OFFSHORE WIND FARM DECOMMISSIONING: INTRODUCING A MULTI-CRITERIA DECISION AID APPROACH Dissertation in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE WITH A MAJOR IN ENERGY TECHNOLOGY WITH FOCUS ON WIND POWER Uppsala University Department of Earth Sciences, Campus Gotland Hans Kerkvliet 22-05-2015 OFFSHORE WIND FARM DECOMMISSIONING: INTRODUCING A MULTI-CRITERIA DECISION AID APPROACH Dissertation in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE WITH A MAJOR IN ENERGY TECHNOLOGY WITH FOCUS ON WIND POWER Uppsala University Department of Earth Sciences, Campus Gotland Approved by: Supervisor, Dr. Heracles Polatidis Examiner, Dr. Simon-Philippe Breton 22-05-2015 iii ABSTRACT The objective of this Thesis is to develop a methodological framework to guide the decision maker in selecting a decommissioning method for offshore wind farms which is supported by the majority of relevant stakeholders. Initially, a literature review has been conducted to find out which methods are available to decommission an off-shore wind farm and which criteria can influence the outcome. Two methods have been found in literature, namely partial and total removal of the foundation. Furthermore, twenty one (21) criteria have been found which could influence the results. These criteria can be divided in four categories which are economical, environmental, social and technical. Subsequently, a methodological framework was developed that included four steps. First, the possible decommissioning methods should be identified. Following on that, information should be collected and stakeholders should be selected. Subsequently, criteria should be selected and as last a multi criteria decision aid method should be used. It is expected that this procedure would lead to a decommissioning method which is supported by most of the stakeholders. To validate the methodological framework, a case study in the Netherlands has been selected. For this case study, four (4) stakeholders were identified and eleven (11) criteria were assessed. The outranking multi-criteria decision aid method PROMETHEE II was selected and results were obtained. Analyzing the results, it was possible to conclude that only one stakeholder preferred the total removal method while the other three stakeholders preferred the partial removal method. Keywords: wind power; decommissioning; off-shore; multi-criteria iv ACKNOWLEDGEMENTS This thesis is written to complete the master Wind Power Project Management at Uppsala University. I would like to show my gratitude to several people who helped or supported me during this research. First, I would like to thank my supervisor Dr. Heracles Polatidis for the support, guidance through the writing process and the fruitful meetings. Furthermore, I would like to thank my family for the support they gave to me during the thesis and the rest of my time in Sweden. v NOMENCLATURE IMO International Maritime Organization MCDA Multi Criteria Decision Aid OSPAR Oslo and Paris Convention UNCLOS United Nations Convention On the Law of the Sea vi Table of Contents ABSTRACT ..................................................................................................................... iii NOMENCLATURE ........................................................................................................... v LIST OF FIGURES ........................................................................................................... ix LIST OF TABLES ............................................................................................................. x CHAPTER 1. INTRODUCTION ................................................................................ 1 1.1 Background .............................................................................................................. 1 1.2 Objective and research questions ............................................................................. 1 1.3 Justification for the research .................................................................................... 2 1.4 Methodology ............................................................................................................ 2 1.5 Outline ...................................................................................................................... 2 CHAPTER 2. LITERATURE REVIEW ..................................................................... 3 2.1 Introduction .............................................................................................................. 3 2.2 General process of decommissioning offshore wind turbines.................................. 3 2.3 Removal of Foundation ............................................................................................ 5 2.3.1 Introduction ....................................................................................................... 5 2.3.2 Total removal of the foundation ........................................................................ 5 2.3.3 Partial removal of the foundation ...................................................................... 7 2.4 Multi Criteria analysis .............................................................................................. 9 2.4.1 Introduction ....................................................................................................... 9 2.4.2 Process ............................................................................................................. 10 2.5 Criteria identification ............................................................................................. 10 2.5.1 General introduction ........................................................................................ 10 2.5.2 Introduction criteria ......................................................................................... 11 2.5.3 Overview of the criteria ................................................................................... 13 2.6 Criteria description ................................................................................................. 14 2.6.1 Economic Criteria ........................................................................................... 14 2.6.2 Environmental Criteria .................................................................................... 16 2.6.3 Social Criteria .................................................................................................. 18 2.6.4 Technical ......................................................................................................... 21 2.7 Stakeholders ........................................................................................................... 22 2.8 Weighting criteria in a MCDA ............................................................................... 23 vii 2.9 Performance Evaluation ......................................................................................... 25 2.10 Sensitivity analysis ............................................................................................... 27 2.11 Tool Selection ...................................................................................................... 28 2.12 Key aspects PROMETHEE II .............................................................................. 28 CHAPTER 3. METHODOLOGY AND DATA ........................................................ 30 3.1 Introduction ............................................................................................................ 30 3.2 Process of decommissioning .................................................................................. 30 3.3 Mathematics of PROMETHEE II .......................................................................... 33 CHAPTER 4. APPLICATION OF THE METHODOLOGY AND RESULTS ........ 36 4.1 Introduction ............................................................................................................ 36 4.2 Description of the case study ................................................................................. 36 4.3 Selected criteria ...................................................................................................... 37 4.4 Criteria Assessment ................................................................................................ 38 4.4.1 Cost of decommissioning ................................................................................ 38 4.4.2 Monitoring costs .............................................................................................. 45 4.4.3 Maintenance cost ............................................................................................. 46 4.4.4 Biodiversity ..................................................................................................... 47 4.4.5 Biomass ........................................................................................................... 48 4.4.6 Impact on marine mammals. ........................................................................... 48 4.4.7 Invasive species ............................................................................................... 49 4.4.8 Opportunity commercial fishing ..................................................................... 49 4.4.9 Opportunity for recreational industries ........................................................... 50 4.4.10 Public access ................................................................................................. 51 4.4.11 Repowering possibility of the