1 Introduction and literature review

Morocco, strategically situated at the intersection of Europe, Africa, and the Middle East, has showcased a commendable commitment to integrating energy-efficient and environmentally friendly solutions within its transportation sector. As a pivotal member of the Middle East and North Africa (MENA) region, Morocco acknowledges the indispensable role of sustainable transportation in fostering economic growth and environmental conservation. This understanding has been translated into several strategic plans and initiatives aimed at bolstering energy efficiency and mitigating carbon emissions in the transport domain.

A noteworthy initiative is the Nationally Determined Contribution (NDC), highlighting Morocco’s pledge to reduce greenhouse gas emissions by 42% by 2030. The bicarbonate strategy further encourages the adoption of clean energy sources such as hydrogen and electricity, particularly in the transportation sector, a critical step given that transport accounted for 39% of global CO2 emissions from final use in 2022 [1].

The aftermath of the COVID-19 pandemic witnessed a resurgence in transportation demand and consequent emissions, predominantly in developing and emerging economies [1, 2]. To realign with the Net Zero Scenario [3], it is imperative to introduce and enforce policies that champion energy-efficient trains and incorporate energy efficiency measures across all transport modes [4]. Public transportation, especially trains, plays a pivotal role in alleviating traffic congestion and its associated externalities. However, it also contributes to air pollution, with subsequent health implications [5, 6].

In the Moroccan scenario, trains are an indispensable part of the transportation matrix, with their demand projected to escalate. This burgeoning demand, juxtaposed with the health hazards of air pollution, accentuates the urgency for research on energy-efficient trains. Morocco’s Ministry of Energy has delineated several strategies to augment energy efficiency in the railway sector [7], which necessitates a thorough evaluation through a life-cycle lens, spanning from fuel extraction to end-use.

Several global studies have shifted their focus to the environmental footprints associated with fuel extraction, refining, and vehicle utilization, leveraging Life Cycle Assessment (LCA) frameworks. Horvath [8] utilized LCA, Economic Input–Output Life Cycle Assessment (EIO-LCA), and Economic Input–Output General Model (EIGM) tools in his transportation analysis. Concurrently, the European High-Speed Train Network study employed logit-based statistical models and cost estimation tools for a strategic environmental assessment [9]. Haseli et al. [10] embarked on a comparative analysis of greenhouse gas mitigation across different train types. A notable study on the California High-Speed Rail (CAHSR) system offered insights into life-cycle energy consumption and emissions across diverse transportation modes using SimaPro and EIO-LCA [11]. Furthermore, a machine learning model was proposed to assess the environmental impacts of embodied carbon in building life cycles, with a case study focusing on Morocco [12]. El Hafdaoui et al. [13] emphasized the potential benefits of transitioning to electric and fuel-cell vehicles in the Maghreb region, which includes Morocco, highlighting energy efficiency and reduced environmental impact. In line with this, a comprehensive model for the social assessment of alternative fuel vehicles, including hybrid-electric, battery-electric, and fuel-cell vehicles, was introduced, emphasizing the importance of prioritizing battery-electric vehicles in Morocco due to their superior environmental impact and social assessment scores [14]. This model underscored the challenges and requirements associated with each vehicle type, emphasizing the need for infrastructure improvements and policy adjustments. Finally, an energy efficiency review in the railway sector examined the impact of various electrification solutions and management techniques on efficiency [15].

In the context of energy and emissions analysis, three critical terms are often used: Well-to-Pump (WTP), Pump-to-Wheels (PTW), and Well-to-Wheels (WTW). The WTP phase refers to the energy used and emissions produced from the extraction of raw materials up to the point where the fuel is ready for distribution. PTW encompasses the energy and emissions from the distribution of the fuel to its actual use in the vehicle. WTW is a comprehensive term that combines both WTP and PTW, providing a holistic view of the energy consumption and emissions from raw material extraction to the actual vehicle operation. These terms are crucial for understanding the complete environmental impact of transportation systems, as they capture different stages of energy use and emissions.

