Hydrogen Production from Nuclear Energy || Hydrogen as a Clean Energy Carrier

Chapter 1

Hydrogen as a Clean Energy Carrier

Abstract In this chapter, the role of hydrogen as a clean energy carrier is

discussed. In the first part of the chapter, a historical perspective on hydrogen

exploration, production, and use is presented. It appears that the modern world

evolved from a mechanization period (when heat engines were developed to

generate motive force from fossil fuels) to an electrification era (when the motive

power developed by power plants is converted to electricity to supply large national

or regional grids) and to a hydrogenation era (when the energy from primary

sources is converted by clean processes to hydrogen as an energy carrier). It is

argued that the hydrogenation era just started and will be implemented during the

first century of the current millennium. Furthermore, this section reviews the main

national/regional research programs deployed in the last 20 years on hydrogen

research. Various uses of hydrogen including as energy carrier in transportation

sector, energy storage medium, and greenhouse gas reduction agent are discussed in

detail. It is shown for a case study of comprehensive life cycle analysis that among

six vehicle types hydrogen and fuel cell vehicles show the greatest potential. Also,

the use of ammonia as synthetic fuel produced from clean hydrogen and nitrogen

represents an attractive alternative to conventional fuels for vehicles.

1.1 Historical Perspective

Modern society requires many types of services to maintain a good standard of

living: electricity, hot water, space heating, air-conditioning, fuels, various

chemicals and materials, etc. Traditional methods of producing these commodities

are primarily driven by combustion of fossil fuels which is a major contributor to

air pollution. The global population and its demand for these services are rapidly

increasing, so the rising use of fossil fuels has a major impact on climate change.

G.F. Naterer et al., Hydrogen Production from Nuclear Energy,DOI 10.1007/978-1-4471-4938-5_1, # Springer-Verlag London 2013

1

This scenario explains the worldwide motivation to develop cleaner, more

efficient production methods, which will be eventually able to replace or supple-

ment traditional processes by incorporating sustainable energy sources and hydro-

gen technologies. Hydrogen is a clean energy carrier because it can be generated by

low- or zero-carbon sources (e.g., nuclear, water, biomass, solar). Subsequently

hydrogen can be converted to electricity, synthetic fuels, or heat with little or no

environmental pollution.

Additionally, hydrogen is an important chemical that enters the constituency of

many materials used in industry and society: plastics, foods, pharmaceuticals,

fertilizers, metallic materials, construction materials, etc. For cleaner generation

of hydrogen, there is less pollution from the production of such hydrogen-

containing materials. Therefore, hydrogen itself can be viewed as a critical com-

modity for future society, which can replace or at least complement fossil fuels (oil,

coal, natural gas) that are extensively used at present. In this section, we follow the

historical evolution of the concept of “hydrogen as clean energy carrier,”

emphasizing the main issues and achievements to date.

Hydrogen was discovered in the Middle Age by Paracelsus (sixteenth century),

who reacted iron with sulfuric acid, a reaction that releases gaseous hydrogen, at

that time called “inflammable air.” Cavendish observed in 1766 that hydrogen

combustion generates only water. In 1783, Lavoisier, Laplace, and Meunier

demonstrated that water is composed from two parts of hydrogen and one part of

oxygen. The name of hydrogen was proposed by Lavoisier to indicate that it is

a constituent of water (“hydro”). In 1784, the steam-iron process has been patented

by Lavoisier and Meunier as the first technology to generate hydrogen in industrial

quantities. Many other researchers—e.g., Gay Lussac, von Humboldt, and

Charles—contributed by the end of the eighteenth century to advances in knowl-

edge, use, and production of hydrogen. Charles demonstrated the first hydrogen

flying balloon in 1783. In Paris, a system for night lighting was installed in 1803,

which uses a syngas comprising 40–60 % hydrogen. The use of hydrogen as a town

gas operated in many towns since the nineteenth century until the middle of the

twentieth century. This is one of the first uses of hydrogen as an energy carrier.

The technological development of society followed together with the evolution

of hydrogen as an energy vector. Consider the history of primary energy that society

uses for supplying its needs. There are three types of energies to be considered,

namely, the energy of coal, fossil hydrocarbons (petroleum, oil shale, oil sands, etc.

and natural gas), and renewable/sustainable sources which are “zero carbon.” The

renewable/sustainable energies are those that do not release greenhouse gas (GHG)

emissions upon their use (although some GHGs are emitted indirectly—for exam-

ple due to the construction of an energy distribution infrastructure). Typical

examples of “zero carbon” energies are biomass, hydroelectric, wind energy,

solar, nuclear, and others. The authors compiled data from past literature (Bareto

et al. 2009) to illustrate the chart in Fig. 1.1 representing the share of “zero-carbon,”

coal, and fossil fuel energy use worldwide since 1800 until the present. The chart is

extrapolated until 2100 based on a prediction model by Bareto et al. (2009).

2 1 Hydrogen as a Clean Energy Carrier

It is interesting that before the industrial revolution, the world energy supply

comprises only “zero carbon” sources: wood, wind, hydro, and animal power.

Starting with the industrial revolution and the introduction of the steam engine,

the consumption of coal increased sharply. One can speak about a “mechanization”

period of extended about 100 years during which Western civilizations

implemented an industrial society. There was remarkable technical and scientific

progress in this period, especially in England and France. Regarding hydrogen, the

discovery of water electrolysis was made by Nicholson in 1800 and the invention of

the fuel cell by Grove in 1839. By the end of the nineteenth century, Wroblewski

realized the liquefaction of hydrogen, a process that was further perfected by Dewar

and made commercially by Claude.

