Chapter 2

School of Engineering
Thermodynamics

Chapter 2: The World Energy System

Dr. Jorge Francisco Estela Uribe

Thermodynamics
Dr. Jorge Francisco Estela

Primary energy:

Primary energy is the total energy contents of a natural resource. It is the
energy in raw form without any transformation. It is the total energy that is
available for transformation and end use.

Energy carriers:

These are forms of energy between primary energy sources, from which
they are transformed, and the end use forms, to which they are converted.

Energy consumption:

As energy is always conserved, the concept of consumption only means
the transformation of energy to the forms of end use, i.e. energy services.

The World Energy System 2/84

Thermodynamics

Energy flows:

Reserves Exports Imports

Primary energy Exports Imports

Transformation Energy carrier

Final use


Thermodynamics

Sources of primary energy:

Non-renewable sources Renewable sources

Fossil fuels Crude oil Solar Direct Thermal
Photovoltaic
Coal Indirect Hydroelectricity
Wind
Natural gas Ocean (waves,
currents, thermal
gradient)
Bioenergy
Mineral fuels Uranium Non- Geothermal
(nuclear energy) solar Tidal


Thermodynamics

Primary energy, energy carriers and energy systems*:

Primary energy sources Energy Energy systems
carriers (conversion
processes)

Non- Crude oil Liquid fuels Oil refinery
renewable
sources
Coal Enthalpy, Fossil fuel power
mechanical station
work, electricity
Natural gas

Uranium Electricity Nuclear power plant

* www.wikipedia.org

Thermodynamics

Primary energy, energy carriers and energy systems*:

Primary energy sources Energy Energy systems
carriers (conversion
processes)
Renewable Solar energy Enthalpy Solar power tower, solar
sources furnace
Electricity Photovoltaic power plant

Wind energy Mechanical work, Wind farm
electricity
Flowing water, Mechanical work, Hydropower plant, wave
tidal energy electricity farm, tidal power station
Biomass sources Enthalpy, electricity Biomass power station

Geothermal Enthalpy, electricity Geothermal power station
energy

* www.wikipedia.org

Thermodynamics

Who uses energy:

Those who drink potable water and eat non-raw food.

Those who need to preserve food and other materials.

Those who need heating, air conditioning or ventilation.

Those who need artificial illumination.

Those who need to travel through long distances.

Those who need mechanical for their work.

And those who do not wish or can not put aside all the technological
amenities, gadgets and services of modern society.


Thermodynamics

Historical uses of energy per capita*:
Period Daily per capita consumption, MJ
Food Home & Industry & Transport Total
commerce agriculture
Primitive 8 8

Stone age 12 8 20

Primitive 16 16 16 48
agriculture
Advanced 24 48 28 4 104
agriculture
Industrial 28 128 96 56 308

Technological 40 264 364 252 920

* E. Cook, The Flow of Energy in an Industrial Society, Scientific American, September 1971

Thermodynamics

Quality of Life and Energy Supply
1.00
Norway
Denmark GermanySwitzerland
New Zeland Sweden Australia Canada
0.90 Greece FranceNetherlands
Japan Austria United States
Spain United Kingdom Finland
0.80 Chile Portugal
Uruguay Argentina
Human Development Index

Colombia Mexico Saudi Arabia
0.70 Venezuela Russia
Brazil China

0.60 Egypt South Africa
Morocco
India
0.50 Pakistan
Haiti
0.40 Sudan
Ethiopia
0.30 Mozambique

0.20

0.10

0.00
0 1 2 3 4 5 6 7 8 9
Energy supply per capita (toe/capita)

International Energy Agency, Key Energy Statistics 2011

Thermodynamics

Energy Supply and GDP 2009
30

World Average
GDP per capita (USD/capita)x1000

OECD

20

10

World Average
Latin America
China Middle East
Asia Non-OECD Europe & Asia
Africa
0
0 1 2 3 4 5 6
Energy Supply per capita (toe/capita)


Thermodynamics

Energy Effciency and GDP 2009
30

World Average
GDP per capita (USD/capita)x1000

OECD

20

10

World Average
Middle East
Latin America
Non-OECD Eurasia China
Asia
0 Africa
0 1 2 3 4 5 6
Energy Efficiency (USD/toe)x1000


Thermodynamics

Is this really necessary? Is it an excess…?


