Moran M.J., Shapiro H.N. Fundamentals of Engineering Thermodynamics

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676 Chapter 13 Reacting Mixtures and Combustion

13.74 Carbon monoxide at 25C, 1 atm enters an insulated re-

actor operating at steady state and reacts completely with the

theoretical amount of air entering in a separate stream at 25C,

1 atm. The products exit as a mixture at 1 atm. Determine in

kJ per kmol of CO

(a) the exergy entering with the carbon monoxide.

(b) the exergy exiting with the products.

Also, evaluate an exergetic efficiency for the reactor. Perform

calculations relative to the environment of Problem 13.63. Ig-

nore kinetic and potential energy effects.

13.75 Liquid octane (C

) at 25C, 1 atm and a mass flow

rate of 0.57 kg/h enters a small internal combustion engine op-

erating at steady state. The fuel burns with air entering the en-

gine in a separate stream at 25C, 1 atm. Combustion products

exit at 670 K, 1 atm with a dry molar analysis of 11.4% CO

2.9% CO, 1.6% O

, and 84.1% N

. If the engine develops

power at the rate of 1 kW, determine

(a) the rate of heat transfer from the engine, in kW.

(b) an exergetic efficiency for the engine.

Use the environment of Problem 13.63 and neglect kinetic and

potential energy effects.

13.76 Evaluate an exergetic efficiency for the gas turbine power

plant of Problem 13.36. Base exergy values on the environ-

ment of Problem 13.63.

13.77 Consider a furnace operating at steady state idealized as

shown in Fig. P13.77. The fuel is methane, which enters at

25C, 1 atm and burns completely with 200% theoretical air

entering at the same temperature and pressure. The furnace de-

livers energy by heat transfer at an average temperature of

60C. Combustion products at 600 K, 1 atm are discharged to

the surroundings. There are no stray heat transfers, and kinetic

and potential energy effects can be ignored. Determine in kJ

per kmol of fuel

(a) the exergy entering the furnace with the fuel.

(b) the exergy exiting with the products.

Also, evaluate an exergetic efficiency for the furnace and com-

ment. Perform calculations relative to the environment of

Problem 13.63.

13.78 Coal enters the combustor of a power plant with a mass

analysis of 49.8% C, 3.5% H, 6.8% O, 6.4% S, 14.1% H

and 19.4% noncombustible ash. The higher heating value of

the coal is measured as 21,220 kJ/kg, and the lower heating

value on a dry basis, (LHV)

, is 20,450 kJ/kg. The following

expression can be used to estimate the chemical exergy of the

coal, in kJ/kg:

where hc, oc, and nc denote, respectively, the mass ratio

of hydrogen to carbon, oxygen to carbon, and nitrogen to

carbon, and s is the mass fraction of sulfur in kg per kg of

fuel.

The environment is closely the same as in Problem 13.64,

but extended appropriately to account for the presence of sul-

fur in the coal.

(a) Using the above expression, calculate the chemical exergy

of the coal, in kJ/kg.

(b) Compare the answer of part (a) with the values that would

result by approximating the chemical exergy with each of

the measured heating values.

exergy in this case using the methodology of Sec. 13.6?

Discuss.

13.79 For psychrometric applications such as those considered

in Chap. 12, the environment often can be modeled simply as

an ideal gas mixture of water vapor and dry air at temperature

and pressure p

. The composition of the environment is de-

fined by the dry air and water vapor mole fractions re-

spectively. Show that relative to such an environment the flow

exergy of a moist air stream at temperature T and pressure p

with dry air and water vapor mole fractions y

and y

, re-

spectively, can be expressed on a molar basis as

where and denote the molar specific heats of dry air and

water vapor, respectively. Neglect the effects of motion and

gravity.

13.80 For each of the following, use the result of Problem 13.79

to determine the specific flow exergy, in kJ/kg, relative to an

environment consisting of moist air at 20C, 1 atm,   100%

(a) moist air at 20C, 1 atm,   100%.

(b) moist air at 20C, 1 atm,   50%.

 RT

ln a

b y

ln a

 1  ln a

bd R ln a

 T

e1y

 y

2 ca

, y

 0.0549

b 6740s

 1LHV2

a1.0438  0.0013

 0.1083

Combustion products

at 600 K, 1 atm

Furnace

Heat transfer

Temperature = 60°C

Methane

, p

)

Air

, p

)

 Figure P13.77

Moran, Availability Analysis, pp. 192–193.

