This report discusses problems related to economic assessment of the environmental impacts and abatement measures in connection with energy projects. Attention is called to the necessity of assessing environmental impacts both in the form of reduced economic welfare and in the form of costs of abatement measures to reduce the impact. In recent years, several methods for valuing environmental impacts have been developed, but the project shows that few empirical studies have been carried out. The final report indicates that some important factors are very difficult to evaluate. In addition environmental impacts of energy development in Norway vary considerably from project to project. This makes it difficult to obtain a good basis for comparing environmental impacts caused by different technologies, for instance hydroelectric power versus gas power or wind versus hydroelectric power. It might be feasible however to carry out more detailed economic assessments of environmental impacts of specific projects. 33 refs., 1 fig., 4 tabs.