By the time of 1900, another source of energy started proliferating in the society,

namely, petroleum. In the same time, advances in electric power generation and the

electrical grid propelled a second industrial revolution of around 100 years, which

is called the “electrification” period (see Winter 2009). With the help of electricity,

devices like pumps, compressors, conveyers, mixers, etc. became more effective,

which encouraged the sharp development of the process industry. Germany was

noted in the beginning of the twentieth century by many and important inventions in

the chemical and process industry. One of the most important processes ever

invented is the Haber–Bosch ammonia synthesis process (1913). Manufacturing

of ammonia by this process became a major consumer of hydrogen in the world.

Further evolution of the process led to synthesis of urea at an industrial scale, which

is a major fertilizer produced from ammonia and carbon dioxide. In the Ruhr region

of Germany, a high development of coal mining and metallurgy occurred at the

1800 1850 1900 1950 2000 2050 21000

20

40

60

80

100

Year

Ener

gy sh

are

(%)

Mechanization Electrification Hydrogenation

CoalFossil hydrocarbonsZero carbon

Future

Fig. 1.1 Shares of world energy supply since the start of the industrial revolution

1.1 Historical Perspective 3

beginning of the twentieth century. Hydrogen was highly needed by the metallur-

gical sector. Consequently, by 1938, a hydrogen pipeline of 240 km was installed to

deliver 250 � 106 Nm3/year of hydrogen obtained from coal. Presently in Europe,

there are about 1,500 km of hydrogen pipelines, while in the USA, there are about

900 km of hydrogen pipelines.

The geopolitical context in the first half of the twentieth century encouraged the

development of engines and fuels for transportation. Gasoline gained in proportion

due to its high octane number, its high energy density, and cheap process of

extraction from crude petroleum. Currently, the road transportation sector uses

mostly gasoline and diesel and the marine transport industry uses heavy petroleum

or diesel. Hydrogen has found uses in space transport as liquefied rocket fuel.

It is observed that by the end of the twentieth century, science became more and

more the dominant driving force influencing the development of society. A self-

conscience was developed (the so-called Noosphere, see Goltsov et al. 2006) that

made humans aware of possible catastrophic scenarios related to the unsustainable

use of fossil energy resources. The intellectual activity and the acquired technolog-

ical and scientific knowledge created the start of a new 100-year era, which will

follow the “mechanization” and “electrification” eras. This has been often cited as

the “hydrogenation” of society (see Winter 2009). According to predictions

suggested in Fig. 1.1, during the next 100 years, the “zero-carbon” energy sources

will increase in share and a “hydrogen civilization” will emerge (see Goltsov et al.

2006). The rise of a hydrogen civilization is induced by preemptive actions founded

on scientific analyses regarding the negative impact of GHG emissions on climate

and the depletion of fossil fuel resources.

The chart in Fig. 1.2 shows how a basic scientific analysis predicts the

decarbonization of the world energy supply, from one based mostly on carbon

(molecular mass 12) to one that is based on hydrogen (molecular mass 2). This

reflects a trend in the direction of “hydrogenation” of the world energy supply,

which is an evolution toward worldwide use of hydrogen as an energy carrier. The

plot is made under the assumption that the average carbon content of fossil

hydrocarbons (mainly natural gas and petroleum) is around 1:3, while 2:3 is the

hydrogen content (the carbon-to-hydrogen ratio for methane is 1:4 while for

gasoline it is ~1:2). Therefore, the carbon content of the global energy supply is

obtained from Fig. 1.1 by addition of the coal curve to one-third of the fossil

hydrocarbon curve. The non-carbon share of the energy supply is obtained by

adding 2/3 of the fossil hydrocarbon curve with the zero carbon curve. Figure 1.2

shows a historical representation of the carbon share and non-carbon share in the

energy mix of the world supply. Note that the non-carbon share is represented by

hydrogen as part of fossil hydrocarbons plus hydrogen from any other sustainable

source, plus electricity. Since hydrogen and electricity are corresponding energy

vectors—which can be converted from one to the other—it is useful to associate the

non-carbon energy and molecular mass of 2 (hydrogen), while carbon energy has a

molecular mass of 12. With these facts, one can plot, as indicated in Fig. 1.2—the

right y-axis—the historical trend of the equivalent molecular mass of the worldwide

energy supply (calculated as a weighted sum of the corresponding atomic masses of


C and H). The curve (Meq) shows an interesting feature: it sharply rises during the

coal-dependent “mechanization era,” decreases with fluctuations during the “elec-

trification” era, and steadily decreases during the future “hydrogenation” era. This

downward character toward energy decarbonization is a result of societal-will

demonstrated during the last 40 years.

The concept of switching to an economy based on hydrogen as an energy carrier

was shaped by the end of the 1960s and beginning of the 1970s. According to

Bocris (2002), it started with the quest of finding a clean energy carrier that can

replace or complement electricity. It was argued that hydrogen can be stored in

large scales in depleted oil fields or in balloons under the sea at pressures of

20–50 bars. In the initial views—characterizing the years of the 1970s—hydrogen

stored in large scales would be transported at long distances (~1,000 km) for which

the economics shows that its transportation is better than electricity. In more recent

years, another concept appeared, namely, hydrogen storage at small scales to satisfy

power generation needs in vehicles or small power generators.

The energy crisis from the beginning of the 1970s influenced positively the

consideration by the scientific community of a hydrogen economy. A key event

impacting the progress of the hydrogen economy concept was the THEME confer-

ence held in Miami (FL) in 1974. The International Association of Hydrogen

Energy (IAHE) was established at that time, which became a world leader in

promoting the hydrogen economy concept. Several other associations were formed

since that time; Table 1.1 contains a sample list of hydrogen associations world-

wide. One of the most known and prolific conferences—initiated and maintained by

IAHE—is the World Hydrogen Energy Conference (WHEC), the first being held in

Miami, 1976. By 2005, the Kyoto Protocol was signed, which represents an

1800 1850 1900 1950 2000 2050 21000

20

40

60

80

100

2

3

4

5

6

7

8

9

10

Year

Ene

rgy

shar

e (%

)

Meq

(kg/

kmol

)

Meq (kg/kmol)CarbonCarbon-free

Fig. 1.2 Illustration of the historical trend of energy decarbonization


engagement of many countries to develop a cleaner energy system; hydrogen is an

important part of this goal.