Comprehensive assessments of national railway systems, especially in terms of energy efficiency, are relatively scarce. For countries like Morocco, which utilize both electric and diesel trains, this paucity of assessments leaves a considerable knowledge gap. This study provides a unique contribution to this under-researched area, offering a national perspective on the effectiveness of energy-efficient trains in the specific context of Morocco.

The purpose of this paper is to conduct an energy and environmental assessment of trains in Morocco from a WTW standpoint, on a national scale. This is the first such research in the MENA region focusing on trains’ energy efficiency and environmental impact. The assessment will consider various aspects of the trains’ operation, including fuel consumption, emissions, and overall environmental performance. By evaluating the existing trains’ energy efficiency and identifying potential areas for improvement, this study aims to provide valuable insights for policymakers and stakeholders in the Moroccan railway sector.

2 Materials and methods

2.1 Objectives and scope

This research aims to augment the existing literature by scrutinizing the energy and environmental impacts of two primary types of trains—electric and diesel—throughout their entire lifecycles, within the Moroccan context. Given the current train routes and fleets in Morocco, this is carried out with the objective of identifying the most eco-friendly and energy-efficient solution for the nation’s railway transportation.

In performing a comprehensive Life Cycle Assessment (LCA) of the existing train alternatives, this study seeks to address a gap in the present body of research. The focus extends beyond a narrow city-level analysis and embraces a broader national evaluation that emphasizes full fuel cycles. The information presented in this paper can potentially aid Moroccan authorities in enhancing their rail transit systems.

Insights gleaned from this study in the Moroccan context may be extrapolated to other global contexts where similar types of trains are prevalent. Furthermore, a nationwide examination of the environmental implications of retaining or transitioning between diesel and electric train fleets has been carried out. Data utilized for this analysis have been collected from “L’Office National des Chemins de Fer (ONCF)”— Morocco’s national railway operator. Hence reflecting the practical conditions under which these systems function.

2.2 Inventory data

The data utilized in this study were collated from an array of distinct sources. This encompasses (1) the Ecoinvent database version 3.9 featured in the OPENLCA software (Version 1.11) generated by GreenDelta, (2) the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model (2023) developed by Argonne National Laboratory, (3) the International Energy Agency, and (4) several stakeholders in Morocco.

The collected data includes geographical information, energy profile specifics, and details regarding train routes and fleets. International impact assessment metrics, imported from the Ecoinvent Centre, will be expanded upon in the Environmental Impact Assessment section of the study.

It is noteworthy to mention that this analysis employs a combination of well-documented data from official databases and unique data gathered from a wide variety of stakeholders in Morocco’s rail industry. This blend of data aims to present a comprehensive and realistic overview of the environmental impacts of different types of train services in Morocco.

2.2.1 Geographical data

The Moroccan railway network encompasses a main passenger transport network that includes a North–South link from Tangier, passing through Rabat and Casablanca, and extending to Marrakech. Additionally, there is an East–West connection that connects Oujda in the East to Rabat via Fes. The North–South and East–West links intersect at Sidi-Kacem, forming crucial connections within the network. Figure 1 provides a visual representation of the Moroccan railway network as of 2018, as well as the planned railway infrastructure.

Fig. 1
figure 1

Morocco’s railmap: past, present, and future [16]

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Morocco’s railway system spans a total length of approximately 2200 km (1400 miles) and operates on a standard gauge of 1,435 mm (4 ft 8 + 1⁄2 in). The main network is electrified with a voltage of 3000 V DC, while the high-speed line operates on 25 kV 50 Hz electrification.

The statistical overview of the Moroccan railway system includes the following data:

  • Ridership: The system serves around 38 million passengers per year.

  • Freight: The railway handles approximately 36 million tons of freight per year.

