An Alternative to Gasoline - thorium-now.orgthorium-now.org/synthetic_gasoline.pdf · NUCLEAR ENERGY AND SUSTAINABILITY PROGRAM An Alternative to Gasoline: Synthetic Fuels from Nuclear

NUCLEAR ENERGY AND SUSTAINABILITY PROGRAM

An Alternative to Gasoline:

Synthetic Fuels from Nuclear

Hydrogen and Captured CO2

B.D. Middleton and M.S. Kazimi

MIT-NES-TR-006—Rev. 2

April 2007

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Abstract

The motivation for this study stems from two concerns. The first is that carbon dioxide from

fossil fuel combustion is the largest single human contribution to global warming. The use of

nuclear power to produce hydrogen on a global scale for any of various possible end uses would

reduce the net amount of carbon dioxide emitted into the atmosphere. The second concern is in

regard to U.S. dependence on foreign oil. Over 58% of petroleum used by the US in 2002 was

imported and most likely a higher fraction is being imported today. With the majority of this oil

originating in highly volatile Middle Eastern countries, there is a potential threat to stability in the

US energy market.

This study was conducted to determine the extent to which nuclear power can contribute to a

transition in the transportation sector; away from an infrastructure that places the US at risk for

depending largely on foreign oil and that makes it inevitable that large quantities of carbon

dioxide will be emitted into the atmosphere. Several scenarios are reviewed in this study for using

nuclear hydrogen in transportation, including:

• Combining hydrogen with carbon dioxide captured from fossil fired plants to produce liquid fuel

• Using nuclear power to aid in the recovery of oil from tar sands or shale oil

Initially, a review of the literature pertaining to the potential contribution of nuclear power to

hydrogen production is performed. Two approaches for producing hydrogen from water are found

that have significant literature related to the subject. These cycles are High Temperature Steam

Electrolysis and the Sulfur Iodine Cycle. The UT-3 cycle is also promising but does not seem to

offer the same advantages with respect to energy efficiency. This work focuses on the High

Temperature Steam Electrolysis option.

A review of possible nuclear reactor concepts is also performed. Many advanced concepts have

been proposed, a large number of which show potential in producing hydrogen. However, there

are drawbacks to many of them for several reasons. The high temperatures needed eliminate some

reactors while lack of operational experience eliminates others. Ultimately, the two concepts that

are proposed for hydrogen production in the literature found are the High-Temperature Gas

Cooled Reactor (HTGR), which uses Helium coolant, and a modified version of the Advanced

Gas Reactor (AGR) using supercritical CO2 as the coolant (S-AGR). The reactor concepts that are

chosen for aiding production of oil from tar sands are the Advanced Candu Reactor (ACR-700),

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the Pebble Bed Modular Reactor (PBMR), and the Advanced Passive pressurized water reactor

(AP600).

A detailed study of how nuclear power can contribute to production of shale oil has not been

performed. Therefore, the section dealing with this particular possibility is much less in depth and

more speculative. However, some preliminary calculations are performed and presented in this

report.

Based on the reference year 2025 case, we find that the United States will need about 6.60 billion

barrels of ethanol (EtOH) or 8.77 billion barrels of methanol (MeOH) in order to replace the

conventional gasoline (CG) that will otherwise be used. About 39.4% of the CO2 that is projected

to be emitted from coal plants will need to be captured to produce this much EtOH and about

41.1% of the CO2 will need to be captured to produce the needed MeOH. For production of

EtOH, we estimate that there will need to be between 700 and 900 GWth of nuclear power to

produce the needed hydrogen and energy to create this amount of EtOH. By the same token, it

will take between 1000 and 1400 GWth of nuclear power to aid in production of the needed

MeOH.

In the same year – 2025 – the entire world will require 16.87 billion barrels of EtOH or 22.49

billion barrels of MeOH to replace the CG that will otherwise be used. This would require capture

of 29.5% of total emitted CO2 for production of EtOH or 28.4% for production of MeOH. This

amount of hydrogen and the associated energy requirements will demand between 1800 and 2300

GWth to produce the needed EtOH or between 2550 and 3500 GWth to produce the needed

MeOH.

These numbers show that there is a very wide market for using nuclear power to aid in the

production of alternative fuels to aid in the transition to the hydrogen economy. The large fraction

of emitted CO2 that need to be captured shows that a benefit of this process would be to

significantly decrease the total greenhouse gas emissions. A total cycle analysis reveals that the

total reduction in CO2 emissions in the U.S. will be slightly more than 20% for either ethanol use

or methanol use. A second benefit would be to decrease a nation’s dependence on imported

petroleum.

In conclusion, it is found that the concept of alternative liquid fuels produced from nuclear

hydrogen and captured carbon dioxide is viable. There is abundant CO2 for use and the hydrogen

can be produced with proven technology. There is also evidence that nuclear power can be

utilized in the production of oil from sand and shale.

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Acknowledgements

The authors greatly appreciate the comments provided by Professor Mike Driscoll of the MIT

Department of Nuclear Science and Engineering on drafts of this report. We are also grateful for

the help of Professor Ron Ballinger and Dr. Jeongyoun Lim, both of the MIT Department of

Nuclear Science and Engineering on issues of thermodynamics of the synthetic fuels. Thanks are

also due to MinWah Leung for editing the initial manuscript, and to Thibault Faney for his

editing of Rev. 2 of this report.

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CANES Publications

CANES reports, which include both progress and technical reports, are published under five series:

1. Advanced Nuclear Power Technology Program (ANP) 2. Nuclear Fuel Cycle Technology and Policy Program (NFC) 3. Nuclear Systems Enhanced Performance Program (NSP) 4. Nuclear Energy and Sustainability Program (NES) 5. Nuclear Space Applications Program (NSA)

Please visit our website (web.mit.edu/canes) to view publications lists and abstracts, and to purchase reports. MIT–NES Program: Publications MIT-NES-TR-008 S. Ansolabehere, Public Attitudes Toward America’s Energy

Options: Insights for Nuclear Energy (June 2007).

MIT-NES-TR-007 M.J. Memmott, M.J. Driscoll, M.S. Kazimi, and P. Hejzlar, Hydrogen Production for Steam Electrolysis Using a Supercritical CO2-Cooled Fast Reactor (February 2007).

MIT-NES-TR-006 R2 B.D. Middleton and M.S. Kazimi, An Alternative to Gasoline: Synthetic Fuels from Nuclear Hydrogen and Captured CO2 (July 2006).

MIT-NES-DES-005 G. Becerra, E. Esparza, A. Finan, E. Helvenston, S. Hembrador, K. Hohnholt, T. Khan, D. Legault, M. Lyttle, K. Miu, C. Murray, N. Parmar, S. Sheppard, C. Sizer, E. Zakszewski, K. Zeller, Nuclear Technology and Canadian Oil Sands: Integration of Nuclear Power and in situ Oil Extraction (December 2005).

MIT-NES-TR-004 Y.H. Jeong, M.S. Kazimi, K.J. Hohnholt, and B. Yildiz, Optimization of the Hybrid Sulfur Cycle for Hydrogen Generation (May 2005).

MIT-NES-TR-003 Y.H. Jeong, P. Saha and M.S. Kazimi, Attributes of a Nuclear-Assisted Gas Turbine Power Cycle (February 2005).

MIT-NES-TR-002 B. Yildiz, K. Hohnholt, and M.S. Kazimi, Hydrogen Production Using High Temperature Steam Electrolysis and Gas Reactors with Supercritical CO2 Cycles (December 2004).

MIT-NES-TR-001 B. Yildiz and M.S. Kazimi, Nuclear Energy Options for Hydrogen and Hydrogen-based Liquid Fuels Production (September 2003).

