Environmental Impact of Energy Systems: What are the Risks? In order to reduce CO emissions and meet growing energy demands during the 21 Century, the world can expect to experience major shifts in the types and proportions of energy-producing systems. These decisions will depend on considerations of cost per energy unit, resource availability, and unique national policy needs. Less often considered is the environmental impact of the different energy producing systems: fossil fuels, nuclear, wind, solar, and other alternatives. One of the challenges has been not only to evaluate the environmental impact but also to develop a systematic basis for comparison of environmental among the energy sources. This course considers the environmental impact of major energy systems. Specifically, the course considers fossil fuels (natural gas, petroleum and coal), nuclear power (U and Th fuel cycles), wind, and solar. For each of these energy sources, the class examines the impact of resource extraction, refining and production, transmission and utilization. We review and use the basic principles of risk analysis in order to compare the energy systems and examine the regulatory framework designed to mitigate negative environmental impacts.