Energy use and greenhouse gas emissions during the Life Cycle stages of a road tunnel - the Swedish case norra länken

Abstract

Inclusion of Life Cycle Assessment during the planning of transport infrastructure is rarely used in practice, but is becoming a widely discussed issue nowadays. This study sought to improve understanding of the life cycle energy use and greenhouse gas emissions of transport infrastructure, using the example of a road tunnel. Two levels of analysis were used: 1) detailed data inventory for the construction of rock tunnels; and 2) screening assessment for the life cycle phases of the whole tunnel infrastructure (including its main parts: concrete and rock tunnels). The first level of analysis showed that production of materials (i.e. concrete and asphalt) made the largest contribution to Cumulative Energy Demand and Global Warming Potential. The second level of analysis indicated that concrete tunnels had much higher Cumulative Energy Demand and Global Warming Potential per lane-metre than rock tunnels. Moreover, the operational phase of the tunnel was found to have the highest share of energy use and greenhouse gas emissions throughout the tunnel's life cycle.