Die approbierte Originalversion dieser Diplom-/Masterarbeit ist an der Hauptbibliothek der Technischen Universität Wien aufgestellt (http://www.ub.tuwien.ac.at). The approved original version of this diploma or master thesis is available at the main library of the Vienna University of Technology (http://www.ub.tuwien.ac.at/englweb/). MSc Program Renewable Energy in Central and Eastern Europe Osmotic Power - A Promising Renewable Energy Source for Croatia? An Analysisof the Potential for Pressure Retarded Osmosis in Croatia A Master’s Thesis Submittedfor the Degreeof “Master of Science” Supervised by Ao.Univ.Prof. Dipl.-Ing. Dr.techn. Reinhard Haas Mag. Werner Klein 7804384 Vienna, September 2010 MSc Program Renewable Energy in Central and Eastern Europe Affidavit I, Werner Klein , hereby declare 1. that I am the sole author of the present Master Thesis, "Osmotic Power – A Promising Renewable Energy Source for Croatia?", 120 pages, bound, and that I have not used any source or tool other than those referenced or any other illicit aid or tool, and 2. that I have not prior to this date submitted this Master Thesis as an examination paper in any form in Austria or abroad. Vienna, September 10, 2010 ____________________________ Mag. Werner Klein Master‘s Thesis Osmotic Power – A Promising Renewable Energy Source for Croatia? Werner Klein Page i MSc Program Renewable Energy in Central and Eastern Europe I Abstract Osmotic Power is a completely renewable and emission-free energy source, and Pressure Retarded Osmosis (PRO) is one of the possible conversion technologies. The development to the current state of PRO has been led by Norway’s Statkraft S.A. and a demonstration plant was opened in Tofte, Norway in November 2009. The goal of this study is to examine the PRO technology in order to: • Understand and describe the principles, processes components and preconditions, • Determine the theoretical, technical and realisable potential and analyse the supporting and limiting factors for a PRO implementation in Croatia, • Analyse and estimate the economic parameters for a business case scenario and possibly apply these to a potential site for a PRO pilot power plant. With information available from public sources (internet, scientific articles), and after direct communication with Statkraft and other experts from relevant industries, probable investment and production costs are calculated for various scenarios. Finally, a promising site for a PRO pilot plant implementation in Croatia is selected, based on favourable environmental and infrastructure conditions. Based on a site visit, some ROI calculation parameters are adapted and the specific investment case analysed. The calculations’ results are put in relation to suggested feed-in tariffs that would support the PRO dissemination within the Croatian subsidy framework for renewable energy. The calculated costs of energy (LCoE) for PRO are found in the range between the costs of wind and photo voltaic, although key technology components like membranes are still in an early stage of development. In order to reach the expectations stated by Statkraft, these calculated costs will have to half until 2020. The main future challenge will be to increase the specific power of membranes and to decrease their specific costs. Enormous production capacities for membranes will be required to build PRO power plants with capacities relevant for utilities. The necessary growth of the production capacity can in fact create the steep learning curve that is required for the predicted cost decrease. Master‘s Thesis Osmotic Power – A Promising Renewable Energy Source for Croatia? Werner Klein Page ii MSc Program Renewable Energy in Central and Eastern Europe II Table of contents AFFIDAVIT I I ABSTRACT II II TABLE OF CONTENTS III III LIST OF FIGURES VI IV LIST OF TABLES VIII V LIST OF ABBREVIATIONS AND SYMBOLS X 1. INTRODUCTION 1 1.1 POWER WATER – WATER POWER 1 1.2 THE SALINITY POWER PROJECT 2 1.3 THE WORLD ’S FIRST OSMOTIC POWER PROTOTYPE 3 2. OBJECTIVES 4 3. THE OSMOTIC POWER TECHNOLOGY 5 3.1 CHEMICAL POTENTIAL ENERGY 5 3.2 OSMOTIC PRESSURE 6 3.2.1 Definition 6 3.2.2 Calculation of Osmotic Pressure 6 3.2.3 Occurrence and Application of the Osmotic Effect 7 3.2.4 Osmotic Processes through Membranes 7 3.2.5 Reverse Osmosis and Desalination 8 3.3 CONCEPTS OF SALINITY POWER GENERATION 9 3.3.1 Reverse Electro-Dialysis (RED) 9 3.3.2 Pressure Retarded Osmosis (PRO) 10 3.3.3 Comparison of Technologies (PRO, RED) 11 3.3.4 Non-Membrane Based Processes 12 4. PRESSURE RETARDED OSMOSIS (PRO) PROCESS FOR POWER GENERATION 14 4.1 PRO BASICS AND PROCESS 