5.1.3.2. Embodied Energy and Embodied Carbon

From a life cycle perspective, the environmental impact and energy consumption of buildings are closely linked to the choice of materials.

The materials selected for constructing a building significantly affect its environmental impact and energy usage across its lifespan. Different materials have varying levels of energy embedded in them due to the processes involved in their extraction, production, and disposal. Therefore, knowing the energy and carbon footprint of each material is crucial for making sustainable building choices.

Think of choosing different kinds of grocery bags. A plastic bag has a certain environmental impact due to the energy required to produce it, while a reusable cloth bag has a lower impact over time. Choosing the right bags affects the overall waste produced, just like choosing the right materials affects a building's ecological footprint.

However, there is often a lack of alignment between the service life of materials (which determines the intervals for material renewal) and the service life of buildings (the duration of the operational phase).

Many building materials have a lifespan that doesn't coincide with that of the building itself. This misalignment can cause issues where materials need to be replaced frequently, leading to higher energy demands, or materials become obsolete before the building itself is retired, which can also increase the carbon footprint due to constant replacements.

Imagine a smartphone that you use for several years, but its battery only lasts for one year before needing a replacement. Every time you replace the battery, you generate waste and consume energy in the process, similar to how materials in a building can lead to ongoing replacements and increased energy usage.

This can result in a trade-off between material selection and building energy demand and so, requires a holistic approach...

Selecting a building material often comes down to a compromise. For instance, while wood may have a lower environmental impact during its lifecycle compared to concrete, the energy demands for cooling a wood structure in warm climates might outweigh the initial benefits. Thus, focusing solely on one attribute (like carbon footprint) without considering the building’s overall energy needs can lead to inefficient outcomes.

Think of it like choosing a car. You might favor a fuel-efficient vehicle for daily commutes, but if you live in a place with rough terrain, a sturdy SUV might be a better long-term solution, even if it uses more fuel. The best choice considers multiple factors, just as evaluating materials does.

Every building material possesses an ‘Embodied Energy’ or Embodied Carbon, which refers to the sum impact of all greenhouse gas emissions attributed to that material during its life cycle from extraction to disposal.

Embodied energy and carbon represent the total energy used and the greenhouse gases emitted during a material's life, from extraction to disposal. This concept is crucial for assessing the overall environmental cost of using specific materials in building projects. The more energy-intensive the production process, the higher the embodied energy and carbon will be.

Consider a sandwich. If you buy a sandwich that used locally-sourced ingredients, it likely has a lower embodied energy compared to one made with ingredients shipped from far away. Each ingredient's journey impacts its overall footprint, similar to how building materials accumulate their environmental costs over time.

The after-use life cycle phase plays a significant role in determining the overall embodied energy of a building...

At the end of a building's life cycle, how its materials are handled can greatly influence the total embodied energy. Effective strategies such as recycling, reusing, or remanufacturing materials can reduce waste and minimize the greenhouse gases associated with disposal. This consideration is necessary not only for sustainability but also for comprehensive life cycle analyses in construction.

Think of it like recycling your old gadgets. If you throw them away, they contribute to landfill waste. If you recycle or donate them, they can be refurbished or reused, reducing your overall carbon footprint. The same logic applies to building materials at the end of their life.

Lupíšek, et al. (2015) innumerate the Design strategies for reduction of embodied energy and embodied carbon...

This research outlines specific strategies to decrease embodied energy and carbon in building design, which can be grouped into three main areas: reduction of material use, substitution with lower impact materials, and minimizing construction-related impacts. Each strategy requires careful planning and decision-making to ensure an overall reduction in environmental impact.

It's akin to preparing a meal with fewer ingredients to reduce waste. Instead of using many complex items that may not be used again, you could focus on versatile ingredients that can be used across various dishes, ultimately decreasing both complexity and waste.

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