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Table of Contents

Abstract ..............................................................................................................iii Acknowledgements ............................................................................................v CANES Publications .........................................................................................vii Table of Contents...............................................................................................ix List of Figures ....................................................................................................xi List of Tables.....................................................................................................xii 1 Introduction....................................................................................................1

1.1 Motivation..............................................................................................................................1 1.2 Overview of Relevant Atmospheric Conditions..................................................................1 1.3 Overview of Relevant Energy Conditions...........................................................................3 1.4 Possible Transition Strategy................................................................................................4 1.5 Use of Nuclear Power to Aid in Recovery of Oil from Tar Sands .....................................5 1.6 Use of Nuclear Power to Aid in Recovery of Oil from Oil Shale .......................................6 1.7 Organization of Report.........................................................................................................6

2 Energy Usage and Projections.....................................................................7 2.1 World Energy Usage and Projections.................................................................................7 2.2 United States Energy Usage and Projections..................................................................10

3 Nuclear Hydrogen for Production of Liquid Fuels....................................12 3.1 Background and Motivation ...............................................................................................12 3.2 Year 2002 ...........................................................................................................................12 3.3 Year 2025 ...........................................................................................................................21 3.4 Other Considerations .........................................................................................................28

4 Nuclear Power to Aid in Recovery of Oil from Tar Sands........................29 5 Nuclear Power to Aid in Recovery of Oil from Oil Shale..........................31 6 Atmospheric Effects of Different Scenarios..............................................33

6.1 Liquid Fuel Scenarios ........................................................................................................33 6.2 Tar Sands ...........................................................................................................................37 6.3 Shale Oil .............................................................................................................................38 6.4 Key Assumptions................................................................................................................38

7 Effects on Foreign Oil Dependence for the United States .......................39 7.1 Liquid Fuels ........................................................................................................................39 7.2 Tar Sands ...........................................................................................................................39 7.3 Oil Shale .............................................................................................................................39

8 Conclusions and Suggested Further Research........................................40 8.1 Liquid Fuels ........................................................................................................................40 8.2 Tar Sands ...........................................................................................................................40 8.3 Oil Shale .............................................................................................................................40 8.4 Suggested Future Research .............................................................................................41

Appendix A: Review of Hydrogen Cycles ......................................................42 Appendix B: Review of Reactor Technology.................................................49 References.........................................................................................................51

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List of Figures

Figure 1.1 Global Average Temperature vs Time (1881-2004) ................................................................... 2 Figure 1.2. Carbon dioxide concentration in the atmosphere, 1000-2003. .................................................. 3 Figure 2.1.1 Electricity generation from nuclear power plants in the U.S................................................... 9 Figure 4.1 Bitumen and oil reserves for major countries throughout the world. .......................................29 Figure 5.1 Shell’s In-Situ Conversion Process ............................................................................................32 Figure 8.1. Top shale oil and tar sands containing countries. .....................................................................41 Figure Appendix 1. Flow diagram of SI cycle. ............................................................................................48 Figure Appendix 2 Schematic of S-AGR-HTSE plant................................................................................49

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List of Tables

Table 2.1.1 Reference Case World Energy Usage and Projections.............................................................. 8 Table 2.1.2 High Economic Growth Case World Energy Usage and Projections....................................... 8 Table 2.1.3 Low Economic Growth Case World Energy Usage and Projections ....................................... 9 Table 2.2 1. Reference Case U.S. Energy Usage and Projections ..............................................................10 Table 2.2 2 High Economic Growth Case US Energy Usage and Projections ..........................................11 Table 2.2 3 Low Economic Growth Case US Energy Usage and Projections...........................................11 Table 3.2.1 Thermodynamic data for the reaction of carbon dioxide with hydrogen to produce

ethanol. .......................................................................................................................................14 Table 3.2.2 Conventional gasoline used for road transport during the year 2002, the equivalent

energy, and the amount of alternative fuel needed to replace the gasoline. ..........................17 Table 3.2.3. Reactants Needed to Produce the Required Alternative Fuel for Road Transport. ..............17 Table 3.2.4 Number of 1500 MWth Reactor-Years required to produce the needed alternative

fuels for 2002. ............................................................................................................................19 Table 3.2.5 Summary of Scenario ii for U.S.: Reactants needed, products supplied, and required

reactor-years for producing the alternative fuel. .....................................................................20 Table 3.2.6 Summary of Scenario ii for entire world. .................................................................................21 Table 3.3.1. Summary of data concerning EIA’s reference case for U.S. in 2025....................................23 Table 3.3.2. Summary of data concerning EIA’s reference case for World in 2025.................................25 Table 3.3.3. Carbon dioxide projected to be emitted from fossil-fired power plants in 2025. .................25 Table 3.3.4. Summary of Scenario ii ............................................................................................................26 Table 3.3.5. Summary of Scenario ii ............................................................................................................28 Table 6.1. CO2 emissions per vehicle mile from gasoline and alternative fuels (grams/mile)

[20] .............................................................................................................................................33 Table 6.2. Annual reductions in CO2 emissions in U.S. assuming all gasoline replaced by

ethanol or methanol. ..................................................................................................................34 Table 6.4 Scenario i : Annual reductions in CO2 Emissions worldwide assuming all gasoline

is replaced by ethanol or methanol ...........................................................................................35 Table 6.5. Scenario ii :Annual reductions in CO2 emissions in the world assuming 45% of

CO2 emitted by fossil-fired power plants is captured and combined with hydrogen to produce liquid fuel. ...............................................................................................................35

Table 6.6 Scenario i : Annual reductions in CO2 emissions in U.S. assuming all gasoline is replaced by ethanol or methanol...............................................................................................36

Table 6.7. Scenario ii : Annual reductions in carbon dioxide emissions in U.S. assuming 45% of carbon dioxide emitted by fossil-fired power plants is captured and combined with hydrogen to produce liquid fuel .......................................................................................36

Table 6.8 Annual reductions in CO2 emissions worldwide assuming all gasoline replaced by ethanol or methanol ...................................................................................................................37

Table 6.9 Annual reductions in CO2 emissions worldwide assuming 45% of CO2 emitted by fossil-fired power plants is captured and combined with hydrogen to produce liquid fuel. .............................................................................................................................................37

1 Introduction

1.1 Motivation

The need for the development of alternative forms of energy has become a very important issue in the past few decades. With the large rate of population growth and rapid development of large economies worldwide, most notably that of China, the demand for energy is expected to increase dramatically over the next 50 years. Estimates suggest that total global energy demand will triple by the year 2050 [1]. Although opinions about availability of natural resources vary, it is a certainty that only a finite amount of fossil fuels exists. If the need for energy continues to increase at the same or a higher rate, then it is obvious that fossil fuel costs will most likely increase greatly since either the reserves will decrease dramatically or much more effort will be expended to find, recover, process, and deliver the resources.

There are other issues that drive the need for alternative forms of energy. One of these is the reality of the rise in mean temperature at the surface of the earth. This is intrinsically a global problem. There are conflicting views about how much human activity has contributed to the phenomenon of global warming. However, there seems to be a growing consensus that the industrial age has had some effect on the rise in sea surface temperature (SST) and land surface temperature (LST). Another issue of interest on a more local scale is that of US dependence on foreign crude oil. This issue has become somewhat more public in the past few years as it has been mentioned publicly in various political arenas. It is conceivable that a disruption in the flow of petroleum and petroleum products into the US (e.g., via wartime difficulties, terrorist activities, natural disasters, etc.) could wreak havoc upon the US economic infrastructure. The combination of these two issues points to a need for another option for obtaining at least some of our transportation fuel. These two issues are the motivation for this report.

In this report, we show that it may be productive to combine hydrogen produced with the help of nuclear energy with carbon dioxide captured from fossil-fired power plants to produce alternative liquid fuels for transportation. Furthermore, the data show that the current amount of carbon dioxide from these sources is more than enough to produce either ethanol or methanol to replace all the oil products used for road transportation, Even if only half the fossil plants participated in the process, there would be enough carbon dioxide to produce more than 85% of the needed alternative fuel. These results indicate that more research into the topic of combining hydrogen produced with the aid of nuclear power and carbon dioxide captured from fossil plants is warranted.

Besides the so-called alternative liquid fuels, there are also alternative sources of non-conventional oil. Specifically, the sources of oil discussed in this report are: oil from tar sands and oil from shale. Although these sources of energy by themselves do not address the problem of greenhouse gases (GHG), they do address the issue of replacing oil obtained from overseas. Also, since recovery of these forms of crude oil is already being planned using heat from fossil fuels, the use of nuclear power to produce the heat required to obtain this energy holds the potential to reduce carbon dioxide emission.

1.2 Overview of Relevant Atmospheric Conditions

The average global temperature of the earth is steadily rising and has been doing so at least since data has been consistently collected. Figure 1.1 shows the global average temperature of the earth

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in twenty-year increments beginning with 1881 [2]. As indicated by the figure, the average temperature of the earth has increased by approximately eight-tenths of a degree Celsius during that period. This alone does not provide enough information to cause alarm since there are no other similar types of data with which to compare the numbers.

However, measurements show that global average sea level has risen approximately 15 to 20 centimeters in that same period [3]. This rise is due mainly to melting of the polar ice caps and an increase in specific volume of the water in the oceans caused by an increase in water temperature. It is estimated that the average temperature of the earth will increase by another 1.4 to 5.8 degrees Celsius by the year 2100, giving rise to an increase in mean sea level by at least 13 centimeters and maybe as much as 94 centimeters [4]. A mean sea level increase of this magnitude would wreak havoc with many highly populated areas. Other possible consequences of global warming include more and stronger hurricanes and other storm systems. The number of Category 4 and 5 hurricanes has risen from about 10 per year to about 18 per year since the 1970s [5]. The consequences of this type of environmental effect are not fully understood.

