Vehicle Use of Hydrogen-Blended Natural Gas
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Life Cycle Assessment of a Demonstration Project Vehicle Use of Hydrogen-Blended Natural Gas Master’s Thesis of DANIEL KILGUS Carried out at Division of Environmental Systems Analysis CHALMERS UNIVERSITY OF TECHNOLOGY Göteborg, Sweden, 2005 In cooperation with Department of Life Cycle Engineering Institute for Polymer Testing and Polymer Science UNIVERSITY OF STUTTGART Life Cycle Assessment of a Demonstration Project Vehicle Use of Hydrogen-Blended Natural Gas DANIEL KILGUS © 2005 Daniel Kilgus ESA report 2005:16 ISSN 1404-8167 Department of Energy and Environment Division of Environmental Systems Analysis (ESA) Chalmers University of Technology SE-412 96 GÖTEBORG Sweden Tel: +46 (0)31 772 1000 Fax: +46 (0)31 772 2172 URL: http://www.esa.chalmers.se Chalmers Reproservice Göteborg, Sweden, 2005 Abstract Hydrogen is often considered as the way out of the environmental and economical problems associated with the use of fossil fuels. However, one of the main implementation barriers is the missing infrastructure. The introduction of hydrogen-blended compressed natural gas (HCNG) as a fuel for natural gas vehicles could serve as a bridging technology by using the existing natural gas infrastructure for the distribution of hydrogen. The unique conditions on site the large petrochemical complex in Stenungsund, Sweden—a hydrogen surplus and the connection to the natural gas grid—initiated a discussion about demonstrating the vehicle use of HCNG by using an already projected natural gas filling station near the industrial area. The hydrogen surplus used in this context will be replaced by natural gas. The intended aim of this demonstration project is learning in dealing with hydrogen as a fuel for vehicles. The purpose of this thesis is to assess and compare the environmental aspects of using natural gas, HCNG with 15% and 30% hydrogen by volume, and hydrogen as vehicle fuels within the scope of the proposed demonstration project. Life Cycle Assessment is used to analyse and quantify the potential environmental impacts from the use of the considered fuels in two different types of light- duty vehicles with internal combustion engines. The results show that the environmental benefits of performing the demonstration project are limited since there are no overall benefits connected to the use of HCNG and hydrogen compared to the use of natural gas. In general, the results reveal that the potential environmental impact from the fuel supply chain considerably increases towards a hydrogen share of 100% in the fuel. Besides these environmental considerations, however, it has to be taken into account that potential environmental impacts as direct project results cannot be consulted alone, when assessing the demonstration project and deciding whether it should be performed or not. Learning should be maximised and, therefore, the assessment of the demonstration project has to be extended by focusing on the dynamics of technological change, which can be given as a suggestion for further studies. iii Preface During my studies in the Environmental Engineering programme as well as my work as a student research assistant at the Department of Life Cycle Engineering, both at the University of Stuttgart, I gained insight into Life Cycle Assessment (LCA), a powerful yet complex environmental assessment tool, representing my ideal conception of the precautionary approach to environmental protection. My impulse to learn more about this method as well as to study at least one semester abroad finally provided the chance to carry out my diploma thesis within this subject at the Division of Environmental Systems Analysis (ESA) at Chalmers University of Technology, Göteborg. Thanks to an outstanding supervision at ESA, I finally got to know many methodological aspects of an LCA as well as some of its weak points and pitfalls. Moreover, methodological extensions aroused my interest, especially with regard to the dynamics of technological change. My interest is still unbroken, and hopefully I will have the opportunity to get back to it after my studies. I gained a lot of experiences during my time in Sweden, both professional and personal, and it was not always an easy way to go. My sincere thanks go to my supervisor Karl Jonasson and my examinator Björn Sandén for all their advice and support in this respect. Furthermore, my special thanks go to my parents. It was their support and encouragement that made all this possible and let me look back now on a successful time in Sweden. Last but not least, I want to thank all the people, who also enabled and encouraged me to realise this project. However, I would be nothing without the other half of my soul—my origin of love. This thesis is dedicated to you. v Table of Contents ABSTRACT.....................................................................................III PREFACE........................................................................................ V TABLE OF CONTENTS ................................................................ VII LIST OF TABLES........................................................................... XI LIST OF FIGURES....................................................................... XIII LIST OF ABBREVIATIONS ..........................................................XV 1 INTRODUCTION ......................................................................1 1.1 Purpose and outline................................................................. 6 2 THEORY...................................................................................9 2.1 Natural gas ............................................................................. 10 2.1.1 General information................................................. 10 2.1.2 Natural gas in Sweden ............................................. 11 2.1.3 Vehicle application.................................................. 13 2.2 Hydrogen................................................................................ 20 2.2.1 General information................................................. 20 2.2.2 Hydrogen projects in Sweden.................................. 21 2.2.3 Vehicle application.................................................. 22 2.3 Hydrogen-blended natural gas............................................. 27 2.3.1 General information................................................. 27 2.3.2 HCNG projects in Sweden ...................................... 27 2.3.3 Vehicle application.................................................. 27 2.4 Technological change ............................................................ 31 2.4.1 Technology life cycle .............................................. 33 2.4.2 Demonstration projects............................................ 35 vii 3 METHOD................................................................................ 37 3.1 Goal definition ....................................................................... 39 3.1.1 Purpose .................................................................... 39 3.1.2 Intended application and audience .......................... 39 3.2 Scope definition ..................................................................... 41 3.2.1 Functional unit......................................................... 41 3.2.2 System boundaries................................................... 41 3.2.3 Data quality ............................................................. 46 3.2.4 Impact assessment method ...................................... 46 3.2.5 Assumptions and limitations ................................... 48 4 RESULTS .............................................................................. 51 4.1 Energy use.............................................................................. 53 4.2 Global warming potential..................................................... 56 4.3 Nitrogen oxides ...................................................................... 59 5 DISCUSSION......................................................................... 63 5.1 Sensitivity analysis................................................................. 64 5.2 Steam reforming versus hydrogen surplus ......................... 69 5.3 Fleet results for vehicle demonstration ............................... 71 5.4 Assessment of demonstration project.................................. 73 6 CONCLUSIONS..................................................................... 75 7 REFERENCES....................................................................... 77 viii APPENDIX .....................................................................................89 A Fuel properties....................................................................... 90 B LCI data and documentation ............................................... 91 B.1 Natural gas supply ....................................................... 91 B.2 Hydrogen supply ......................................................... 95 B.3 Electricity production ................................................ 101 B.4 Filling station operation............................................. 103 B.5 Vehicle use ................................................................ 108 C LCI results............................................................................ 115 D Sensitivity analysis data ...................................................... 124 ix List of Tables Table 2-1: Composition of processed natural gas ........................... 12 Table 4-1: Fuel properties of CNG, HCNG and hydrogen.............