Sustainability and Carbon Capture
Racing towards a Green Economy through Circularity: Future of Business in the AEC Sector
The built environment could become clean and head towards TRUE emission neutrality (ZNE buildings) adopting Circular Economy measures.
Built environment and construction are responsible for releasing large amounts of global greenhouse gas (CO2eq) that alter our ecosystem by increasing global temperatures. The global outcry for sustainability has required a radical shift in design thinking from architecture, engineering, and construction (AEC) businesses to develop truly sustainable projects. Various organisations have thus declared support towards the net-zero economy vision, although having not completely stated how it intends to achieve it. Under these circumstances, the market trends are shifting and a new model for business is in development — the circular systems. This article investigates ways in which the construction sector could adopt circularity measures for the development of the built environment, to support a sectoral reduction in greenhouse gas emissions. Focus here is mostly on embodied emission (materials), and not operational emissions (energy efficiency), as the former remains unchecked in the sector’s current framework for achieving carbon neutrality.
An earlier article by the author elaborates on ways carbon emissions (CO2eq) are presently calculated in the AEC sector after reviewing the best practice guidance presented by UKGBC (Green Building Council) and UNFCCC (United Nations Framework Convention on Climate Change). The lack of focus on embodied emissions, that is CO2eq emissions from materials, procurement, construction, and disposal, has resulted in the sector turning a blind eye towards many polluting materials. Circularity measures could limit dependence on virgin materials when considered early on in the design phase.
What is Circular Economy?
Circular economy or circularity is the principle of developing products where materials used are circular in nature. The idea is to challenge the design and product development process to create sustainable products either by reducing consumption of virgin materials or increasing dependency on biological materials that can reduce the impact on the environment over its life cycle.
According to Ellen MacArthur Foundation,
‘A circular economy is based on the principles of designing out waste and pollution, keeping products and materials in use, and regenerating natural systems’
Currently, the general business models follow a take, make and dispose approach, referred to as a linear economy. In circular systems, products retain its utility, are not down-cycled, and are disassembled and recirculated in one way or the other without depreciating its value. Such systems are referred to as circular economy or circularity.
‘Circular economy is a manifestation of economic models that highlight business opportunities where cycles rather than linear processes, dominate. It is restorative and regenerative by design and aims to keep products, components, and materials at their highest utility and value at all times’ — Sustainabilityguide.eu
In construction, where the vast majority of materials at their end-of-life reach only landfills, circularity could become a useful measure and are currently being investigated upon by various organisations to redefine design thinking.
1. Can the AEC sector reduce greenhouse gas emissions through circularity actions?
In order to completely understand the emission of the building sector, one has to evaluate the various stages in a building’s development for its emitting or polluting power. In the image below, the five stages in the life of a project are indicated with ways to support circularity.
1.01 Design — Purpose
The purpose of a building is to be purposeful throughout its life span. Considering the amount of pollution generated in realising a construction project, any unused asset could be deemed an environmental hazard. Therefore, at the design phase possibilities for adaptive reuse must be explored to keep a building purposeful throughout its longevity. Principles of regenerative design could help structure this stage.
1.02 Procure — Material
Building design must be evaluated for material production and procurement emissions, and alternative resources should be considered in place of heavily polluting materials. A feedback-loop could be introduced to use recycled materials and limit the reliance on virgin raw materials.
The five main building components that are emitting the highest amount of CO2eq greenhouse gases are Steel, Cement, Paper, Plastic, and Aluminium. Read the previous article for more information.
While considering materials for a project, a simple chart like the one below can help designer identify potential and make appropriate suggestions.
1.03 Construct — Develop
Method of construction, sourcing, and construction wastes can contribute largely to carbon emissions. Constructing modularly provides opportunities to easily disassemble and reconfigure at a later stage without wastage. Many retrofit projects benefit from this sort of construction. There is also an opportunity to save cost by reselling materials.
1.04 Utilise — Live
Operational emissions are largely controlled or evaluated by following energy-efficient building designs. Energy efficiency is particularly a challenge for retrofit and renovation projects, where old and energy leaking buildings are being converted to suit modern needs.
1.05 Decompose/Decommission — Breakdown/Re-purpose/Refurbish/Recirculate
The first four phases are fairly simple. When it comes to decommissioning and repurposing building materials, many variables are at play, such as logistic, material management, quality assurance, waste management, facilities to store materials (not a landfill), policies to support circularity in practice, and so on. This stage inevitably requires cross-sectoral cooperation and governmental support through abatement and policies to support such initiatives.
Suggestions have been made by the EU Circular Economy Action Plan to introduce Material Passports to assure knowledge of material properties are available and retained. BIM has been identified as a tool to withhold this material knowledge for each project.
European Environment Agency identifies the key challenges in implementing circularity in Construction and demolition waste as;
- Price competition with virgin raw materials high
- Confidence in the quality of secondary materials
- Hazardous content in wastes
- Lack of knowledge on materials in a decommissioned building
- Delay in sourcing and procurement from old buildings
Who are driving Circular system thinking and measures in the building sector in 2020?
Ellen MacArthur Foundation, although provides guidance for circularity in practice, not so much focus is on the building sector.
Buildings as Material Banks (BAMB2020) are introducing tools and measures to maintain the longevity of materials such that buildings can become valuable material banks. Materials are sourced from decommissioned building and recirculated while maintaining its value. Often in construction, the issue with reusing materials is that it may not be eligible for any insurance. Discussions are on-going to engineer reverse logistics for products, where materials are called back to reassess its quality. BAMB is formulating a cradle-to-cradle system framework that can limit dependence on virgin materials.
Most efforts are divided between recommendations or framework suggestion and require rigorous government initiative to mandate its applications.
Several online websites provide guides, training and courses to support circular thinking. Engineers and designers should be educated on their role as leaders of circular mission, providing them with free/mandatory training to support the green initiative. Limiting this knowledge to a few consultancies and practices will not drive a global change.
Hello and thanks for checking out my post! Feel free to shoot any questions you may have as comments. Also, get in touch with me on LinkedIn if you would like to connect. I am an architect (COA) and tech enthusiast from London. I am interested in the built environment and leveraging data sciences for architecture broadly around design, performance, and insights. I work on various topics from time to time such as generative design, spatial analytics, and energy and environmental studies. I am a Project Manager (AEC) at a biotech innovation company, developing a large-scale sustainable project in North Africa.