Design & Open Ended Problems: Exploring Engineering Practice 677

Design & Open Ended Problems: Exploring Engineering Practice

13.1D The term acid rain is frequently used today. Define what

is meant by the term. Discuss the origin and consequences of

acid rain. Also discuss options for its control.

13.2D Many observers have expressed concern that the release

of CO

into the atmosphere due to the combustion of fossil fuels

is contributing to global warming. Write a paper reviewing the

scientific evidence regarding the contribution of fossil fuel

combustion to global warming. Compare and contrast this ev-

idence with comparable data for the combustion of biomass fuel

derived from plant matter.

13.3D About 234 million tires are discarded in the U.S. annu-

ally, adding to a stockpile of two to three billion scrap tires

from previous years. Write a memorandum discussing the po-

tential advantages and disadvantages of using scrap tires as a

fuel. How does the heating value of scrap tires compare with

the heating values of gasoline and commonly used coals? How

does the ultimate analysis of scrap tires compare with the ul-

timate analysis of commonly used coals?

13.4D A coal with the following ultimate analysis:

is burned in a power plant boiler. If all of the sulfur present in

the combustible portion of the fuel forms SO

, determine if the

plant would be in compliance with regulations regarding sul-

fur emissions. Discuss options for removing SO

from the stack

gas. Assess the effectiveness of various technologies available

for this purpose and consider environmental problems

associated with them.

13.5D Figure P13.5D shows a natural gas–fired boiler for steam

generation integrated with a direct-contact condensing heat ex-

changer that discharges warm water for tasks such as space

heating, water heating, and combustion air preheating. For

7200 h of operation annually, estimate the annual savings for

fuel, in dollars, by integrating these functions. What other cost

considerations would enter into the decision to install such a

condensing heat exchanger? Discuss.

13.6D A factory requires 3750 kW of electric power and high-

quality steam at 107C with a mass flow rate of 2.2 kg/s. Two

options are under consideration:

Option 1: A single boiler generates steam at 2.0 MPa, 320C,

supplying a turbine that exhausts to a condenser at 0.007

MPa. Steam is extracted from the turbine at 107C, return-

ing as a liquid to the boiler after use.

Option 2: A boiler generates steam at 2.0 MPa, 320C, sup-

plying a turbine that exhausts to a condenser at 0.007 MPa.

A separate process steam boiler generates the required

steam at 107C, which is returned as a liquid to the boiler

after use.

The boilers are fired with natural gas and 20% excess air. For

7200 h of operation annually, evaluate the two options on the

basis of cost.

75.8% C, 5.1% H, 8.2% O, 1.5% N,

1.6% S, 7.8% noncombustible ash

13.7D Figure P13.7D illustrates the schematic of an air preheater

for the boiler of a coal-fired power plant. An alternative design

would eliminate the air preheater, supplying air to the furnace di-

rectly at 30C and discharging flue gas at 260C. All other fea-

tures would remain unchanged. On the basis of thermodynamic

and economic analyses, recommend one of the two options for

further consideration. The analysis of the coal on a mass basis is

The coal higher heating value is 26,000 kJ/kg. The molar analy-

sis of the flue gas on a dry basis is

13.8D Fuel or chemical leaks and spills can have catastrophic

ramifications; thus the hazards associated with such events

must be well understood. Prepare a memorandum for one of

the following:

(a) Experience with interstate pipelines shows that propane

leaks are usually much more hazardous than leaks of nat-

ural gas or liquids such as gasoline. Why is this so?

(b) The most important parameter in determining the acciden-

tal rate of release from a fuel or chemical storage vessel is

generally the size of the opening. Roughly how much faster

would such a substance be released from a 1-cm hole than

from a 1-mm hole? What are the implications of this?

57.8% CO

, 1.2% CO, 11.4% O

, 79.6% N

576% C, 5% H, 8% O, 11% noncombustible ash6

Liquid

water

56C

Liquid

water

51C

Saturated mixture

at 50C

Baffles

Spray heads

Direct-contact

condensing heat exchanger

Feedwater Process steam

Boiler

Natural gas,

3.85 m

/min

16%

Excess air

Combustion products

at 207C

 Figure P13.5D

678 Chapter 13 Reacting Mixtures and Combustion

13.9D By the year 2010, as much as 60,000 MW of electric

power could be generated worldwide by fuel cells. A step in

this direction has been taken at Santa Clara, California, where

a 2-MW fuel cell demonstration power plant was installed un-

der the auspices of a consortium of electric and gas utilities.

