This book discusses the main renewable energy resources, along with the current challenges that make it difficult achieve 100% decarbonized energy sources. It presents the perspectives of international expert authors in the field, giving readers a multi-dimensional view of the subject. The book explores numerous approaches for a smooth transition from fossil fuels to renewable energies, including those based on engineering methods, as well as policies, strategies, and social perceptions. It presents several case studies and examples from industry, showcasing the potential role of renewable sources and their challenges. The inclusion of both established methods and cutting-edge developments will make this book of interest to academics, industry professionals, policy makers, and graduate students alike.