Revision with unchanged content. Global warming and diminishing energy supplies are two major current concerns. Disposal of plastic wastes is also a major concern. The aim of this work is to address these three concerns by developing a solar powered process, using waste plastics as fuel to generate energy. Research into solar concentrators for thermochemical processes and pyrolysis/gasification of waste plastics has been separately reported in the literature. In this study we bring these fields of research together to understand design aspects of solar receiver-reactor suitable for the production of a synthesis gas consisting of hydrogen from waste plastics. In this book, studies of plastic decomposition behaviour using the thermal analysis method called thermogravimetric analysis is presented. Also presented are studies on solar concentrators and their potential to be used for thermochemical processes. The thermal decomposition behaviour of common plastics, namely low density polyethylene (LDPE), high density polyethylene (HDPE), polyethylene terephthalate (PET) and polyvinyl chloride (PET), were studied and the kinetic parameters for decomposition determined. Hence, this book provides studies on plastic decomposition and useful background required in developing a solar reactor suitable to decompose plastic wastes to useful gases.