Understanding Embodied Carbon for Data Centre & Gigafactory Developers

Embodied Carbon - What is it and why is it important?

Following on from our recent article, 'EU Sustainability Legislation Advice for Data Centre Operators | LinkedIn', another important priority for data centre operators and advanced industrial facility developers alike is the topic of 'embodied carbon'.

Embodied carbon relates to the total greenhouse gas (GHG) emissions (often simplified to “carbon”) generated to produce a built asset. This includes emissions caused by extraction, manufacture/processing, transportation and assembly of every product and element in an asset. In some cases, (depending on the boundary of an assessment), it may also include the maintenance, replacement, deconstruction, disposal and end-of-life aspects of the materials and systems that make up the asset. It excludes operational emissions of the asset (I.e. The use of electrical energy and water in the day to day running of a data center)

Sustainability assessment schemes are currently one of the main drivers for measuring the embodied carbon of a built asset. I.e. BREEEAM Mat01, Mat02 and Mat04 (relating to life cycle impacts, hard landscaping, boundary protection and insulation respectively) plus bonus credits for the use of products with EPDs (Environmental Product Declaration) and the use of whole building LCA (Life Cycle Assessment) software tools.

Another assessment scheme includes LEED; which includes MR credits for 'Building Life-Cycle Impact Reduction' and 'Building Product Disclosure and Optimization—Environmental Product Declarations', in addition to the requirement for a building level LCA demonstrating a minimum 10% reduction in impact, compared with a national baseline building.

Likewise, projections by Architecture 2030 illustrate that embodied carbon emissions are almost half the total impact for a new construction scenario compared to the operational carbon emissions of the building over its projected service life.

Legislative drivers

The Energy Performance of Buildings Directive (EPBD) is the single most important legislation targeting the building sector at EU level. It requires Member States to set energy performance levels for their buildings, strategically plan the decarbonisation of building stock through long-term renovation strategies and implement additional measures.

The EU Commission has adopted a legislative proposal to revise the EPBD, with a proposal for all new buildings in the EU to be zero-emission buildings as of 2030, while all new public buildings must be zero-emission as of 2027.

A welcome aspect of the EPBD recast is that it mandates the assessment and reporting of embodied carbon in new buildings and whole life greenhouse gas emissions (that is, both embodied and operational emissions). It also sets out requirements to calculate and establish targets to reduce building related emissions throughout the building’s life-cycle. Member States are obligated to ensure that new buildings achieve zero-emission status by January 1, 2030, for all new buildings.

The Corporate Sustainability Reporting Directive (CSRD) is directly coupled with associated 'European Sustainability Reporting Standards (ESRS)'. Together they dictate detailed sustainability reporting requirements. Most data center owners and operators, colocation tenants and cloud users will need to report climate-related financial risks, including their Scope 1, 2 and 3 carbon footprint and energy use, under the EU’s CSRD. The embodied carbon of built assets is included within Scope 3 emissions, reported as 'Purchased Goods and Services' or 'Capital Goods' and 'Upstream and Downstream transportation'.

Finally, there are several well-established international standards available to guide LCA methodology for embodied carbon in buildings. Namely, ISO 14040:2006, ISO 14044:2006, ISO 21929-1:2011 and ISO 21931-1:2022. The British Standard BS EN 15978:2011 also sets out the overall principles of embodied and whole life carbon measurement in the built environment.

Credit: GHG Protocol Scope 3 Standard - Overview of the GHG Protocol scopes and emissions across the value chain

Embodied Carbon Strategies for Lower Carbon Buildings

There are several ways to reduce a building's embodied carbon, namely through 'building reuse', 'material efficiency' and 'lower carbon products'. Where building reuse effectively reduces the new for new materials, plus minimises construction waste streams. Material efficiency relates to limiting the number of products used in construction, by way of advanced framing techniques, consolidated distribution systems (i.e. hot water systems and insulation), and minimalistic design decisions (i.e. polished concrete floors).

Credit: NBI's Embodied Carbon Building Code

Life cycle stages and assessment scope

A typical project life cycle can be split into stages and modules as defined by BS EN 15978. This standard specifies the calculation method, based on LCA to assess the environmental performance of a building.