14 4.1.1 Osmosis Power Potential 14 4.1.2 Pressure retarded Osmosis Process Details 18 4.2 PRO CRITICAL COMPONENTS 20 4.2.1 Membranes 20 4.2.2 Energy Recovery Devices (Pressure Exchanger) 25 4.3 PRO PROCESS PARAMETERS 26 4.4 EXPECTED SCALING EFFECTS 27 4.5 PRO PLANT CONCEPTS 30 4.6 ENVIRONMENTAL INFLUENCES AND CHALLENGES 31 4.6.1 Plant size 31 4.6.2 Water Quality 32 Master‘s Thesis Osmotic Power – A Promising Renewable Energy Source for Croatia? Werner Klein Page iii MSc Program Renewable Energy in Central and Eastern Europe 4.6.3 Access Points 32 4.6.4 General Water Usage and Residual Flow 37 4.7 LEGAL PERSPECTIVE 38 4.7.1 Renewable Energy Directive 2009/28/EC 38 4.7.2 Patents 39 5. CROATIA AND ITS SUITABILITY FOR PURSUING OSMOTIC POWER PLANT PROJECTS 40 5.1 GENERAL COUNTRY INFORMATION 40 5.1.1 Facts and Figures 40 5.1.2 Croatia and the European Union 41 5.1.3 Croatia in the International Community 42 5.1.4 Croatia’s Economic Situation and Investment Climate 42 5.1.5 Environmental Situation and Regime 44 5.1.6 Environmental Impact Assessment 45 5.1.7 Protected Areas 47 5.2 ELECTRICITY MARKET AND CONDITIONS 49 5.2.1 Electric Power Sector and Market Players 49 5.2.2 Electricity Supply, Demand and Price Levels 51 5.2.3 Consumption Trends and Supply Strategies 53 5.2.4 Grid and Grid Access 55 5.2.5 RES-E Policy and Framework 57 6. POTENTIALS FOR OSMOTIC POWER IN CROATIA 60 6.1 DEFINITIONS 60 6.2 THEORETICAL POTENTIAL FOR PRO 60 6.2.1 Hydrological Situation and Discharge 61 6.3 TECHNICAL POTENTIAL 63 6.3.1 Further Definitions and Specification 63 6.4 REALISABLE POTENTIAL 65 6.4.1 Introduction of the “Reasonable Potential” 65 6.4.2 Analysis of Croatian Rivers’ Discharge 66 6.4.3 Reasonable Potential = Total Realisable Potential 76 6.4.4 Realisable Potential up to the Year 2030 77 6.4.5 Existing or Planned Hydropower Projects Impacting PRO Projects 79 7. PRO PROJECT AND PERFORMANCE CHARACTERISTICS 81 7.1 CHARACTERISTICS OF THE PRO POWER GENERATION 81 7.1.1 Base Load Supply 81 7.1.2 Expected Maintenance Demand 81 7.2 CHARACTERISTICS OF A PRO PROJECT DEVELOPMENT 81 7.2.1 Complex decision making and certification process 81 7.3 A SIMPLIFIED ROI-MODEL 82 Master‘s Thesis Osmotic Power – A Promising Renewable Energy Source for Croatia? Werner Klein Page iv MSc Program Renewable Energy in Central and Eastern Europe 7.3.1 Input Parameters for ROI Scenarios 83 7.3.2 Best Estimate Scenario 84 7.3.3 Worst Case Scenario 87 7.3.4 Best Case Scenario 88 7.4 SENSITIVITY ANALYSIS FOR SELECTED PARAMETERS 89 7.4.1 Sensitivity of Capital Expenses (Best Estimate Scenario) 89 7.4.2 NPV Sensitivity to Operating Costs and selected Indices (Best Estimate Scenario) 90 7.5 REQUIRED SUBSIDIES – FEED -IN TARIFFS 90 8. INVESTIGATING A FEASIBLE PILOT SITE: HE DUBROVNIK 94 8.1 SITE DESCRIPTION 94 8.2 SITE APPLICABILITY FOR A PRO POWER PLANT 97 8.2.1 Fresh Water 98 8.2.2 Sea Water 98 8.2.3 Infrastructural 98 8.2.4 Limiting factors 98 8.3 SITE PARAMETERS AND ROI FOR A 5 MW PRO PLANT 99 9. SUMMARY 103 9.1 CROATIA ’S PRECONDITIONS FOR RENEWABLE ENERGY 103 9.2 HYDROLOGY PRECONDITIONS FOR POWER GENERATION 103 9.3 HYDROLOGY CONDITIONS FOR PRO POTENTIAL CALCULATION 104 9.4 REASONABLE AND REALISABLE PRO POTENTIAL IN CROATIA 104 9.5 INHIBITORS FOR THE REALISABLE PRO POTENTIAL 105 9.6 THE STATE OF PRO TECHNOLOGY AND ITS ECONOMICS 105 9.7 POTENTIAL PILOT SITE SELECTION AND ITS ECONOMICS 106 10. CONCLUSIONS 108 11. REFERENCES 110 12. APPENDIX 120 12.1 POTENTIALS AND DEVELOPMENT SCENARIO 120 Master‘s Thesis Osmotic Power – A Promising Renewable Energy Source for Croatia? Werner Klein Page v MSc Program Renewable Energy in Central and Eastern Europe III List of Figures Figure 1: Hydropower plant Krka, 1895 1 Figure 2: Statkraft demonstration plant in Tofte-Norway 3 Figure 3: History and future of osmotic power 3 Figure 4: conversion of chemical potential energy into heat and light 5 Figure 5: Schema of Forward Osmosis (FO), Reverse Osmosis (RO) and Pressure Retarded Osmosis (PRO) 8 Figure 6: Desalination with Reverse Osmosis – plant schema 9 Figure 7: Schema of a reverse electro-dialysis process 10 Figure 8: Schema of a pressure retarded osmosis process 11 Figure 9: Average power density and energy recovery, calculated by Post et.al. (2007) for PRO and RED for mixing sea water with river water and for mixing brine with river water 12 Figure 10: Membrane power, flux and energy recovery, calculated by Thorsen and Holt (2009) for PRO under specified conditions 12 Figure 11: Average salinity of the world's oceans 15 Figure 12: Process schema and parameters of the PRO technology 18 Figure 13: Transferred mass vs.