2.2.2 Energy profile information

The focus of this study is to assess the energy efficiency and environmental impact of trains in Morocco. Specifically, the analysis considers the performance of electric trains and diesel trains, taking into account their respective energy sources and associated emissions. The electricity generation mix, which is crucial for determining the energy profile of electric trains in terms of their charging source, is depicted in Fig. 2. For a more detailed understanding of the evaluation of electric trains, the analysis also considers the electricity generation scenario projected for Morocco in 2030. This scenario is further outlined in Fig. 3, which has been published by national authorities in their National Low Carbon Strategy of 2050 [7] and the International Energy Agency [17].

Fig. 2
figure 2

Moroccan electricity generation composition

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Fig. 3
figure 3

Moroccan energy profile and pathways [18]

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On the other hand, diesel trains are powered by diesel fuel. The energy consumption and associated emissions of diesel trains are considered in accordance with their conventional diesel propulsion. To conduct the LCA analysis, the GREET (Greenhouse gases, Regulated Emissions, and Energy use in Transportation) model is utilized. This model incorporates the energy profiles of both electric and diesel trains and allows for a comprehensive assessment of their respective energy consumption and emissions.

To illustrate the energy pathways and emissions associated with electric and diesel trains, Fig. 3a and b are utilized. Figure 3a represents the current and prospective energy pathways of diesel trains, including processes such as fuel storage, transport, dispensing, and refueling station operations. Energy losses during these processes, as well as vehicle emissions, are accounted for in the analysis. Figure 3b illustrates the power plant infrastructure and energy sources that contribute to the electricity generation for charging electric trains.

The figure provides insights into the current power plant mix, including renewable energy sources such as hydropower, photovoltaic, thermal, and wind power. The efficiency and emissions data of the power plants are incorporated into the analysis, considering both renewable and fossil fuel-based sources.

These figures, along with the underlying assumptions, help to capture the energy profiles and associated emissions of electric and diesel trains. By considering the specific energy sources and their corresponding efficiency and emissions data, a comprehensive assessment of the energy efficiency and environmental impact of trains in Morocco can be conducted.

2.2.3 Train routes and fleets

In our study focusing on trains in Morocco, we have collected data related to train routes, fleets, and their characteristics. The data include information on the type of train, first station, final station, distance traveled (in kilometers), and various attributes of the train fleets.

Table 1 presents detailed information about the train fleets, including series, model numbers, fuel types, applications, fleet quantities, continuous power output, and top speeds.

Table 1 Train fleet characteristics
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To further understand the operation and utilization of the trains, we have collected data on the number of train fleets for both weekdays (Table 2) and Sundays/holidays (Table 3). These tables offer a breakdown of the train fleets according to different days of the week, enabling us to assess the variations in fleet usage and demand.

Table 2 Weekday train fleet distribution
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Table 3 Sunday and holiday train fleet distribution
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The collected data allows us to analyze the energy efficiency and environmental impact of trains based on their specific characteristics and utilization patterns. By considering the distances traveled, fleet quantities, and other relevant factors, we can assess the energy consumption and emissions associated with train operations in Morocco.

2.3 Impact assessment

The environmental appraisal leverages the Egalitarian Eco-indicator 99 methodology. This approach is primed to address critical aspects of human health and environmental quality, with a particular emphasis on climate change, and respiratory effects, as well as acidification and eutrophication. The relative impact of various air pollutant emissions is delineated in Table 4. Each point (Pt) symbolizes the environmental load, and this score is represented as a weighted aggregation of diverse air pollution emissions.

Table 4 Egalitarian weight distribution for eco-indicator 99
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Eco-indicator 99 integrates a pragmatic approach to assessing environmental impacts with comprehensive life cycle analysis. It offers a quantitative measure that captures a range of environmental consequences, and effectively communicates the aggregated score, thereby fostering a holistic perspective of environmental footprints within a life cycle framework.

3 Results and analysis

3.1 Energy consumption

The Total Energy Use figures presented in Fig. 4 represent the actual energy consumption of the three different types of trains currently operating in Morocco: goods transport, passenger transport, and combined goods-passenger transport. It’s noteworthy that these trains largely rely on electricity as their primary source of power. This consumption is reflected across the stages of WTP, PTW, and WTW. The alternative energy sources—fossil fuels, coal, natural gas, and petroleum—are hypothetical scenarios derived from GREET simulations. These alternatives represent potential shifts in energy sourcing that could be pursued. However, each presents unique implications regarding energy efficiency, infrastructure requirements, and environmental impacts that need to be carefully considered in the context of Morocco’s specific energy landscape and sustainability goals.