In Table 1.1, the Nuclear Hydrogen Division (NHD) of IAHE is an organization

that promotes and fosters collaborations amongst countries pursuing nuclear pro-

duction of hydrogen. In the Generation IV International Forum (GIF), 12 countries

around the world are laying the groundwork for the next generation of nuclear

reactors, which will produce hydrogen as well as electricity. In addition to

organizing and promoting nuclear hydrogen meetings and activities, NHD aims

to serve as public outreach, and advocacy to policy makers on the nuclear expansion

is under way at this time around the world. Technology roadmaps are being

developed that will foster the emergence of hydrogen as a key commercial product

of nuclear plants in the future.

By the end of the 1980s, the hydrogen economy concept became well known.

Russia started publication of Nuclear-Hydrogen Energy Technology periodicals

showing a systematic scientific effort for developing a hydrogen economy from

nuclear energy. By the end of the 1990s, many of the fundamental problems

of hydrogen production, transportation, distribution, storage, utilization, materials,

and safety were solved. As a result of the sustained effort in promoting hydrogen—

the future energy carrier—many governments initiated research programs on the

topic; some relevant of these programs are listed in Table 1.2. These led to many

accomplishments, some of them very spectacular like the first flight demonstration

of a large-size hydrogen passenger plane—Tupolev 155—in Moscow in 1988,

marketing of the first 1 MW SOFC with 70 % efficiency by Westinghouse in

Table 1.1 Worldwide associations which are active in hydrogen energy

Name Yeara Description

CHFCA 2009 Canadian Hydrogen and Fuel Cell Association collaborates with IAHE to

promote hydrogen adoption in Canada. It was formed in 2009 as a result

of a merger of the Canadian Hydrogen Association (CHA) and Hydrogen

and Fuel Cells, Canada. Through the former CHA, the CHFCA has been

active in the field of hydrogen energy for over 25 years.

NHD 2009 Nuclear Hydrogen Division of IAHE organizes and promotes activities that

foster development of nuclear systems for hydrogen production, including

thermochemical cycles, electrolysis, and related elements such as safety

and materials science.

NH3FA 2003 Ammonia Fuel Association promotes ammonia as a source of hydrogen for

better and more compact storage. It indirectly sustains a hydrogen

economy. It started as a series of annual conferences since 2003, named

the Annual Ammonia Alternative Fuel Conferences.

ISO 1990 International Organization for Standardization formed ten subcommittees to

implement international standards for hydrogen energy technologies.

IAHE 1974 International Association of Hydrogen Energy is the main pillar in the

hydrogen movement and its initiator. It governs the World Hydrogen

Energy Conference and it is responsible for publishing the International

Journal of Hydrogen Energy.aYear since the organization became involved in hydrogen energy activities


2001, and the orbiting aerospace plane “Venture Star” by Boeing and Lockheed-

Martin that uses a mixture of cryogenic liquid–solid H2 for propulsion (Veziroglu,

2000). The Japanese hydrogen submarine Urashima 600 was equipped with fuel

cells and was launched in 2000. A French submarine with hydrogen and fuel cells

with installed power of 300 kW each was built in recent years; it stores the

hydrogen in FeTi metal hydrides that contain 1.8 t of fuel onboard. The weight of

the storage tank is about 90 times heavier (Bose and Malbrunot, 2007).

One promising option is nuclear hydrogen production. Although nuclear energy

is discouraged in some countries, there are fundamental, technical, economical, and

sociopolitical advantages in favor of nuclear energy. In Europe, Germany is

Table 1.2 Sample national or international hydrogen programs

Region Program Year Description

Japan WE-NET 1993 “Clean Energy Systems Utilizing Hydrogen” is a

program aiming to realize the “World Energy

NETwork.” The project term is 1993–2020.

Texas, USA ARISE 1990 NSF Center for H2 research. Electrolysis and

photo-electrolysis of H2S to generate hydrogen.

Photo-catalysis of water.

USA Freedom Car and

Hydrogen

2005 DOE program to promote hydrogen economy in

the USA.

Europe Shell Hydrogen 2000 $500M for hydrogen programs.

CUTE Clean Urban Transport for Europe.

ECTOS 2000 Ecological City Transport System.

Quickstart 2003 Hydrogen production from renewables to use and

propel vehicles.

HyCHAIN 2006 Over 160 FC vehicles in Germany, Spain, and

Italy.

Canada–Europe Euro-Quebec 1992 European-Canadian project to study the transport

of hydropower from Quebec to Hamburg in the

form of cryogenic hydrogen moved on barges.

Canada NRC—

Vancouver

2010 Around ten hydrogen-fuelling stations were

installed in Vancouver during the Olympic

games.

Ontario, Canada Cu-Cl cycle 2011 International consortium of five countries

developing an integrated plant of the copper-

cycle of thermochemical water splitting for

nuclear hydrogen production.

Germany–Saudi

Arabia

HySolar 1986 Promoting hydrogen as an energy carrier for long

distances. Development of hydrogen

production methods.

France PAN’H 2005 National Programme for Hydrogen Action.

Iceland Iceland 1998 Aim to convert Iceland to a complete hydrogen

economy by 2030.

