Data from the World Green Building Council estimates that the buildings and construction sector is responsible for about 39% of total carbon emissions globally. Of this, building operations such as heating and electricity use contribute around 28%, while the production of building materials and construction activities, known as embodied carbon, accounts for approximately 11%. With such worrying statistics, stakeholders in the industry and environmental activists are increasingly calling for more comprehensive sustainability measures. One of the most effective tools in this effort is the Whole Lifecycle Carbon Assessment (WLCA), a comprehensive method for evaluating the carbon footprint of buildings throughout their entire lifecycle. It allows for better informed decision-making during the design and construction phases by taking embodied carbon into account in addition to operating emissions.. This method supports worldwide efforts to satisfy environmental standards while also improving sustainability in the construction industry.
What is Whole Lifecycle Carbon Assessment (WLCA)?
Whole Lifecycle Carbon Assessment (WLCA) is a systematic approach that measures the total carbon emissions associated with a building or infrastructure project from its inception to its end of life. This includes emissions from the extraction of raw materials, manufacturing, transportation, construction, operation, maintenance and eventual demolition or decommissioning.
Key Stages in WLCA
WLCA follows a structured method with clearly defined stages from cradle to grave. These include:
- Material Production (A1-A3): This stage assesses carbon emissions from extracting raw materials, their transport and subsequent manufacture into building materials.
- Construction (A4-A5): Assesses emissions which stem from the transportation of building materials to site and energy consumed during the construction to power machinery, and equipment.
- Operation (B1): Refers to the environmental impacts associated with the building being in use, excluding specific operational aspects like energy and water consumption. Examples include the release of refrigerants and their embodied carbon.
- Maintenance and Repair (B2-B3): Regular maintenance and repairs contribute to carbon emissions over the building's lifespan.
- Refurbishment (B5): Evaluating the carbon impact of materials and processes used during renovation or upgrade projects to enhance building performance.
- Operational Energy Use (B6): Often accounting for the largest portion of a building's carbon footprint, this stage includes energy use for heating, cooling, lighting and appliances.
- Operational Water (B7): Assessing the carbon footprint associated with water consumption, including treating wastewater throughout the building's operational life.
- End of Life (C1-C4): This stage evaluates emissions from demolishing the building and disposing of its materials.
Importance in Construction Sustainability
The built environment is responsible for approximately 43% of global carbon emissions. By providing a comprehensive understanding of a building's carbon footprint, WLCA helps architects, developers and policymakers identify areas where carbon emissions can be minimised. It aligns with various international standards and frameworks, such as ISO 14040/14044, BS EN 15978 and the Royal Institution of Chartered Surveyors’ (RICS) Whole life carbon assessment for the built environment. It is also a requirement under the Greater London Plan and the UK Green Building Council’s (UKGBC) Net Zero Carbon framework definition.
Learn how Tunley’s unique approach and our experienced PhD-qualified team helped one of Europe’s largest construction companies, PORR achieve a remarkable 88,564 tCO2e reduction in emissions.
Implementing WLCA in Construction Projects
Early Design Phase Integration
Integrating WLCA from the early design phase enables architects to make informed decisions about materials, construction methods and energy systems. Tools such as embodied carbon calculators help simulate and assess the carbon impacts of different design choices. This approach allows for the optimisation of building layout, incorporation of natural light and ventilation strategies and the use of energy-efficient building systems to reduce the operational footprint.
At Tunley Environmental, we integrate Carbon Management Plans throughout the various construction stages, conducting Whole Life Cycle Assessments (WLCAs) as part of these plans. Our WLCAs follow the Royal Institute of British Architects (RIBA) stages from concept design onwards, depending on the specific requirements of our clients. This helps to facilitate complete management and of greenhouse gas emissions over the total project lead time.
WLCA thinking should be embedded within the design process from the outset. A carbon assessment should be prepared using the cost plan's material descriptions and quantities, forming the baseline carbon budget. This granular analysis of the project's WLCA cost enables the design team to choose low carbon and preferably cost-neutral options.
Material Selection and Sourcing
Material selection plays a crucial role in reducing embodied carbon emissions. Concrete and steel have a high embodied carbon footprint, while timber can have a low embodied carbon. At Tunley Environmental, our carbon reduction scientists can leverage LCAs to evaluate the environmental footprint of construction materials and components, considering factors such as embodied carbon, energy efficiency and recyclability.
Sustainable sourcing strategies include:
- Using recycled materials and ethically sourced wood
- Minimising virgin materials
- Investing in energy-efficient manufacturing
- Local sourcing to reduce transportation distances
Construction Methods and Technologies
Innovative construction methods and technologies can significantly reduce carbon emissions during the construction phase. Some effective approaches include:
- Modular construction: Prefabricated components can decrease on-site construction time and related emissions.
- Fuel-efficient equipment: Utilising newer, more fuel-efficient construction equipment.
- Alternative fuels and electrification: Using biofuels and electrically powered equipment in place of conventional diesel.
- Renewable energy on-site: Exploring options for using renewable energy sources like solar panels to power temporary structures or equipment.
- Waste management plan: Implementing a plan to segregate, recycle and divert construction waste from landfills.
During construction and operation phases, project teams use LCAs to monitor resource consumption, energy usage and emissions. This contributes to proactive management of the environmental impacts and adherence to sustainability targets.
End-of-life Considerations
WLCA informs decisions regarding end-of-life scenarios, such as demolition, decommissioning or recycling. By assessing the environmental consequences of disposal options, stakeholders can adopt strategies that minimise waste generation and promote circularity. This approach ensures that the entire lifecycle of the building is considered, from material extraction to eventual demolition or repurposing.
Benefits and Challenges of WLCA
Environmental Impact Reduction
By considering all stages, WLCA provides a comprehensive understanding of a building's carbon footprint. This holistic approach helps architects, developers, and policymakers identify areas where carbon emissions can be minimised, promoting more sustainable building practices.
Cost Savings and Long-term Value
WLCAs inherently foster long-term thinking, which helps to inform the future resilience of buildings and what component maintenance, repair and replacement may be required or avoided. This approach can lead to significant cost savings over time.
Regulatory Compliance
Adoption of WLCA helps ensure major building projects are in line with regulatory requirements. For instance, the London Plan requires major developments to be net-zero carbon and mandates WLCA for major developments. Many London boroughs now require WLCA to be submitted as part of planning applications for new buildings and refurbishments of existing buildings.
Data Collection and Analysis Challenges
Despite its numerous benefits, implementing WLCA presents several challenges:
- Insufficient WLCA understanding within the industry
- Lack of consensus on conducting and reporting assessments
- Global reference designs versus regional carbon information
- Lack of widely available and accurate industry data
As the industry progresses, these challenges are being addressed through improved methodologies, databases tools and increased cooperation amongst stakeholders.
The Bottom Line
Through comprehensive lifecycle analysis of a building's carbon emissions, Whole Life Cycle Assessment (WLCA) assists industry professionals in making better decisions, complying with regulations, and realising long-term financial gains. As the sector continues to evolve, integrating WLCA into everyday practices becomes essential for promoting sustainable development and achieving global environmental goals. . Book a free consultation with our sustainability experts to see how we can incorporate WLCA in your next construction project.