Marine Fuels & Emissions Witherby Seamanship International A Division of Witherby Publishing Group Ltd 4 Dunlop Square, Livingston, Edinburgh, EH54 8SB, Scotland, UK Tel No: +44(0)1506 463 227 - Fax No: +44(0)1506 468 999 Email: info@emailws.com - Web: www.witherbyseamanship.com First edition published 2013 ISBN: 978-1-85609-578-5 eBook ISBN: 978-1-85609-579-2 © Witherby Publishing Group Ltd, 2013 British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library. Notice of Terms of Use All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior permission of the publishers. While the advice given in this book (Marine Fuels & Emissions) has been developed using the best information currently available, it is intended purely as guidance to be used at the user’s own risk. Witherby Publishing Group accepts no responsibility for the accuracy of any information or advice given in the document or any omission from the document or for any consequence whatsoever resulting directly or indirectly from compliance with or adoption of guidance contained in the document even if caused by failure to exercise reasonable care. This publication has been prepared to deal with the subject of Marine Fuels & Emissions. This should not, however, be taken to mean that this publication deals comprehensively with all of the issues that will need to be addressed or even, where a particular issue is addressed, that this publication sets out the only definitive view for all situations. Published by Witherby Publishing Group Ltd 4 Dunlop Square, Livingston, Edinburgh, EH54 8SB, Scotland, UK Tel No: +44(0)1506 463 227 Fax No: +44(0)1506 468 999 Email: info@emailws.com Web: www.witherbys.com Printed and bound in Great Britain by Charlesworth Press, Wakefield Cover image shows a mobile AMP™ unit at the World Cruise Center, Port of Los Angeles (courtesy of the Port of Los Angeles) v Foreword It is obvious to anyone with even a passing interest in the shipping industry that it is now well and truly in the “environmental crosshairs”. Its environmental performance is being scrutinised and legislated for as never before. Shipping’s environmental performance with respect to emissions to air is perhaps the issue receiving the most regulatory and public attention. Sulphur dioxide (SOx), nitrogen oxides (NOx) and volatile organic compounds (VOCs) have all been the subject of international (IMO) and, in some parts of the world, local regulation. Carbon dioxide has received attention indirectly in the regulations concerning vessel fuel efficiency. It is doubtful whether anyone would bet against exhaust gas black carbon and particulates being the subject of some form of regulation in the near future. The common thread joining all these issues is ship’s fuel, both in terms of quality and quantity. Changing either, or both, of these factors has a marked effect on the emissions to air from a ship. It is at this point that life for the ship manager or operator becomes difficult. Not only do the regulations need to be complied with, but they need to be complied with in such a way that the vessel remains competitive. In shipping, as in other things in life, there is more than one way to “skin a cat”. The path to compliance, with an eye to the future, is a maze rather than a freeway and very careful consideration must be given to each and every vessel. Even sister vessels have differing trading patterns and therefore each solution will be more or less bespoke. With the rise of the emission to air scrutiny and legislation, there has naturally been a corresponding rise in the number of organisations coming forwards with technological and operational solutions to the maze. All very well, but which one to pick? In Marine Fuels & Emissions, the authors have provided essential and comprehensive information about the myriad of factors that must be considered before often expensive decisions concerning compliance and beyond are made. The book may be justifiably considered as a timely and welcome guide out of the emissions maze. John Aitken (former Secretary General of SEAaT) vii Acknowledgements Thanks to: Alfa Laval MAN Diesel & Turbo Belco Technologies Corporation Mitsubishi Heavy Industries (MHI) Equipment Europe Couple Systems NYK Group Europe DANSK TEKNOLOGI Port of Gothenburg DEC Marine Port of Los Angeles Det Norske Veritas Rolls-Royce Marine Ecofys SEAaT Ecospec Global Technology Skangass Envitech Inc Stena LNG Gasnor Totempower Energy Systems Germanischer Lloyd Wärtsilä Corp Green Tech Marine Wilhelmsen Technical Solutions Hydrex ix Contents Foreword ......................................................................................................................................................................v Acknowledgements ....................................................................................................................................................vii List of Figures .............................................................................................................................................................xiii CHAPTER ONE – Introduction .................................................................................................................1 1 Introduction ...........................................................................................................................................................3 1.1 Non-GHG Emissions ................................................................................................................................3 1.1.1 Population Health .......................................................................................................................4 1.2 Reducing Emissions .................................................................................................................................4 1.2.1 Changing the Fuel ......................................................................................................................5 1.2.2 Using Less Fuel .........................................................................................................................5 1.2.3 Abatement Technologies ............................................................................................................5 1.3 The Future ................................................................................................................................................5 References ...................................................................................................................................................................6 CHAPTER TWO – Marine Fuels ................................................................................................................7 2 Marine Fuels .........................................................................................................................................................9 2.1 Blending ..................................................................................................................................................10 2.2 Fuel Standards and Quality ...................................................................................................................11 2.2.1 Standards .................................................................................................................................11 2.2.2 Technical Specifications and Fuel Sulphur Content .................................................................11 2.2.3 Sulphur .....................................................................................................................................14 2.2.4 Off-Specification Fuel ...............................................................................................................14 2.3 Cutting Emissions ...................................................................................................................................15 2.3.1 Refiner’s Point of View ............................................................................................................15 2.3.2 Low Sulphur Fuels ....................................................................................................................16 2.3.3 Fuel Switching ..........................................................................................................................17 2.3.4 Safety and Potential Problems .................................................................................................17 References .................................................................................................................................................................19 CHAPTER THREE – Natural Gas as a Fuel ...........................................................................................21 3 Natural Gas as a Fuel .........................................................................................................................................23 3.1 LNG (Liquefied Natural Gas) ..................................................................................................................24 3.1.1 Properties of LNG .....................................................................................................................24 3.2 Training and Safety .................................................................................................................................24 3.3 Class Societies .......................................................................................................................................25 3.4 Bunkering................................................................................................................................................26 3.4.1 Ports/Regions Developing LNG Capabilities ............................................................................29 3.5 Rules and Regulations............................................................................................................................33 3.6 Engine Technology .................................................................................................................................34 3.6.1 Dual Fuel Engine Technology ...................................................................................................34 3.6.2 Potential Technical/Design Problems .......................................................................................34 3.7 Ship Designs and Orders........................................................................................................................37 3.8 The Economics of LNG as a Marine Propulsion Fuel .............................................................................38 References .................................................................................................................................................................39 CHAPTER FOUR – Non-Fossil Marine Fuels and Power Sources ......................................................41 4 Non-Fossil Marine Fuels and Power Sources .....................................................................................................43 4.1 Biofuels ...................................................................................................................................................43 4.1.1 Production ................................................................................................................................44 4.1.2 Bioethanol .................................................................................................................................44 x Marine Fuels & Emissions 4.1.3 Biomethane ..............................................................................................................................45 4.1.4 Biodiesel ...................................................................................................................................45 4.1.5 Environmental Credentials .......................................................................................................47 4.1.6 Use of Biofuels in the Marine Sector ........................................................................................49 4.1.7 The Oil Companies ...................................................................................................................50 4.1.8 Biofuels of the Future ...............................................................................................................50 4.2 Wind Power ............................................................................................................................................51 4.2.1 Kite Systems .............................................................................................................................51 4.2.2 Wind Turbines ...........................................................................................................................51 4.2.3 Rotors .......................................................................................................................................52 4.2.4 Rigid Sails .................................................................................................................................52 4.2.5 Rigid Sail and Solar Power in Combination ..............................................................................52 4.3 Solar Power ............................................................................................................................................53 4.3.1 Marine Use ...............................................................................................................................53 4.4 Fuel Cells ................................................................................................................................................54 4.5 Battery Power .........................................................................................................................................56 4.6 Shore Power ...........................................................................................................................................57 4.6.1 Emissions .................................................................................................................................57 4.6.2 Costs and Problems .................................................................................................................58 4.6.3 Regional Development of Onshore Power ...............................................................................59 4.6.4 Ships Using Cold Ironing ..........................................................................................................60 4.6.5 Legislation ................................................................................................................................61 4.7 Nuclear Power ........................................................................................................................................61 References .................................................................................................................................................................62 CHAPTER FIVE – Efficient Energy Management ..................................................................................63 5 Efficient Energy Management .............................................................................................................................65 5.1 Ship Operation ........................................................................................................................................65 5.1.1 Speed .......................................................................................................................................65 5.1.2 Propeller and Rudder Maintenance ..........................................................................................67 5.2 Ship Design ............................................................................................................................................68 5.2.1 Fuel Efficient Designs ...............................................................................................................68 5.3 The Effect of Legislation .........................................................................................................................70 5.3.1 Encouraging Green Investment ................................................................................................70 5.3.2 Environmental Ship Index (ESI) ...............................................................................................70 References .................................................................................................................................................................73 CHAPTER SIX – Emissions and Pollutants...........................................................................................75 6 Emissions and Pollutants ....................................................................................................................................77 6.1 Greenhouse Gases (GHG) .....................................................................................................................77 6.1.1 Sources and Sinks of GHGs .....................................................................................................77 6.1.2 Shipping and GHGs ..................................................................................................................77 6.2 The Different Pollutants ..........................................................................................................................78 6.2.1 Carbon Dioxide (CO2) ...............................................................................................................78 6.2.2 Nitrogen Oxides (NOx) .............................................................................................................81 6.2.3 Sulphur Oxides (SOx) ...............................................................................................................83 6.2.4 Particulate Matter (PM) .............................................................................................................85 References ..........................................................................................................................................................89 CHAPTER SEVEN – Regions of Emission Control ...............................................................................91 7 Regions of Emission Control ...............................................................................................................................93 7.1 Designation of an ECA............................................................................................................................93 7.2 Emission Control Areas ..........................................................................................................................94 7.2.1 The Two European ECAs: The Baltic Sea SOx-ECA and the North Sea and English Channel SOx-ECA .......................................................................................................95 xi 7.2.2 The North American SOx/NOx-ECA ........................................................................................96 7.2.3 United States Caribbean Sea SOx/NOx-ECA ..........................................................................96 7.2.4 California Regulated Waters Sulphur in Fuel Standards ..........................................................97 7.2.5 The European Union Sulphur Directive at Port ........................................................................98 CHAPTER EIGHT – Emissions Regulations and Compliance .............................................................99 8 Emissions Regulations and Compliance ...........................................................................................................101 8.1 Carbon Dioxide Emission Regulations .................................................................................................101 8.1.1 IMO CO2 Legislation ...............................................................................................................101 8.1.2 European Union Legislation ...................................................................................................103 