ABOUT THE AUTHOR Chetan Singh Chauhan is an engineering and maintenance professional with experience in industrial electrical systems, preventive maintenance, critical spares, equipment reliability, energy management, documentation, and plant operations. His professional interests include electrical engineering, renewable energy, industrial maintenance, power systems, energy efficiency, automation, and practical technical education. His approach emphasizes connecting textbook concepts with equipment behavior, maintenance practices, safety, and day-to-day plant decision making. This book reflects that practical orientation. Instead of treating hydrogen only as a scientific topic, it presents hydrogen technology through the viewpoint of an engineer who must understand equipment, energy flows, controls, protection, maintenance, reliability, and operational risk. The author’s objective is to make technical subjects accessible without removing the engineering discipline behind them. Readers are encouraged to verify numerical design decisions against current standards, manufacturer data, project specifications, and qualified engineering review.