A life cycle model for high-speed rail infrastructure: environmental inventories and assessment of the Tours-Bordeaux railway in France

TL;DR

This study develops a comprehensive life cycle assessment model for high-speed rail infrastructure, quantifying environmental impacts across stages and components, with a focus on the Tours-Bordeaux railway in France.

Contribution

It introduces a detailed process-based LCA framework for HSR infrastructure, incorporating diverse environmental indicators and specific data collection methods.

Findings

Rails, roadbed, and civil structures are major impact contributors.

Recycling at end-of-life reduces overall environmental impacts.

Steel production is the dominant process affecting environmental outcomes.

Abstract

Method: a process-based LCA compliant with ISO 14040 and 14044 is performed. Construction stage LCIs rely on data collection conducted with the concessionaire of the HSR line combined with EcoInvent 3.1 inventories. Use and End-of-Life stages LCIs rest on expert feedback scenarios and field data. A set of 13 midpoint indicators is proposed to capture the diversity of the environmental damage: climate change, consumptions of primary energy and non-renewable resources, human toxicity and ecotoxicities, eutrophication, acidification, radioactive and bulk wastes, stratospheric ozone depletion and summer smog. Results: The study shows major contributions to environmental impact from rails (10-71%), roadbed (3-48%), and civil engineering structures (4-28%). More limited impact is noted from ballast (1-22%), building machines (0-17%), sleepers (4-11%), and power supply system (2-12%). The two last components, chairs and fasteners, have negligible impact (max. 1% and 3% of total contributions, respectively). Direct transportation can contribute up to 18% of total impact. The production and maintenance stages contribute roughly equally to environmental deterioration (resp. average of 62% and 59%). Because the End-of-Life (EoL) mainly includes recycling with environmental credit accounted for in our 100:100 approach, this stage has globally a positive impact (-9 to -98%) on all the impact categories except terrestrial ecotoxicity (58%), radioactive waste (11%) and ozone depletion (8%). Contribution analyses show that if concrete production is one of the important contributing process over the construction stage, primary steel production is unquestionably the most important process on all the impact categories over the entire life cycle.