Embodied Carbon vs Operational Carbon – The Key to Sustainable Construction

Embodied Carbon vs Operational Carbon Emissions - Understanding the Difference.

Embodied Carbon vs Operational Carbon – The Key to Sustainable Construction background

Published on 27th May 2024

 

Embodied Carbon vs Operational Carbon – The Key to Sustainable Construction

The global push for sustainability and the race towards net zero have really put carbon-heavy industries like construction in the spotlight.

Did you know the built environment is responsible for nearly 40% of global greenhouse gas emissions? That's why cutting down on carbon emissions in construction is so important. Imagine this: every week, we build the equivalent of a city the size of Paris. Yet, shockingly, less than one per cent of these buildings get their carbon footprint assessed. With such rapid growth, it’s crucial that every new building, house, or development tackles both embodied and operational carbon. These are the two main parts of a building’s whole life carbon.

In the world of sustainable construction, embodied carbon and operational carbon are key terms. Embodied carbon includes the emissions from producing, transporting, and assembling building materials, covering everything from raw material extraction to construction. Operational carbon, on the other hand, is all about the emissions from a building's daily operations, like heating, cooling, and energy use.

Understanding the difference between these types of carbon emissions helps in making informed decisions for sustainable construction. Focusing on reducing both embodied and operational carbon can greatly decrease a building’s overall carbon footprint, paving the way for a more eco-friendly future.

Getting a handle on these carbon types will help reduce whole-life carbon, boost energy efficiency to save on costs and cut waste, and create spaces that support healthy, happy living. Historically, the construction industry hasn’t been quick to embrace new technologies and sustainability initiatives. But now, the rise of sustainable buildings and practices is changing the game.

In this article, we’ll dive deeper into embodied carbon and operational carbon, exploring their significance, measurement methods, and strategies for mitigation. So, let’s get started and unravel the complexities of sustainable construction!

 

Embodied Carbon vs Operational Carbon 

Embodied carbon represents the carbon dioxide equivalent (CO₂e) tied to the non-operational phase of a construction project. This includes emissions from the extraction, manufacturing, and transportation of materials, as well as their deconstruction, disposal, and end-of-life processes.

On the other hand, operational carbon covers the emissions from a building’s everyday use. This involves the energy and water consumption needed for heating, cooling, ventilation, lighting, and other regulated energy uses during the building’s occupancy. Buildings consume a large chunk of global energy, and the energy sources often rely on fossil fuels, which release carbon dioxide when burned.

Buildings can be designed and operated to minimize operational carbon emissions. This can be achieved through energy-efficient measures like incorporating insulation, using high-performance windows, installing efficient heating and cooling systems, and utilizing renewable energy sources. By cutting energy consumption and switching to renewable energy, the operational carbon of a building can be significantly reduced.

Next, we'll dive into a detailed exploration of both embodied carbon and operational carbon, breaking down their unique contributions to a building's overall carbon footprint. Let’s unravel the details and better understand how each impacts the whole life carbon footprint of a building.

Common low-embodied carbon materials are:

  1. Timber and Bamboo: Renewable and naturally occurring, these materials have low embodied carbon because they sequester carbon during growth and require less energy to process.

  2. Recycled Materials: Using recycled steel, aluminium, glass, or plastic reduces the need for new raw materials and lowers the carbon footprint associated with production.

  3. Rammed Earth: A natural building material made from compacted earth, which has low embodied energy and carbon emissions.

  4. Straw Bale: Straw is an agricultural byproduct that can be used as a construction material. It’s renewable, biodegradable, and has low embodied carbon.

  5. Hempcrete: Made from the inner woody core of the hemp plant mixed with a lime-based binder, hempcrete is lightweight, durable, and has low embodied carbon.

  6. Cork: Harvested from the bark of cork oak trees, cork is a renewable resource with low embodied carbon and excellent insulating properties.

  7. Natural Insulation Materials: Wool, cellulose (recycled paper), and cotton are examples of natural insulation materials with low embodied carbon compared to traditional synthetic insulation.

