Textbook in PDF format This book presents cutting-edge research and technological developments at the intersection of mechatronics and sustainable energy systems. It is designed for researchers, and professionals engaged in renewable energy, thermal systems, and advanced control technologies. The chapters cover a wide range of topics focused on two major areas: the thermochemical conversion of agricultural and biomass wastes into biofuels and the integration of phase change materials (PCMs) into solar thermal energy systems for enhanced energy storage and efficiency. By linking sustainable energy challenges with practical engineering solutions, this book offers insights into how mechatronics can drive the future of green energy systems. Readers will benefit from in-depth analyses, case studies, and real-world applications that demonstrate how emerging technologies can be harnessed to meet environmental and energy goals