Comparison of methodologies for externality assessment

The production of energy causes different kinds of damage to the environmen t depending on the specific type of technology used in producing a given en ergy supply. The common term that expresses the costs of these environmenta l damages is externalities. These costs are not included in the cost and pr ice structure faced by the producer and the consumer. During the last few y ears, external costs related to power production technologies have been cal culated making use of different methodologies. The external costs may turn out to be very different:for the same fuel cycle depending on the methodolo gy that has been used to assess the externalities. The article will focus o n some of the most important reasons for differences in the numbers. To ill ustrate the importance of knowing the exact data and assumptions used, two studies using the same approach and with integrated computer models are com pared. The models are based on the same concept with air dispersion modules and dose-response functions for the calculation of impacts. Although the m odels are comparable, the resulting external costs turn out to differ with a factor of five in the two studies for the same power plant due to differe nt assumptions, different dose-response functions used and different impact s included in the studies. In the paper the most important differences to b e aware of will be illustrated. (C) 2000 Elsevier Science Ltd. All rights r eserved.