Sustainability of electricity supply technology portfolio

Abstract

This paper outlines the approach to the evaluation of sustainability of current and future electricity supply options of interest for a major Swiss utility Axpo Holding AG. The motivation behind this effort has been to provide a solid basis for a state-of-the-art interdisciplinary assessment and use this framework within a dialog with a wide spectrum of stakeholders. The development and implementation of the methodology was coordinated by Axpo in co-operation with the Paul Scherrer Institut (PSI) and other scientific institutions. The evaluation covers environmental, social and economic dimensions of sustainability. Methods used include among others life cycle assessment (LCA), impact pathway approach (IPA) and probabilistic safety assessment (PSA). The associated databases developed by PSI have been extensively used, subject to major extensions necessary for analyzing the future technologies. Learning curves were employed for future cost estimates. Furthermore, particularly in the social area expert surveys were used. The results were aggregated using total (internal plus external) costs approach and multi-criteria decision analysis (MCDA). For MCDA a set of criteria and the associated indicators was established. In total 75 indicators were quantified, including 11 environmental, 33 social and 31 economic. Eighteen current and 18 future technologies have been analysed including nuclear as well as fossil and renewable technologies. Total costs were estimated for these technologies providing a clear ranking with nuclear having the lowest costs and some of the renewables showing remarkable cost reductions until 2030. This ranking is partially controversial mainly due to the limited representation of social aspects in the total costs. The results of MCDA-applications involving elicitation of preferences from a relatively homogeneous stakeholder group, i.e. 85 employees of the Axpo Group (including also NOK, EGL, CKW and Axpo IT), are summarized. In addition, sensitivity of technology ranking to preference profiles is demonstrated. Broader consideration of social factors favours renewables and depending on the specifics of preference profiles may lower the ranking of nuclear. Further applications of the MCDA-approach with various stakeholder groups are planned.