Concrete, the second most used material on the planet after water, is responsible for approximately 7.5% of total anthropogenic (human-caused) carbon dioxide emissions. As society mobilises to tackle the causes and impacts of climate change, addressing embodied carbon in construction has become crucial to decarbonising the industry.

Traditionally, carbon assessments in masterplan developments have focused primarily on buildings. Various industry benchmarks, such as the Low Energy Transformation Initiative (LETI) or the pilot version of the UK Net Zero Carbon Buildings Standard (NZCBS) provide clear targets and guidelines for reducing Whole Lifecycle Carbon (WLC) in the built environment. However, infrastructure such as roads, drainage systems, utilities, and public spaces are generally overlooked in WLC assessments for new development, especially where new infrastructure is needed to facilitate new buildings.

To determine what impact this might have, Savills Earth conducted research to compare the initial embodied carbon emissions (A1-A5 stages) of infrastructure with those of buildings for an illustrative masterplan project. The study found that infrastructure added approximately 100 kg CO₂ per sqm of dwelling area, increasing overall embodied carbon by roughly 33%. This has the potential to dwarf any building specific embodied carbon savings through the use of low cement concrete, recycled steel and natural materials. However, by using innovative, low-carbon materials, the infrastructure emissions could be reduced significantly.

Change can occur now, without the need for innovative materials, construction methods or design strategies. From the inception of a project, masterplanners, designers, and technical consultants can influence the embodied carbon in infrastructure. They set the key parameters and vision that shapes the design. Unlike operational emissions, which can be reduced by energy-efficient upgrades, the emissions embedded in infrastructure materials are irreversible.

The Savills Urban Design team uses several design strategies that can be highly effective in reducing the carbon impact of infrastructure within new developments. For example, replacing excessive grey infrastructure with green and blue integrated networks is a simple but impactful approach. Additionally, challenging the parking ratio of a development can release additional site area for community benefits (such as doorstep play spaces and natural open areas) whilst also providing the opportunity for integrated Sustainable drainage systems (SuDs) solutions and rich ecological chains through urban areas. Other straightforward strategies, like narrowing carriage widths or material choices can substantially impact the quantum of carbon heavy materials required - especially in larger developments - whilst also creating a more pedestrian-friendly streetscape that is less dominated by cars and infrastructure.

Many of the ingredients of ‘good placemaking’ and ‘desirable communities’ are happy by-products of carbon conscious infrastructure design decisions, and vice versa. Given it is a ‘win-win’, why are we not frequently seeing new developments considering a broader approach to WLC assessment, aiming to minimise emissions from the whole site, instead of consistently producing infrastructure-dominated developments? Strategic design alongside technical calculations can cut carbon, and improve public health and environmental quality. By broadening the scope of carbon assessments to include infrastructure and adopting, low-carbon materials and design strategies, we can make significant strides towards a more sustainable built environment.

Further information

Contact Taby Halliwell or Matthew Laidman

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