It was the pioneer of modern business management Peter Drucker who first coined the phrase “If you can’t measure it, you can’t improve it.” When the words were first said they were gospel; in the context of decarbonising industry they have become axiomatic.

Carbon measurement and benchmarking in the built environment is particularly complex.

Embodied carbon refers to total greenhouse emissions generated during the manufacture and installation of the materials and products used in the construction and refurbishment of new and existing buildings and infrastructure.

Measuring the embodied carbon of construction projects is complicated by the intricate supply chains industry relies on, and different ways products can be assessed for their environmental impacts. Different life cycle assessment methodologies (LCAs) – have emerged to help navigate carbon mitigation.

The Materials Embodied Carbon Leaders’ Alliance (MECLA) has worked closely with LCA specialists, rating tool agencies, private industry partners, government, and the Green Building Council to progress measurement and benchmarking for embodied carbon, with a discussion paper Measuring Upfront Carbon in the Built Environment released at the end of 2022.

This paper was launched alongside the NABERS consultation paper for incorporating embodied carbon into its proposed assessment rating scheme and the GBCA’s paper on embodied carbon emissions.

Buildings and infrastructure are complex assemblies of thousands of products, that often take three to five years to build. Different approaches to measuring must be incorporated in different ways throughout the project to maximise carbon savings – starting at the business case. There are also different LCA methodologies that apply at the material or product level versus whole of building.

So, what are the different kinds of LCAs? Carbon Product Declarations (CPDs) and Environmental Product Declarations (EPDs) are process based LCAs focused on product specific environmental impacts.

CPDs provide a single impact focus on embodied carbon exclusively.

EPDs give a variety of other eco-indicators including energy, toxicity, resource depletion etc.

Input-output model

Another LCA method is the input-output model which uses a carbon intensity coefficient for particular sectors informed by macro-economic and environmental input-output data.

Input-output is time efficient and effective at the policy and planning level. Input-output is vital for achieving embodied carbon reductions in the early stages of design, before quantities are available, and for filling the gaps in EPD and CPD data.

Both approaches have their strengths and weaknesses. And both measurement methodologies have important, albeit different roles to play in Australia’s journey to reduce embodied carbon in construction. The important message is that we need to do more measurement and be better at it.  After all, if we can’t measure it, we can’t improve it.

What is an EPD? Process based LCAs

An EPD is a bottom-up approach that, alongside myriad other environmental metrics, gives you a carbon estimate per unit for a specific material. EPDs are often used to model at the asset or product level in building and infrastructure projects.

When it comes to developing EPDs Stephen Mitchell, director at EPD Australasia says:

We are still at an early stage compared to Europe and the US. However, we are moving very quickly because a lot of suppliers, particularly of building and construction products – companies that operate globally – and are using their expertise gained in US and EU markets are developing EPDs here.

Big Manufacturers of concrete, steel and timber see the value in transparency of the information they provide to specifiers and the standardised nature of the reporting.

So far, in Australia, EPDs have been primarily market and rating tool driven.

“It started with GBCA, but NABERS is the one really taking the ball advancing it,” says Nicole Sullivan Head of Strategy, and Impact Australia at Thinkstep-ANZ.

In December 2022 NABERS launched a discussion paper on a proposed embodied emissions tool that takes the tool to the broader market.

“The work that NABERS has been doing is a great lever because it takes it” out of a top tier niche market into a much broader market,” Sullivan says.

Prices starting to fall thanks to new tools and popularity

Conducting an EPD can be very complex and costly for manufacturers because of the depth of data collection and analysis across the process.

However, as LCA modelling becomes more common, tools are now emerging that reduce the cost burden – such as OneClick LCA.

The key to EPDs and CPDs is industry uptake. EPDs don’t make value judgements on data. But when available across multiple products they allow informed understanding of the environmental impact of a product compared to others.

Product declaration does not mean the product is good

It is important to note that just having a product declaration does not mean the product is the lowest impact of its type.

So far there still just a few material providers that have produced EPDs for their products in the Australian market.

The more EPDs and CPDs there are, the better the data, and the more competitive the marketplace for low emissions building materials becomes.

“If you are measuring what the manufacturer is doing, you are measuring the opportunity for change for that manufacturer as well,” Sullivan says.