8.1.3 Compliance and Enforcement ................................................................................................103 8.1.4 Incentives for Reducing CO2 Emissions .................................................................................104 8.2 Nitrogen Oxide Emission Regulations ..................................................................................................104 8.2.1 IMO Mandatory Global and Regional NOx Legislation ..........................................................104 8.2.2 The CARB (California Air Resources Board) At-Berth (OGV) Emissions Regulation ............107 8.2.3 Incentives for Reducing NOx Emissions ................................................................................108 8.2.4 Inland Waterway Legislation ...................................................................................................108 8.3 Sulphur Dioxide Emission Regulations .................................................................................................109 8.3.1 IMO SOx Regulations .............................................................................................................109 8.3.2 California SOx Legislation ......................................................................................................112 8.3.3 The European Union (EU) Sulphur Directive at Port ..............................................................113 8.3.4 Legislation for SOx-Reducing Systems ..................................................................................114 8.4 Particulate Matter Emission Regulations ..............................................................................................116 8.4.1 Marine Particulate Matter Standards ......................................................................................116 8.4.2 Inland Waterway Legislation ...................................................................................................117 References ...............................................................................................................................................................117 CHAPTER NINE – Abatement Technologies and Engines ..................................................................119 9 Abatement Technologies and Engines ..............................................................................................................121 9.1 Abatement Technologies ......................................................................................................................121 9.2 EGTS for SOx Emissions .....................................................................................................................121 9.2.1 Open Loop or Seawater Scrubbing ........................................................................................123 9.2.2 Closed Loop or Fresh Water Scrubbing .................................................................................123 9.2.3 Hybrid Scrubbing ....................................................................................................................124 9.2.4 Dry Scrubbing .........................................................................................................................124 9.3 EGTS for NOx Emissions .....................................................................................................................124 9.3.1 SCR (Selective Catalytic Reduction) ......................................................................................124 9.3.2 EGR (Exhaust Gas Recirculation) ..........................................................................................125 9.4 LNG Engines and Related Technologies ..............................................................................................125 9.4.1 Spark-Ignited Engines ............................................................................................................126 9.4.2 Dual Fuel Engines ..................................................................................................................126 9.4.3 Single Fuel Gas Engines ........................................................................................................126 9.5 Exhaust Monitoring for Emissions Compliance ....................................................................................127 References ...............................................................................................................................................................127 CHAPTER TEN – Data Sheets for a Selection of Abatement Technology Systems ........................129 10 Data Sheets for a Selection of Abatement Technology Systems ......................................................................131 10.1 SOx Abatement Systems ......................................................................................................................131 10.1.1 Alfa Laval PureSOx ...............................................................................................................131 10.1.2 BELCO Marine Scrubber ........................................................................................................132 10.1.3 Clean Marine Hybrid Scrubber ...............................................................................................133 10.1.4 DryEGCS Scrubber ................................................................................................................134 10.1.5 Ecospec CSNOx ....................................................................................................................135 10.1.6 Envitech Marine Ship-based and Land-based SO2 Scrubber Systems ..................................136 Contents xii Marine Fuels & Emissions 10.1.7 GTM R15 Scrubber ................................................................................................................137 10.1.8 MES EcoSilencer Scrubber ....................................................................................................138 10.1.9 Wärtsilä Closed Loop Exhaust Gas Scrubber ........................................................................139 10.1.10 Wärtsilä Open Loop Exhaust Gas Scrubber ...........................................................................140 10.2 NOx Abatement Systems......................................................................................................................141 10.2.1 BLUNOX SCR System ..........................................................................................................141 10.2.2 DEC Marine SCR System ......................................................................................................142 10.2.3 MAN Diesel & Turbo Exhaust Gas Recirculation (EGR) System ...........................................143 