Figure 1.1 Global Average Temperature vs Time (1881-2004)

(Data from Buckley [2].)

It is widely accepted in the scientific community that the increase in greenhouse gases (GHG) produced by humankind is at least partially responsible for the increase in global temperature. The major effect of these GHGs is due to carbon dioxide (CO2) released via combustion of fossil fuels for transportation and industrial processes. Figure 2 shows the estimated concentration of CO2 in the atmosphere from AD 1000 to AD 2003 [2]. The sharp increase in concentration during approximately the past century coincides with the increase in global temperature discussed previously.

In 2002, total CO2 emissions (figures for the US are in parenthesis) world-wide topped 24.1 billion metric tons (5.65 billion metric tons); of these emissions, 8.51 billion metric tons (2.27 billion metric tons) were produced due to public electricity and heat generation. This represents approximately 35.1 percent of the total emissions (40.2 percent). Emissions from the category labeled ‘Road Transportation’ by the International Energy Agency (IEA) topped 4.2 billion metric tons (1.4 billion metric tons). This represents more than 17.4 percent (26.2 percent) of the total emissions. Thus, public electricity and heat generation combined with road transport accounts for more than 52.5 percent (66.4 percent) of total CO2 emissions [6]. It is expected that

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electricity demand will quadruple in the next 50 years [7] and transportation energy demand will double [8]. The major source of primary energy for electricity generation is coal and the major primary source of transportation energy is petroleum. It is easy to see that by the middle of the century, global (and US) emissions of CO2 will increase dramatically under a business as usual scenario.

Figure 1.2. Carbon dioxide concentration in the atmosphere, 1000-2003.

1.3 Overview of Relevant Energy Conditions

If the generally accepted hypothesis of CO2 contribution to global warming is correct, then it is imperative from a global perspective that steps be taken to mitigate this increase. Even if this hypothesis is not accepted, it is still extremely important for the US to consider alternative means for producing transportation fuels. Of the more than 7.2 billion barrels of petroleum that the US used in 2002, over 4.2 billion barrels were imported; this represents over 58 percent of US petroleum usage. Although it is not likely that the suppliers of this fuel will try to isolate themselves from the US – due to the sheer volume of money that is represented – the rapid development of other world economies, most notably China, is likely to cause a continued increase in the cost of petroleum and petroleum products. There is also the possibility of foreign states or independent terrorist entities to find a way to cripple the US economic infrastructure if a means of interrupting the flow of petroleum into the country is found.

The current trend, politically as well as scientifically, is to work toward what is generally termed the ‘hydrogen economy’. In most instances, any statements about the hydrogen economy refer to what can be thought of a “pure” hydrogen economy, meaning the use of hydrogen to produce energy without the unwanted side effects of GHG emissions associated with fossil fuels and without the issues associated with nuclear waste. This is the terminology that is adopted in this report.

However, since hydrogen does not exist in a form useful for energy production in nature, it is necessary to find one or more acceptable means of producing hydrogen in large enough quantities and at low enough cost for it to be a viable energy carrier for the general population. There are several methods to produce hydrogen currently, including steam methane reforming, coal

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gasification, ammonia dissociation, and electrolysis of water. Of these, only electrolysis produces hydrogen without any unwanted by-products. The problem with electrolysis is that it uses various amounts of electricity and heat, depending upon temperature and pressure of the process; as the temperature increases, the required electricity decreases in general [9]. This electricity and heat must, in turn, be produced by some other means. Since the goal is to reduce GHG emission, the current technologies for producing electricity with fossil fuels are unacceptable. Therefore, the first problem that must be addressed is the problem of producing the electricity and heat needed that can in turn be used to produce hydrogen.

There are other problems with trying to make the transition to a hydrogen economy. The volumetric energy density of hydrogen is extremely low in gaseous form. However, liquid hydrogen at reasonable temperatures requires very high pressures. Thus, there are storage and transportation issues that have not yet been fully addressed. If and when these problems are solved in principle, building the infrastructure needed to transport and store the hydrogen and supplying the automobiles, planes, trains, and other transportation means that are equipped to operate on hydrogen fuel will take years and maybe decades.

In short, the problem can be stated as follows. The need to drastically reduce CO2 emission world-wide seems to be of paramount importance. Locally, eliminating dependence on foreign oil has the potential to dramatically decrease the volatility of the US economy and increase national security. The long-term solution seems, at this point in time, to be an economy that uses hydrogen as the major carrier of transportation energy and possibly the energy carrier for other sectors of the economy. However, the technology and infrastructure development will take decades to develop. Even the plan revealed by President Bush in 2003 acknowledges that the realization of the hydrogen economy may take as long as 20-40 years [10]; and these plans are inherently optimistic based on their political nature.

The scenario for evolution of energy demand as it has been stated presents some interesting questions that should be addressed. They are:

• Is there any acceptable means of significantly decreasing the global GHG emissions during the time that it will take to solve the scientific and engineering problems associated with the hydrogen economy?

• Is there any acceptable means of decreasing the US dependence on foreign oil during this same time period?

• If and when the hydrogen economy is fully realized, will this transitional solution (if it exists) be obsolete?

1.4 Possible Transition Strategy

One possible means of transitioning from today’s fossil fuel economy to the ultimate goal of a pure hydrogen economy involves using synthetic fuels. These fuels can be produced by various means. The preliminary analysis done to this point includes production of methanol and ethanol. These two fuels have been chosen for the preliminary study for two major reasons. Data are more easily obtained for these two alternative fuels and the technology is already in place to utilize them. Automobiles are currently being driven that use fuel that contains from 10–90% ethanol (EtOH) or methanol (MeOH) by volume. The remaining volume of the fuel is conventional gasoline.

Currently, most of the production of ethanol in the U.S. involves using corn as the feedstock [11]. This method takes advantage of the fact that during the lifetime of the corn (or other biomass), CO2 is converted into oxygen (O2), thereby decreasing the net emission of GHGs into the atmosphere. However, the process requires both large areas of land to produce the biomass and a

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system capable of economically transporting the biomass to the ethanol generating facility. As of yet, no economical system has been proven. Thus, production of ethanol via biomass feedstock seems to be an unlikely method of solving the problem that is presented.

Methanol (MeOH), another fuel that can be created synthetically, is also sometimes mentioned as a possible alternative liquid fuel. Methanol, however, has its own problems. Methanol can be produced by using biomass as a feedstock, but is more often produced by using one of two commercial processes. The first involves the use of natural gas as a feedstock, while the second uses coal as a feedstock. Both produce some amount of carbon as by-products, thereby making this possibility even less attractive.

There is, however, another possible approach. For the production of methanol or ethanol, the feedstock is used as a source of the reactants needed to produce the final product and as a heat source. For both fuels, the reactants needed are H2 and CO2. In both cases, the real need is a means of producing these reactants so that they may be combined to form the fuel. CO2 is produced in large quantities as a by-product of the combustion of coal, petroleum, and natural gas for the production of heat and electricity as stated previously. The technology is also available for capture of most, if not all, of this CO2. A reasonable estimate would be 90% capture of the CO2 at any given power plant [12].

Research needs to be performed to determine which overall process is the more viable of the two. There should also be research to determine if there are other hydrocarbons that could be even more attractive as a fuel.

Most renewable energy technologies have major logistical issues that may or may not ever be resolved. For example, hydroelectric power can only be produced in certain regions throughout the world and with the need for water in agriculture and other areas, this can be a problem. Power from windmills is intermittent at best, and solar technology requires very large land areas to produce the required levels of power. This leaves nuclear power as the most viable option for producing the hydrogen. Nuclear power plants can produce the needed electricity and heat to produce hydrogen via electrolysis. Since neither nuclear power nor the production of hydrogen via electrolysis produces significant quantities of GHGs, this option seems to be quite viable. Based on this view, the work reported here investigates the option of using nuclear power to provide the heat and electricity to produce hydrogen, then combining the hydrogen with carbon dioxide captured from fossil-fired power plants in order to create liquid hydrocarbons for transportation fuel.

1.5 Use of Nuclear Power to Aid in Recovery of Oil from Tar Sands

Another source of energy that is becoming more prevalent is the oil extracted from tar sands (also known as tar sands). For example, it was expected that Canada’s tar sands production would surpass their conventional oil production in 2005 (final numbers not available yet) [13]. Both open-pit mining and in-situ methods are employed to recover oil; however, the open-pit mining methods are environmentally unfriendly. The most generally accepted, current means of producing oil from tar sands involves an in-situ technique called Steam Assisted Gravity Drainage (SAGD). This technique requires injecting large amounts of steam into the ground, causing the condensate and bitumen to drain into a production well via gravity [13]. Other techniques that rely on water heating are possible [14].