Thermodynamics

Are these really necessary or are they excessive waste of energy?


Thermodynamics

Sustainable energy: why is it so important?
The supply of energy is essential for the well-being of society.
The current energy systems have been built around the multiple
advantages of the fossil fuels.
The duration of the fossil fuels reserves is a highly disputed issue, but
those are essentially finite and will run out completely.
The reserves of fossil fuels are concentrated on a relatively few countries,
which leads to instability, crises and conflicts.
The exploitation of fossil fuels entails significant threats to human health
due to their extraction, distribution and final use.
The combustion of fossil fuels produces enormous amounts of
greenhouse gases.

G. Boyle, B. Everett, J. Ramage, Energy Systems and Sustainability: Power for a Sustainable Future,
Oxford University Press, 2003.
Sustainability 14/84

Thermodynamics

There is a sound scientific consensus about the connections between the
anthropogenic emissions of greenhouse gases and the unprecedented
increase in ambient temperatures since the last ice age.
The increase in global temperatures will severely disrupt agriculture, all
ecosystems and the economic system in a generalised scale.
Nuclear energy does not emit greenhouse gases but its development has
been limited by high operating costs and the public concern about the
release of radioactive materials, catastrophic accidents, the disposal of
radioactive wastes and the proliferation of materials for nuclear weapons.
The efficiency of the conversion of energy from resources down to the
energy services is very low and the cost of those services is very low.

Thermodynamics


The above two circumstances make the environmental and social effects
of the energy systems larger than what those should really be.

The renewable energy sources are based on energy flows, not on energy
stocks, and are expected to play a much larger role in the future.

The environmental and social impacts of the renewable energy sources
are, in general, smaller than those from the conventional sources.

However, there are other constraints for their widespread use such as
their intermittence and limited availability, the lack of a global infrastructure
for their distribution and use and the high costs for the end user.

Thermodynamics

Total Primary Energy Supply and Consumption by Sectors 2009
TPES: 12150 Mtoe; TFC: 8353 Mtoe; Total Losses: 3797 Mtoe
Oil: Coal: Natural Gas: Nuclear: Hydraulic: Biofuels, Others:
3987 3300 2540 703 280 Waste: 1238 102
51
330

Liquid fuels: 3874

31 236 2139 1006 703 280 94 102
206 Consumption for electricity/heat: 4591
Non-energy: 747

20
Conversion losses: 2641 1950
37
237 269
64
553

136

2136 3 70 52 23 11 310 644 441 186 690 433 147 618 842 1000

Transport: 2284 Industry: 2282 Res., Comm., Agr.: 3040

Thermodynamics

Total Primary Energy Supply and Total Final Consumption 2009

12150

Hydraulic Others
12000
Biofules/Waste
Losses in
conversion and
10000 Nuclear 3797
transmission

Natural Gas
8000 8353 Non-energy
Electricity/Heat
Mtoe

Residential,
6000 Biofuels/Waste Commercial,
Coal Agricultural
Natural Gas

4000 Coal
Industry

2000 Oil Liquid fuels
Transport

0
Primary Energy Energy in Carriers Consumption by Sectors


Thermodynamics

Petroleum:
Petroleum is a naturally occurring complex flammable liquid mixture of
hydrocarbons and other organic compounds [1].

Petroleum was formed by the decomposition, under high temperature and
pressure in sedimentary rocks, of marine organisms, i.e. zooplankton and
algae [2]. Thus, petroleum is currently found in sedimentary basins where
marine sediments accumulated over time (the Middle East, the Gulf of
Mexico or the North Sea).