Fig. 4
figure 4

Energy consumption per train category in Morocco

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Total Energy Use vs. Coal: Coal also shows potential as an alternative energy source. For goods-only trains, coal could provide 1461 MJ of energy, or approximately 26% of the total energy used. For passenger-only trains, the figure is 2921 MJ, representing 47% of the total energy used. And for mixed-use trains, coal could provide 575 MJ, amounting to 66% of the total energy used. This suggests that coal has the potential to meet a significant proportion of the total energy needs of trains, especially for mixed-use trains. However, it’s crucial to consider that coal is a significant contributor to greenhouse gas emissions and other environmental pollutants.

Total Energy Use vs. Natural Gas: As for natural gas, the energy potential is lower than that of coal. For goods-only trains, it could provide 606 MJ, which is approximately 11% of the total energy used. For passenger-only trains, the energy potential from natural gas is 680 MJ, amounting to roughly 11% of the total energy used. For mixed-use trains, natural gas could provide 97 MJ, representing 11% of the total energy used.

Total Energy Use vs. Petroleum: The last alternative fuel in the dataset, petroleum, could provide 3431 MJ for goods-only trains, representing approximately 60% of the total energy used. For passenger-only trains, petroleum could provide 2256 MJ, accounting for about 36% of the total energy used. For mixed-use trains, petroleum could provide 126 MJ, amounting to approximately 14% of the total energy used. From this analysis, it is clear that no single alternative fuel type would be able to fully meet the total energy needs of the trains based on the current usage data. A mix of these fuels would likely be needed to meet energy requirements. However, it is crucial to consider that each of these fuel types has environmental implications and infrastructural needs that need to be factored into any decisions on potential transitions.

Total Energy Use vs. Fossil Fuels: Fossil fuels, in a broad sense, encompass a range of non-renewable energy sources, including coal, coal products, natural gas, derived gas, crude oil, petroleum products, and non-renewable wastes. However, for the purpose of this analysis, when we refer to “fossil fuels,” we are specifically considering those not detailed elsewhere in this section, thereby excluding coal, natural gas, and petroleum. Given this narrowed definition, these specific fossil fuels still present a considerable energy potential. Trains transporting goods could, in theory, be powered by these specific fossil fuels to achieve an energy potential of 5499 MJ, in contrast to their present energy consumption of 5702 MJ. For passenger trains, this specific fossil fuel energy potential stands at 5855 MJ, compared to their actual energy consumption of 6240 MJ. Mixed-use trains exhibit a diminished fossil fuel potential of 798 MJ when set against their total energy use of 872 MJ. From this comparative analysis, it emerges that if trains were to rely exclusively on these specific fossil fuels for their energy needs, they could potentially satisfy about 96% of the energy demand for goods-only trains, 94% for passenger-only trains, and 91% for mixed-use trains. Conversely, a transition towards such an energy paradigm would heighten the dependence on these non-renewable sources. This could lead to a rise in greenhouse gas emissions and other environmental contaminants, intensifying challenges related to climate change and deteriorating air quality.

3.2 Greenhouse gas emissions

Greenhouse gases, principally comprised of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), are crucial indicators of the environmental footprint of the transportation sector. Figure 5 illustrates the GHG emissions from the different types of train services in Morocco, across the fuel life cycle—from WTP, PTW, and WTW.

Fig. 5
figure 5

GHG emissions of different train categories in Morocco

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In the WTP stage, it is evident that trains carrying passengers only yield the highest GHG emissions (265.5 tonnes of CO2e) compared to those carrying goods only (185.7 tonnes of CO2e) and those carrying both (74 tonnes CO2e). This discrepancy could be attributed to various factors, such as the energy sources employed, the fuel efficiency of the train models, and the train operational characteristics specific to passenger transportation.

