Ordinal Measurements with Interval Constraints in the EIA Process for Siting a Waste Storage Area

Abstract

We describe application of multicriteria decision analysis (MCDA) in the Environmental Impact Assessment (EIA) procedure for siting a waste storage area. The world’s largest biofuel-based combined heat and power (CHP) plant was built in Pietarsaari, Finland. The plant produces certain byproducts, such as flue dust and bottom ash, which need to be processed and stored to prevent releases to the environment. Different storage sites will have different impacts on people, nature, and the economy. Cardinal measurement of the different impacts was considered too costly. Instead, ordinal measurement of all criteria was applied; i.e., experts ranked the alternative storage sites according to each criterion. In addition to pure ordinal information, the experts were able to state that some ordinal intervals were more significant than others. To properly treat this kind of information, we extended the Ordinal Stochastic Multicriteria Acceptability Analysis (SMAA-O) MCDA method and used it to evaluate the acceptability of the different sites. Three of the alternatives were found acceptable subject to some valuations and one of them was acceptable subject to a wide range of different valuations. This alternative was then chosen for implementation.