Petroleum is converted into useful products by distillation (fractioning), i.e.
separation by differences in boiling points of the liquid components. Those
products are complex blends suited to particular commercial uses.
1. www.wikipedia.org
2. G. Boyle, B.Everett, J. Ramage, Energy Systems and Sustainability, Power for a Sustainable Future, Oxford
University Press, Oxford, 2003.


Thermodynamics

Broad composition by fractions and uses*:

Fractions Carbon Hydrocarbons Uses
atoms
Petroleum gases 1– 4 Methane - Butane Gaseous fuels,
petrochemicals
Light distillate 5–8 Pentane - Octane Gasoline

Medium distillate 9 – 16 Nonane - Diesel fuel,
Hexadecane kerosene, jet fuel
Heavy distillate 17 – 25 Fuel oil, lubricating
oil, marine diesel
Asphaltenes 26 – 35 Waxes, asphalts

* www.wikipedia.org


Thermodynamics

Conventional and non-conventional petroleum*:
Petroleum that is obtained by the natural pressure of an underground
reservoir is called conventional oil. Conventional oil is extracted by two
methods and applies to roughly half of the petroleum reserves:

Primary recovery: applies when the pressure of the reservoir is sufficient
to drive the crude oil to the surface.

Secondary recovery: the pressure of the reservoir has to be increased by
the injection of natural gas or water.

Non-conventional petroleum applies to oil extracted by tertiary recovery
(with high-pressure natural gas or CO2 to recover the remaining crude in
the reservoirs) or from all other sources, i.e. shale oil, tar sands and heavy
oil.
* G. Boyle, B.Everett, J. Ramage, Energy Systems and Sustainability, Power for a Sustainable Future, Oxford

Thermodynamics

The World Energy System - Petroleum 22/84

Thermodynamics


Thermodynamics

Coal:

Coal is a combustible black or brownish-black sedimentary rock usually
occurring in layers called coal beds or coal seams [1]. Coal is composed
primarily of carbon, hydrogen, oxygen, nitrogen and sulphur.

Coal was formed by the decomposition, under high temperature and
pressure and in the absence of oxygen, of dead vegetation. This is why
coal deposits are widely spread in the world.

According to its heating value (heat released in combustion) and contents
of volatiles, coal is classified in ranks. In ascending order of heating value,
these are: peat, lignite, sub-bituminous, bituminous and anthracite.


Thermodynamics

The World Energy System - Coal 27/84

Thermodynamics


Thermodynamics

Natural Gas:

Natural gas is a naturally occurring hydrocarbon mixture, primarily
composed of methane, other hydrocarbons (ethane up to octane), nitrogen,
carbon dioxide and hydrogen sulphide [1].

Natural gas is found in deep underground formations or associated with
coal seams and petroleum deposits. Natural gas is created either by two
processes: a biogenic process (decomposition) of organic material in
shallow sediments, or by thermogenic process at great depths.

Before use, natural gas has to undergo extensive treatment to remove
undesirable components, such as nitrogen, carbon dioxide and hydrogen
sulphide.


Thermodynamics

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Thermodynamics


Thermodynamics

The World Energy System – Natural gas

Thermodynamics


Thermodynamics

Nuclear energy:
Nuclear energy results from the sustained use of the energy released by
nuclear fission to generate electricity and heat [1].

In nuclear fission, the nuclei of heavy atoms (i.e. Uranium-235) split into
lighter nuclei and free neutrons. As the combined mass of the fission
products is slightly smaller than that of the original nucleus, the mass
defect is converted into energy in the form of photons (gamma radiation)
and kinetic energy of the products. The kinetic energy is transformed into
thermal energy, which is then used to generate electricity in a power cycle.
The released neutrons hit other nuclei causing their fission. Thus, a chain
reaction is established so that a sustained nuclear energy operation is
possible in practice.


Thermodynamics

Nuclear energy:
Nuclear energy has always been a controversial issue. Its is an important
component of the world energy system for it produces about 7 per cent of
the world primary energy supply and about 14 per cent of the electricity [1].