Turkey UNIDO-ICHET 2004 International Centre for Hydrogen Energy

Technologies formed as a UNIDO project

funded by the Ministry of Energy and Natural

Resources of Turkey with the role to promote

the hydrogen economy.


focusing its efforts on the development of a nuclear-free energy infrastructure

involving production of hydrogen from renewable sources such as wind, solar,

and biomass. It is interesting to note that a wind power plant must occupy about 100

times more land area than a nuclear power plant site. On the contrary, France bases

its energy supply on nuclear power plants. France exploits the only commercial

breeder reactor.

Potential pathways to implementing nuclear hydrogen production, where

hydrogen has the role of an energy carrier and storage medium, were developed

initially in the 1970s. These include the Gas Research Institute and General

Atomics in the USA, which identified a number of thermochemical cycles for

water splitting, which can be coupled to nuclear reactors to generate hydrogen.

More recently, the interest in thermochemical cycles was renewed in 2003 at the

Argonne National Laboratory (ANL; see Lewis 2003). A large-scale international

program to develop the copper–chlorine cycle in conjunction with generation IV

nuclear reactors is currently in progress. It involves a collaboration between

Canada, USA, Argentina, Czech Republic, Romania, and Slovenia, led by the

University of Ontario Institute of Technology (UOIT), together with Atomic

Energy of Canada Limited (AECL) and ANL, and collaborating with the Genera-

tion IV International Forum. This program and its accomplishments will be

described in detail in this book.

The present worldwide production of hydrogen is around 50 Mt per year.

In Canada, which is very active in hydrogen development, hydrogen is utilized

as a feedstock for various chemical processes in industries and refineries. Canada

produces more than 3 Mt of hydrogen per year (see Dincer and Zamfirescu 2011).

Presently there is a significant use of hydrogen in Canada for upgrading heavy oil,

particularly for the oil sand sites in Alberta. In the past, hydrogen has been used in

Canada for oil refining, ammonia production, methanol production, and process gas

in metallurgical sectors. The growth of hydrogen utilization trends in Canada is

reported in Fig. 1.3. The oil refining sector and ammonia production accounted in

1983 for 48 % and 40 %, while at present it is observed that the oil refining and

heavy oil upgrading has a total share of hydrogen utilization of 47 %. Based on

forecasts, by 2025, the oil refining share for hydrogen demand will reach 62 %.

Oil refining, 24%

Heavy oil upgrading,

23%

Chemical production (ammonia and other),

35%

Chemical process by-products

(Methanol, Metallurgy etc), 18%

Oil refining and synfuel,

62%Ammonia,

25%

Methanol, 6%

Metallurgy sector, 7%Oil refining

and synfuel, 48%

Ammonia, 40%

Methanol, 8%

Metallurgy sector, 4%

1983 2010 2025

Fig. 1.3 Past and forecasted hydrogen utilization in Canada adapted from Dincer and Zamfirescu

(2011)


1.2 Physical Properties

Hydrogen is the most abundant chemical element in the universe (atomic number

Z ¼ 1). Having the simplest molecular structure, hydrogen can easily lose valence

electrons and therefore it is very reactive. Therefore, hydrogen generally cannot be

found as an individual element on earth, but rather in chemical compounds. Water

is the most abundant source of hydrogen on earth; also, hydrogen is part of most

fossil fuels and biomass. On earth, hydrogen can also be found in the form of

hydrogen sulfide (H2S). Hydrogen has a high calorific value, the lowest molecular

weight, the highest thermal conductivity among all gases, and the lowest viscosity.

Table 1.3 summarizes the main thermophysical properties of hydrogen, while

Fig. 1.4 shows its T–s diagram.

The heating value per unit of weight of hydrogen is much higher than that of

conventional fuels. However, hydrogen cannot be kept easily in a condensed phase

because its density is too low. Therefore, regardless of its storage method, the

heating value of hydrogen per unit of volume is the lowest as compared to

conventional fuels. Nevertheless, the efficiency of power generation systems

fuelled with hydrogen is much higher than that obtained with conventional fuel.

This compensates for the low storage density problem of hydrogen. An important

advantage is that hydrogen combustion is completely clean, producing only water

vapor in the exhaust gas. Heat recovery can be applied to hydrogen combustion to

obtain liquid water which may be recycled back to produce hydrogen.

Table 1.3 Thermophysical properties of hydrogen

Property Description Property Description

Melting point

(MP)

Transformation solid–liquid at

1 atm, MP ¼ 14.01 K

Boiling point

(BP)

Transformation liquid-

vapor at 1 atm,

BP ¼ 20.3 K, 99.8 %

para-hydrogen

Critical point 32. 97 K, 12.9 bar Liquefaction 14.1 MJ/kg theoretical

energy

Flame Flame speeda 2.75 m/s, adiabatic

flame temperature 2,400 K

Ortho-para

percent

At standard temperature,

75 % ortho and 25 %

para hydrogen

Vapor density 0.1 kg/m3 at 1 atm and 298 K Liquid density 70.79 kg/m3 at 1 atm and

20.3 K1.34 kg/m3 at 1 atm and 20.3 K

LHV Lower heating value, 119.9 MJ/kg HHV Higher heating value,

141.8 kJ/kg

Flammability 4–18 % and 59–75 %mix with air,

ignition temperature 858 K

Detonation 13–65 % mix with air with

2 km/s, suppression of

shock wave at 1.47 MPa

Diffusivity In air, 0.61 cm/s Conductivity 0.177 W/m KaSix times faster than that of gasoline

1.2 Physical Properties 9

1.3 Transportation

There are relatively few difficulties related to hydrogen transport in pipelines. As

mentioned previously, hydrogen in the form of town gas was used for at least 150

years to supply networks of many metropolitan cities. There are however energy

costs due to hydrogen transportation and distribution. The approximate orders of

magnitude of energy losses from hydrogen production to hydrogen delivery are

listed as follows (see Dincer and Zamfirescu 2011).

• Production: 10 % if produced via fossil fuel reforming and 25 % if electrolysis is

used.

