1、automotive engineering international SAE INTERNATIONAL technology profiles Alternative FUELS Transportation Fuels for Today and Tomorrow Richard L. BechtoldAlternative Fuels Transportation Fuels for Today and Tomorrow Richard L. Bechtold Society of Automotive Engineers, Inc. Warrendale, Pa. Copyrigh
2、t 2002 Society of Automotive Engineers, Inc. eISBN: 978-0-7680-7049-1All 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 written
3、 permission of SAE. For permission and licensing requests, contact: SAE Permissions 400 Commonwealth Drive Warrendale, PA 15096-0001 USA E-mail: permissionssae.org Fax: 724-772-4028 Tel: 724-772-4891 For multiple print copies, contact: SAE Customer Service E-mail: CustomerServicesae.org Fax: 724-776
4、-0790 Tel: 877-606-7323 (inside USA and Canada) 724-776-4970 (outside USA) ISBN 0-7680-0907-3 Library of Congress Control Number: 2002092330 Copyright 2002 Society of Automotive Engineers, Inc. Positions and opinions advanced in this document are those of the author(s) and are not necessarily those
5、of SAE. The author(s) is solely responsible for the content. SAE Order No. T-100 Printed in the United States of America.Contents Preface . v Executive Summary ix Chapter 1 The Argument for Alternative Fuels 1 Chapter 2 Methanol 9 Chapter 3 Ethanol . 23 Chapter 4 Propane . 39 Chapter 5 Natural Gas 4
6、7 Chapter 6 Electricity . 57 Chapter 7 Biodiesel 63 Chapter 8 Hydrogen 75 Chapter 9 Gas-to-Liquids 85 iiiPreface The vitality and economic growth of the United States is linked to affordable transportation. In comparison to most countries, the United States is sparsely populated, and when developmen
7、t is pursued it assumes ready access by highway vehicles. The availability of good roads and inexpensive fuel made possible large-scale freight movement by truck and facilitated the ability of everyone to see the country by car. The decade of the 1960s was one of the most productive in U.S. history
8、due in part to a thriving automotive industry and inexpensive petroleum fuel. This fortuitous situation came to a rapid end in 1974 when the Organization of Petroleum Exporting Countries (OPEC) dramatically raised the price of crude oil. The resulting increase in fuel prices caused auto sales to dec
9、line and, in large part, induced a long period of slow growth and inflation in the United States. This first OPEC-induced petroleum “crisis“ caused the industrial, utility, home heating, and commercial sectors of the United States to diversify their dependence on petroleum fuels. In particular, many
10、 industrial and utility operations now have the capability of burning more than one fuel, which allows them to switch fuels when needed. The transportation sector is the one sector that has not been able to make this transition to date. Our high- way transportation system is entirely dependent on pe
11、troleum fuels (with the exception of about 2.5% oxygenates added to gasoline). While vehicles today are more efficient than they were 25 years ago, the average fuel economy of new vehicles has not changed over the past 10 years, in part due to the growth of light trucks (pickups, vans, and sport uti
12、lity vehicles). Since 1998, more than half of the petroleum the U.S. economy requires has been supplied by imports. The almost inexorably increasing share of imports is due to the steady growth in transportation fuel demand and reduced domestic oil production. Whereas world oil production has yet to
13、 peak, domestic production has been in decline almost continuously since 1970. Domestic oil production now stands at 5.9 million barrels per day (mbpd), well below the peak of 9.6 mbpd in 1970. Declining domestic production has created a gap between the oil demands of transportation and vdomestic su
14、pply. This gap is projected to roughly double by 2020 as domes- tic oil resources continue to decline and demand continues to grow. The Energy Information Agency (EIA) of the Department of Energy projects U.S. dependence on imported petroleum will grow to 62% in 2020 from 53% in 20001. Oil imports a
15、mounted to $60 billion in 1999, equal to 18% of the total U.S. trade deficit. For the first six months of 2000, oil imports were 26% of the trade deficit. The EIAs latest forecast of transportation energy demand to 2020 shows that jet fuel demand is projected to grow 2.5% annually, diesel fuel deman
16、d is projected to grow 2.4% annually, and gasoline demand is projected to grow more modestly at 1.6% annually (between now and 2020). These increases in demand are projected despite significant improvements in vehicle fuel economy and aircraft efficiency. The demand for transportation continues to i
17、ncrease faster than efficiency improvements can be made. Outside the United States, transportation fuel demand is projected to grow even faster due to rapid development of transportation systems and personal vehicles in many less-developed countries. Their demand for petroleum fuels will rapidly bec