The advocates of nuclear energy claim it is a sustainable form of energy for
it does no release greenhouse gases, but the processing of uranium
minerals do have important environmental impacts. The opponents sustain
that nuclear energy poses serious threats to human health and the
environment. Those threats come from the accidental release of
radioactive materials and from the very important issue of the disposal of
used nuclear fuels. There are also the security concerns as nuclear
reactors can be used to produce radioactive materials for weapons use.


Thermodynamics

Nuclear reactors:
About 80 per cent of reactors use light water as moderator. Three quarters
of those are pressurised water reactors [1].

Pressurised water reactors (PWRs): the reactor core is in a high-pressure
vessel is cooled by a primary circuit of pressurised water. The primary
water transfers heat to a secondary circuit in a steam generator. Then, the
secondary water drives the power cycle.

Boiling water reactors (BWRs): they are PWRs but water boils directly in
the pressure vessel. Therefore, these are simpler and safer than PWRs.

Other technologies include the pressurised heavy water reactor (PHWR),
the gas cooled reactors (GCR) and a number of experimental designs.


Thermodynamics

The World Energy System – Nuclear energy 38/84

Thermodynamics


Thermodynamics

Hydroelectricity:
Hydroelectricity is electricity generated by hydropower, i.e. from the
potential energy of water falling through a difference of elevation. This is
the second largest source of renewable energy, accounting for about a
sixth of the world’s electricity generation [1].
The technologies are: the conventional dams; pumped storage (at times of
low demand, water is pumped to higher elevations to be used at times of
high demand) and run-of-the-river (it does not use a dam and the water is
taken directly from the river to the generator).
Hydroelectricity is cheap and does not release carbon dioxide. But it has
important environmental impacts because of the disruption of habitats (by
the areas that have to be inundated) and the decay of vegetation under
water releases methane (a more powerful greenhouse gas than carbon
dioxide).


Thermodynamics

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Thermodynamics

The World Energy System – Hydroelectricity 43/84

Thermodynamics

Renewable energy:
Renewable energy rely on natural processes that are continuously
replenished [1]. Apart from the comparatively very small amount of
geothermal and tidal energy, ultimately almost all renewable energy forms
are transformations from solar energy.
Renewable energy accounts for around 16 per cent of the total primary
energy supply and participates with about 19 per cent in the generation of
electricity.
Climate change awareness, high oil prices and peak oil are driving a very
rapid expansion in investment, development and commercialisation of
renewable energy technologies. Those markets are growing at rates far
exceeding 20 per cent per annum.
Renewable energy technologies are expected to play quite significant a
role in power generation, space heating and transport fuels.


Thermodynamics

Advantages of renewable energy sources:

The very fact that they are continuously replenished by natural processes.

The fact that they are fluxes and not stocks of energy.

They are considerably more benign in environmental and health impacts
than fossil fuels and nuclear energy.

Disadvantages of renewable energy sources:

They are intermittent, so that storage technologies are needed.

Their distribution and availability is very limited because the infrastructure
for distribution and commercialisation is, so far, very limited.

They remain to be expensive to the end user.


Thermodynamics

The World Energy System – Solar energy 46/84

Thermodynamics


Thermodynamics

The World Energy System – Wind energy 52/84

Thermodynamics

The World Energy System – Geothermal energy 53/84

Thermodynamics

The World Energy System – Ocean energy 54/84

Thermodynamics

The World Energy System – Bioenergy 55/84

Thermodynamics

The World Energy System – Bioenergy 56/84

Thermodynamics

Oil and natural gas: why are they so special?

Oil and natural gas comprise half of the world primary energy supply and

consumption because of the following undisputable advantages:

The are cheap and easily available.

They are less contaminant than coal.

They are convenient and easy to use.

They are easy to distribute, store and transport.

For many countries, the supply is ensured from domestic production.