• Conditioning: purification and compression or liquefaction. Purification is done

to 4 ppm for compressed hydrogen or 1 ppm for liquefaction. Conditioning totals

10–15 % losses at compression (to 20–80 MPa, respectively), and 30–150 %

losses at liquefaction (for 1 t/h and 0.01 t/h, respectively).

• Transport: Via pipeline 1.4 % per 150 km.

• Distribution at gas station: 7.5–40 % losses due to electrical energy to pump H2

(for 100 and 2,000 cars per day, respectively).

Apart from pipelines, there are many other alternatives for hydrogen transporta-

tion. One possibility is to transport hydrogen via the existing infrastructure of

natural gas pipelines. In order to pursue this without modifications, hydrogen is

mixed with natural gas in a proportion of 1:9. Hydrogenation of natural gas

pipelines is an excellent way of reducing GHG emissions.

Pipelines dedicated to hydrogen transport exist in Europe and USA (mentioned

previously). It is found that for practical reasons, the diameter of the pipeline is

-5 0 5 10 15 20 25 30 35 4015

20

25

30

35

40

45

50

s (kJ/kgK)

T(K)

925 kPa

425 kPa

155 kPa

40 kPa 0.2 0.4 0.6 0.8

0.0

35

0.1

7

0.4

0.9

1

2.0

7

4.7

m3/

kg Hydrogen

Fig. 1.4 T–s diagram of hydrogen


ideally in the range of 100–200 mm and the operating pressure varies between 0.34

and 10 MPa. Material embrittlement poses some significant technical problems;

however there are various technical solutions available (see Bocris 2002).

Road transport is typically done in canisters of compressed hydrogen carried by

trucks. Due to the large weight of the canisters, a typical truck of 40 t can transport

only ~700 kg hydrogen. The typical pressure of compressed hydrogen is 20 MPa

with a storage density of 14 kg/m3 (gas). The mass of gas with respect to the storage

tank is only 6 %. There is technology of hydrogen compression and storage up to

70 MPa which improves the hydrogen packing up to 8 % from the storage tank

weight. The longest distance for hydrogen transport in a compressed gas phase is

around 500 km, when the cost of transport balances the cost of carried hydrogen.

A more compact transportation method of hydrogen is in its cryogenic liquid

state. There are cryogenic cisterns for road transport which can carry 3.5 t of

hydrogen in a 40 t heavy truck. The cryogenic mode of transportation is applicable

to rail and road transport too.

Other means of hydrogen transport involve chemical transformations. Two main

possibilities exist: (1) hydrogen is converted into methanol based on an established

technology which uses carbon dioxide recovered from any type of process, and (2)

conversion of hydrogen in ammonia via the mature Haber–Bosch process. There is

an energy cost in both cases with the intermediate carrier synthesis, but this is

compensated by cheaper transportation and distribution. Retrieving hydrogen from

ammonia or methanol at a distribution point is straightforward. It requires relatively

little energy, which can be derived onsite from renewables.

Figure 1.5 illustrates the hydrogen through ammonia transportation scheme. A

simplified cost analysis of this scheme in comparison to road transport in cryogenic

and compressed gas states was performed by Dincer and Zamfirescu (2011). It shows

that although converting hydrogen from ammonia introduces a 25 % cost penalty,

due to its cheaper distribution and reformation, transportation of hydrogen via

ammonia competes well with road transport of compressed and liquefied hydrogen.

The last segment of hydrogen transport is its distribution (or delivery) to the

users. Two types of fuelling stations exist up to now for hydrogen applications

(vehicles): compressed gas or cryogenic liquid stations. Two versions exist for

vehicles fuelling with compressed hydrogen: transfer via a special hose from the

DistributionInfrastructure

(alreadyexistent)

Fuelingstation

AmmoniaReforming

to hydrogenNH3

NH3

RefrigeratedAmmoniastorage

NH3 storage@ 8 barHaber-Bosch

synthesis unit

Hydrogen

Nitrogen

Fig. 1.5 Hydrogen through an ammonia transportation scheme

1.3 Transportation 11

high-pressure reservoir of the fuelling station to the fuel tank of the vehicle, or using

interchangeable fuel tanks. The latter solution can be done with a certain degree of

automation; it can be fast and adapted to light vehicles. For transfer of liquid

hydrogen, the only practiced solution is to convey the fuel via a liquid pump.

1.4 Storage

The issue of hydrogen storage can be discussed only in conjunction with the storage

scale. One can have very large storage capacities of order of hundreds of thousands

of cubic meters or more, or one can have intermediate storage in large-size

reservoirs, small-scale storage in road transport, or even microscale storage in

portable power applications (e.g., powering laptops). For each case, it corresponds

a specific set of solutions.

Very-large-scale storage can be applied in the vicinity of industrial producers of

hydrogen, including future nuclear hydrogen facilities. In this case, hydrogen can

be injected into exhausted oil wells, underground caverns, or salt domes. There is

good experience of hydrogen storage in salt caverns. Praxair has a hydrogen

pipeline in the Gulf of Mexico that is integrated with a storage facility in caverns.

Linde stores hydrogen underground in porous rocks at pressures up to 40 atm.

For medium-size storage, an interesting possibility is hydrogen storage in the

form of ammonia or urea. Ammonia can be stored seasonally as refrigerated liquid

at atmospheric pressure in tankers of 60 kt. This strategy is widely applied because

ammonia is a product produced throughout the year and consumed mostly in

summers (as fertilizer). A typical sealed reservoir is a building size of 50 m

diameter and 30 m height.

Figure 1.6 illustrates a storage facility of ammonia. Since a molecule of ammo-

nia embeds three atoms of hydrogen, it is relatively straightforward to retrieve

hydrogen from ammonia under an energy cost of 15 % from the lower heating value

of the extracted hydrogen. The amount of hydrogen generated from 60 kt of

ammonia is about 10 kt.