Report on the Santa Clara demonstration project in a brief

memorandum. Include a schematic of the system. For further

study of fuel cells:

(a) What are the principal features that make fuel cell tech-

nology attractive for power generation? Is fuel cell per-

formance limited by the Carnot efficiency? Discuss.

(b) The types of fuel cells listed in Table 13.1 are considered

to hold commercial promise. Investigate the specific

realms of application of these fuel cell types. Write a re-

port including at least three references.

critical for fuel cell development. What is meant by stack

life and why is it important? What is the projected installed

cost, in $ per kW, of current fuel cell technology for large-

scale power generation? To be competitive with conven-

tional power systems such as gas turbines, what should be

the target installed cost for fuel cells? Discuss.

(d) What principal issues must be resolved for fuel cells to be

widely used to power automobiles and trucks? Write a re-

port including at least three references.

13.10D Adapting procedures developed in the second part of

this chapter, develop expressions for estimating the chemical

exergy for each of several common coal types in terms of the

coal ultimate analysis and available thermodynamic data.

13.11D Airborne Soot Adds to Weather Woes, Some Say (see

box, Sec. 13.1). Investigate the underlying modeling assump-

tions and characteristics of computer simulations used to

predict global weather patterns. Write a report including at least

three references.

13.12D Goodbye Batteries, Hello Fuel Cells? (see box,

Sec. 13.4). Investigate the advantages and disadvantages of

hydrogen and methanol as fuels for fuel cell-powered

portable electronic devices. Write a report including at least

three references.

Coal, 25°C

Boiler

Feedwater, 50°C

Saturated vapor, 30 bar,

m = 2 × 10

kg/h

Flue gas, 260°C

Flue gas,

150°C

Preheater

Ash, 450°C,

= 1.0 kJ/kg⋅K

Air, 30°C,

1 atm, = 30%

 Figure P13.7D

679

Chemical and

Phase Equilibrium



 chapter objective

thermodynamic

equilibrium

14.1 Introducing Equilibrium Criteria

A system is said to be in thermodynamic equilibrium if, when it is isolated from its sur-

roundings, there would be no macroscopically observable changes. An important requirement

for equilibrium is that the temperature be uniform throughout the system or each part of the

system in thermal contact. If this condition were not met, spontaneous heat transfer from one

location to another could occur when the system was isolated. There must also be no un-

balanced forces between parts of the system. These conditions ensure that the system is in

thermal and mechanical equilibrium, but there is still the possibility that complete equilib-

rium does not exist. A process might occur involving a chemical reaction, a transfer of mass

between phases, or both. The object of this section is to introduce criteria that can be applied

to decide whether a system in a particular state is in equilibrium. These criteria are devel-

oped using the conservation of energy principle and the second law of thermodynamics as

discussed next.

ENGINEERING CONTEXT The objective of the present chapter

is to consider the concept of equilibrium in greater depth than has been done thus far. In

the first part of the chapter, we develop the fundamental concepts used to study chemical

and phase equilibrium. In the second part of the chapter, the study of reacting systems ini-

tiated in Chap. 13 is continued with a discussion of chemical equilibrium in a single phase.

Particular emphasis is placed on the case of reacting ideal gas mixtures. The third part of

the chapter concerns phase equilibrium. The equilibrium of multicomponent, multiphase,

nonreacting systems is considered and the phase rule is introduced.

EQUILIBRIUM FUNDAMENTALS

In this part of the chapter, fundamental concepts are developed that are useful in the study

of chemical and phase equilibrium. Among these are equilibrium criteria and the chemical

potential concept.