Thermodynamics

Regional Distribution of Fossil Fuel Reserves

100

90
North America
80
S&C America
70
Percentage

60 Europe/Eurasia

50 Middle East
40
Africa
30
Asia/Pacific
20

10

0
Oil Natural Gas Coal

British Petroleum, BP Statistical Review of World Energy, June 2011

Thermodynamics

Reserves/Production Ratios of Fossil Fuels 2009

North America

South & Central America

Europe & Eurasia

Middle East
Average Middle East and Africa

Africa

Asia Pacific

World Average

0 50 100 150 200 250
Years

Oil Natural Gas Coal
British Petroleum, BP Statistical Review of World Energy, June 2011

Thermodynamics

Environmental and social impacts associated with energy sources*:

Source Potential impacts and concerns
Oil Global climate change, air pollution by vehicles, acid rain, oil spills, oil
rig accidents.
Natural gas Global climate change, methane leakage from pipes, methane
explosions, gas rig accidents.
Coal Global climate change, acid rain, environmental spoliation by open-cast
mining, land subsidence due to deep mining, ground water pollution,
mining accidents, health effect on miners.
Nuclear power Radioactivity (routine release, risk of accidents, waste disposal),
misuse of fissile and other radioactive materials, proliferation of nuclear
weapons, land pollution by mining, health effects on uranium miners.
Biomass Effects on landscape and biodiversity, ground water pollution due to
fertilisers, use of scarce water, competition with food production.



Thermodynamics

Environmental and social impacts associated with energy sources*:

Source Potential impacts and concerns
Hydroelectricity Displacement of communities, effects on rivers and ground water,
dams (visual intrusion and risk of accidents), seismic effects,
downstream effects on agriculture, methane emission from submerged
biomass.
Wind power Visual intrusion in sensitive landscapes, noise, bird strikes, interference
with telecommunications.
Tidal power Visual intrusion and destruction of wildlife habitat, reduced dispersal of
effluents (apply only to tidal barrages).
Geothermal Release of polluting gases (SO2, H2S, etc.), ground water pollution by
energy chemicals including heavy metals, seismic effects.
Solar energy Sequestration of large land areas (centralised plants), use of toxic
materials in manufacture of PV cells, visual intrusion.



Thermodynamics


Thermodynamics

CO 2 Emissions by Fuel 2009
Oil 10643
28999 x 10 6 ton
36.7%

Renewables 116
0.4%

Coal 12470
Natural Gas 5771
43%
19.9%

Asia 3153 11% China 6877 25%

Latin America 975 3%
Africa 928 3%
Non-OECD Eurasia 2497 9%
CO 2 Emissions by Region

28999 x 10 6 ton Middle East 1509 5%

OECD 1204 43%

Thermodynamics

CO2 Emissions and Energy Supply 2009
15

World Average
CO2 Emissions per capita (ton/capita)

10
OECD

Middle East

Non-OECD Eurasia

5 China
World Average

Asia Latin America

Africa
0
0 1 2 3 4 5 6
Energy Supply per capita (toe/capita)


Thermodynamics

Emissions scenarios:

OECD Rest of the Total
world
Base line 2009
Population, million 1,225 5,536 6,761
TPES/cap, toe/cap 4.276 1.249 1.97
TPES, Mtoe 5,238 6,582 12,150
Intensity CO2, Mton/Mtoe 2.300 2.53 2.387
Emissions, Mton/year 12,045 16,954 28,999
Growth scenarios
Population 0.5 1.0
TPES/cap 0.5 2.0
CO2/TPES 1.5 -0.5


Thermodynamics

Emissions scenarios:

OECD Rest of the Total
world
Projections 2050
Population, million 1,503 8,325 9,828
TPES/cap, toe/cap 5.246 2.813 3.85
TPES, Mtoe 7,885 23,418 31,302
Intensity CO2, Mton/Mtoe 1.237 1.97 1.806
Emissions, Mton/year 9,757 46,772 56,529
Released CO2, Mton 445,292 1,204,731 1,650,023
Stock CO2, Mton 3,029,031
Accumulated CO2, Mton 3,771,541
Concentration CO2, ppm 482


Thermodynamics

Strategies for the control of atmospheric carbon dioxide*:

Strategies Technologies and patterns of use

Efficiency of end •Increase the fuel economy of 2000 million automobiles from 48
uses and km/gallon to 96 km/gallon.
conservation •Reduce the use of 2000 million automobiles from 16,000 km/year
to 8,000 km/year at and average 50 km/h.
•Reduce in 25 per cent the electricity consumption in residential
and commercial uses.

