Embodied Carbon in Buildings

18.07.2024

• What is embodied carbon and how does it relate to operational carbon? Carbon emissions for buildings come from operational carbon plus embodied carbon. While until recently there has been a greater focus on operational carbon, embodied carbon – the greenhouse gases emitted during the manufacture, transportation, construction, maintenance and disposal of building materials – is becoming increasingly significant. This is because the proportion of operational emissions in buildings is falling due to the decarbonisation of the energy grid and more energy-efficient building regulations and processes, raising the proportion of embodied carbon in a building's total lifecycle emissions. This has shifted the focus onto the need for action to reduce embodied carbon in building materials and construction processes to meet global climate goals.

• How does embodied carbon connect to global energy needs? With the global population expected to increase by one-third by 2050, and an additional 2.5 billion people projected to live in urban areas, there will be a demand for approximately 230 billion square metres of new floor space over the next 40 years – roughly an area the size of Paris every week. This presents a significant challenge for managing the associated carbon emissions from construction. Strategic urban planning and sustainable building practices are crucial to mitigate the impact of this massive urban expansion.

• How does construction contribute to carbon emissions? The construction sector is responsible for 37% of energy-related CO2 emissions globally. Within this, concrete accounts for around 8%, and the steel sector for approximately 11% of global CO2 emissions. The production of these materials has seen significant increases, with concrete production having risen 25 times since 1950. To address this, there is a critical need for innovation in building materials, increased use of low-carbon alternatives, and more efficient building practices.

• Financial and policy drivers The push towards net-zero carbon buildings is driven by increasing public awareness, political commitments, and financial institutions' focus on sustainable investments. Investors and governments are increasingly demanding sustainable practices, which is leading to the development of policies and standards that enforce reporting and limit embodied carbon emissions in construction.

• Strategic implementation of low carbon standards Frameworks like the UK Net Zero Carbon Building Standard and campaigns for new ‘Part Z’ building regulations advocate for mandatory reporting and setting limits on embodied carbon. These policies are designed to capture and mitigate the worst carbon offenders, pushing the industry towards more sustainable practices.

• Role of local authorities and practitioners Local authorities are instrumental in integrating embodied carbon considerations into planning and building regulations. By setting numerical limits on embodied carbon, requiring whole-life carbon assessments, and promoting retrofit-first policies, local governments can drive significant reductions in emissions. Empowering local authorities to implement and enforce these measures is crucial to support meeting national and global climate commitments. o London Borough of Barking & Dagenham’s development arm, Be First, has responded with a Sustainability Framework and Pattern Book that can be tailored to target and reduce embodied carbon. It is seeking to connect low embodied carbon practices across new build and retrofit programmes.

• Practical steps to reduce embodied carbon include:

o Adopting demountable Modern Methods of Construction (MMC)

o Using regenerative and low-carbon materials

o Minimising material use and waste

o Using lower rather than high-rise forms of density, for example, mansion blocks rather than point blocks

o Avoiding basements

o Reducing long spans with more columns

o Emphasising a fabric-first approach

o Improving building envelopes

o Using tools like TM65 for assessing the embodied carbon of MEP (Mechanical, Electrical, and Plumbing) systems to help identify carbon hotspots, such as refrigerant leakage, and making informed decisions early in the design process

Speakers

Dr Natasha Watson, Embodied Carbon – UK Lead, Buro Happold

Alex McCann, Sustainability Consultant, Bio Regional

Simon Sturgis, Founder, Targeting Zero

Tim den Dekker, Associate, Feilden Clegg Bradley Studios

Alice Jackson, Sustainability Consultant, Hoare Lea

Amber Fahey, Sustainability Associate, Be First