Decarbonising Construction in East Anglia: Embodied vs Operational Carbon

Reducing carbon emissions in the built environment is essential if we’re to meet climate goals and avoid further damage to vulnerable ecosystems. With the construction sector contributing significantly to carbon emissions and waste in the UK, understanding where those emissions come from - and how to reduce them - is critical.

While operational carbon has long been the focus of energy-efficiency initiatives, embodied carbon is increasingly recognised as the next major challenge. As renewable energy reduces operational emissions, the proportion of carbon associated with materials and construction continues to grow.

What’s the Difference Between Embodied and Operational Carbon?

Operational carbon refers to emissions produced during a building’s use-mainly from heating, cooling, lighting, and power. These are ongoing emissions and can be mitigated through improved insulation, energy-efficient systems, and the use of renewable energy sources.

Embodied carbon, on the other hand, includes all emissions associated with materials, construction, and end-of-life processes. This covers:

• Raw material extraction

• Manufacturing and processing

• Transportation to site

• Construction activities

• Maintenance and refurbishment

• Demolition and disposal

  
  

As operational emissions decline thanks to decarbonised energy grids, embodied carbon will represent the majority of built environment emissions by 2035.

The UK Context

The built environment is responsible for approximately 40% of the UK’s carbon emissions and generates over half of total construction waste. According to the Department for Energy Security & Net Zero, fossil fuel electricity generation has been falling - down 31% in Q3 2023 - while renewable electricity rose by over 44%.

This shift is positive, but it also highlights that reducing operational carbon alone is no longer enough. Embodied carbon is fast becoming the biggest piece of the puzzle.

What Can Structural Engineers Do?

Structural engineers play a crucial role in reducing embodied carbon. While we can’t directly influence operational emissions, we are well-positioned to drive sustainability in material selection, design strategy, and construction methodology.

Our responsibility includes:

• Advising clients on sustainable design choices

• Reducing material quantities through lean design

• Specifying lower-carbon alternatives

• Advocating for reuse and circular design principles

Key Ways to Reduce Embodied Carbon

Optimise with Lean Design

One of the most effective carbon-saving principles is also the simplest: don’t build more than necessary. Reusing existing structures, even in part, can dramatically reduce embodied carbon.

If the superstructure can’t be reused, what about the substructure? Foundations typically account for around 20% of a building’s embodied carbon and are often overlooked for reuse potential.

Designing elements closer to their full utilisation - particularly in steel-framed buildings - can also reduce waste. Average steel utilisation is often below 50%, leaving room for smarter, lighter designs that reduce both material use and carbon.

Choose Materials Wisely

Each structural material has a different embodied carbon footprint:

• Masonry: Can be optimised with piers and better joint detailing to extend life and reduce the need for reinforcement.

• Concrete: Cement content is the biggest issue. Using waffle slabs or reducing cement through longer curing times can help.

• Steel: Optimise sizes and, where possible, reuse steel to eliminate emissions from manufacture.

• Timber: Biogenic and low-carbon, but must be detailed properly to avoid degradation and maximise lifespan.

  
  

Natural or alternative materials such as straw bales, cob, and rubble stone can also offer low-carbon options for suitable projects.

Collaborate Early and Influence the Brief

The biggest embodied carbon savings happen before construction begins. By engaging early with clients, architects, and other consultants, structural engineers can shape briefs that favour reuse, lightness, and efficient material choices.

Small design decisions - like shortening spans, using glulam instead of steel, or altering load assumptions - can have a significant cumulative impact.

Open-plan layouts, for example, may be desirable, but they often require deeper beams and more material. Could a discreet column reduce span length and embodied carbon? Could the structure above be lighter? These are the trade-offs we can help evaluate and optimise.

The Balance Between Embodied and Operational Carbon

Reducing one shouldn’t come at the cost of increasing the other. A smaller building footprint, reuse of materials, and better structural detailing can all contribute to both lower embodied and operational carbon - if considered early.

Our Approach

REFEA, working in collaboration with JMS Engineers and GC Robertson, believe structural engineers have a leading role in shaping a more sustainable built environment. We use design tools, material databases, and early-stage collaboration to help reduce embodied carbon in real, measurable ways.

But ultimately, the biggest influence lies with the client. By choosing to prioritise sustainability from the outset, and working with an engineering team that understands the trade-offs, we can make reuse and low-carbon design the rule - not the exception.