Handbook of Power-to-X Systems: Processes, Technologies, and Simulation Models is a comprehensive guidebook on Power-to-X technologies, leading the energy engineer from fundamental principles of these electrochemical techniques to complex practical applications for conversion and management in energy systems. This book begins with an overview of the Power-to-X background, clarifying fundamental questions of components, frameworks, uses in sustainable energy, and the history of the technology. This is followed by in-depth analysis of the essential techniques electrolysis and carbon capture, including methods of modelling and practicalities for implementation. Chapters 4-8 break down the role of various power-to-X processes: Power-to-Gas, Power-to-Liquids, Power-to-Chemicals, Power-to-Heat, and Power-to-Power are each assessed. Chapters 9 and 10 provide pragmatic guidance on regulatory and policy frameworks and assessment of environmental and social impacts. Finally, the book assesses innovations and future technologies and provides a wealth of resources for the energy engineer to build understanding. The Handbook of Power-to-X Systems: Processes, Technologies, and Simulation Models is an indispensable roadmap for students, researchers, and engineers looking to advance their expertise in a challenging, multidisciplinary area of electrical engineering and power systems.