18、ome a significant market force and accelerate the day when crude oil production peaks and petroleum fuels become increasingly more costly. The term “alternative fuel“ has been used to describe any fuel suggested for use in transportation vehicles other than gasoline or diesel fuel. Alternative fuels
19、 are not a new concepteven Henry Ford envisioned many of todays concerns about fuel availability and the environment by investigating the use of ethanol as a renewable, home-grown fuel whose production would benefit agriculture. Alternative transportation fuels today generally include ethanol, metha
20、nol, natural gas, propane, hydrogen, biodiesel, and electricity (electricity is included even though it is not a fuel). Liquids made from natural gas (prima- rily diesel fuels, but gasolines are possible as well) are being made in increasing quantities and may soon be marketed as alternative fuels i
21、n the United States. The climatological and scientific community has warned that increasing concentrations of greenhouse gases in the atmosphere will cause global 1 “2002 Annual Energy Outlook,“ Energy Information Administration, U.S. Department of Energy, www.eia.doe.gov. viclimate change. The sing
22、le most prevalent greenhouse gas is carbon dioxide, the primary combustion product of petroleum fuels. (The typical vehicle using 600 gallons of gasoline per year releases just over five metric tons per year of carbon dioxide.) The United Nations has been instrumental in getting developed and emergi
23、ng nations to agree to limit greenhouse gas emissions (i.e., the Kyoto Protocol). The United States has declined to be a signatory to the Kyoto Protocol because of the large negative effect it would have on our economy, given the policy options and technology available now to reduce greenhouse gases
24、, even though the United States accounts for about 25% of world greenhouse gases. President Bush has indicated that he intends to develop U.S. alternatives to the Kyoto Protocol, including the National Climate Change Technology Initiative. Renewable alternative fuels such as ethanol and biodiesel ha
25、ve very low greenhouse gases, and other countries are implementing them as part of their plans to reduce greenhouse gases. For example, the European Union is proposing that ethanol and biodiesel account for 5.75% of fuels sold by 2010; Japan is considering intro- ducing a policy of blending ethanol
26、at a 10% ratio with gasoline to reduce transportation carbon dioxide emissions by 5.2% by 2012 to meet its Kyoto Protocol target. Alternative transportation fuels with very low greenhouse gases will no doubt become more in demand as pressures increase on the United States to reduce greenhouse gas em
27、issions, especially from the trans- portation sector. In 2001, the terrorist attacks on the United States highlighted the political and cultural turmoil that currently exists in many of the countries on which we depend for much of our petroleum fuel. In early January 2002, the federal government and
28、 the auto industry announced the successor to the Partner- ship for a New Generation of Vehicles (PNGV) called FreedomCAR. The FreedomCAR Program will focus on fuel cell powertrains that use hydrogen for fuel. While that hydrogen will probably come from fossil fuels for some time, it marks a turning
29、 point in that it lays out a vision of a transition for not only the auto industry, but the energy providers as well. While many have proclaimed the “death“ of alternative fuels over the past 20 years, the reality is that alternative fuel growth continues each year. There are now more alternative fu
30、el models available for purchase than ever before, and alterna- tive fuel use keeps growing. Interest in “home-grown“ fuels such as ethanol and biodiesel continues to grow. It appears we could be on the brink of a revolution in our transportation system with a transition to alternative fuels. viiCha
31、pter 1 The Argument for Alternative Fuels The vitality and economic growth of the United States is linked to affordable transportation. In comparison to most countries, the United States is sparsely populated, and when development is pursued, it assumes access by highway vehicles. The interstate hig
32、hway system made possible large-scale freight movement by truck and facilitated the ability of everyone to see the country by car. The decade of the 1960s was one of the most productive in U.S. history due in part to a thriving automotive industry and inexpensive petro- leum fuel. The fragility of t
33、his fortuitous situation was exposed in 1974 when the Organization of Petroleum Exporting Countries (OPEC) dramatically raised the price of crude oil. At about the same time, there was a growing realization that transportation vehicles were a significant contributor to degraded air quality, and the
34、Environmental Protection Agency was formed to provide remedies. Alternative transportation fuels were seen as a way to address both of these issues and provide economic benefits as well. In his second week in office, President Bush established the National Energy Policy Development Group which relea