680 Chapter 14 Chemical and Phase Equilibrium

Consider the case of a simple compressible system of fixed mass at which temperature

and pressure are uniform with position throughout. In the absence of overall system motion

and ignoring the influence of gravity, the energy balance in differential form (Eq. 2.36)

If volume change is the only work mode and pressure is uniform with position throughout

the system, W  pdV. Introducing this in the energy balance and solving for Q gives

Since temperature is uniform with position throughout the system, the entropy balance in

differential form (Eq. 6.33) is

Eliminating Q between the last two equations

(14.1)

Entropy is produced in all actual processes and conserved only in the absence of irre-

versibilities. Hence, Eq. 14.1 provides a constraint on the direction of processes. The only

processes allowed are those for which Thus

(14.2)

Equation 14.2 can be used to study equilibrium under various conditions.  for

example. . .

a process taking place in an insulated, constant-volume vessel, where dU 

0 and dV  0, must be such that

(14.3)

Equation 14.3 suggests that changes of state of a closed system at constant internal energy

and volume can occur only in the direction of increasing entropy. The expression also im-

plies that entropy approaches a maximum as a state of equilibrium is approached. This is a

special case of the increase of entropy principle introduced in Sec. 6.5.5. 

An important case for the study of chemical and phase equilibria is one in which tem-

perature and pressure are fixed. For this, it is convenient to employ the Gibbs function in

extensive form

Forming the differential

or on rearrangement

Except for the minus sign, the right side of this equation is the same as the expression ap-

pearing in Eq. 14.2. Accordingly, Eq. 14.2 can be written as

(14.4)

where the inequality reverses direction because of the minus sign noted above.

dG  V dp  S dT  0

dG  V dp  S dT 1T dS  dU  p dV 2

dG  dU  p dV  V dp  T dS  S dT

G  H  TS  U  pV  TS

dS4

U,V

 0

T dS  dU  p dV  0

ds  0.

T dS  dU  p dV  T ds

dS 

 ds

dQ  dU  p dV

dU  dQ  dW

Gibbs function

Fixed U, V

max

14.1 Introducing Equilibrium Criteria 681

It can be concluded from Eq. 14.4 that any process taking place at a specified tempera-

ture and pressure (dT  0 and dp  0) must be such that

(14.5)

This inequality indicates that the Gibbs function of a system at fixed T and p decreases dur-

ing an irreversible process. Each step of such a process results in a decrease in the Gibbs

function of the system and brings the system closer to equilibrium. The equilibrium state is

the one having the minimum value of the Gibbs function. Therefore, when

(14.6)

we have equilibrium. In subsequent discussions, we refer to Eq. 14.6 as the criterion for

equilibrium.

Equation 14.6 provides a relationship among the properties of a system when it is at an

equilibrium state. The manner in which the equilibrium state is reached is unimportant, how-

ever, for once an equilibrium state is obtained, a system exists at a particular T and p and no

further spontaneous changes can take place. When applying Eq. 14.6, therefore, we may spec-

ify the temperature T and pressure p, but it is unnecessary to require additionally that the

system actually achieves equilibrium at fixed T and fixed p.

 14.1.1 Chemical Potential and Equilibrium

In the present discussion, the Gibbs function is considered further as a prerequisite for ap-

plication of the equilibrium criterion dG]

T,p

 0 introduced above. Let us begin by noting

that any extensive property of a single-phase, single-component system is a function of two

independent intensive properties and the size of the system. Selecting temperature and pres-

sure as the independent properties and the number of moles n as the measure of size, the

Gibbs function can be expressed in the form G  G(T, p, n). For a single-phase, multicomp-

onent system, G may then be considered a function of temperature, pressure, and the num-

ber of moles of each component present, written G  G(T, p, n

, n

, . . . , n

If each mole number is multiplied by , the size of the system changes by the same fac-

tor and so does the value of every extensive property. Thus, for the Gibbs function we may

write

Differentiating with respect to  while holding temperature, pressure, and the mole numbers

fixed and using the chain rule on the right side gives

This equation holds for all values of . In particular, it holds for   1. Setting   1, the

following expression results:

(14.7)

where the subscript n

denotes that all n’s except n

are held fixed during differentiation.

The partial derivatives appearing in Eq. 14.7 have such importance for our study of

chemical and phase equilibrium that they are given a special name and symbol. The

G 

i1

T, p,n

G 

0 1an



0 1an



###



0 1an

aG 1T, p, n

, n

, . . . , n

2 G 1T, p, an

, an

, . . . , an

dG4

T,p

 0

dG4

T,p

 0

equilibrium criterion

multicomponent system

Fixed T, p

min

chemical potential of component i, symbolized by 

, is defined as

(14.8)

The chemical potential is an intensive property. With Eq. 14.8, Eq. 14.7 becomes

(14.9)

The equilibrium criterion given by Eq. 14.6 can be written in terms of chemical poten-

tials, providing an expression of fundamental importance for subsequent discussions of equi-

librium. Forming the differential of G(T, p, n

, . . . , n

) while holding temperature and pres-

sure fixed results in

The partial derivatives are recognized from Eq. 14.8 as the chemical potentials, so

(14.10)

With Eq. 14.10, the equilibrium criterion dG]

T,p

 0 can be placed in the form

(14.11)

Like Eq. 14.6, from which it is obtained, this equation provides a relationship among prop-

erties of a system when the system is at an equilibrium state where the temperature is T and

the pressure is p. Like Eq. 14.6, this equation applies to a particular state, and the manner

in which that state is attained is not important.

