Advances in Fuel Cell Renewable Hybrid Power Systems

Dear Colleagues,

Global concern over climate change has led governments to set ambitious goals to reduce greenhouse gas emissions. This focus has driven the development of innovative technologies to reduce reliance on fossil fuels. Renewable energy sources, such as wind, solar, and hydroelectric power, are promising but present a challenge due to their intermittent nature, which highlights the need for effective energy storage solutions. Here, green hydrogen, generated from renewable sources, emerges as a viable solution, serving as a high-density energy carrier for storing and transporting energy. In this context, fuel cells are gaining relevance as a clean and efficient alternative to internal combustion engines, especially in transportation.

Fuel cells are characterized by their high efficiency in converting the chemical energy of the fuel into electricity, outperforming internal combustion engines. Compared to other alternatives such as batteries, they offer higher energy density, which allows storing more energy in less space and facilitates faster recharges. This makes them ideal for vehicles with hybrid propulsion systems that combine fuel cells and electric motors. However, the widespread adoption of this technology faces challenges in terms of cost, infrastructure, and technological maturity.

In road transportation, fuel cell electric vehicles (FCEVs) are positioning themselves as a viable option. Among the types of fuel cells, proton exchange membrane fuel cells (PEMFCs) are the most widely used in hybrid propulsion systems, thanks to their low operating temperature and fast start-up. FCEVs offer advantages such as a longer range and faster refueling times than battery electric vehicles, but they face challenges such as a high production cost, and the need for hydrogen refueling infrastructure and sustainable hydrogen production.

In railway, maritime, and air transportation, fuel cells offer a significant ecological alternative. They reduce greenhouse gas emissions in trains and decrease maritime and atmospheric pollution in maritime transportation. Although they are still in the early stages of being introduced in aviation, they could reduce the environmental impact of short-haul flights. However, the adoption of fuel cells in these sectors faces challenges such as insufficient hydrogen supply infrastructure and having an energy density that still does not match conventional fuels, especially in air transportation. Despite these challenges, continued advances in research and development promise to overcome these barriers, paving the way for a more sustainable energy transition in transportation.

This Special Issue encourages works from both industry and academia focused on the analysis of efficiency improvements and pollutant emission formation and control in decarbonized powertrain platforms. These include (but are not limited to):

• Research on the production and storage of green hydrogen;
• Studies on the integration of renewable energy sources;
• Development and optimization of fuel cells;
• Fuel cell modeling and simulation;
• Development of innovative materials for fuel cells;
• Applications of fuel cells in transportation;
• Economic and environmental evaluation;
• Life cycle analysis and sustainability;
• Advances in hydrogen refueling infrastructure;
• Socioeconomic and market aspects;
• Safety and risk aspects of hydrogen use;
• Innovations in hybrid propulsion systems;
• Future prospects and emerging technologies.

Dr. Pedro Piqueras
Dr. Enrique José Sanchis
Dr. Marcos López
Guest Editors

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• sustainable transportation
• green hydrogen
• fuel cell technology
• proton exchange membrane fuel cells (PEMFCs)
• fuel cell electric vehicles
• innovative materials
• decarbonized powertrains
• hybrid propulsion systems
• energy storage solutions
• renewable energy integration
• infrastructure development
• economic and environmental assessments