This book is constructed by experts in diverse fields of renewable energy and its related materials. Chapter 1 is organic-inorganic hybrid lead halide perovskites: optical properties and optoelectronic applications by JJ Zhu. Chapter 2 is semiconductor materials and solar cells based on Cu2ZnSnS4 thin films by JH Tao, Chapter 3 is systematic experimental studies of thermoelectric technologies by AJ Jin, Chapter 4 is smart grid and renewable energy by J Su, Chapter 5 is ferroelectric and multiferroic tunnel junctions by ZJ Ma, Chapter 6 is challenges for smart grids of 100% sustainable wood procurement of forest industry by T Palander, Chapter 7 is two-dimensional nanomaterials supported electrochemical energy storage for smart grids by QJ Chi, Chapter 8 is recent advances in fabrication of nano bio-materials by HL Cong, Chapter 9 is advanced carbon materials for the development of lithium-ion and sodium-ion batteries by WM Chen, and Chapter 10 is sustainable energy and green infrastructure: analysis on the practices of Zurich, Copenhagen, and Singapore by D Zhu. Jiajun Zhu has invited the contributed researchers with the help of the promotion specialists Roger Sun and Frank Li.