For a smaller scale, hydrogen is difficult to store. It is very difficult to store

hydrogen in a satisfactory dense phase so that the packed energy density is similar

to that of common fuels used today for vehicles. On a higher heating value base,

1 kg of gasoline is equivalent to 0.3 kg of hydrogen. Gasoline has 1.3 L/kg, while

the equivalent liquefied hydrogen contains 3.5 times more volume. Compressed

hydrogen at 400 bar and 298 K occupies 9.6 times more volume than gasoline. The

following storage methods are considered for hydrogen for small-size storage:

• Cryogenic liquid at standard pressure and 20 K

• Compressed gas at standard temperature and very high pressure

• Physical binding of hydrogen molecule in a solid material matrix

• Chemical binding to synthesize a denser chemical that can later release

hydrogen


Two processes can be used for storing hydrogen in a solid matrix: physisorption

and chemisorption. In general, it requires some thermal energy at the discharging

phase and some cooling is applied at charging. Sodium, lithium, magnesium, and

boron can create chemical hydrides that store hydrogen more densely than possible

in metal hydrides via physisorption and chemisorption. Decomposition of chemical

hydrides is irreversible. Therefore, sophisticated processes must be put in place to

recycle the chemical compounds after hydrogen release. Consequently the devices

that generate hydrogen out of chemical hydrides are voluminous.

If the volume of the hydrogen storage and that of the system that extracts

hydrogen from it are included, many chemical hydrides appear non-satisfactory

for vehicular applications. For example, based on a recent assessment, the US

Department of Energy (DOE) assessed boron-based hydrides as not applicable for

road vehicles. However, ammonia borane is a good choice for portable applications.

It is one of the most promising hydrogen storage systems with 120 g/L in a weight

concentration of 19 % (see Dincer and Zamfirescu 2011). Ammonia borane releases

hydrogen by thermal cracking according to the following reaction occurring at

successively higher temperatures:

2NH3BH3 ��!<120 �C ðNH2BH2Þ2 þ 2H2

ðNH2BH2Þ2 ��!�150 �C ðNHBHÞ2 þ 2H2

ðNHBHÞ2��!>500 �C

BNþ 2H2

9>>=

>>;

:

It is interesting to note from the above reactions that ammonia borane can release

hydrogen at temperatures lower than 120 �C; if properly conducted, the decompo-

sition reaction can release hydrogen even at room temperature. Releasing hydrogen

60 kt Liquid NH3 -33oC, 1atmSource for

10 kt of Hydrogen

2 stagescompressor

withintercooling

Desuperheater

Condenser

Throttling valve

1

2

34

LiquidAmmoniaCharging/Discharging

Coolant

Fig. 1.6 Seasonal storage of hydrogen, chemically embedded in ammonia

1.4 Storage 13

at low temperature is a crucial characteristic for storage systems with regard to cold

start-up of small engines.

Metal amines were proposed as an alternative solution for hydrogen storage via

ammonia intermediates, e.g., magnesium chloride which forms Mg(NH3)6Cl2. This

molecule embeds hydrogen at 109 g/L and 92 g/kg and releases ammonia by

thermal desorption.

Ammonia can also be used to store hydrogen “chemically” in small-scale

applications. An alternative to ammonia is urea, which is a source of ammonia

that can be obtained by hydrolysis. Urea is very stable, can be stored for very long

time and it is allowed on passenger cars. When synthesized from biomass, urea is a

“zero carbon” fuel and hydrogen source. For extraction of hydrogen from urea, a

sustainable thermal energy source can be used, for example heat recovery from

exhaust gases. Ammonia-based compounds—as shown in the above example

urea—have good capability of hydrogen storage and release.

Figure 1.7 presents the hydrogen storage density with various technologies in

terms of volumetric storage (x-axis) and gravimetric storage (y-axis). The

ammonia–boron compound with a chemical formula NH4BH4 appears to be the

most “dense” hydrogen storage medium.

1.5 Applications

1.5.1 Reduction of GHG Emissions in the Residential Sector

Consider a case study of the analysis of the potential to reduce GHG emissions in

the residential sector of Canada by using hydrogen as an energy carrier. This

example is based on the work of Lubis et al. (2009). The residential sector in

Canada consumes mainly fossil fuels and requires energy according to the graph of

0

5

10

15

20

25

30

35

40

10 30 50 70 90 110 130 150

Ene

rgy

dens

ity (

HH

V),

MJ H

2/kg

Volmetric density, kgH2/m3

800 bar H2

Composite tank

800 bar H2

Steel tank

Liqu

id H

2, 2

0.3

K

NH3

10 bar

Liquid CH4

111 KNH4BH4

NH3BH3

Lighthydrides

Metalhydrides

Urea

Fig. 1.7 Density of hydrogen storage with various technologies


Fig. 1.8. The objective is to analyze the reductions in GHGs achievable through the

use of hydrogen technologies, as a substitute for electricity provided by the grid and

space heating from natural gas furnaces for single-family detached houses.

It is assumed that electricity is required for lighting, space cooling, and

appliances, while heating and water heating requirements are provided by a furnace

(see Table 1.4). The alternative system delivers the required electrical and thermal

energy using hydrogen in fuel cells and furnaces. The calculation of GHGs for each

case considers the emissions at the consumption of energy as well as production of

fuels. For the alternative energy system, hydrogen is combusted in the furnace to

generate heat and supplied to the fuel cell to produce electricity. Therefore, at the

end use, there are no direct emissions of GHG. For the reference system, the furnace

is supplied with natural gas, which is modeled as methane.