10.2.4 Wärtsilä NOx Reducer System ..............................................................................................144 10.2.5 Wilhelmsen NOx Care Marine ...............................................................................................145 10.3 Engines with LNG Capability ................................................................................................................146 10.3.1 Caterpillar M 46 DF Medium Speed Dual Fuel Engine ..........................................................146 10.3.2 MAN B&W 2-Stroke Dual Fuel ME-GI Engine .......................................................................147 10.3.3 MAN Diesel & Turbo 4-Stroke Dual Fuel Engines ..................................................................148 10.3.4 Mitsubishi Gas Engines ..........................................................................................................149 10.3.5 Rolls-Royce Bergen B-series and C-series Lean-Burn 4-Stroke Gas Engines .....................150 10.3.6 Wärtsilä Dual Fuel Engines ....................................................................................................151 3 1 Introduction It is very difficult to understand the complicated variations of our climate, as well as its fluctuations over long time periods. The validity of climate change data is being questioned, but this is not necessarily a negative or unusual circumstance. Scientific achievements are rooted in questioning theories, testing results, rigorous checking and repeating experiments. Public perception about climate change is strongly influenced by media reporting and it can be very difficult for the individual to identify the truth from the ‘sensational’. One of the major manmade emissions that causes concern is carbon dioxide (CO2). Black carbon (BC) emissions may also have a significant impact on the climate (see Chapter 6). All fossil fuels contain carbon and all release CO2 on combustion, which stays in the atmosphere for many years. It also takes a long time for the CO2 to be recaptured through the natural environmental processes. Many think that atmospheric increases in CO2 and other ‘greenhouse gases’ (GHGs) levels will have long-term effects on the composition of the atmosphere and so affect global climate patterns. An alternative argument is that the levels of CO2 in our atmosphere are so low (about 0.039% or 390 ppm), and manmade increases even smaller, that the effects of water vapour as a GHG are actually a much more powerful, variable and uncontrollable influence on global climate change (see Chapter 6). (courtesy National Oceanic and Atmospheric Administration, NOAA) Recent Global Monthly Mean CO2 CO 2 Parts Per Million 394 392 February 2012 390 388 386 384 382 380 200720102011201220082009 Year Figure 1.1 Recent monthly mean carbon dioxide globally averaged over marine surface sites It is therefore reasonable to state that, although scientists are confident that human activity is changing the composition of the Earth’s atmosphere, they are not yet sure by how much, at what rate and what the consequences will be. Economy and Efficiency Many countries, organisations, companies and individuals have an interest in emission reduction. However, turning that interest into action can be costly. The difficult economic climate over the past years has forced a strategic re-think in many areas. As an example, when fuel prices are low, there is no incentive to economise. However, for boxships, it has been estimated that bunker costs can make up nearly 80% of the cost of ship operations. Such a high percentage means that efficiencies and fuel savings become highly desirable and the motivation to optimise operations will be very high. The amount of fuel consumed is directly proportional to the amount of CO2 produced, so using less fuel is eco-friendly as well as cost effective. SEAaT (Shipping Emissions Abatement and Trading), which is a cross-industry group formed to raise awareness of emission reduction solutions for the shipping community, believes that a competitive market can achieve environmental goals by encouraging innovation and driving down costs. The IMO has facilitated legislative development and established a regulatory regime to control and reduce emissions of GHG from ships by adopting amendments to MARPOL Annex VI in July 2011 (see Chapter 8). 1.1 Non-GHG Emissions It is not just the GHG characteristics of some emissions that are creating concern. Other substances, such as sulphur oxides (SOx), NOx (a combination of nitric oxide and nitrogen dioxide) and particulate matter (PM) are also considered undesirable. Heavier fractions of fuel oil contain significant quantities of sulphur, nitrogen and ash. Emissions of SOx are a result of a fuel’s natural and variable sulphur content. Different fossil fuels contain different concentrations of sulphur as an impurity and this can be present in various forms - attached to hydrocarbons, as hydrogen sulphide gas (H2S) or as elemental sulphur. These forms of sulphur are changed and combine with other substances during the combustion process. 4 Marine Fuels & Emissions Nitrogen combustion leads to the formation of NOx compounds. The volume of NOx produced during combustion varies with the type of fuel, any pollution control technology used and the operation and maintenance of the engines. NOx emissions are also linked with GHGs. NOx compounds are ozone precursors. When ozone is present in the incorrect layer of the atmosphere, it acts as a GHG. Particulate matter consists of carbon-based particles produced mainly through the incomplete combustion of fossil fuels. PM varies in size, with the smallest particles being of most concern as they can be inhaled deep into the respiratory tract and cause serious health problems. 1.1.1 Population Health Emissions of SOx, NOx and PM all have a significant and detrimental effect on the health of populations. Approximately 70% of the emissions from international shipping occur within 400 km of land. Although airborne pollutants can be carried far inland, coastal and port populations are particularly affected by polluting emissions from shipping (see Figure 1.2). In 2007, it was estimated that about 60,000 premature deaths from cardiopulmonary disease and lung cancer were caused annually by PM emissions from ocean-going ships. This was expected to increase by 40% by 2012. There are also additional health implications to be considered, such as those associated with non-fatal heart attacks, asthma, hospital visits and lost work days. In July 2011, the latest IMO ‘sulphur in fuel’ rules and emission abatement methods were incorporated into European Union legislation. This action strengthened the effectiveness of the fuel standards. It has been estimated that the resulting public health savings could be in the range of €15 to €34 billion. If correct, these would far outweigh the estimated costs to the shipping industry of between €2.6 billion and €11 billion ($3.7 to $15.6 billion). In Canada, which has been subject to the effects of the North American SOx/NOx-ECA since August 2012, the cost of health savings is also projected to surpass the expense of compliance. It has been estimated that implementing ECA standards in Canada will produce an annual saving of $900 million in health benefits. The additional fuel costs to the Canadian marine industry are estimated at $500 million. The EPA estimates the overall cost of the North American SOx/ NOx-ECA in the United States at $3.2 billion in 2020. In that same year, it estimates the monetised health-related benefits in the US to range from $47 billion to $110 billion. 