 14.1.2 Evaluating Chemical Potentials

Means for evaluating the chemical potentials for two cases of interest are introduced in this

section: a single phase of a pure substance and an ideal gas mixture.

SINGLE PHASE OF A PURE SUBSTANCE. An elementary case considered later in this

chapter is that of equilibrium between two phases involving a pure substance. For a single

phase of a pure substance, Eq. 14.9 becomes simply

(14.12)

That is, the chemical potential is just the Gibbs function per mole.

m 

 g

G  nm

i1

 0

dG4

T, p



i1

dG4

T, p



i1

T, p, n

G 

i1

 a

T, p, n

682 Chapter 14 Chemical and Phase Equilibrium

chemical potential

14.1 Introducing Equilibrium Criteria 683

IDEAL GAS MIXTURE. An important case for the study of chemical equilibrium is that of

an ideal gas mixture. The enthalpy and entropy of an ideal gas mixture are given by

where p

 y

p is the partial pressure of component i. Accordingly, the Gibbs function takes

the form

(14.13)

Introducing the molar Gibbs function of component i

(14.14)

Equation 14.13 can be expressed as

(14.15)

Comparing Eq. 14.15 to Eq. 14.9 suggests that

(14.16)

That is, the chemical potential of component i in an ideal gas mixture is equal to its Gibbs

function per mole of i, evaluated at the mixture temperature and the partial pressure of i in

the mixture. Equation 14.16 can be obtained formally by taking the partial derivative of

Eq. 14.15 with respect to n

, holding temperature, pressure, and the remaining n’s constant,

and then applying the definition of chemical potential, Eq. 14.8.

The chemical potential of component i in an ideal gas mixture can be expressed in an

alternative form that is somewhat more convenient for subsequent applications. Using

Eq. 13.23, Eq. 14.14 becomes

where p

ref

is 1 atm and y

is the mole fraction of component i in a mixture at temperature T

and pressure p. The last equation can be written compactly as

(14.17)

where is the Gibbs function of component i evaluated at temperature T and a pressure of

1 atm. Additional details concerning the chemical potential concept are provided in Sec. 11.9.

Equation 14.17 is the same as Eq. 11.144 developed there.

 g °

 RT ln

ref

1ideal gas2

 h

1T 2 T s °

1T 2 RT ln

ref

 h

1T 2 T as °

1T 2 R ln

ref

 h

1T 2 T s

1T, p

 g

1T, p

1ideal gas2

G 

i1

1T, p

1ideal gas2

1T, p

2 h

1T 2 T s

1T, p

1ideal gas2



i1

1T 2 T s

1T, p

1ideal gas2

G  H  TS 

i1

1T 2 T

i1

1T, p

H 

i1

1T 2

and

S 

i1

1T, p

684 Chapter 14 Chemical and Phase Equilibrium

CHEMICAL EQUILIBRIUM

In this part of the chapter, the equilibrium criterion dG]

T,p

 0 introduced in Sec. 14.1 is

used to study the equilibrium of reacting mixtures. The objective is to establish the

composition present at equilibrium for a specified temperature and pressure. An important

parameter for determining the equilibrium composition is the equilibrium constant. The equi-

librium constant is introduced and its use illustrated by several solved examples. The

discussion is concerned only with equilibrium states of reacting systems, and no information

can be deduced about the rates of reaction. Whether an equilibrium mixture would form

quickly or slowly can be determined only by considering the chemical kinetics, a topic that

is not treated in this text.



14.2 Equation of Reaction Equilibrium

In Chap. 13 the conservation of mass and conservation of energy principles are applied to

reacting systems by assuming that the reactions can occur as written. However, the extent to

which a chemical reaction proceeds is limited by many factors. In general, the composition

of the products actually formed from a given set of reactants, and the relative amounts of the

products, can be determined only from experiment. Knowledge of the composition that would

be present were a reaction to proceed to equilibrium is frequently useful, however. The equat-

ion of reaction equilibrium introduced in the present section provides the basis for determining

the equilibrium composition of a reacting mixture.