The four primary stages include 'Product (Raw material, transport, manufacturing)', 'Construction (Incl. construction installation process)', 'Use (Incl. repair, refurbishment, replacement)' and 'End of Life (Reuse, recovery, recycling)'.

Therefore, any assessments related to embodied carbon should clearly outline what is included in the respective measurement. For example, the assessment scope may be defined as:

A project level, e.g. new construction or fit-out;

An asset level;
An activity level, e.g. solely the structure of a single asset or across a portfolio

A best practice approach is to consider 'whole life embodied carbon' from 'cradle-to-cradle'.

Credit: UK Green Building Council - Embodied Carbon; Developing a Client Brief

Assumptions and certainty

Embodied carbon assessments are estimates unless the calculation is performed on an as-built asset with a complete embodied carbon data set and only measuring up to the point of handover. Consequently, the level of uncertainty in an assessment depends on where the project is in the life cycle and how far into the future the calculation is taken. An awareness that these assumptions have been used is valuable in understanding the final result of an embodied carbon assessment.

To address EPD data quality uncertainty, it is important to present not just a single embodied GWP number, but also a range of the potential GWP values. This methodology is preferable to putting one’s trust in a single, potentially underestimated carbon value.

During the early design stages, it is best to use generic data to represent products and materials. As the design progresses, the aim is to use data that most accurately represents the products and materials being used in the asset. At later design stages, this is ideally a specific EPD from the manufacturer for the product being used. However, if this is not available, representative generic data or sometimes even a proxy EPD may have to be used, with varying uncertainty in terms of the representativeness of the data.

During the detailed design, construction and post-completion phases, these uncertainties around the data used are managed using carbon data confidence scores - which can be translated into a carbon data uncertainty factor.

Credit: Brightworks Sustainability / WAP Sustainability Consulting - Sector Supplement for Measuring & Accounting for Embodied Emissions in the Built Environment

Obtaining data for embodied carbon calculations

The foundation for any calculation relating to embodied carbon is a database containing CO2 emissions data for all components that have an input in your facility. I.e. Into building a data centre or any advanced facility.

One of the relevant data sources for whole-life carbon measurement is Environmental Product Declarations (EPDs), or Product Environmental Profiles (PEPs) which provide an overview of the lifecycle environmental impacts of construction products.

When this certificate is not available, other third party verified information can be used such as UK CIBSE TM65 or equivalent.

Examples of potential EPD sources include the BECD, the ICE database, and the Impact database, plus those illustrated below.

Life Cycle Assessment Tools

Various tools are available including The Embodied Carbon in Construction Calculator (EC3) tool and CIBSE's TM65 tool which can be implemented in both the design and procurement phases of a construction project to look at a project’s overall embodied carbon emissions, enabling the specification and procurement of the low carbon options. Various consultancies have also developed their own sector specific tools. For example, RED Engineering Design is strongly promoting an embodied carbon per MW IT approach as a single number for comparing the carbon efficiency of different designs.

Getting results

Embodied carbon calculations need conversion factors to convert quantities of materials into embodied carbon figures.

E.g. Material Quantity (kg) x carbon factor (kgCO2e/kg) = embodied carbon (kgCO2e)

An example calculation for a simple building structure would include inputs such as quantities for the foundations and floor slab (including their components, i.e. rebar / footings), in addition to the building frame and roof slab. The inputs would then be multiplied by the relevant carbon factors according to the life cycle stage(s) they occur. General site activities and end-of-life stage emissions would also be calculated.

An overall carbon footprint would be expressed based on the given area (m3) - Taking into account the extraction-production-construction stages (A1-A5), with separate figures factoring in biogenic sequestration, whole life carbon (A1-C4+sequestration) and finally reuse, recovery and recycling stages (D)

The results can then be represented graphically on a structural or even component level. Comparisons can also be made between carbon sources, differing projects / locations etc., with a focus on identifying carbon hotspots upon which carbon reduction initiatives can be focussed.

We hope you found this article useful!

If you are looking for professional sustainability support relating to your next industrial mega-facility design & build project...please reach out to us!

Contact — Biyat Energy & Environment Ltd (biyatenergyenvironment.com )

This article was written by Luay Zayed, Founder' of Biyat Energy & Environment Ltd. A global energy and environmental consultancy specializing in turnkey engineering solutions that protect the environment and improve energy efficiency in the manufacturing & industrial sectors.