Embodied carbon is not a term you hear that often, but it’s something we should all be aware of.

When you buy a new car, for example, the embodied carbon in that car is the total emissions from mining and processing the raw materials, manufacturing the car parts, assembling the car, and shipping it to the dealership.

The emissions from using the car over its lifetime – fuel consumption, for example – are not included in embodied carbon.

Types of Carbon in Buildings?

  • Embodied carbon
  • Operational carbon

Embodied carbon

Embodied carbon refers to the carbon dioxide (CO2) and other greenhouse gases emitted during the production of building materials and products. It is a significant source of greenhouse gas emissions, accounting for approximately 11% of global emissions from the construction sector.

Operational carbon

The total carbon produced by the operation of all energy sources used to maintain our buildings warm, cool, ventilated, illuminated, and powered is referred to as operational carbon.

This comprises of electricity, natural gas, oil, propane, and wood. Indirect emissions from the production of these energy sources (also known as “life-cycle” or “Scope 3” emissions) are also included in this calculation.

Life Cycle Assessment

The assessment of embodied carbon is a subset of the larger field of Life Cycle Assessment (LCA), which examines a range of environmental impacts. As a result, many of the concepts are applicable to both techniques.

Whole Life-Cycle Carbon

A Whole Life-Cycle Carbon (WLCC) strategy is one that takes the full life cycle of a product or structure into account, beginning with raw material extraction and ending with disposal or recycling.

The operational and embodied carbon dioxide emissions of a building’s WLCC are the total of all its operations and inhabitant CO2 emissions.

Why the Focus on Construction?

With the world’s building stock expected to double by 2060, the construction sector is one of the most significant contributors to worldwide greenhouse gas emissions.

With this in mind, the industry has a critical role to play in mitigating climate change.

Cement, unfortunately, is one of the most significant components in concrete and contributes to a significant amount of construction industry pollution. In reality, cement manufacturing accounts for about 8% of global CO2 emissions.

If you think about it, if the cement industry were a country, it would rank number three as an emitter of greenhouse gases in the world.

What are the Solutions to Reducing Embodied Carbon?

There are a number of ways to reduce embodied carbon in buildings, including:

Reuse existing structures rather than constructing new ones

You may reduce carbon in a structure by using wood instead of steel and concrete, or wood siding rather than vinyl.

Concrete mixtures with a low carbon content should be chosen

Use lower carbon concrete mixtures to build stronger structures. Collaborate with your structural engineers to develop them.

Use mass timber products in construction

Look for opportunities to use certified wood products, which have a lower carbon footprint than other building materials.

Include green roofs and living walls

Add these features to your project to help offset the embodied carbon of the building.

Reduce the use of carbon-intensive materials

When it comes to reducing embodied carbon, thoughtful usage is critical for products such as aluminum, plastic, and foam insulation.

Lower carbon alternatives should be chosen

Where possible, use lower-carbon materials such as bamboo, rammed earth, and straw bale in construction.

Carbon sequestering materials should be used

In construction, using agricultural inputs that store carbon, such as hemp, can aid to balance the building’s embodied carbon.

Reuse materials

Look for salvaged materials such as brick, metals, damaged concrete, or wood from previous demolishments. These can frequently be reused in new construction.

Increase structural efficiency by maximizing it

Since most embodied carbon is in the structure of a building, making the structure more efficient will have the biggest impact on reducing embodied carbon.

Reduce the number of finish materials used

Where possible use structural materials as finish materials to reduce the number of products brought to the job site.

Reduce waste as much as possible

Designing modules or using just-in-time delivery can help reduce the amount of waste generated on construction sites.

Ensure that products are responsibly sourced

When choosing products, consider their full life cycle impact, including their embodied carbon.

Products with recycled content or that can be recycled at the end of their useful life have a lower embodied carbon than those that cannot.

Educate clients and the public about embodied carbon

Awareness is key to reducing embodied carbon in buildings. Education and outreach can help decision-makers understand the importance of embodied carbon and how it can be reduced.

FAQs

How do you calculate embodied carbon?

Embodied carbon = quantity × carbon factor
The carbon content of each material or product utilized in construction is multiplied by its carbon factor to determine the embodied carbon for that material or product.

What is net-zero embodied carbon?

Net-zero embodied carbon means that the total carbon emissions associated with a product or building over its entire life cycle are offset by carbon credits or other means. This can be accomplished through a variety of measures, such as using low-carbon materials, recycling or reusing materials, and increasing energy efficiency.

How do you get net zero operational carbon?

Operational energy demands and embodied carbon emissions are limited to levels that are considered consistent with a net-zero carbon future, where all demands can be met by a combination of on-site renewable energy generation and/or zero-carbon energy imported from the grid.

How much embodied carbon is in concrete?

The embodied carbon in CEM I EPD varies between 732 and 941 kg CO2e per tonne of cementitious material. CEM I, with a 30-40% fly ash content, has the highest value at 941 kg CO2e/tonne of cementitious material.

Do GHG emissions include embodied carbon?

No, GHG emissions only include operational emissions. Embodied carbon would need to be calculated separately.

About the Author

Passionate about helping households transition to sustainable energy with helpful information and resources.

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