And once the material data is available, EPDs can move to fabricators and more developed building products. The data builds upon itself.

As Stephen Mitchell explained:

We’ve got a very firm framework in the EPD system tied to international and best practice standards. You have the raw material suppliers, and all over the world manufacturers are developing EPDs, then you look at the fabricators, and then the next layer on top of that until you get to interior fitout and finished products. So, you can see we are building a whole system to provide embodied carbon data and other environmental data for specifiers to incorporate in decision making.

Global moves are strong – including in the US

In other countries government support has spurred the development of EPDs. In the US, the Inflation Reduction Act dedicated 250 million USD to support manufacturers develop EPDs for their products.

In Europe, Germany recognises EPDs for federal projects and Belgium requires sustainability marketing claims.

With a new global market fast emerging, Australia may miss out on opportunities unless it begins to build EPDs and CPDs into legislative frameworks, and financially support their development.

What is an Input-Output LCA?

An input-output LCA, also known as a top-down LCA, gives decision makers visibility on carbon at the project conception level before any discussion around material use takes place.

Input-output is a value-based methodology that assigns a carbon intensity for every dollar of a given product. Every country has coefficients for various sectors that can be applied to the analysis. The difference here is that these metrics are not product specific, but general across industry.

Caroline Noller, founder and chief executive of the Footprint Company explained that “for buildings, it is super helpful to us to drive a [carbon and cost] budget at the early stage.”

Most embodied carbon reduction is available at the early stages of design, well before quantities are available. Quantification of a whole building or road requires a detailed inventory of materials for process analysis to be possible. This is generally not possible until late in the final design stage. Input-output in early stage design provides critical analytic guidance for recognising carbon reduction opportunities.

Furthermore, as the process market continues to build itself out, there are bound to be gaps in the data.

As Noller points out:

Even when people are doing process based EPDs they are integrating part of this process into that because there is always missing data. It is impossible to get the full chain. So, they are actually doing a hybrid LCA technically.

It’s not about one material over the other, it is about setting targets, which will drive innovation in industry.

Top-down LCAs capture everything from an economic level that EPDs do not capture, so it is a good methodology for helping to understand what is happening in a macro sense.

It has immense potential in the early stages of a project, when evaluating feasibility and benchmarking targets.

As Noller says, “by having the performance target in a number, it allows industry to innovate to the lowest cost pathway.”

This type of data in early stages allows the broadest possible marketplace for competitiveness since every project will involve different processes to achieve lower carbon outcomes.

However, there is some concern over the coefficients used in top down LCAs. According to Nicole Sullivan, “There is some debate about how those economic impacts are allocated. Some people don’t think impacts are being allocated correctly.”

Similar to process based analysis, there is an opportunity for more government support in managing the data for input-output LCAs and ensuring that the best possible data is available to industry.

The hybrid model

There is opportunity to combine these two approaches into a hybrid model, combining the strengths of each respective one and using it where it is best suited. When it comes to setting benchmarks and considering embodied carbon in the business case and at early design stages, input-output LCAs provide the macroeconomic carbon visibility necessary. When it comes to material selection, industry can mobilise EPDs and CPDs to achieve the lowest possible carbon construction pathway.

How the different approaches work together to achieve the best Embodied Carbon outcomes. Diagram: The Footprint Company

According to Caroline Noller, “They are both valid methods, they both have weaknesses, but together they mitigate those weaknesses.”

Industry will continue to progress measurement and benchmarking of embodied carbon. Further government support is critical to accelerate progress. And when it comes to which methodology we should use.

In Sullivan’s words:

If we can get the best of both worlds that’s the best answer, it’s just that we are not there yet but that doesn’t mean we can’t get there. And I think we can.

The important thing now is to accelerate the uptake of measurement in all forms and develop a common understanding of how these various methodologies can be used.

Summing up Noller says: “We need all these systems to come together. We need everyone to come to the table and have some kind of google translate to make sure everyone understands.”

MECLA is there to make this happen.

This is part of a series of articles from MECLA on how it is helping to reduce embodied carbon in the built environment, published with the financial assistance of MECLA and WWF.

This article first appeared in the Fifth Estate. 
Click here to read the original version.