  8. Geopolymer Cement: An alternative to traditional Portland cement, geopolymer cement produces significantly less carbon dioxide during production.

  9. Sustainably Sourced Local Materials: Using materials sourced locally reduces transportation emissions and supports local economies.

  10. Cross-Laminated Timber (CLT): Engineered wood panels made from glued layers of solid-sawn lumber, CLT has low embodied carbon and is a strong, sustainable alternative to steel and concrete.

By opting for these materials, builders can significantly reduce the embodied carbon footprint of their construction projects.

 

Sources for embodied carbon in construction are:

In construction, there are various sources of embodied carbon that contribute to a building's overall carbon footprint. One major source is the extraction of raw materials. Mining minerals like limestone for cement or iron ore for steel requires energy and releases carbon emissions. Plus, processing and manufacturing these materials involve energy-intensive processes, adding to the embodied carbon.

Transportation is another factor in embodied carbon. Shipping materials over long distances, especially from different regions or countries, ramps up carbon emissions. Even assembling materials on-site contributes to embodied carbon, thanks to the extra energy needed for construction equipment and the use of carbon-intensive materials like adhesives and sealants.

As for operational carbon—think energy and water used by building occupants—there's been a promising 18% reduction reported by the UKGBC’s Net Zero Whole Life Carbon Roadmap Progress Report, from 2018 to 2022. This drop is attributed to improvements in decarbonizing the electricity grid and boosting energy efficiency. However, the UK built environment emissions only decreased by 13% during the same period, falling short of the Roadmap's targeted 19% reduction. This highlights the need for further enhancements to meet our sustainability goals.

 

Ways to measure and reduce embodied carbon footprint

To effectively reduce embodied carbon, accurate measurement and quantification are essential. Life Cycle Assessment (LCA) is a widely used method that evaluates a building's environmental impact across its entire lifespan, considering factors like embodied carbon, water usage, land occupation, and potential toxicity.

Various tools and databases offer data on the embodied carbon of different building materials, aiding architects, designers, and builders in making informed choices. Opting for low-carbon alternatives and optimizing material use can significantly slash a building's embodied carbon.

Beyond material selection, construction techniques also play a vital role. Prefabrication and modular methods minimize waste and energy use, reducing overall carbon emissions. Additionally, recycling and reusing materials from existing buildings can diminish the demand for new materials and their associated embodied carbon.

Another effective approach to cut embodied carbon is reusing existing foundations and structures through renovation projects, potentially saving up to 75% of embodied carbon.

Concrete, crucial for its strength and adaptability, is a major emitter, contributing at least 8% of global emissions. Decarbonizing the concrete sector is pivotal for construction carbon reduction. Innovations like cement replacements such as Pulverised Fuel Ash (PFA) and Ground Granulated Blast-furnace Slag (GGBS) show promise, but eliminating their generation processes is crucial for long-term sustainability.

Incorporating low-carbon building materials and second-hand materials further reduces a building’s embodied emissions. For instance, recycled steel carries a much lower embodied carbon footprint compared to brand-new steel, emphasizing the importance of sustainable choices for a greener construction industry.

 

Some sources of operational carbon in buildings are:

The sources of operational carbon in buildings can vary depending on factors such as the building's size, function, and location. The main contributors to operational carbon include heating, cooling, ventilation, lighting, and the use of appliances and equipment.

Heating and cooling systems, especially those powered by fossil fuels, are major sources of operational carbon emissions. Traditional HVAC systems, which rely on the combustion of fossil fuels, have a significant carbon footprint. However, advancements in technology have led to the development of more energy-efficient and low-carbon alternatives, such as heat pumps and geothermal systems, which can significantly reduce operational carbon.

Lighting also contributes to operational carbon, particularly if inefficient lighting systems, such as incandescent bulbs, are used. Switching to energy-efficient LED lighting can help reduce energy consumption and, consequently, operational carbon emissions. Additionally, the use of appliances and equipment, such as refrigerators, computers, and printers, also adds to the operational carbon of a building. Choosing energy-efficient models and implementing smart power management systems can help minimize energy usage and carbon emissions.

