## 1 Introduction  
### Background  
The last few decades show clearer than ever the impact of technology development and industrialization on the environment, leading to significant climate change that impacts industries such as agriculture, insurance, or the food industry. These effects have urged the majority of governments and international organizations to take action and implement direct measures that aim to mitigate the impact on the environment and quality of life. Sustainability, carbon neutral processes, and alternative energy sources are key references when discussing steps to be taken in any industry in order to align with the main scope of fixing the causes of environmental destruction and degradation. In the transportation industry, the main applicable cause is carbon pollution, mainly coming from burning fossil fuels for the benefit of powering plants, mines, and adjacent manufacturing processes, as well as using non-renewable sources (e.g., coal, natural gas, and crude oil) to run the internal combustion engines in vehicles and aircraft [1]. As a direction of regulation and development in the industry, utilizing sustainable energy sources and processes leads to the electrification of powertrains, along with the development of new carbon neutral combustible fuels [2]. As electrical energy can be obtained from renewable sources, such as solar, wind, or water, and existing battery technologies and electric motor components enable easier implementation in commercial and passenger vehicles, an increasing number of solutions is coming to the market [3]. The electric vehicle market grows rapidly year by year, supported by new legislation that leads manufacturers away from internal combustion engines that run on conventional fuels [4]. Studies show that battery electric vehicles (BEVs) have a lower impact on greenhouse gas emissions (GHG) compared to internal combustion engine vehicles (ICEVs) while performing a well-to-wheel analysis. Depending on the source of electrical energy in each country, as analyzed by [PERSON] et. al. in 2022 [5]. In rural areas, where there are low-voltage electrical energy distribution systems, the application of renewable energy sources offsets the GHG emissions of electric vehicles in comparison to vehicles with conventional powertrains. In these cases, the pollutant emissions of EVs would otherwise exceed those of ICEVs [6]. Leading the global trends of electrification and optimization of the transportation area, European authorities represent one of the main forces that implement strict regulations in a timely manner, exploring all viable solutions and addressing all points in which the impact on the environment is felt by humanity. In regard to transportation solutions for cargo and passengers, the electrification approach seems to be one of the preferred alternatives to internal combustion [7]. In mass passenger transport, the last two decades have brought a variety of vehicles, such as buses, shuttles, and cabs, consisting of battery electric vehicles (BEVs) and fuel cell electric vehicles (FCEVs) [8]. For some applications that are not yet compatible with fully electric or fuel cell technologies, due to their drawbacks (e.g., accessibility, effective range, or cost), the approach is to look into hybridization of the powertrains and slowly move away from the dependency on conventional fuels [9; 10]. Significant research and innovation efforts are made in fuel cell technology, addressing energy management strategies (EMS), such as the recent work of [PERSON] et al., which utilizes deep reinforcement learning (DRL) to propose a health-conscious approach [11]. By tackling fuel cell-specific drawbacks and challenges, [PERSON] et al. propose a prediction model for the degradation of proton exchange membrane fuel cells (PEMFCs), fusing bi-directional long short-term memory (BiLSTM) networks, and multi-head self-attention (MHSA) mechanisms [12].