35、sed the National Energy Policy (NEP) in May 2001. The NEP took a critical look at our current energy supplies and demands, and made several recommendations to correct imbal- ances. One of the major imbalances is supply and demand for petroleum fuels. Our highway transportation system is entirely dep
36、endent on petro- leum fuels (with the exception of about 2.5% oxygenates added to gasoline). While vehicles today are more efficient than they were 25 years ago, the average fuel economy of new vehicles has not changed over the past 10 years, in part due to the growth of light trucks (pickups, vans,
37、 and sport utility vehicles). The NEP recommended that consideration be given to 1increasing the fuel economy of new vehicles and the use of domestic renew- able fuels (alternative fuels) wherever economically viable. While the NEP states that increased domestic production of petroleum fuels is desi
38、rable in the near term to help solve our transportation energy problem, it recognizes that in the long term, more efficient vehicles and non-petroleum fuels are needed to be part of the solution. In Europe, a similar need for alternative fuels has been recognized. The European Commission (EC) has pr
39、oposed new legislation to promote the use of alternative fuels for transport, starting with the regulatory and fiscal pro- motion of biofuels, such as biodiesel and bioethanol. A regulatory package (COM 2001 547) was adopted in November 2001 which includes an action plan and two proposals for Direct
40、ives that would establish minimum biofuel content in transportation fuels and allow reduced taxation rates for biofuels1. The action plan outlines a strategy to achieve a 20% substitution of diesel and gasoline fuels by alternative fuels in the road transport sector by 2020. It concludes that only t
41、hree options would have the potential to achieve indi- vidually more than 5% of total transport fuel consumption over the next 20 years: (1) biofuels that are already available, (2) natural gas in the medium term, and (3) hydrogen and fuel cells in the long term. The first proposed Directive would e
42、stablish a minimum level of biofuels as a proportion of fuels sold from 2005, starting with 2% and reaching 5.75% of fuels sold in 2010. The second proposed Directive would give Member States the option of applying a reduced rate of excise duty to pure or blended biofuels, when used either as heatin
43、g or motor fuel. What Are Alternative Fuels? The term “alternative fuel“ has been used to describe any fuel suggested for use in transportation vehicles other than gasoline or diesel fuel. Alternative fuels are not a new concepteven Henry Ford envisioned many of todays concerns about fuel availabili
44、ty and the environment by investigating the use of ethanol as a renewable, home-grown fuel whose production would benefit agriculture. Alternative transportation fuels today are generally conceded to 1 Communication from the Commission to the European Parliament, the Council, the Economic and Social
45、 Committee, and the Committee of the Regions on Alternative Fuels for Road Transportation and on a set of measures to promote the use of biofuels. 2include ethanol, methanol, natural gas, propane, hydrogen, biodiesel, and electricity (electricity is included even though it is not a fuel). Liquids ma
46、de from natural gas (primarily diesel fuels, but gasolines are possible as well) are being made in increasing quantities and may soon be marketed as alternative fuels in the United States. In addition to reducing the demand for petroleum fuels, each alternative fuel has some characteristic that give
47、s it an environmental advantage over petro- leum fuels. Most are less damaging to the environment if spilled, and in general, the emissions from alternative fuels are less reactive and toxic. This results in reduced amounts of ozone being produced, with the benefit of improved air quality. With the
48、advent of improved emission control technol- ogy, combined with cleaner petroleum fuels such as low-sulfur reformulated gasoline and ultra-low sulfur diesel fuel, petroleum-fueled vehicles have emission levels low enough to significantly depreciate most of the emissions benefits of alternative fuels
49、. However, many alternative fuels also produce much lower levels of greenhouse gases, which petroleum fuels will never be able to match without some sort of remediation of carbon dioxide. Unlike other energy-using sectors, which have introduced substitute fuels and fuel switching flexibility since the oil shocks of the 1970s and 1980s, the transportation sector remains overwhelmingly dependent on petroleum- based fuels and on technologies that provide virtually no fuel flexibility. The transportation sector currently accounts for approximately two-thirds of all U.S. petroleum use a
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