This book embarks on a transformative exploration of sustainable urban development, integrating Internet of Things (IoT) technologies in energy efficiency assessments of renewable energy systems and microgrids within smart cities. This work transcends conventional approaches, seamlessly blending theoretical insights with practical applications, and prioritizing real-time, IoT-enabled assessments for optimal energy utilization. Evolving the understanding of renewable energy systems and microgrids, the book distinguishes itself through its hands-on application of IoT technologies. It not only delves into theoretical aspects but also equips readers with actionable insights, guiding the implementation of IoT for informed decision-making in the dynamic landscape of smart city environments. From IoT sensor deployment strategies to data analytics techniques and practical considerations, the book's expansive scope offers a comprehensive roadmap for creating resilient and efficient energy ecosystems. Tailored for professionals, researchers, and policymakers in energy management, urban planning, and IoT technology, this resource speaks to a diverse audience. Whether the reader is an engineer aiming to optimize microgrid performance or a policymaker driving urban sustainability, the book provides indispensable insights. It serves as a compass, informing city planners on energy-efficient infrastructure, guiding researchers in developing impactful IoT applications, and assisting policymakers in formulating forward-thinking, eco-friendly regulations. In a world embracing smart technologies, this book emerges as an essential guide, steering stakeholders toward a future where the seamless integration of energy efficiency and IoT defines the landscape of truly smart and sustainable cities.