Power •Increase the thermal efficiency from 40 to 60 per cent in 1,600
generation large power stations (> 1 GW).
•Replace 1,400 large power stations with CCGT.
Capture and •Install CCS systems in 800 large power stations.
storage of CO2 •Install CCS systems in carbon gasification plants.
(CCS) •Install CCS systems in hydrogen production plants for 1500
million vehicles.
*R.H. Sokolow, S.W. Pacala, A Plan to Keep Carbon in Check, Scientific American, September (2006,
28-35.


Thermodynamics

Strategies for the control of atmospheric carbon dioxide*:

Strategies Technologies and patterns of use

Alternative •Double the generation of nuclear energy to displace carbon
energy sources consumption.
•Multiply by 40 the generation of wind power to displace carbon
consumption..
•Multiply by 700 the generation of solar energy to displace carbon
consumption..
•Multiply by 80 the generation of wind power to produce hydrogen
for automobiles.
•Power 2000 million automobiles with ethanol produced from 1/6 of
the total cultivable land and biomass with yield of 15 ton/ha.
Agriculture and •Stop all deforestation.
forestry •Extend conventional agriculture practices to the whole cultivable
management land.

*R.H. Sokolow, S.W. Pacala, A Plan to Keep Carbon in Check, Scientific American, September (2006,
28-35.


Thermodynamics

Renewables Share of World TPES 2009
Others: 0.5% Tide: 0.0004%

Oil
Hydroenergy: Wind: 0.064%
34.3%
2.2%

Solar: 0.039%

Renewables
Coal
Combustible
13.1%
Renewables
25.1% Geothermal:
and waste:
Nuclear 10.6% 0.414%
6.5%
Natural Gas
20.9%


Thermodynamics

Potential resources of renewable energy*:
Source Potential, 1018 J/year
Biomass: equivalent of 35 x 109 ton/year. >440
Hydroelectricity: equivalent to half of the energy of 70
all the rivers in the world.
Wind: 35 per cent of the potential in continental areas >630
and coastal waters.
Tidal: potential of the most promising locations. >20
Geothermal: potential of the most promising >20
locations.
Solar: 10 per cent efficiency of conversion solar >1,600
radiation.
Total renewable sources: >2,800
TPES (2009): 500 x 1018 J. TPES (2100): 510 – 2700 x 1018 J.
* Intergovernmental Panel on Climate Change, Third Assessment Report, 2001


Thermodynamics

Renewable energy scenarios:

As of 2009, all renewable sources (hydroelectricity, biofuels, waste and others)
accounted for 13.3 per cent of the world TPES.
International Energy Agency: Scenarios to 2030
Current Policy Scenario: All renewable sources would increase to 14.2 per cent.
450 Policy Scenario: All renewable sources would increase to 22.1 per cent.
British Petroleum: Scenario to 2030
It foresees the doubling of the percentage of renewable energy in the TPES.
US Energy Information Administration: Scenario to 2035
It also foresees the doubling of the share of renewable energy in the TPES.
Royal Dutch Shell: Scenario to 2050
It foresees that renewable energy would account around 25 to 30 per cent of TPES.


Thermodynamics

The hydrogen economy:
It means the proposed extensive use of hydrogen as an energy carrier.
Hydrogen does not occur freely in nature. Therefore, hydrogen is not a
primary energy source, it is an energy carrier.
Hydrogen is produced basically by reforming of natural gas. It is also
produced by electrolysis of water and by biotechnological processes
involving algae and micro organisms.
Hydrogen is currently used for: petroleum refining (hydrocracking), the
production of ammonia, methanol and hydrochloric acid, the hydrogenation
of vegetable oils, the reduction of minerals, the treatment of metals,
welding in reducing atmosphere, cooling of generators and for rocket fuels.
As the production of hydrogen is an energy expensive process, the
feasibility of the hydrogen economy depends on coupling it with a zero- or
low-emission energy source.