Conversely, the PTW stage portrays a different scenario. Trains carrying goods exclusively produce considerably lower GHG emissions (22 tonnes of CO2e) than passenger-only services (115.5 tonnes of CO2e). The absence of emissions for the mixed service trains during this stage might be attributed to different operating conditions or data limitations, necessitating further investigation.

The comprehensive WTW analysis reveals that passenger-only trains have the highest GHG emissions (514.4 tonnes of CO2e). Conversely, mixed-service trains demonstrate the lowest emissions (74 tonnes of CO2e), positioning them as a more environmentally friendly option when considering GHG emissions alone.

However, it’s critical to remember that these figures offer just a glimpse into the environmental impact of these train services. Other factors, including energy use and air pollutant emissions, as explored earlier, along with broader considerations such as geographical context, operational characteristics, and passenger or goods volume, should be incorporated into a more holistic assessment. The ultimate aim is to leverage such data in crafting effective strategies for the transition toward more sustainable and less carbon-intensive transportation alternatives.

3.3 Air pollutant emissions

Figure 6 demonstrates a breakdown of the air pollutant emissions attributed to the three types of train services in Morocco. These pollutants, which include Carbon Monoxide (CO), Nitrogen Oxides (NOx), Particulate Matter (PM10 and PM2.5), Sulphur Oxides (SOx), Black Carbon (BC), Organic Carbon (OC), Methane (CH4), Nitrous Oxide (N2O), Carbon Dioxide (CO2) and Volatile Organic Compounds (VOC), are exhaustively accounted for in the WTP, PTW, and WTW stages. Note that the y-axis scale is logarithmic to better visualize the wide range of air pollutant emissions. Original values are given in kilograms (kg).

Fig. 6
figure 6

Air pollutant emissions of different train categories in Morocco

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A preliminary observation reveals significant differences in emission levels across the train services. For instance, goods-only trains exhibit the highest CO2 emissions (198 kg per km for WTW), while the passenger-only service presents the highest NOx emissions (1.06 kg per km for WTW). The combined goods-passenger service shows the lowest emissions across all pollutants, but it’s important to note the zero emissions in the PTW and WTW stages, which could be attributed to specific transport modalities or data limitations. Looking at the methane (CH4) emissions, potent greenhouse gas goods-only trains again report the highest levels (3.56 kg per km for WTW), followed by passenger-only (0.75 kg per km for WTW) and combined service (0.11 kg per km for WTW). The emission of particulate matter, both PM10, and PM2.5, is remarkably low across all services, although goods-only trains emit slightly higher quantities. Particulate matter is known for its adverse health effects, and its low levels suggest an encouraging aspect of the current train systems.

This preliminary analysis offers valuable insights into the environmental footprint of Morocco’s train services. A transition to alternative fuels, as explored in our earlier energy use analysis, would require careful consideration of these emission profiles to ensure we are not just improving energy efficiency, but also mitigating the environmental and public health impacts of railway transportation. More comprehensive research and modeling, incorporating factors such as train type, energy source, operational characteristics, and geographical context, would be essential to adequately guide such transformative decisions.

3.4 Environmental impact assessment

Climate change, respiratory effects, and acidification/eutrophication are computed to provide a comprehensive view of the daily environmental impact assessment of different train types and are visualized in Fig. 7. We utilized a logarithmic scale on the y-axis to effectively represent the wide range of values and provide a clear comparison.

Fig. 7
figure 7

Daily environmental impact assessment of different train categories in Morocco

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When considering these environmental impacts, we see distinct patterns based on the type of service the train provides: goods only, passengers only, or a combination of both. Passenger-only trains exhibit the highest environmental impacts in all three categories. With scores reaching into the hundreds of thousands for climate change and the thousands for respiratory effects and acidification/eutrophication, these trains, due to their high energy consumption and the extensive emissions they produce, contribute significantly to environmental impact.