It has been shown that nuclear power can be useful in aiding production of oil via SAGD. The preferred nuclear reactor technology is the Advanced Candu Reactor (ACR-700) [13]. It should be noted that one of the reasons for choosing the ACR-700 is that the production of sand oil is assumed to occur in Canada, where licensing for the ACR-700 will be easier than most other

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options and the construction of the ACR-700 will be more easily accepted in the local communities.

This topic is discussed in further detail in Part 4 of this report.

1.6 Use of Nuclear Power to Aid in Recovery of Oil from Oil Shale

The second “unconventional oil” source that is reviewed in this report is oil derived from shale oil. The term “shale oil” refers to a sedimentary rock that is rich in organic matter containing more than 10 percent kerogen. The implications of a technology that could help utilize a significant portion of this particular source of oil would be enormous, especially for the United States. It is estimated that the energy that could be extracted from shale oil deposits – assuming an acceptable and economic technology – is greater than any other single source of energy from oil, including conventional oil [15]. The majority of this – more than 70% of the total – is located in North America, of which almost the entire portion is located in the western United States.

This shale can be burned in power plants in its natural state. However, if the purpose is to extract oil from the rock, the rock must be heated to approximately 600°C and the oil is captured as it boils off. The yield is quite low per ton of shale. However, if the oil can be captured by an in-situ method, the yield would be very high per acre of land involved since the shale is contained in very thick layers.

This topic is discussed in more detail in Part 5 of this report.

1.7 Organization of Report

This report states the findings of a study that explores the possibility of using nuclear power for various options. The options that are reviewed were chosen, and are studied in the context of providing a benefit by at least one of the following means: either decreasing the emissions of greenhouse gases (GHGs) or decreasing the US dependence on foreign oil.

Part 2 of this report discusses the current and projected energy scenarios for the US and the world. This part of the report is intended to set up the cases upon which the rest of the report is based. Data from the year 2002 and projections for the year 2025 are used in reporting the information obtained. Part 3 presents the results for combining nuclear hydrogen with carbon dioxide captured from fossil-fueled power plants. Part 4 presents an overview of an MIT study on the use of nuclear power for aiding the production of oil from Canadian tar sands. Part 5 reviews the possible uses of nuclear power to aid in the recovery of oil from shale oil. Part 6 compares the atmospheric effects of the different scenarios. Part 7 compares the implications of the different scenarios helping to reduce the United States’ dependence on foreign oil. Part 8 presents the conclusions of the study.

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2 Energy Usage and Projections

Any study that is conducted with hopes of having an effect on the energy future of the world must take into account the rates at which different forms of energy are produced and consumed. The latest year for which complete data has been found is the year 2002. Therefore, data are presented that show the state of energy production and consumption in the year 2002 for both the world as a whole and for the United States as a separate entity. A good report on energy issues should also include discussion of future ramifications of the proposed strategies. For that reason, this report includes projections of the amount of energy that will be used in the year 2025. These projections have not been calculated during the course of the study. Rather, they have been taken from sources which make it their business to perform the types of calculations that result in these projections. The US Department of Energy’s Energy Information Agency (EIA) was an invaluable resource for this type of data.

For the US scenario, data are also presented that discuss the fraction of fuel that is imported. These data are necessary in order to understand the effects that any of the scenarios explored can have on the stability of the US energy supply. The stability of the US energy supply is of critical importance in ensuring that the energy needs of the citizens of the United States are met. These needs include everyday personal energy needs such as transportation fuel, electricity, and home heating and cooling. They also include commercial energy requirements for maintaining a productive economy. Due to the volatile nature of many of the countries from which the US imports much of its oil, it is foreseeable that a major disruption to the flow of oil into the country could happen, either due to terrorist activities or due to major complications among the administrations of the US and the exporting countries. Thus, it is necessary to pursue all avenues that can potentially strengthen the US energy supply.

Section 2.1 of this report discusses the world energy usage in 2002 and projections for the year 2025. Section 2.2 does the same for the United States.

2.1 World Energy Usage and Projections

The world’s total primary energy consumption increased by more than eighteen percent between the years of 1990 and 2002. This amounts to an average of about 1.5% per year [16]. Making projections about the amount of energy that will be used in the future is very complex. Models for future world energy supply and demand must take into account many uncertain factors; these include – but are not limited to – future resource discovery, population and economic growth, possible technological advances, and possible international conflicts. Therefore, it is very difficult to predict with any certainty what the future world consumption of energy will be.

The United States Department of Energy’s Energy Information Agency produces a report each year, entitled the International Energy Outlook, that attempts to predict future energy usage. Understanding the difficulty with which these predictions are made, the department uses various scenarios; they include a reference case, a high economic growth case, and a low economic growth case. An overview of the results for the world as presented in the IEO 2005 is shown below. The data have been converted to SI units for calculational purposes.

Table 2.1.1 compares the data concerning how much energy was used in the year 2002 and the projected energy usage for the year 2025 assuming what EIA considers a reference case. Table 2.1.2 compares the data concerning how much energy was used in the year 2002 and the projected energy usage for the year 2025 assuming what EIA considers a high economic growth case. Table 2.1.3 compares the data concerning how much energy was used in the year 2002 and

8

the projected energy usage for the year 2025 assuming what EIA considers a low economic growth case. The reference case assumes midrange values for both the economic growth rate and world oil prices. The high economic growth case assumes greater than average economic growth and midrange oil prices while the low economic growth case assumes lower than average economic growth and midrange oil prices.

These data indicate increases of 56.7%, 72.1%, and 42.4% in total primary energy usage for the reference, high economic growth, and low economic growth cases, respectively. Of particular interest to this study is the increase in fossil energy usage. Oil usage is projected to increase approximately 53.0%, natural gas 71.0%, and coal 60.2% for the reference case. This amounts to very large increases in carbon dioxide emissions. If the high economic growth scenario is realized, the increases in carbon dioxide emissions will be even higher. Analysis of these effects will be presented in Part 6 of the report.

Table 2.1.1 Reference Case World Energy Usage and Projections

This table shows the amount of energy used in various forms for the year 2002. It also shows projections for energy to be used in the year 2025. The projected energy use for year 2025 is based on the DOE’s reference case scenario, which includes midrange economic growth and midrange oil price. Data taken from reference [16].

Table 2.1.2 High Economic Growth Case World Energy Usage and Projections

This table shows the amount of energy used in various forms for the year 2002. It also shows projections for energy to be used in the year 2025. The projected energy use for year 2025 is based on the DOE’s high economic growth scenario. Data taken from reference [16].

2002 2025 % Change Oil 1.68E+14 MJ 2.85E+14 MJ 69.4

Natural Gas 1.00E+14 MJ 1.90E+14 MJ 89.3 Coal 1.03E+14 MJ 1.82E+14 MJ 75.6

Nuclear 2.84E+13 MJ 3.60E+13 MJ 26.8 Other 3.39E+13 MJ 5.44E+13 MJ 60.7

TOTAL 4.34E+14 MJ 7.47E+14 MJ 72.1




TOTAL 4.34E+14 MJ 6.80E+14 MJ 56.7

9

Table 2.1.3 Low Economic Growth Case World Energy Usage and Projections

This table shows the amount of energy used in various forms for the year 2002. It also shows projections for energy to be used in the year 2025. The projected energy use for year 2025 is based on the DOE’s low economic growth scenario. Data taken from reference [16].




TOTAL 4.34E+14 MJ 6.18E+14 MJ 42.4

It should be noted that the projections for nuclear power assume that nuclear energy production will grow much more slowly than the other types of energy production. Historically, this has not been the case. Actual nuclear power generation in the United States has increased by more than 100% since 1985 [17]; see Figure 2.1.1. However, for the purpose of this report, the numbers stated are not critical. The more important numbers are those which project the usage of coal and oil. According to the Organization for Economic Cooperation and Development [18], total energy production in the United States increased by 2.1% between the years of 1993 and 2003 while nuclear power production increased by about 21.8% during that same time period.

Figure 2.1.1 Electricity generation from nuclear power plants in the United States (1973-2005). Inset shows capacity factor of US nuclear power plants from 1989-2005. [17]

10

2.2 United States Energy Usage and Projections

The total primary energy consumption in the United States increased by nearly sixteen percent between the years of 1990 and 2002. Oil consumption in that same time period increased by nearly sixteen percent, also. This amounts to an average of more than 1.3% per year for each case [16]. In 2002, over 58% of all petroleum used in the United States was imported [17]. Much of this oil was imported from the Middle East region; this region of the world has been very volatile in the past. This situation creates an unstable energy dependence for the United States. It would be very beneficial for the United States to decrease its dependence on this foreign source of oil. Therefore, an analysis of the various ways in which nuclear power can aid in the production of non-traditional oil recovery is presented in Parts IV, V, and VI.