Thermodynamics

Technological challenges for the hydrogen economy:
Production:
If it is produced by reforming of hydrocarbons, it has to be coupled with
CCS systems. If it is produced by electrolysis of water, the electricity must
come from zero-emissions sources.
Storage in vehicles:
The mass energy density of hydrogen of 120 MJ/kg is much higher than
that of gasoline (46 MJ/kg). But, due to its very low molar mass, the
hydrogen volume energy density (10 MJ/m3) is much smaller than that of
gasoline (35000 MJ/m3). Therefore, it has to be used either as
compressed gas (∼70 MPa) or as cryogenic liquid (∼-253° C), but both
processes would consume up to 30 per cent of the carried energy. The use
as metallic hydrides, that solve the problem of volume storage, would
otherwise impose heavy penalties in terms of weight and cost.

Thermodynamics

Hydrogen economy based on fossil fuels:

Homes,
Fuel cells industry,
transport

Gas turbines

Liquefaction
Gas turbines

Hydrogen from
reforming of
Gaseous hydrogen natural gas
Natural gas wells
Liquid hydrogen
Natural gas
CO2 capture
CO2
Geologic storage
Electricity
Reforming: CH4 + 2H2O → CO2 + 4H2

Thermodynamics

Solar and nuclear hydrogen economy:

Homes,
Fuel cells industry,
transport

Gas turbines

Liquefaction

Gaseous hydrogen Hydroelectricity
Liquid hydrogen Wind
Hydrogen from Photovoltaic
Electricity electrolysis
Waves
Nuclear


Thermodynamics

Energy sustainability: how to achieve it*:

To achieve a sustainable world energy system, the following is needed:

To develop much improved technologies for the exploitation and use of

fossil and nuclear fuels with much lower environmental and social impacts.

To significantly develop and implement renewable energy technologies in a

significantly greater scale.

To significantly improve the efficiency of the conversion, distribution and

end use of energy and change the patterns of use of energy.


Thermodynamics

More sustainable fossil fuels*:

Improve the efficiency of combustion:
Highly efficient combined-cycle gas turbines (CCGT, IGCC).
Combined use of heat and power (co-generation).
Improved heating systems and appliances.
More efficient internal combustion engines.

Reduce the combustion emissions:
Removal of sulphur dioxide.
Smaller emissions of nitrogen oxides and particulates.
Capture and storage of carbon dioxide (CCS).

Non-combustion conversion of energy:
Fuel cells.



Thermodynamics

Technology perspectives for energy sustainability*:
Transforming the energy services:
Improved energy efficiency in buildings, industry and vehicles.

Transforming the energy supply:
Advanced combustion and CCS.
Generation of electricity from natural gas and nuclear energy.
Generation of electricity from renewable sources.
Use of biofuels and hydrogen fuel cells in vehicles.

Transforming the electric system:
Advanced storage technologies for intermittent renewable sources.
Integration of power transmission and telecommunications.
* International Energy Agency, Energy Technologies Perspectives; Energy Technologies for a Sustainable
Future, 2005 .


Thermodynamics

Conclusions:
The world energy system is the largest and most complex industrial operation in
the world. This is so because energy is essential for our civilisation.
Although we cannot dispense with the energy supply, the world energy system
has significant environmental impacts and threats to human health.
Due to the undeniable conveniences of fossil fuels, about 80 per cent of the world
energy system relies upon the use of these fuels. Climate change results from the
carbon dioxide emitted by combustion of coal, oil and natural gas. The increase in
temperatures, the raise of sea level and changes in rain patterns will affect all
aspects of human life by the second half of the century.
A shift to extensive use of low-emissions renewable energy sources is the only
solution to mitigate in the medium term the effects of climate change. A number of
promising technologies are well identified, but much more research and investment
is needed to progress towards the extensive commercialisation of renewable
energy.


Chapter 2

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