The furnace efficiency is assumed to be 60 %, and then the rate of fuel

consumption is determined according to

η ¼_Quseful

_mfuelLHVfuel

: (1.1)

Space heating, 63%

Water heating, 16%

Appliances, 13%

Lighting, 5%Cooling, 3%

Fig. 1.8 Shares of energy usage in residential sector of Canada [data from Lubis et al. (2009)]

Table 1.4 Breakdown by task and province of energy consumption (in TJ) in Canada in 2005

Service

Energy

carrier

Province

NFL PEI NS NB QUE ON MAN SAS AB BC

Space heating Fuel 68.4 60.8 58.7 87.2 95.5 90.5 68.4 76.0 116.0 63.0

Water heating Fuel 11.6 19.3 15.7 12.2 13.5 25.6 19.0 22.1 29.6 23.6

Operating

appliances

Electricity 17.7 7362 18.4 18.1 18.4 17.1 20.6 16.5 15.9 19.3

Lighting Electricity 6.0 2.5 6.9 6.0 7.2 7.3 7.5 6.6 6.7 8.8

Space cooling Electricity 0.02 0.05 0.22 0.29 2.0 9.2 4.2 0.84 0.08 0.50

NFL Newfoundland, PEI Prince Edward Island, NS Nova Scotia, NB New Brunswick, QUEQuebec, ON Ontario, MAN Manitoba, SAS Saskatchewan, AB Alberta, BC British Columbia

1.5 Applications 15

For the hydrogen furnace system, the efficiency is assumed within the practical

range of 40–50 %. From (1.1), the hydrogen fuel consumption is determined for any

given heat demand. For the fuel cell system, it is assumed that the availability factor

is 91.3 %. The evaluation of GHG emissions of hydrogen production considers

some indicators as 20.5 kg/GJ when hydrogen is generated from wind energy, and

30.6 kg/GJ if photovoltaic arrays are used. It results in the specific grid emission in

each province according to Table 1.5.

The GHG emission reductions for heating systems when hydrogen technologies

are used in place of natural gas are shown in Fig. 1.9. The GHG emission reductions

for electricity consumption systems when hydrogen technologies are used in place

of grid-based electricity are shown in Fig. 1.10. It shows that the greatest annual

reduction, 7.2 t CO2, occurs in Alberta when hydrogen from wind energy is used,

mainly because it is the province with the largest thermal energy requirements for

heating as well as a large population. It can be concluded that the heating system in

Canada must be improved to reduce air pollution.

Regarding the electrical energy supply, the results shown in Fig. 1.10 demon-

strate that GHG emissions are reduced in most Canadian provinces when solar- or

wind-based hydrogen technologies are used in place of grid-based electricity. In

two provinces, Quebec and Manitoba, the hydrogen technologies are not attractive

for electrical power generation because they increase the GHG emissions with

respect to the reference case. The greatest annual reduction in GHG emissions

occurs in Saskatchewan mainly because the GHG emission factors for the

Table 1.5 Greenhouse gas emission factors for the electricity of each Canadian province

Province NFL PEI NS NB QUE ON MAN SAS AB BC

GHG (kg/GJ) 234 235 243 221 1 251 3 334 143 104

0

2

4

6

8

GH

G r

educ

tion

(t C

O2/ye

ar)

NFL

H2 from wind

H2 from solar

PEI NS NB QC ON MAN SAS AB BC

Fig. 1.9 Reductions in greenhouse gas emissions associated with heating systems in the residen-

tial sector in Canada, for the alternative case considered


electricity grid in Saskatchewan are higher than other provinces. Although the

differences in the reductions or increases in GHG emissions are dependent on

whether the hydrogen is derived from wind or solar energy, this dependence is

not noticeable when hydrogen supplies heat.

The analysis suggests that the hydrogen technologies considered in the alterna-

tive cases have significant potential for reducing emissions of GHGs in Canada’s

residential sector. Noting that the residential sector consumes a 20 % share of

Canada’s overall energy supply, it indicates that the potential of hydrogen energy is

significant for reducing GHG emissions nationally.

1.5.2 Comparative Life-Cycle Assessment of Hydrogen andConventional Vehicles

This case study demonstrates the advantages of using hydrogen as energy carrier in

passenger vehicles. This example is detailed elsewhere (Dincer and Zamfirescu

2011); this section provides an overview of main results and analysis. Sustainable

development requires environmentally benign vehicles characterized by little or no

atmospheric pollution during their life cycle. In Canada, 70 million tons of GHGs

are emitted per year from vehicle driving.

Six types of vehicles are considered in Table 1.6. The material inventory for

batteries and fuel cell stacks is indicated in Table 1.7. The inventory includes

analyses regarding the fuel processing stages (both gasoline and hydrogen cases).

The hydrogen production efficiency from natural gas is 78 % while that of gasoline

from crude oil is 85 %. The analysis also considered the case of hydrogen

-4

-2

0

2

4

6

8

GH

G r

educ

tion

(t C

O2/ye

ar)

NFL

H2 from windH2 from solar

PEI NS NB

QC

ON

MAN

SAS AB BC

Fig. 1.10 Reductions in greenhouse gas emissions associated with electricity use in the residential

sector in Canada, for the alternative case considered

1.5 Applications 17

production from wind energy and from photovoltaics. Figure 1.10 presents the life-

cycle GHG emissions for 1 MJ of mechanical work generated at the vehicle shaft.

The emissions are correlated with the vehicle efficiency. Taking into account

that the efficiency of the hydrogen vehicle is high (>40 %) and that of the gasoline

vehicle is low (~20 %), these results show that the gasoline vehicle emits the most

during its lifetime. The result from Fig. 1.11 is further used to determine the GHG

emissions for the vehicles. For an assessment of environmental impact, the air

pollution indicator (AP) is calculated and both the AP and GW (global warming

parameter in kg CO2 equivalent per 100 km) are correlated with the curb mass of

car. The formulae used for calculations and the amounts of GHGs and AP are

presented in Table 1.8.

