The building and construction industry is a significant consumer of non-renewable energy resources and is contributing to changing the earth’s environment in damaging and irreversible ways. These impacts are being felt in climate-related shifts that include increases in the earth’s average temperature and rising sea levels. 

A new report by NASA and the National Oceanic and Atmospheric Administration shows that 2018 was the fourth-hottest year since 1880, the earliest year for which reliable global temperature data is available. The three hottest years on record were 2015, 2016 and 2017. 

Additionally, the rise in sea levels is causing “nuisance floods” to become more common. From the 1950s to the early 2000s, the days of flooding in the 27 most vulnerable cities across the United States grew from two per year to nearly 12. 

These and other environmental impacts underscore the urgency of battling climate change and how critical it is for all industries—including construction—to stem the tide on this issue. 

Reducing embodied energy in the built environment is one way the building and construction sector can do its part to address one of the major challenges of this century.

What Is Embodied Energy?

Embodied energy is defined as the total energy required for the extraction, processing, manufacturing and delivery of buildings. It does not include the operation and disposal of building materials, which would be considered in a life cycle approach. Embodied energy, therefore, encompasses the upstream or front-end components of buildings that are made up of a complex combination of processed materials. 

While significant progress has been made in reducing the operational energy of the built environment, embodied energy has largely been ignored. The proportion of embodied energy in buildings today has increased to more than 40% of energy consumption, and the embodied energy content of a building can be the equivalent of many years of operational energy.

Materials Selection Matters

To create low-carbon buildings, project teams need to choose low-carbon building materials. But right now, choosing these materials is challenging because the data is not readily available or lacks transparency to ensure it’s accurate. But additional tools are becoming available. 

Microsoft is the first large corporate user of the Embodied Carbon Calculator for Construction (EC3) to track the carbon emissions of raw building materials, introduced by Skanska and supported by the University of Washington Carbon Leadership Forum, Interface and C-Change Labs.

Recognizing the factors that contribute to a material’s embodied energy can help the construction industry make more sustainable building materials choices. 

Some of the factors that contribute to a material’s embodied energy include the distance needed to transport it, the amount of raw materials used, the complexity of the manufacturing process and the recycling potential.

For example, cement, steel and bricks are major contributors to embodied energy.  

Keeping these factors in mind, the construction industry can work to lower embodied energy in the built environment by:

• using locally sourced materials to reduce transport;
• selecting materials with a high recycled content;
• selecting materials that can be easily reused or recycled at the end of their lives using existing recycling systems; and
• giving preference to materials that have been manufactured using renewable energy sources.

Change Needed at the Supply Chain Level 

Most life cycle assessments (LCA) show that the majority of embodied energy comes from the supply chain. As such, the drive toward reducing embodied energy in the built environment should include a movement to make changes at the supply chain level, encouraging producers of steel, concrete and other materials to shift toward more sustainable practices. 

It makes sense to look for options that minimize the initial energy investment—the embodied energy—in the built environment. The building and construction community can make a significant impact by selecting materials that have an LCA or an environmental product declaration, helping impact climate change by making smarter, sustainable choices in the products they use.