Review of externality valuation

摘要

This report covers the work done regarding assessment of externalities in the project 'Investigation of Pricing Incentives in a Renewable Energy Strategy in Thailand'. The report gives a review of different valuation issues, which are used in different externality studies and focuses on why the numbers often are different for the same fuel cycles using different methodologies for assessment of the externalities. The review of externality valuation focuses in this report on the assessment of environmental externalities, and less attention is paid to the non-environmental externalities. The report points out different parameters, which are important to consider when externalities estimated for the same fuel cycle in different studies are compared. For instance some studies transfer dose-response functions and monetization values from other studies. It is in this case important to consider for each of the functions if it is possible to use functions from other studies, or if it is necessary to develop a function for a new region. An important parameter in estimating externalities based on earlier studies is the fact that some studies only include regional and local impacts and do not take the global impacts related to greenhouse gasses into account. Considerable uncertainty is related to the global externalities regarding time horizon for the greenhouse effect, choice of dose-response function and monetization values. Assumptions on famine and the monetization of human life may be the totally dominating factor estimating external costs. 7 studies have been chosen for further analysis and comparison in order to show the variation in external costs. The studies have been chosen in order to cover as well old, well-known studies as new, unknown, but interesting studies. Some of the new studies are based on results from earlier studies, while others implement new ideas concerning the methodology. (au) 21 refs.