Executive Summary

Carbon is inherent in all stages of the built asset lifecycle. From the raw material supply, manufacturing, construction, use and repair, to end of life and transportation throughout. All processes involve carbon emissions. Darren Chuang, AssetFuture has carried out a project to develop a formula to calculate the Embodied Carbon Factor of a built asset in the first phase of its lifecycle, from cradle to gate.

Introduction

The statistics are startling: cutting out one return flight from Sydney to Melbourne saves 200kg of CO2e per year. Cutting meat, dairy and beer from your diet cuts 2,000kg. While reducing 20% of embodied energy in the built environment saves 200,000kg of embodied energy each year. Even small changes can have a huge impact.

We can manipulate the environment we live in to make life easier, safer and more comfortable and yet we feel overwhelmed in the face of rapid climate change. The greatest challenge is the race against time towards net zero carbon by 2050. How can we best invest our time to effectively to make an outsized impact?

Built facilities consume over 40% of global energy annually, according to estimates, representing over 33% of the world’s total carbon emissions.  The builders, owners and managers of buildings clearly have a significant role to play in meeting global emissions targets. But how to these numbers break down to the impact of a single building? AssetFuture has carried out a project to develop a formula to calculate the Embodied Carbon Factor of a built asset in the first phase of its lifecycle, from cradle to gate.

 

Developing a formula for carbon

A holistic approach to lifecycle accounts for all costs from cradle to grave. British Standard 15978 focuses on the calculation method to assess the environmental performance of buildings, breaking down lifecycle assessment into four stages:

• Product – 50% emissions from harvesting the raw material, processing, manufacturing and the transportation in-between
• Construction – 5% of total emissions from getting the product to site to build
• Use – 43% of total emissions from maintenance, repair, replacement to energy consumption in electricity and water
• End of Life – 2% of total emissions from the removal, transport and waste disposal

It is critical that lifecycle modelling factors in all these stages when making decisions.

AssetFuture, as part of the initial stages of research and development, has focused on the first stage – product, cradle to gate – and the associated Embodied Carbon Factor (ECF), measured in kilogram(s) of carbon dioxide equivalent (kgCO₂e). The equation developed is:

Embodied Carbon Factor (kgCO₂e) = Quantity_material x Carbon Factor_material

To test the cost impact of embodied energy, a double modular demountable sized building at 163.2m² (24m length x 6.8m width x 2.7m height) was simulated using five common wall cladding materials: aluminium, concrete, face brick, steel and weatherboard. The cumulative cost of each of these materials was projected 120 years into the future, based on an Australian temperate climate zone.

Over the projected timeframe, weatherboard has the highest and aluminium the lowest cumulative cost respectively. Weatherboard, with relatively lower lifespan and average to high unit cost, incurs ~50% more cost over time than other cladding materials.

But when the embodied energy cost is added to the modelling, concrete becomes significantly more cost intensive. Although concrete has one of the longest design lives (100 years), the ECF for pre-cast concrete panels is 2.31 times higher than the other four materials combined equating to $2,450 a year in embodied energy cost.

Asset Management Best Practice: taking a lifecycle approach

The solution isn’t to stop using concrete. It’s still a cost effective and efficient way for growing populations in developing countries to build affordable, durable housing. All current alternative materials are a distant second choice in providing equivalent characteristics.

But when presented with choice, facilities managers should be aware of the embodied energy cost and take a lifecycle approach. In Asset Management, this refers to a comprehensive framework for managing physical assets throughout their entire lifecycle, from acquisition to disposal. A lifecycle approach recognises that assets have a finite lifespan and will eventually require maintenance, repair, replacement, or disposal.

By blending embodied energy data with existing lifecycle cost models, asset managers can incorporate sustainability and work towards a zero emissions future in the built environment. If we don’t consider embodied carbon, we are missing a critical piece for decision making.

Materials must be used efficiently to ensure that buildings constructed, operated, refurbished or disposed are safe, durable and sustainable, and their maintenance costs over time must be factored in. Short-term savings in cheaper, less carbon efficient materials in construction and maintenance/repair may be most costly in the long-term.

Taking this holistic approach helps organisations to optimise asset performance while minimising downtime and maintenance cost and improving overall efficiency. It also helps organisations to align their asset management strategies with their overall business objectives, reduce risks, and comply with regulations and standards.

Benefit to the Community

Sustainability in construction and built asset management has numerous benefits for the community, creating a healthier, more sustainable, and more equitable built environment.

1. Environmental Protection: Reducing carbon emissions, conserving natural resources, and using renewable energy sources can help in creating a cleaner and healthier environment for the community, as well as helping the progress towards 2050 global emissions targets.
   
   
2. Social Benefits: Using sustainable materials and designing buildings for energy efficiency can create a more comfortable and healthier indoor environment, while taking a holistic lifecycle approach increases safety and reduces risk and cost for occupants.
   
   
3. Improved Quality of Life: Sustainable practices can help in creating a more livable community, with better access to public transportation, green spaces, and affordable housing. This can lead to a better quality of life for community members.

Darren Chuang’s Vision

Sustainability is a top priority for AssetFuture. We are committed to empowering organisations to make the right decisions for their portfolio as well as for the planet. As regulation increases, these two considerations are in increasingly close alignment. By considering carbon and taking steps to reduce it, asset managers will also realise gains and efficiencies in the assets they manage.

Darren Chuang’s passion and experience in sustainability is a driving force within AssetFuture to achieve this vision. Through his work, we are able to show our clients key ways in which they can work towards sustainability, both in decarbonising existing assets as well as minimising carbon for new projects.

If we are all to achieve net zero carbon by 2050, the work needs to start now. Sustainability must be built into Strategic Asset Management Plans (SAMPs). It is going to be challenging and will require investment, but it will also drive innovation in the industry that will result in much greater efficiency and sustainability, as well as higher value for more environmentally sustainable assets.