The European Power Plant Conceptual Study (PPCS) reported in the summer of 2004. Several conceptual designs ("Models") for commercial fusion power plants were developed, spanning a range from relatively near term to more substantial extrapolations. The parameters of the Models were chosen by systems analysis to be economically optimal, given the assigned constraints on plasma and technology performance. The conceptual designs were developed in some detail and analyses were made of their safety, environmental impacts and economic performance. The calculated cost of generating electricity from the Models is in the range of published estimates for the future costs from other sources. Even the near-term Models are economically viable. External costs are very low, for all the Models: similar to wind power and much less than for fossil fuels. Economic optimization of the designs did not jeopardize their safety and environmental performance. All the Models proved to have the attractive and substantial safety and environmental advantages found in earlier studies, now established with greater confidence.