Quantifying energy demand and greenhouse gas emissions of road infrastructure projects: An LCA case study of the Oslo fjord crossing in Norway

The road sector consumes large amounts of materials and energy and produces large quantities of greenhouse gas emissions, which can be reduced with correct information in the early planning stages of road project. An important aspect in the early planning stages is the choice between alternative road corridors that will determine the route distance and the subsequent need for different road infrastructure elements, such as bridges and tunnels. Together, these factors may heavily influence the life cycle environmental impacts of the road project. This paper presents a case study for two prospective road corridor alternatives for the Oslo fjord crossing in Norway and utilizes in a streamlined model based on life cycle assessment principles to quantify cumulative energy demand and greenhouse gas emissions for each route. This technique can be used to determine potential environmental impacts of road projects by overcoming several challenges in the early planning stages, such as the limited availability of detailed life cycle inventory data on the consumption of material and energy inputs, large uncertainty in the design and demand for road infrastructure elements, as well as in future traffic and future vehicle technologies. The results show the importance of assessing different life cycle activities, input materials, fuels and the critical components of such a system. For the Oslo fjord case, traffic during operation contributes about 94 % and 89 % of the annual CED and about 98 % and 92 % of the annual GHG emissions, for a tunnel and a bridge fjord crossing alternative respectively.