Environmental assessment through LCA of Wavebreaker’s noise cancelling technology -Potential environmental benefits and drawbacks

Abstract

Wavebreaker AB wanted to evaluate their new noise mitigation product for railway infrastructure from an environmental perspective. An environmental performance comparison through a Life Cycle Analysis (LCA) in OpenLCA with an attributional approach of the product in two use cases was chosen. Based on one Swedish wooden absorptive noise barrier system (Bsk-14F) and a representative conventional reflective reinforced concrete noise barrier (CNB), one worst case, one base case and one best case of soil conditions for the Norwegian concrete foundations Mofix was chosen to provide an adequate spread of possible use cases seen on the European market. This combination was chosen in an attempt to help future stakeholders assess what environmental performance benefits and drawbacks the choice of implementing Wavebreaker’s noise mitigation system over installing higher noise barriers could potentially entail. The comparison was performed between a lower wooden noise barrier utilizing Wavebreaker’s new product against a higher wooden noise barrier from the same material, designed for an insertion loss of 19dB, and then repeated for a noise barrier made from reinforced concrete. In order to assess the foundation requirements contribution, a simple variation analysis of the impact of soil conditions was also performed on both comparisons. The Life Cycle Inventory Analysis results for the wooden use case indicated an overall improvement in Wavebreaker’s favour of 17%, and an overall improvement in Wavebreaker’s favour of 14% for the reinforced concrete alternative (in normal soil conditions) in 17 out of the 18 impact categories covered in this LCA. This in comparison to the 20-25% material reduction by lowering the height of the wall 0,7-1 m. The only drawback that was identified, was that both material alternatives proved to perform between 2-10% worse in the fossil fuel scarcity impact category, when implementing Wavebreaker’s noise mitigation system over installing higher noise barriers (depending on material choice and soil conditions). One of the largest contributing factors to this result was identified as the high amount of virgin HD-PE plastics, required to produce the Wavebreaker product, and by doing a breakeven point analysis a reduction of HD-PE production of approximately 20% was deemed adequate to assure a performance better or equal to the higher barrier alternative for both materials in a majority of soil conditions.