Life Cycle Assessment of Current Portuguese Railway and Future Decarbonization Scenarios

Abstract

Given the current EU decarbonization targets, the railway transport is a key player to boost mobility toward more sustainable transportation, as it is currently the cleanest high-volume mode of locomotion available. However, a study analyzing the life cycle environmental impact of the existing conventional Portuguese railway has never been performed. Aiming to address this research gap, this paper presents an attributional life cycle assessment (LCA) to quantify the environmental impacts of the Portuguese railway infrastructure and rolling stock, using the Douro line case study. Through the LCA methodology, the current setting (using electric and diesel rolling stock) and three scenarios of full-line electrification (considering 2019, 2030, and 2050 electricity mixes) were analyzed for hotspot identification and an outlook on EU-aligned long-term sustainability prospects. In the current scenario, railway operation accounts for 74% of the total carbon footprint, mostly due to the fuel use of diesel trains and the expended electricity of electric train and infrastructure operation. The total electrification of the line and rolling stock can reduce carbon emissions by 38%, 56%, and 63%, if the 2019, 2030, and 2050 electricity mixes are considered, respectively. Further reductions could also be achieved with on-site renewable energy generation and through future low-carbon construction work strategies.

Greenhouse Gas Emissions in Railways: Systematic Review of Research Progress

“…The consumed energy is then related to carbon emission factors, which indicate the amount of carbon dioxide released into the atmosphere per unit of energy consumed. This approach considers the carbon footprint of the entire system and is often used in life cycle analysis studies [19,61].…”

“…Life Cycle Assessment (LCA) in the railway system is a comprehensive approach for evaluating the emission of GHGs throughout all phases of the life cycle of a railway system, from raw material extraction to final disposal. LCA considers the environmental aspects related to material production, construction, operation, maintenance, and eventual disposal of a railway system [19]. LCA is a valuable tool for quantifying and evaluating GHG emissions and other environmental impacts associated with the railway system.…”

“…In this context, railways transportation has the potential to assume a central role in long-term transport sector decarbonization and provide huge opportunities with the modernizing of infrastructure, contributing to the reduction of GHG emissions and the development of more efficient and environmentally responsible transportation systems [19]. The life cycle analysis in the railway context is an approach that enables a complete understanding of the common environmental impact hotspots of railway operations, from the design and construction of infrastructures to the operation and maintenance of railway systems.…”

LCT-Based Framework for the Assessment of Sustainability: From the Perspective of Literature Review

“…Being LCT approaches, LCC, LCA, and SLCA could play a significant role in guiding the selection of environmental, social, and economic indicators. Indeed, LCA, LCC, and SLCA are approaches applied to estimate environmental, economic, and social indicators, respectively (Petit-Boix et al, 2017;Ramos da Silva et al, 2023;Toniolo et al, 2020;Wang et al, 2023). LCA is a practice for the assessment of the environmental impacts of an activity, product, or process.…”

“…The application of LCA for decision-making includes an environmental performance assessment of the entire life cycle from "cradle to grave" (Yahya et al, 2016). This method has been extensively used in the decision-making process and has been utilised to a range of disciplines involving energy, transport, and road infrastructure project (Celauro et al, 2023;Ramos da Silva et al, 2023;Visentin et al, 2020).…”