This book offers a clear overview of how digital technologies and numerical methods are transforming modern energy systems. With rising demand for sustainable solutions, industries face challenges such as optimizing energy use, improving system reliability, and enhancing the performance of electric vehicles, microgrids, and energy storage systems. This book shows how tools like numerical analysis, deep learning, machine learning, and real-time simulation are being used to address these issues. It highlights advances that strengthen grid stability, improve EV and storage performance, and protect critical infrastructure from cyber threats. Through practical examples and case studies, this book demonstrates how digital innovation is shaping a smarter, more efficient, and more secure energy future. It is a valuable resource for engineers, researchers, and professionals working to advance modern energy technologies.