1.2 Reducing Emissions It is critical to link the fuels we use with the emissions they produce. The nature of the emissions we produce depends on the type of fuel we use and how much and how efficiently we burn it. Fossil fuels all contain carbon and through combustion they produce CO2. Therefore, the more fossil fuels we use, the more CO2 will be produced. Fossil fuels are also 30°E45°E60°E75°E90°E105°E120°E 30°E45°E60°E75°E90°E105°E120°E 40°N 30°N 20°N 10°N 0° 40°N 30°N 20°N 10°N 0° NOX emissions from shipping g(NO 2 )/box/s 1500 1200 900 600 300 100 50 10 Figure 1.2 NOx signature of shipping in the Indian Ocean using data from August 2002 to April 2004 (from Richter et al, 2004) Introduction 5 a finite resource and are likely to become increasingly uneconomic to extract. Reducing the amount of fossil fuel the shipping industry uses by making better use of what we have or by finding alternative energy sources is both pragmatic and progressive. 1.2.1 Changing the Fuel This strategy can be used to reduce emissions in several ways: •Reducing the concentration of unwanted substances, eg lowering sulphur levels in fuels during the refining process, although this is more expensive (see Chapter 2) •using fossil fuels that emit fewer harmful emissions, eg LNG (see Chapter 3), although if methane slip is not controlled, the overall GHG potential is as high as conventional fuel •using alternative renewable sources of power, such as biofuels, fuel cells, solar or wind power. Shore power or ‘cold ironing’ (also called alternative maritime power) while at berth is also an attractive alternative. These ‘green’ energy sources are currently under developed, although they are generating interest in many quarters (see Chapter 4). 1.2.2 Using Less Fuel Alternative designs and/or fuel efficient operation can lower levels of CO2, SOx, NOx and particulate emissions (see Chapter 5). Changing the specification of vessels to create more fuel efficient designs is a longer term strategy than improving the operational efficiency of a ship. Recently, the German Class Society, Germanischer Lloyd (GL), noted a shift from designing ships for maximum speed to designing for the optimum and most fuel efficient speed for the operating conditions. This is particularly evident in the container ship sector and is a reaction to the cost and legislative pressures felt by the shipping community. While trialling enhanced navigation tools to optimise the ship’s speed and obtain a balance between fuel economy and passenger comfort at the start of 2011, Captain Jessing of the DFDS ferry ‘Crown of Scandinavia’ said, “A seven-minute delay leaving port will cost us an extra tonne of fuel ”. 1.2.3 Abatement Technologies Changing the fuel affects emissions from the exhaust, but if further reductions are necessary abatement technology can be used (see Chapter 9). Exhaust gas treatment systems (EGTSs) for SOx, which also reduce PM emissions, include open and closed loop wet scrubbing and dry scrubbing techniques. Selective catalytic reduction (SCR) and exhaust gas recovery (EGR) are the most likely EGTSs for NOx emissions reduction. However, the operation of abatement technologies uses energy and produces CO2, so a balance has to be achieved between the need to remove certain emissions and the production of others. Investment in emission-reducing technology requires high up-front expenditure, which is why incentive schemes to encourage investment in, and aid the development of, abatement technology have been so successful. Processing fuel to lower sulphur levels is also an expensive process and this cost is passed on to the shipping companies, who traditionally have used the cheapest, lowest quality fuel. 1.3 The Future The IMO commissioned a study to assess the likely future impact of its CO2 reduction legislation (EEDI, Energy Efficiency Design Index, and SEEMP, Ship Energy Efficiency Management Plan) mandated at MEPC 62 in 2011. The results of the study indicated that SEEMP measures (mainly operational) have an effect mostly in the medium term (eg 2020), while EEDI measures (technical) should have more significant impact in the long term (eg 2030-2050). Fleet renewal and the establishment of new technologies will influence this longer term effect. The study concluded that, although the EEDI and SEEMP methods of reducing CO2 will result in a significant reduction in fuel consumption, leading to a significant saving in fuel costs, the overall emission levels are still likely to rise over time, but at a much slower rate. For the marine sector, looking at the variety of different fuels and their availability, whether regular fossil fuel that has reduced sulphur, alternative fossil fuel eg LNG, biofuels, hydrogen, electricity (either via fuel cells or shore power), or wind or solar power, it is clear that there will not be one fuel type for all shipping. One fuel or power source will not suit every set of circumstances, and multiple fuel options for each vessel may become commonplace. “Experts believe there could be up to 500 gas- powered ships in northern Europe within the decade, and a range of other power or fuel sources being added to what is being called ‘shipping’s energy mix’.” Lloyd’s List 2012 6 Marine Fuels & Emissions References Review of UK Shipping Emissions, Committee on Climate Change, November 2011 Solomon S, Rosenlof K H, Portman R W, Daniel J S, Davis S M, Sanford T J and Plattner G-K. Contributions of Stratospheric Water Vapor to Decadal Changes in the Rate of Global Warming, Science Volume 327, no. 5970, March 2010 Assessment of IMO Mandated Energy Efficiency Measures for International Shipping (MEPC 63/INF.2) by Z Bazari and T Longva, October 2011 World Energy Outlook 2011 by the International Energy Agency Revised Hedley Environmental Index by the Independent public policy think tank Civic Exchange and the University of Hong Kong’s School of Public Health, January 2012