Introduction: A Chain Nobody Joins Up
The electricity contract behind an electric-arc-furnace steel mill quietly shapes the steel’s EPD, the building’s embodied carbon, and ultimately its BREEAM or LEED score. Four links most people treat in isolation.
Ask a procurement manager what a steel mill’s power purchase agreement has to do with a building’s sustainability rating, and you will usually get a blank look. Yet the two are directly connected. This article traces the chain — and shows why a decision made at the mill ends up on the building’s certificate.
The Four Links
1. The grid mix (or the PPA)
Electric-arc-furnace (EAF) steelmaking is electricity-intensive. The carbon intensity of that electricity — a coal-heavy grid versus a renewable power purchase agreement — varies enormously by country and contract.
2. The steel’s EPD
In an EN 15804 EPD, the electricity emission factor flows straight into the product’s A1–A3 global warming potential. The same EAF billet can carry a markedly different GWP depending purely on how its electricity was sourced. (Notably, CBAM ignores these indirect emissions for steel — but the EPD does not, which is exactly why the two numbers diverge.)
3. The building’s embodied carbon
Designers add up the EPDs of the materials to calculate the building’s embodied carbon. Steel is often a major contributor, so its EPD figure moves the whole-building number.
4. The rating
That embodied-carbon figure feeds BREEAM, LEED and EPBD whole-life-carbon assessments. A lower-carbon steel, backed by clean electricity and a credible EPD, can lift credits the project would otherwise miss.
The Insight
A power-sourcing decision at the mill propagates all the way to the building certificate. Specify steel from a producer running on low-carbon electricity, with a verified EPD that shows it, and you improve the building’s rating without changing the design. Ignore the link, and you may pay for a higher embodied-carbon number you never had to accept.
It also explains a common confusion: a steel’s CBAM figure and its EPD GWP can differ sharply, because CBAM (for steel) counts only direct emissions while the EPD counts the electricity too. Same product, two numbers, two purposes — we unpack that in EPD and CBAM.
What to Do
- Ask suppliers for an EN 15804 EPD with the +A2 GWP breakdown, and for the electricity basis behind it.
- Favour EAF/scrap steel backed by clean power where embodied carbon or a green rating matters.
- Use the EPD in your whole-life-carbon model, not a generic industry default.
How EPD Polska / Multicert Can Help
We prepare and verify EPDs that make the electricity story transparent, and help specifiers use them correctly in embodied-carbon and rating calculations. Contact us to connect the chain.
FAQ
Does cleaner mill electricity really change a building’s rating?
Indirectly but materially: it lowers the steel’s EPD GWP, which lowers the building’s embodied carbon, which feeds BREEAM/LEED/EPBD. For steel-heavy structures the effect is significant.
Why does CBAM ignore the electricity if the EPD counts it?
For iron and steel, CBAM counts only direct emissions; indirect (electricity) emissions are out of scope. The EPD, by contrast, includes them — so the two figures are not the same.