Table 1.6 Main characteristics of vehicles

Vehicle Fuel type Engine type

Fuel consumption

(MJ/100 km)

Driving

range (km)

Conventional Gasoline ICE 237 540

Hybrid Gasoline ICE + electric 138 930

Electric Electricity Electric 67 164

Fuel cell Hydrogen Electric 129 355

H2-ICE Hydrogen ICE 200 300

NH3-H2-ICE Ammonia ICE 175 430

Source: Dincer and Zamfirescu (2011)

Table 1.7 Inventory of main construction materials

Component Mass Remarks

Battery hybrid

vehicle

53 kg 1.8 kWh capacity; 1.96 MJ electricity and 8.35 MJ

petroleum per kg

Battery electric

vehicle

430 kg 27 kWh capacity; 1.96 MJ electricity and 8.35 MJ

petroleum per kg

PEMFC stack Electrode 4.44 kg Contains platinum, ruthenium, carbon

paper

Membrane 5.64 kg Nafion

Bipolar plate 53 kg Contains polypropylene, carbon fibers,

carbon powder

End plate 2.8 kg Aluminum alloy

Current collectors 1.14 kg Aluminum alloy

Tie rod 2.05 kg Steel

Vehicle Breakdown of life-cycle energy consumption (GJ/unit)

Vehicle type ICE PEMFC

Material production 50 55

Vehicle assembly 25 24

Vehicle distribution 2.1 2.1

Vehicle use 819 195

Disposal 0.30 0.3



This analysis considers all phases of a product (system, technology) life cycle,

starting with the extraction of resources, manufacturing of materials and parts,

assembly, use, maintenance, and disposal. It shows that the lowest global warming

impact is that of hydrogen—internal combustion engine (either directly supplied by

hydrogen or indirectly, via ammonia—the NH3-H2-ICE case). Also H2-ICE

vehicles show lower air pollution indicators (see Table 1.8). In Table 1.8, the fuel

cell vehicle has high air pollution due to the manufacturing phase of the vehicle

which involves many air polluting processes. In conclusion, hydrogen-fuelled

vehicles are a good choice for the future hydrogen economy, although nowadays,

due to high costs and a lack of infrastructure, they do not yet compete with the

existing gasoline technology.

0

100

200

300

400

500

0.2 0.3 0.4 0.5 0.6

CO

2equ

ival

ent,

g/M

J

h

Gasoline & H2 from N.G. (same emissions)

H2 from solar PV

H2 from wind

Fig. 1.11 GHG emissions for the entire life cycle, during fuel processing and utilization

Table 1.8 Environmental impact for life cycle of case-study vehicles

Vehicle

Air pollution (AP) and global warming

(GW) equations

AP

(g/100 km)

GW (kg CO2

equiv/100 km)

Conventional AP ¼ mcurbAPm; GW ¼ mcurbGWPm 3.6 1.5

Hybrid AP ¼ ðmcurb � mbatÞAPm þ mbatAPbat;GW ¼ ðmcurb � mbatÞAPm þ mbatGWPbat

4.2 1.7

Electric AP ¼ ðmcurb � mbatÞAPm þ mbatAPbat;GW ¼ ðmcurb � mbatÞAPm þ mbatGWPbat

6.2 2.0

Fuel cell AP ¼ ðmcurb � mfcÞAPm þ mfcAPfc;GW ¼ ðmcurb � mfcÞAPm þ mfcGWPfc

17.8 4.1

H2-ICE AP ¼ mcurbAPm; GW ¼ mcurbGWPm 4.0 1.5

NH3-H2-ICE AP ¼ mcurbAPm; GW ¼ mcurbGWPm 3.0 1.4


1.5 Applications 19

1.6 Conclusions

This chapter discussed the role of hydrogen as a potential energy carrier for better

environmental and sustainable development. A focus on hydrogen is given with

respect to historical perspectives, physical properties, and comparisons with other

fuels and options, as well as its use in transportation, and options with respect to

storage and other applications.

Nomenclature

AP Air pollution indicator, g/100 km

GW Global warming indicator, kg CO2/100 km

GWP Global warming potential, kg CO2/100 km

LHV Lower heating value (MJ/kg)

_m Mass flow rate (kg/s)_Q Heat flux (kW)

Greek Letters

η Efficiency

Subscripts

Fuel Natural gas or hydrogen

References

Bareto L, Makihira A, Riahi K (2009) The hydrogen economy in the 21st century: a sustainable

development scenario. Int J Hydrogen Energy 28:267–284

Bocris JO’M (2002) The origin of idea of a hydrogen economy and its solution to the decay of the

environment. Int J Hydrogen Energy 27:731–740

Bose T, Malbrunot R (2007) Hydrogen. Facing the energy challenges of the 21st century. John

Libbey Eurotext, Esher, UK

Dincer I, Zamfirescu C (2011) Sustainable energy systems and applications. Springer, New York

Goltsov VA, Veziroglu TN, Goltsova LF (2006) Hydrogen civilization of the future—a new

conception of the IAHE. Int J Hydrogen Energy 31:153–159

Lewis D (2003) Hydrogen and its relation with nuclear energy. Prog Nucl Energy 50:394–401

Lubis L, Dincer I, Naterer GF, Rosen MA (2009) Utilizing hydrogen energy to reduce greenhouse

gas emissions in Canada’s residential sector. Int J Hydrogen Energy 34:1631–1637

Veziroglu TN (2000) Quarter century of hydrogen movement 1974–2000. Int J Hydrogen Energy

25:1143–1150

Winter C-J (2009) Hydrogen energy—abundant, efficient, clean: a debate over the energy-system-

of-change. Int J Hydrogen Energy 34:S1–S52


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