This book is essentially a must-have reference for people involved in generation expansion planning of power systems in this modern era. Using Jamaica's electricity system as a case study, the author shows how to foster the transition of electricity generation systems along more sustainable paths by internalizing the externalities of electricity in the generation expansion planning process, among other things. This involves incorporating the damage costs of power plants’ emissions into their traditional levelized costs of electricity, in addition to their external costs from other life cycle phases. Additionally, the book shows how the capacity contribution of wind generation can be determined, taking into consideration the stochastic nature of the resource. Finally, we see how the generation expansion planning parameter used in Jamaica, specifically the generation system reliability criterion, was investigated to ascertain whether it reflects the socio-economic optimum.