The Cost of Mitigating Climate Change by Building with Renewable Materials

Abstract

While the reduction of operational greenhouse gas emissions is prioritized for the existing building stock, embodied emissions dominate the environmental impact of newly constructed buildings that fulfil zero emission standards. One option to reduce embodied emissions is the use of biogenic materials in construction. However, this usually requires an increase in investment costs. This contribution explores the costs of avoided and temporarily saved greenhouse gas emissions in buildings if non-renewable materials are substituted with biogenic materials. To investigate this question, we use life cycle assessment and life cycle costing, aligning the economic and ecological perspectives. We consider material options of different building parts, exterior walls, and slabs. We use the construction element with the lowest cost as a baseline and determine emission savings of different material choices and related costs. This reveals how changing material choices, e.g., from a concrete core to a wooden core, can cause high prevention costs of more than ten times the current values for emissions certificates, if a short time horizon is considered. In a life-cycle perspective, prevention costs can be even higher, depending on the carbon accounting method used. However, replacing cheaper, short lasting, higher-emitting materials with more expensive, long-lasting materials, with lower emissions, is a win-win option if the whole life cycle is considered. We conclude that construction based on reinforced concrete and other non-renewable materials bears a great risk of carbon lock-in if carbon taxes and emissions trading remain the main legislation to prevent greenhouse gas emissions. The study shows that there are currently only very limited economic incentives to avoid and temporarily store embodied greenhouse gas emissions by using biogenic materials instead of non-renewable materials in buildings, and that new policies need to be developed to unlock this potential.