Table 2.2.1 compares the data concerning how much energy was used in the United States during the year 2002 and the projected energy usage for the year 2025 assuming what EIA considers a reference case. Table 2.2.2 compares the data concerning how much energy was used in the year 2002 and the projected energy usage for the year 2025 assuming what EIA considers a high economic growth case. Table 2.2.3 compares the data concerning how much energy was used in the year 2002 and the projected energy usage for the year 2025 assuming what EIA considers a low economic growth case. The reference case assumes midrange values for both the economic growth rate and world oil prices. The high economic growth case assumes greater than average economic growth and midrange oil prices while the low economic growth case assumes lower than average economic growth and midrange oil prices. The IEO ignores the potential growth of nuclear energy due to new plants. It prefers to assume that new plants will not attract investors. The high price of natural gas in 2005 and 2006, coupled with government incentives for the first 6000 MWe of nuclear power additions to the (approved in 2005), are likely to prove the IEO wrong.

These data indicate increases of 35.0%, 44.7%, and 27.2% in total primary energy usage for the reference, high economic growth, and low economic growth cases, respectively. In comparison with the world case, fossil energy usage is even more responsible for the increase of primary energy, since nuclear power usage increases slightly by only 6.4% . This amounts to very large increases in carbon dioxide emissions. If the high economic growth scenario is realized, the increases in carbon dioxide emissions will be even higher. Analysis of the environmental effects created by this change in carbon dioxide emission will be presented in Part 6 of the report.

Table 2.2 1. Reference Case U.S. Energy Usage and Projections

This table shows the amount of energy used in various forms for the year 2002. It also shows projections for energy to be used in the year 2025. The projected energy use for year 2025 is based on the DOE’s reference case scenario, which includes midrange economic growth and midrange oil price. Data taken from reference [16].

2002 2025 % Change Oil 4.23E+13 MJ 5.86E13 MJ 38.5

Natural Gas 2.49E13 MJ 3.35E13 MJ 34.5 Coal 2.08E13 MJ 2.94E13 MJ 41.6

Nuclear 8.65E12 MJ 9.20E12 MJ 6.4 Other 6.23E12 MJ 8.77E12 MJ 40.8

TOTAL 1.03E+14 MJ 1.39E14 MJ 35.0

11

Table 2.2 2 High Economic Growth Case US Energy Usage and Projections

This table shows the amount of energy used in various forms for the year 2002. It also shows projections for energy to be used in the year 2025. The projected energy use for year 2025 is based on the DOE’s high economic growth scenario. Data taken from reference [16].




TOTAL 1.03E+14 MJ 1.49E14 MJ 44.7

Table 2.2 3 Low Economic Growth Case US Energy Usage and Projections

This table shows the amount of energy used in various forms for the year 2002. It also shows projections for energy to be used in the year 2025. The projected energy use for year 2025 is based on the DOE’s low economic growth scenario. Data taken from reference [16].




TOTAL 1.03E+14 MJ 1.31E14 MJ 27.2

12

3 Nuclear Hydrogen for Production of Liquid Fuels

3.1 Background and Motivation

Part 3 of this report is concerned with the possible use of nuclear power to produce hydrogen and combine it with carbon dioxide produced from fossil-fired power plants to produce alternative liquid fuels. Although there are many different forms of hydrocarbons that can be used for liquid fuel, two of them – methanol and ethanol - stand out as having been studied in much greater detail than the others. Furthermore, these two fuels have been shown to be very useful as fuels for road transportation. A small percentage of vehicles now produced have the ability to run on either gasoline or a mix of gasoline and either methanol or ethanol. The fraction of the fuel that is comprised of ethanol or methanol can vary, reaching as high as 90%. These vehicles are termed flexible-fueled vehicles (FFVs). In 2005, more than 53% of all new automobiles sold in Brazil are FFVs [19]. A few vehicles in the United States are also FFVs.

The greatest incentive for finding and producing an alternative liquid fuel for road transportation at the current time is to reduce the emissions of carbon dioxide into the atmosphere. However, if the United States can find a way to do this, the process can be used as a means to decrease its dependence on foreign oil. Both these subjects are discussed in this part of the report.

Since the most immediate use for ethanol or methanol is as a replacement for conventional gasoline as a fuel for road transport, this is the focus of Part 3 of this report. Two scenarios are discussed for year 2002 and the same scenarios are discussed for year 2025:

Scenario 1: Enough alternative fuel is created to replace the needed motor gasoline

Scenario 2: 45% of the carbon dioxide emitted from fossil-fueled power plants is combined with hydrogen to produce alternative fuels; in this scenario, it is assumed that 90% capture efficiency is achieved and 60% of all fossil-fueled plants participate.

The initial comparisons use energy content (LHV) as the basis for comparison. Afterward, some proposed differences are considered; one such difference assumes that vehicles using ethanol would obtain higher energy efficiency because ethanol burns more slowly than conventional gasoline.

3.2 Year 2002

In 2002, the United States emitted 5.65 billion metric tons of carbon dioxide into the atmosphere; the world as a whole emitted 24.1 billion metric tons. Of this amount, 2.27 billion and 8.51 billion metric tons, respectively, were emitted by fossil-fueled public heat and electricity generation; also, 1.48 billion and 4.28 billion metric tons, respectively, were emitted by road oil [17]. These numbers form the basis for the calculations performed in this part of the report.

It is not feasible to assume that all the carbon dioxide could be utilized in order to create alternative liquid fuels. Therefore, in this study, special attention is paid to the largest so-called point sources of carbon dioxide. These point sources are the fossil-fired power plants. For the purposes of this report, it is assumed that 50% of all fossil plants participate in a process to capture carbon dioxide and combine it with hydrogen produced with the aid of nuclear power. A good estimate for the efficiency of the carbon dioxide capture process for coal power plants is 90% [12]. The combustion of coal is the process responsible for most of the carbon dioxide emitted from point sources. Also, the capture processes for all power plants should be similar.

13

Therefore, in this report, it is assumed that the capture efficiency for all carbon dioxide used is equal to 90%. With the 50% participation assumed in the report, this translates to capturing 45% of the carbon dioxide emitted from fossil-fired power plants.

The relevant reactions for this part of the report are the reactions converting hydrogen and carbon dioxide into either ethanol or methanol. These reactions are below.

Ethanol Reaction

!

2CO2

+ 3H2"C

2H5OH +

3

2O2 (3.2.1)

Methanol Reaction

!

CO2

+ 3H2"CH

3OH + H

2O (3.2.2)

Initially, it might seem that these reactions indicate that it is more efficient to use hydrogen to produce ethanol because all of the hydrogen in the product is contained within the fuel. By contrast, one-third of the hydrogen in the methanol reaction is converted into water. However, this is not the entire story. In order for a reaction to spontaneously occur, the change in the Gibbs free energy for the reaction must be negative. That is to say, the free energy of formation of the products must be less than the free energy of formation of the reactants. These calculations are presented below for both reactions, using information that can be gathered from any standard chemistry book for room-temperature reactions.

mol

kJG

mol

kJG

mol

kJGG

mol

kJGG

OHCH

formation

CO

formation

OHHC

formation

O

formation

OH

formation

H

formation

27.166 4.394

78.174 0

1.237 0

32

522

22

,0,0

,0,0

,0,0

!="!="

!="="

!="="

mol

kJ

mol

kJG

EtOH

reaction02.614)4.394(2)0(3)78.174(1)0(

2

3,0=!

"

#$%

&''''+=( (3.2.3)

[ ]mol

kJ

mol

kJG

MeOH

reaction97.8)0(3)4.394(1)27.166(1)1.237(1,0 !=!!!!+!="

(3.2.4)

Therefore, although it seems that much of the reactant hydrogen is wasted in the formation of water for the MeOH reaction, the positive EtOH

reactionG

,0! shows that it would be necessary to raise the

temperature in order for the reaction to occur spontaneously, assuming this is possible. For MeOH, however, the MeOH

reactionG

,0! value is negative, implying that the reaction is spontaneous at

room temperature. The leading zero in the superscripts is to indicate that the values are at 25°C.

