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Welcome to Episode 4 of Sustainable Infrastructure, the ORIS podcast where engineers, policymakers, and construction leaders share how the world can build infrastructure fit for the environmental and social challenges of the 21st century.
Our guest is Andreas Linnet, Senior Chief Consultant and Global Decarbonization Lead for Infrastructure at Ramboll. With over a decade of experience in the transport sector, he leads global decarbonisation initiatives across Ramboll's infrastructure division, develops carbon management tools and frameworks, and represents Ramboll in FIDIC's Carbon Collaboration Initiative. He holds a specialisation in lifecycle assessment and has spent his career turning carbon quantification into a standard part of how engineers design and deliver infrastructure projects.
Andreas didn't plan to become a decarbonization lead. A lifecycle assessment course at university clicked with how he already thought: don't solve the problem in front of you while creating a new one further down the chain. That principle, and an early stint trying to understand whether electric vehicles were genuinely better across their full life cycle, gave him the intellectual scaffolding he'd spend the next decade applying to roads, bridges, and rail.
When he joined Ramboll as a junior engineer, LCA wasn't part of any project brief. So he did what motivated people in large organisations typically do: found others who cared, formed an informal group, and quietly started embedding carbon quantification wherever they could. The goal was to have an impact: more information makes better decisions.
For most public infrastructure clients, success still means on time and under budget. Andreas sees this as the structural barrier holding back the whole industry. When Ramboll reviewed highway bridge designs for the Danish Road Directorate, they found significant optimisation potential, not because engineers had made poor decisions, but because no one had been asked to consider carbon efficiency. There was no mandate, no KPI, no budget for the question.
His argument: asset owners don't need to add complexity. They need to add one more dimension to the metrics they already manage. A carbon budget alongside a financial budget changes what teams prioritise before the design is locked — which is the only stage where change is still cheap.
The clearest example of how quickly culture changes when requirements arrive: the Danish Metro set a 50% reduction target on embodied carbon (A1–A5) relative to a comparable previous project. Overnight, carbon quantification stopped being the sustainability team's side project and became a core engineering constraint. Project managers tracked it. Design teams worked on it. The sustainability lead no longer had to argue for time in the schedule. The mechanism is simple: mandatory requirements create aligned organisations.
Andreas is unusually direct on this: sustainability managers can't build decarbonised infrastructure. Designers can. Which means the tools for carbon comparison have to live where designers already work: inside Civil 3D, inside BIM workflows, at the moment of decision rather than in a separate reporting platform consulted after the fact. Carbon impact needs to be visible in real time, which changes what engineers propose rather than just what they report.
Andreas is part of FIDIC's Carbon Collaboration Initiative, pushing for a harmonised framework (FIDIC's Carbon Management Framework) that spans national standards. His view on fragmentation is pragmatic: it was a problem when they started, but it also justified building their own methodology. Now the challenge is to make that methodology interoperable and to make collective knowledge from thousands of projects available as a starting point rather than a retrospective report. The experience-based database he envisions is simple in principle: engineers in Denmark and Singapore should both start from a calibrated, regionally appropriate baseline — not a theoretical calculation.
For any organisation beginning its carbon maturity journey, Andreas' advice is to stop waiting for perfect data and start quantifying. Find out where carbon is embodied. Ask whether the design is over-engineered for outdated safety requirements. Use substitute materials where the data supports it. Build from there.