INTRODUCTORY CASE. Consider a closed system consisting initially of a gaseous mixture

of hydrogen and oxygen. A number of reactions might take place, including

(14.18)

(14.19)

(14.20)

Let us consider for illustration purposes only the first of the reactions given above, in

which hydrogen and oxygen combine to form water. At equilibrium, the system will consist

in general of three components: H

, and H

O, for not all of the hydrogen and oxygen ini-

tially present need be reacted. Changes in the amounts of these components during each dif-

ferential step of the reaction leading to the formation of an equilibrium mixture are governed

by Eq. 14.18. That is

(14.21a)

where dn denotes a differential change in the respective component. The minus signs signal

that the amounts of hydrogen and oxygen present decrease when the reaction proceeds to-

ward the right. Equations 14.21a can be expressed alternatively as

(14.21b)

which emphasizes that increases and decreases in the components are proportional to the sto-

ichiometric coefficients of Eq. 14.18.

Equilibrium is a condition of balance. Accordingly, as suggested by the direction of the

arrows in Eq. 14.18, when the system is at equilibrium, the tendency of the hydrogen and

oxygen to form water is just balanced by the tendency of water to dissociate into oxygen and

hydrogen. The equilibrium criterion dG]

T,p

 0 can be used to determine the composition at

dn



dn



dn





14.2 Equation of Reaction Equilibrium 685

an equilibrium state where the temperature is T and the pressure is p. This requires evalua-

tion of the differential dG]

T,p

in terms of system properties.

For the present case, Eq. 14.10 giving the difference in the Gibbs function of the mixture

between two states having the same temperature and pressure, but compositions that differ

infinitesimally, takes the following form:

(14.22)

The changes in the mole numbers are related by Eqs. 14.21. Hence

At equilibrium, dG]

T,p

 0, so the term in parentheses must be zero. That is

When expressed in a form that resembles Eq. 14.18, this becomes

(14.23)

Equation 14.23 is the equation of reaction equilibrium for the case under consideration. The

chemical potentials are functions of temperature, pressure, and composition. Thus, the com-

position that would be present at equilibrium for a given temperature and pressure can be

determined, in principle, by solving this equation. The solution procedure is described in the

next section.

GENERAL CASE. The foregoing development can be repeated for reactions involving

any number of components. Consider a closed system containing five components, A, B,

C, D, and E, at a given temperature and pressure, subject to a single chemical reaction of

the form

(14.24)

where the ’s are stoichiometric coefficients. Component E is assumed to be inert and thus

does not appear in the reaction equation. As we will see, component E does influence the

A  n

C  n



 1m

1m



 1m

 0

dG4

T, p

 11m



 1m

2 dn

dG4

T, p

 m

 m

hydrogen fuel cells.

The fuels cells will

emit only water, and

thus also contribute to

Iceland’s societal goal

of reducing green-

house gas emissions.

While cars and

busses can store hy-

drogen fuel in special

pressurized cylinders,

storage on board fish-

ing vessels for cruises

lasting up to six weeks presents unique challenges. The best

near-term solution, engineers say, is to use fuel cells running

on liquid methanol instead of hydrogen. They propose to syn-

thesize methanol from hydrogen and the carbon dioxide and

carbon monoxide emitted from industrial plants.

Iceland Aims to Be Fossil-Fuel Free

Thermodynamics in the News...

The island nation of Iceland dares to dream about a future

in which all energy needs are met domestically from their

abundant renewable hydroelectric and geothermal sources.

The key, Icelandic engineers say, is to take advantage of ex-

tra renewable capacity to make hydrogen that can be used

to power cars, busses, and Iceland’s large fishing fleet, all

presently using petroleum-based fuels. This will free Iceland

completely from the need to import fossil fuels and make this

nation of 276,000 people energy self-sufficient. Iceland then

will be able to claim the title of being the world’s first

hydrogen economy.

Iceland’s fertilizer industry has long produced hydrogen

on a large scale using electricity generated from renewable

sources to break down water through the process of

electrolysis. By ramping up production, planners see all of the

country’s transportation needs eventually being met by