Since the EtOHreactionG

,0! value is positive, it is necessary to look more closely at the thermodynamics

of the reaction to determine the necessary parameters for the reaction to occur. Table 3.2.1 lists EtOH

reactionG

,0! for eleven different temperatures ranging from room temperature to 1000° C. As can

14

be seen by the data, the extra energy needed to drive the reaction increases with temperature. Since we are assuming the hydrogen will be produced via HTSE and the carbon dioxide will be captured from coal power plants, the temperature of the reactants will be well above the optimum temperature. However, it may be possible to cool the reactants and in the process recuperate some of the heat to use as the driving energy for the reaction.

Table 3.2.1 Thermodynamic data for the reaction of carbon dioxide with hydrogen to produce ethanol.

The delta G values are all positive, indicating that the reaction is not spontaneous. The delta H value is the minimum energy that must be added to drive the reaction.

2CO2+3H2→C2H6O+1.5O2 Temperature (C) delta H (MJ/barrel) delta G (MJ/barrel)

25 1391.45 1677.10 125 1395.90 1772.57 225 1416.37 1865.22 325 1460.47 1951.61 425 1535.75 2028.24 525 1649.74 2091.49 625 1809.96 2137.72 725 2023.90 2163.25 825 2299.09 2164.41 925 2643.00 2137.49

1000 2950.56 2096.65

Estimates are made for the amounts of both EtOH and MeOH needed and produced, respectively, in scenarios i and ii, described later.

Based on equation 3.2.1 and basic stoichiometric conversions, one can show the following.

!

YEtOH tons of CO2 = XEtOH barrel of EtOH

42gal

bar" 2988

grams# EtOH

gal" 2

mol #CO2mol # EtOH

" 44grams#CO2mol #CO2

46grams# EtOH

mol # EtOH"106

grams#CO2ton #CO2

$

%

& & & &

'

(

) ) ) )

!

" YEtOH

# 0.24 XEtOH

tons of CO2 (3.2.5)

By the same token, the amount of hydrogen needed to produce a barrel of ethanol can be shown to be:

!

ZEtOH

tons of H2

= YEtOH

tons of CO2

3mol "H2

2mol "CO2

#

2grams"H

2

mol "H2

44grams"CO

2

mol "CO2

$

%

& & & &

'

(

) ) ) )

!

" ZEtOH

=3

44Y

EtOH tons of H

2 (3.2.6)

The data concerning density of EtOH is taken from the GREET v.1.7 software [20].

15

Using this same methodology, one can show that the conversion formulas for the amount of carbon dioxide and hydrogen needed to create MeOH are, respectively:

!

YMeOH tons of CO2 = XMeOH barrel of EtOH

42gal

bar" 3006

grams#MeOH

gal"1

mol #CO2mol #MeOH

" 44grams#CO2mol #CO2

32grams#MeOH

mol #MeOH"106

grams#CO2ton #CO2

$

%

& & & &

'

(

) ) ) )

!

" YMeOH

# 0.17XMeOH

tons of CO2 (3.2.7)

!

ZMeOH

tons of H2

= YMeOH

tons of CO2

3mol "H2

1mol "CO2

#

2grams"H

2

mol "H2

44grams"CO

2

mol "CO2

$

%

& & & &

'

(

) ) ) )

!

" ZMeOH

=3

22Y

MeOH tons of H

2

(3.2.8)

The data concerning density of MeOH is taken from the GREET v.1.7 software [20].

The calculations concerning nuclear power needed to produce hydrogen are based on the MIT report Hydrogen Production Using High Temperature Steam Electrolysis Supported by Advance Gas Reactors with Supercritical CO2 Cycles, MIT-NES-TR-002 [9]. The reported reactor of choice was a modified AGR using a supercritical CO2 cycle – termed the S-AGR. This design has an operating power of 1500 MWth. All calculations concerning the number of reactors needed to produce the required hydrogen in this part of the report are performed using these assumptions.

The hydrogen efficiency, for the purposes of this report, is defined as the lower heating value (LHV) of the hydrogen produced divided by the total thermal energy input of the process. According to Yildiz et al, the overall hydrogen efficiency (

H! ) is between 38.6% and 52.2%. The

lower percentage is calculated as a conservative estimate with a reactor exit temperature of 550°C with electrolysis occurring at a temperature of 900°C and a pressure of 7 MPa. The higher efficiency is calculated as a best estimate with a reactor exit of 700°C with electrolysis occurring at a temperature of 900°C and a pressure of 3 MPa. Calculations are performed to determine the number of reactors needed to produce the required hydrogen for various cases using both scenarios in this report. The conversion needed for this type of calculation is shown below. The calculations are left in units of reactor-years since there is no data concerning the availability of the S-AGR. The subscripts are used to denote the quantity of an item that is needed for the particular fuel. This is necessary since the MeOH reaction does not require extra energy input, but the EtOH reaction does.

!

NMeOH reactor years = ZMeOH tons of H2

119600 MJ

ton

1500MJ

Rx " sec

#

$ %

&

' ( 3.15576 )10

7 sec

yr

#

$ %

&

' ( )*H

#

$

% % % %

&

'

( ( ( (

!

NMeOH

=2.5266 "10#6

$H

ZMeOH

(3.2.9)

16

To calculate the number of reactor years necessary to produce ethanol, we must add another term which accounts for the extra energy to drive the reaction. Since the combination of carbon dioxide and hydrogen to form ethanol and oxygen is essentially the reverse of the combustion of ethanol, the energy required to drive the reaction will be greater than or equal to the change in the enthalpy from reactants to products. Therefore, at standard temperature and pressure, we must add about 1391.45 MJ of energy per barrel of ethanol produced. A portion of this energy can be recuperated from the reactants themselves since they are produced at very high temperatures. However, the efficiency of this recuperation and the pumping power required to move the reactants to the site where the reaction will take place are presently not known. Therefore, in order to be conservative, this recuperated heat will not be considered in the calculations shown.

!

NEtOH reactor years = ZEtOH tons of H2

119600 MJ

ton

1500MJ

Rx " sec

#

$ %

&

' ( 3.15576 )10

7 sec

yr

#

$ %

&

' ( )*H

#

$

% % % %

&

'

( ( ( (

+

+HEtOHMJ

bar - EtOH

#

$ %

&

' ( XEtOH bar - EtOH( )

1500MJ

Rx " sec

#

$ %

&

' ( 3.15576 )10

7 sec

yr

#

$ %

&

' (

NEtOH =2.5266 )10"6

*HZEtOH + 2.9395 )10

"8 XEtOH

(3.2.10)

Scenario i: Creating enough alternative fuel to replace conventional road gasoline

In 2002, the United States used 3.23 billion barrels of conventional gasoline (CG) for road transport [17]. Conventional gasoline contains about 5140 MJ of energy per barrel for combustion. This equates to 1.66×1013 MJ of energy used for combustion. Ethanol (EtOH) contains approximately 3381 MJ of energy per barrel, meaning that it would take about 4.91 billion barrels of ethanol to replace the conventional gasoline used for road transport in the United States in 2002, assuming the same energy conversion efficiencies for the different types of engines. A barrel of methanol (MeOH) contains approximately 2537 MJ of combustible energy, meaning that it would take about 6.54 billion barrels of MeOH to replace the CG used for road transport in the United States in the year 2002 under the same assumptions as those for EtOH.

In the same year (2002), a total of 7.30 billion barrels of CG was used for road transport throughout the world. This equates to 3.75×1013 megajoules of combustible energy. Using the same conversion factors as in the previous paragraph, it would take 11.1 billion barrels of ethanol or 14.8 billion barrels of methanol in order to replace the conventional gasoline used for road transport throughout the world in the year 2002.

Table 3.2.2 contains data on the amount of CG used in the US and in the world during the year 2002 and the equivalent combustible energy. Table 3.2.2 also contains data on the amount of EtOH and MeOH required to displace the CG used.

17

Table 3.2.2 Conventional gasoline used for road transport during the year 2002, the equivalent energy, and the amount of alternative fuel needed to replace the gasoline.

(Data on CG usage taken from EIA website [17]. Conversion ratios taken from GREET v.1.7 [20].)

United States World Conventional Gasoline (billions of barrels) 3.23 7.30

Equivalent Energy (megajoules) 1.66x1013 3.75x1013

EtOH Required to displace CG (billions of barrels) 4.91 11.1 MeOH Required to displace CG (billions of barrels) 6.54 14.8

Equations 3.2.5 and 3.2.6 are used to calculate the required carbon dioxide and hydrogen to produce the needed EtOH.

For the United States’ EtOH requirement of 4.91 billion barrels for road transportation, the needed carbon dioxide amounts to approximately 1.18 billion metric tons. Fossil-fired power plants emitted approximately 2.27 billion metric tons of carbon dioxide into the atmosphere during the year 2002 [17]; therefore, capture of about 52% of the carbon dioxide emitted would have to be attained. At the assumed capture efficiency of 90%, this indicates that in order to produce the needed EtOH to displace CG in the United States, one would have to assume approximately 57.8% participation in a carbon dioxide capture program by the fossil plants. This carbon dioxide would have to react with 80.3 million metric tons of hydrogen.

