon impacts more effectively, leading to better-informed decisions and more effective carbon reduction strategies.
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What benefits does aligning investment portfolios with LCA data offer?
Aligning investment portfolios with LCA data offers several benefits, including supporting projects with lower embodied carbon, promoting sustainable construction practices, and driving innovation in low-carbon technologies. This alignment helps investors contribute to global sustainability goals and achieve better long-term returns.
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How can the Embodied Carbon Reduction Framework help the construction industry?
The Embodied Carbon Reduction Framework provides a structured approach to managing and reducing embodied carbon. It emphasises standardising data, improving data collection methods, and aligning investments with LCA findings, which collectively enhance transparency, improve decision-making, and encourage sustainable practices within the construction industry.
