What We Build From Matters: Embodied Energy in Perth's Building Materials

Embodied Energy of Building Materials: Perth's Perspective

The built environment makes up for a large percentage of carbon emissions - by some estimates the construction and operation of buildings makes up as much as 40% of global emissions. Embodied energy - the amount of energy consumed to extract, process and transport material to site, makes up around 12% of global emissions. So w,hen we talk about sustainable building in Perth, or anywhere for that matter, understanding embodied energy is crucial. Embodied energy refers to the total energy consumed by all processes associated with producing a product, from raw material extraction to manufacturing, transportation, and installation. In the context of Perth's push towards sustainable architecture, evaluating the embodied energy of standard materials like steel, concrete, brick, and alternative materials like hempcrete is essential. I’ve kept this super brief to provide the quickest of snapshots, but broadly steel bad, timber good, hempcrete great.

Steel

Embodied Energy

Steel, primarily composed of iron, demands a high amount of energy in the production phase, especially during the smelting process.

Perth Perspective

Unfortunately, the fact that Western Australia is a significant iron ore hub doesn’t help in reducing embodied energy, as we don’t process that iron ore locally. Recycling and reusing steel can substantially lower its embodied energy, making it a more sustainable choice.

Concrete

Embodied Energy

Concrete, primarily made of cement, aggregates, and water, has a significant embodied energy mainly due to the cement component. The cement production process is energy-intensive and emits considerable amounts of CO2.

Perth Perspective

Opting for fly ash or slag as replacements for cement can reduce the embodied energy. Rammed recycled concrete is also an option, albeit more experimental. Given Perth's Mediterranean climate, using concrete's thermal mass properties can provide passive heating and cooling, offering long-term energy savings.

 

Brick

Embodied Energy

Traditional fired bricks require substantial energy in the kiln firing process, increasing their embodied energy.

Perth Perspective

Brick has long been a favourite in Perth's construction scene, valued for its thermal properties. Using locally sourced clay reduces transportation energy. Additionally, unfired or 'mud' bricks can be a sustainable alternative with significantly lower embodied energy.

Timber

Embodied Energy

Timber, as a renewable resource, generally has lower embodied energy compared to many other construction materials, especially when locally sourced and processed. The energy used is mainly in the milling, transportation, and occasionally, treatment processes.

Perth Perspective

Western Australia boasts vast forest resources, making timber an accessible choice for Perth's construction scene. When sourced sustainably, timber not only provides aesthetic appeal but also contributes to carbon sequestration. Given Perth's climate, timber offers good insulation properties and can work in synergy with other materials to enhance a building's thermal efficiency.

Hempcrete

Embodied Energy

Hempcrete, made from the hemp plant's woody core and a lime-based binder, boasts a notably low embodied energy. The hemp plant grows quickly, sequesters carbon, and requires minimal processing. However, this is still somewhat of an innovative construction methodology and comes with risks and challenges - for example, finding builders that have experience in using it.

Perth Perspective

Given the growing interest in sustainable and green building materials, hempcrete emerges as a promising alternative for Perth. It offers excellent insulation and is breathable, regulating indoor air moisture and ensuring a comfortable living environment.

What We Use

While each project is unique, we strongly favour timber buildings. Not only does it have a significantly lower embodied energy than most viable alternatives, but it is easy to work with, and when dressed with insulation and appropriate cladding, has good thermal and insulation properties.

Conclusion 

The choice of building materials plays a pivotal role in the overall sustainability and environmental impact of a structure. By understanding and choosing materials based on their embodied energy and suitability to Perth's unique climate, builders and homeowners can make informed decisions, favouring both the environment and the building's long-term efficiency.