To create the amount of EtOH required to replace the CG used worldwide for road transport would take about 2.66 billion tons of carbon dioxide and 181 million metric tons of hydrogen. A total of 8.51 billion metric tons of carbon dioxide was emitted from fossil-fired power plants worldwide during 2002. Therefore, it would take approximately 31.3% of the available carbon dioxide to produce the needed EtOH. At 90% capture efficiency, this equates to a desired participation of 34.7% from the fossil plants.

Using equations 3.2.7 and 3.2.8, one obtains the needed carbon dioxide and hydrogen to produce methanol instead of ethanol. To replace CG used in the United States for road transportation, the required amount of carbon dioxide is 1.14 billion metric tons and the required amount of hydrogen is approximately 154.8 million metric tons. To completely replace the CG used for road transport throughout the world in 2002, 2.57 billion metric tons of carbon dioxide would need to be reacted with 350.1 million metric tons of hydrogen.

Table 3.2.3 displays the carbon dioxide and hydrogen needed to create the required alternative fuels.

Table 3.2.3. Reactants Needed to Produce the Required Alternative Fuel for Road Transport.

Carbon Dioxide (Millions of Metric Tons)

Hydrogen (Millions of Metric Tons)

US World US World EtOH 1180 2660 80.3 181.0 MeOH 1135 2568 154.8 350.1

Using the values for hydrogen efficiency quoted by Yildiz et al, the number of reactors needed to produce the required hydrogen can be calculated. Hydrogen has a LHV of about 119,600 megajoules per metric ton. Using the data calculated above, this implies that the hydrogen

18

required to produce enough EtOH to replace CG for road transport in the United States during the year 2002 (80.3 million metric tons) contains approximately

9.6×1012 MJ of energy. Using the efficiencies reported above and equation 3.2.10, the number of reactor-years required to produce the ethanol can be calculated.

!

NUS,EtOHlower =

2.5266 "10#6

$Hhigher

" ZUS,EtOH + 2.9395 "10#8XUS,EtOH

=2.5266 "10#6

.522" 80.3M + 2.9395 "10#8( ) 4.91"109( ) % (389 +144) reactor - years

= 533 reactor - years

NUS,EtOHhigher = 389

$Hhigher

$Hlower

+144 % 389.522

.386+144 = (526 +144) reactor - years = 670 reactor - years

To calculate the number of reactor-years needed for worldwide use, perform the same calculations using the needed hydrogen for worldwide use.

!

Nworld ,EtOHlower =

2.5266 "10#6

$Hhigher

" Zworld ,EtOH + 2.9395 "10#8XUS,EtOH

=2.5266 "10#6

.522"181M + 2.9395 "10#8( ) 11.1"109( ) % (876 + 326) reactor - years

=1202 reactor - years

Nworld ,EtOHhigher = 876

$Hhigher

$Hlower

+ 326 % 876.522

.386+ 326 = (1185 + 326) reactor - years

=1511 reactor - years

The same calculations can be made for methanol by using equation 3.2.9.

!

NUS,MeOHlower

=2.5266 "10#6

$Hhigher

" ZUS,MeOH =2.5266 "10#6

.522"154.8M % 750 reactor - years

NUS,MeOHhigher

= NUS,MeOHlower $H

higher

$Hlower

% 750.522

.386=1013 reactor - years

!

Nworld ,MeOHlower

=2.5266 "10#6

$Hhigher

" Zworld ,MeOH =2.5266 "10#6

.522" 350.1M %1695 reactor - years

Nworld ,MeOHhigher

= Nworld ,MeOHlower $H

higher

$Hlower

% 2154.522

.386= 2292 reactor - years

Table 3.2.4 displays the data concerning the number of reactor-years required to produce the needed hydrogen under the scenarios considered.

19

Table 3.2.4 Number of 1500 MWth Reactor-Years required to produce the needed alternative fuels for 2002.

Low Estimate (Assumes

H! of 52.2%)

High Estimate (Assumes

H! of 38.6%)

US World US World EtOH 533 1202 670 1511 MeOH 750 1695 1013 2292

(Efficiency data from Yildiz et al. [21])

Scenario ii: Converting 45% of carbon dioxide available to alternative fuel.

In this scenario, the problem is approached from a different angle. Instead of just trying to replace the CG that was used in 2002, the assumption is that 45% of the carbon dioxide produced from fossil-fired power plants can be captured and used to create alternative fuel. The basis for this assumption is that 50% of all plants will participate in a carbon dioxide capture program with 90% capture efficiency [12].

In 2002, fossil-fired power plants in the United States emitted about 2.27 billion metric tons of carbon dioxide into the atmosphere. Capturing 45% of this carbon dioxide would mean that about 1.02 billion metric tons of carbon dioxide is available to combine with hydrogen in order to create liquid fuel. Using equations 3.2.5 through 3.2.9, one can calculate the amount of hydrogen needed, the number of barrels of either EtOH or MeOH that can be created, and the number of reactor-years required to use all the carbon dioxide.

!

1.02 B tons CO2

0.24tons CO2

barrels EtOH

= 4.25 B barrels of EtOH (about 86.6% of amount needed to replace CG)

1.02 B tons CO23

44

tons H2

tons CO2

"

# $

%

& ' = 69.5 M tons of H2 required to make EtOH

NUS,EtOHlower =

2.5266 (10)6

.522

"

# $

%

& ' ( 69.5M + 2.9395 (10

)8( ) ( 4.25B * 461 reactor - years

NUS,EtOHhigher =

2.5266 (10)6

.386

"

# $

%

& ' ( 69.5M + 2.9395 (10

)8( ) ( 4.25B * 580 reactor - years

1.02 B tons CO2

0.1736tons CO2

barrels EtOH

= 5.88 B barrels of MeOH (about 89.9% of amount needed to replace CG)

1.02 B tons CO23

22

tons H2

tons CO2

"

# $

%

& ' = 139.1 M tons of H2 required to make MeOH

NUS,MeOHlower =

2.5266 (10)6

.522

"

# $

%

& ' (139.1M * 674 reactor - years

NUS,MeOHhigher =

2.5266 (10)6

.386

"

# $

%

& ' (139.1M * 911 reactor - years

20

Table 3.2.5 displays the previous data.

Table 3.2.5 Summary of Scenario ii for U.S.: Reactants needed, products supplied, and required reactor-years for producing the alternative fuel.

EtOH MeOH H2 Needed (millions of metric tons) 69.5 139.1

Fuel Created (billions of barrels) 4.25 5.88 Percentage of Fuel Needed to Replace CG 86.6% 89.9%

Reactor-years (lower estimate) 461 674 Reactor-years (upper estimate) 580 911

In 2002, fossil-fired power plants throughout the world emitted about 8.51 billion metric tons of carbon dioxide into the atmosphere. Capturing 45% of this carbon dioxide would mean that about 3.83 billion metric tons of carbon dioxide is available to combine with hydrogen in order to create liquid fuel. Using equations 3.2.5 through 3.2.9, one can calculate the amount of hydrogen needed, the number of barrels of either EtOH or MeOH that can be created, and the number of reactor-years required to use all the carbon dioxide.

!

3.83 B tons CO2

0.24tons CO2

barrels EtOH

=15.96 B barrels of EtOH (about 143.8% of amount needed to replace CG)

3.83 B tons CO23

44

tons H2

tons CO2

"

# $

%

& ' = 261.1 M tons of H2 required to make EtOH

NWorld,EtOHlower =

2.5266 (10)6

.522

"

# $

%

& ' ( 261.1M + 2.9395 (10

)8( ) (15.96B * 1733 reactor - years

NWorld,EtOHhigher =

2.5266 (10)6

.386

"

# $

%

& ' ( 261.1M + 2.9395 (10

)8( ) (15.96B * 2178 reactor - years

!

3.83 B tons CO2

0.1736tons CO2

barrels EtOH

= 22.06 B barrels of MeOH (about 149.1% of amount needed to replace CG)

3.83 B tons CO23

22

tons H2

tons CO2

"

# $

%

& ' = 522.3 M tons of H2 required to make MeOH

NWorld,MeOHlower

=2.5266 (10)6

.522

"

# $

%

& ' ( 522.3M * 2529 reactor - years

NWorld,MeOHhigher

=2.5266 (10)6

.386

"

# $

%

& ' ( 522.3M * 3419 reactor - years

Table 3.2.6 displays the previous data.