Goods-only trains and mixed-use trains (both goods and passengers), on the other hand, demonstrate dramatically lower impacts across all categories, but this disparity is especially apparent when we consider the logarithmic scale of our plot. Despite their smaller size on the chart due to the logarithmic scale, the impacts of these train types are not negligible. These trains, with their more streamlined operations and reduced passenger load, generate fewer air pollutant emissions, which translate into markedly reduced environmental impact scores.

The noticeably low values for goods-only and mixed-use trains, when compared with passenger-only trains on a logarithmic scale, highlight the benefit of optimizing train usage. A mixed-use train, carrying both goods and passengers, for example, minimizes the overall number of trains in operation, reducing overall emissions.

However, it should be noted that the data doesn’t account for the capacity utilization of the trains. A fully loaded passenger train might have a lower environmental impact per passenger than a less utilized goods-only or mixed-use train, even when represented on a logarithmic scale. This analysis suggests that efforts to mitigate the environmental impacts of train usage should focus on passenger-only services. Potential mitigations could include optimizing schedules to maximize capacity utilization, implementing newer and more fuel-efficient engines, or exploring alternative fuel options.

4 Discussion and conclusion

Our study offers a detailed environmental impact assessment of various train types in Morocco, shedding light on the differential impacts of goods-only, passenger-only, and mixed-use trains. It’s evident from our findings that passenger-only trains, due to their high energy consumption and emissions, pose the most significant environmental challenges in categories such as climate change, respiratory effects, and acidification/eutrophication. In contrast, goods-only and mixed-use trains demonstrate reduced impacts, a testament to their efficient operations and lesser passenger load.

Delving deeper into these findings, several factors contribute to the pronounced environmental impacts of passenger-only trains. Firstly, passenger trains, especially during peak hours, operate at high frequencies to accommodate the commuter demand, leading to increased energy consumption. Additionally, the stop-and-go nature of passenger trains, with frequent stops at stations, results in higher energy expenditure compared to goods-only trains that often have more streamlined routes with fewer stops. Furthermore, the energy infrastructure supporting passenger trains, including station lighting, HVAC systems for passenger comfort, and auxiliary services, adds to their overall energy footprint. Goods-only and mixed-use trains, on the other hand, benefit from more consistent operational patterns and fewer auxiliary energy demands, leading to their reduced environmental impacts.

The environmental implications of these train services are intricately linked to their operational characteristics, capacity utilization, and Morocco’s power generation mix. While our findings are rooted in the Moroccan context, they may vary in countries with different energy profiles or train services. Nevertheless, the overarching message remains consistent: there’s an imperative need to enhance the efficiency of passenger-only train services.

In the broader context of environmental conservation, our study paves the way for future decarbonization strategies for Morocco’s rail transport. We underscore the importance of in-depth economic evaluations, life cycle assessments, and total cost of ownership analyses. Such evaluations can guide rail companies towards sustainable operations, balancing environmental concerns with economic viability.

Transitioning to sustainable rail systems is a multifaceted challenge, encompassing technological, financial, and institutional dimensions. While our study doesn’t aim to deter the shift towards green rail systems, it emphasizes the importance of informed decision-making, considering potential risks and challenges.

Drawing from state-of-the-art guidelines, our findings underscore the importance of:

  1. 1.

    Integrating life cycle assessment (LCA) methodologies into rail system evaluations, ensuring a holistic understanding of environmental impacts from production to disposal.

  2. 2.

    Prioritizing energy-efficient technologies and alternative fuels, aligning with global best practices for sustainable rail operations.

  3. 3.

    Engaging stakeholders in the decision-making process, ensuring that policies and strategies are both feasible and effective.

In conclusion, our research bridges a critical knowledge gap, offering insights into the environmental ramifications of different train types in Morocco. The urgency to optimize passenger-only trains is evident, and our findings serve as a cornerstone for policymakers, transit agencies, and stakeholders. By aligning with state-of-the-art guidelines and prioritizing sustainability, Morocco can pave the way for a rail system that’s both efficient and environmentally responsible, echoing global ambitions for climate conservation and sustainable development.