 

What are the strategies for reducing operational carbon?

Reducing operational carbon requires a well-rounded approach that blends energy-efficient design, renewable energy generation, and changes in behavior. By incorporating passive design strategies, like maximizing natural lighting and ventilation, we can reduce the need for artificial lighting and mechanical cooling. Plus, smart energy management systems can fine-tune energy usage, cutting down on wastage.

To really make a difference, we can tap into renewable energy sources such as solar panels or wind turbines right on-site. This allows us to produce clean energy to power the building, offsetting the carbon emissions associated with grid electricity and promoting a more sustainable energy mix. And let's not forget about people: engaging occupants through awareness campaigns and promoting energy-saving practices can lead to behavioral changes that lower energy consumption and operational carbon.

Implementing energy-efficient measures, like using energy-efficient appliances, optimizing insulation, and integrating renewable energy sources, can significantly slash operational carbon. For instance, installing solar panels on an office roof generates clean, renewable energy from sunlight, reducing operational carbon. Shifting away from traditional energy sources, such as fossil fuels, helps minimize reliance on carbon-intensive sources, ultimately cutting carbon emissions linked to daily operations.

While building regulations and certifications often prioritize minimizing operational carbon, it's crucial to consider the whole life carbon footprint of every development. By taking a holistic approach, we ensure that our structures not only perform well day-to-day but also contribute to a greener future.

 

Strike The Right Balance: Embodied vs. Operational Carbon

The UK construction industry needs to ramp up efforts in cutting both embodied and operational carbon to reach the country's ambitious goal of achieving net-zero emissions by 2050. This aligns with the Paris Agreement's aim of limiting global warming to 1.5°C.

Concentrating solely on operational carbon ignores emissions from material extraction, manufacturing, and disposal. Similarly, solely focusing on embodied carbon might miss ongoing emissions during product or building usage. By reducing both embodied and operational carbon, or what we call the whole life carbon, we gain a more comprehensive perspective. This informs decisions in sustainable design, construction, and operation, guiding us towards a greener future.

 

Whole Life Carbon and the Lifecycle Assessment

Whole life carbon is all about looking at the total emissions a building produces throughout its entire existence. This means considering everything from where the materials come from to when the building is eventually dismantled.

Striving for lower whole life carbon is like aiming for efficiency at every stage of a building's life. It's not just good for the environment; it also helps in the fight against climate change.

To figure out a building's whole life carbon, developers use something called a Life Cycle Assessment (LCA). It's like taking a detailed look at the building's environmental impact from start to finish. For developers, it's a really useful tool for understanding and managing their environmental footprint.

 

What is life cycle Assessment?

A life cycle assessment is a method used to evaluate the environmental impacts of a product, process, or service across all stages of its life cycle. In construction, this means calculating the whole life carbon of a development.

 

Takeaway: Balancing embodied carbon and operational carbon for a sustainable future

Understanding the difference between embodied carbon and operational carbon is crucial for making smart decisions in sustainable construction. Embodied carbon refers to the emissions from materials and construction, while operational carbon focuses on the energy used during a building's operation. Both types of emissions add to a building's overall carbon footprint and need to be addressed to meet sustainability goals.

By measuring, reducing, and optimizing both embodied and operational carbon, developers and builders can significantly contribute to a more sustainable built environment. Choosing the right materials, using efficient construction techniques, designing for energy efficiency, and incorporating renewable energy can all help minimize the environmental impact of buildings and promote a greener future.

In conclusion, the key to sustainable construction is understanding and managing both embodied and operational carbon. By taking a holistic approach that considers the entire lifecycle of a building, we can make sure our built environment is environmentally responsible and contributes to a sustainable future. Let’s strive to balance embodied and operational carbon to create a world where construction is not only functional but also in harmony with the environment.