21

Table 3.2.6 Summary of Scenario ii for entire world.

Reactants needed, products supplied, and required reactor-years for producing the alternative fuel.

EtOH MeOH H2 Needed (millions of metric tons) 261.1 522.3

Fuel Created (billions of barrels) 15.96 22.06 Percentage of Fuel Needed to Replace CG 143.8 149.1

Reactor-years (lower estimate) 1733 2529 Reactor -years (upper estimate) 2178 3419

3.3 Year 2025

In this section, projections for the amount of liquid fuel needed in the year 2025 are used in order to estimate the scale of any proposed plan that may be used to try and replace CG as the fuel of choice for road transport. Due to the many volatile factors involved, it is impossible to predict the energy needs for any given sector of the world with any certainty very far into the future. Therefore, any mid-range or long-range projections for the future of energy use must contain more than one possible value. The US Department of Energy’s Energy Information Agency releases a document each year entitled the International Energy Outlook [16]. The 2005 version of this document bases projections on three different scenarios: a reference case, a high economic growth case, and a low economic growth case. Section 3.3 of this report presents calculations for the amount of alternative fuel that would be necessary to replace the conventional gasoline as well as the scale of the hydrogen and carbon dioxide involved and the number of reactors needed to produce the hydrogen.

The US Department of Energy’s Energy Information Agency produces a report entitled the Annual Energy Outlook which states projections for energy in the United States [17]. This report is quite detailed and provides information concerning the projected gasoline usage in the United States for the year with which we are interested (2025). However, the same detail in international data has not been found. Therefore, in order to project the amount of gasoline that will be used worldwide, the fraction of total oil that is used for gasoline is assumed to be constant for the world as a whole. This is in line with what is projected for the United States, with the ratio of barrels of gasoline to barrels of petroleum in 2002 equal to 44.9% and in 2025 equal to 43.4% [16]. Although the percentage drops a small amount in the United States, this should not be the case for the world as a whole since a large portion of the world growth is expected to be in the so-called emerging markets [16]. The fraction of people living in these areas who own automobiles should increase over the time span of interest. Thus, the calculations reported in this section assume a constant ratio of barrels of gasoline used to barrels of petroleum consumed.

If it is assumed that the ratios of carbon dioxide emitted per unit of fossil fuel combusted are constant and the fractions of the fuels used for energy generation are constant, then calculations can be performed to make projections concerning the amount of carbon dioxide that will be emitted in the year 2025 by using the following equations.

22

!

CO2 emitted from coal

power plants in 2025

"

# $

%

& ' = CO2 emitted from coal power plants in 2002(

Energy from coal in 2025

Energy from coal in 2002

"

# $

%

& '

CO2 emitted from oil


"

# $

%

& ' = CO2 emitted from oil power plants in 2002(

Energy from oil in 2025

Energy from oil in 2002

"

# $

%

& '

CO2 emitted from gas


"

# $

%

& ' = CO2 emitted from gas power plants in 2002(

Energy from gas in 2025

Energy from gas in 2002

"

# $

%

& '

Using these assumptions and the data contained in Tables 2.1.1 through 2.1.3, as well as the data from the IEA that is used in Section 3.2 of this report, one obtains the following results.

tonsmetric M 0.413102.49

103.35 tonsmetric M 307

2025 in plantspower

gas USfrom emitted CO

tonsmetric M 2.91104.23

1086.5 tonsmetric M 8.65

2025 in plantspower

oil USfrom emitted CO

tonsmetric B69.21008.2

102.94 tonsmetric B90.1

2025 in plantspower

coal USfrom emitted CO

13

132

13

132

13

132

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MJ

MJ

MJ

MJ

MJ

MJ

tonsmetric B 63.2101.00

101.71 tonsmetric B 54.1

2025in plantspower

gas worldfrom emitted CO


1057.2 tonsmetric M 766

2025in plantspower

oil worldfrom emitted CO


101.65 tonsmetric B 20.6

2025in plantspower

coal worldfrom emitted CO

14

142

14

142

14

142

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MJ

MJ

MJ

MJ

MJ

MJ

Using these calculations, one can see that this equates to approximately 3.19 billion metric tons of capturable carbon dioxide in the United States during the year 2025 under the reference economic case. This also leads to approximately 13.73 billion metric tons of capturable carbon dioxide world wide.

Scenario i: Creating enough alternative fuel to replace conventional road gasoline

The reference case for energy projections in the year 2025 is based on mid-range economic growth between 2002 and 2025. Even with modest economic growth, the total primary energy growth between 2002 and 2025 in the United States is projected to increase by more than 35%. During the same time period, the world’s total primary energy growth is expected to be nearly 57%. Much of this growth is driven by emerging economies, with China’s total primary energy growth expected to by nearly 153% [16]. This large expected growth in primary energy obviously has implications for the amount of fuel used for road transport which has traditionally been dominated by gasoline.

23

Based on the reference case, it is expected that the United States will use 4.33 billion barrels of gasoline in the year 2025 [22]. With an energy content of 5140 MJ per barrel of gasoline, this equates to approximately 2.23×1013 MJ of energy. Since EtOH contains approximately 3381 MJ of energy per barrel, this implies a need for approximately 6.60 billion barrels of EtOH to replace the CG that is projected to be used in the year 2025. A barrel of MeOH has an energy content of 2537 MJ per barrel; this means that it would take 8.77 billion barrels of MeOH to replace the CG under the reference case in the year 2025.

Using equation 3.2.5, the needed carbon dioxide to produce 6.60 billion barrels of EtOH amounts to approximately 1.58 billion metric tons. Equation 3.2.6 shows that the required hydrogen to produce this EtOH is equal to 108.0 million metric tons. Using equation 3.2.9 with hydrogen efficiencies of 52.2% and 38.6% [21], one can calculate the number of reactor-years necessary to produce the required hydrogen:

!

NUS,EtOHlower =

2.5266 "10#6

.522

$

% &

'

( ) "108.0M + 2.9395 "10

#8( ) " 6.60B * 717 reactor - years

NUS,EtOHhigher =

2.5266 "10#6

.386

$

% &

'

( ) "108.0M + 2.9395 "10

#8( ) " 6.60B * 901 reactor - years

Following the same process as that for EtOH, one finds that the required volume of MeOH to replace the CG projected for use in the reference case during the year 2025 to be equal to 8.77 billion barrels. The carbon dioxide required is equal to 1.52 billion metric tons and the needed hydrogen is 207.7 million metric tons. Using equation 3.2.9, with hydrogen efficiencies of 52.2% and 38.6% [21], the calculated number of reactor-years is equal to:

!

NUS,MeOHlower

=2.5266 "10#6

.522

$

% &

'

( ) " 207.7M *1006 reactor - years

NUS,MeOHhigher

=2.5266 "10#6

.386

$

% &

'

( ) " 207.7M *1360 reactor - years

At the beginning of this section, the total amount of carbon dioxide that is projected to be emitted in the United States under the reference case in the year 2025 is calculated as approximately 4.01 billion metric tons. This means that the 1.58 billion metric tons of carbon dioxide needed to create enough EtOH to replace CG is equal to about 39.4% of total available carbon dioxide available. Assuming 90% capture efficiency, this means that the needed plant participation is equal to about 43.8%. By the same token, it would take about 37.9% of the total available carbon dioxide to create enough MeOH. This would imply a needed participation rate of about 42.1%.

Table 3.3.1 displays the data concerning the amount of gasoline that is projected to be used in 2025 under the reference case. It also contains calculations concerning required alternative fuel, carbon dioxide, hydrogen, and reactors in order to create the alternative fuel.

Table 3.3.1. Summary of data concerning EIA’s reference case for U.S. in 2025.

(Data for gasoline usage taken from Annual Energy Outlook [22]. Number of reactor-years calculated assuming a 1500MWth S-AGR.)

24

Reference Case Year 2025 Projection Summary for Scenario i (Creating Enough Alternative Fuel to Replace Conventional Gasoline)

Projected Gasoline Used 4.33 billion barrels EtOH MeOH

Alternative Fuel Required to Replace Gasoline (billions of barrels) 6.60 8.77 Carbon Dioxide Required to Create Alternative Fuel

(millions of metric tons) 1580 1520

Hydrogen Required to Create Alternative Fuel (millions of metric tons) 108.0 207.7 Lower Estimate for Number of Reactor-Years Needed 717 1006 Upper Estimate for Number of Reactor-Years Needed 901 1360

The world is

Documents

An Alternative to Gasoline - thorium-now.orgthorium-now.org/synthetic_gasoline.pdf · NUCLEAR ENERGY AND SUSTAINABILITY PROGRAM An Alternative to Gasoline: Synthetic Fuels from Nuclear