All natural energy on Earth comes from solar radiation, heat from the Earth's mantle, and gravity. Fossil fuels like coal, oil, and natural gas are limited, non-renewable sources that have formed from ancient organic matter over millions of years. Energy can also be generated renewably from solar, wind, hydroelectric, geothermal, and biomass sources. Nuclear fission of uranium and thorium isotopes in the Earth's crust is another non-renewable source of energy. Hydrogen may become a sustainable energy source in the future.

1. Energy production & consumption
Data collection and presentation by Carl Denef

2. Energy is the physical entity indispensable for performing work. It comes in
different forms: mechanical, kinetic, thermal, radiative, electric, magnetic,
chemical, nuclear, gravitational and others. Energy can be transformed to different
forms at various efficiencies. An energy source can also be called a fuel.
All natural energy on earth comes from the radiative energy of the sun, heat in the
earth’s mantle (geothermal energy), and gravity.
About 0.01% of solar energy is converted to plants. Over millions of years residues
of living matter have been transformed under the soil and the sea to fossil
hydrocarbon energy in the form of coal, oil and natural gas. These energy
sources are limited and not renewable. Potential energy in it is transformed to
usable power by burning. The rest products are greenhouse gasses, causing global
warming and climate change.
Energy can also be converted directly from solar radiation, gravity, the Earth crust
and living plants by human technology (wind, solar, hydroelectric, geothermal
and biomass power). These energy forms are renewable.
In addition, the Earth crust contains uranium and thorium isotopes, that release
high amounts of heat energy upon nuclear fission.
Human-made hydrogen can also become a sustainable source of energy in the
future.
© picture: WWF-Canon / Edward Parker
2
2

3. © picture: WWF-Canon / Edward Parker
One of the units of measurement of energy is the Joule (J). It is a measure of the capacity
or power to generate work, such as locomotive work in a combustion motor of a car, light
generation by electric power, electricity generation in a turbine by wind power etc.
Another unit, called Watt (W), is the power which in one second of time gives rise to 1
joule of energy
1 W = 1 J/sec
1 kilowatt (kW) = 1000 J/sec
1 megawatt (MW) = 106 J/sec
1 gigawatt (GW) = 109 J/sec
1 terawatt (TW) = 1012 J/sec
Amounts of energy can also be expressed in terms of its flow over time during power
conversion, with as unit the Watt.sec
1 W.sec = 1 J
1 kW.hour (kWh) is the energy flow with a power of 1 kW sustained during 1 hour
1 kWh = 1000 x 3600 = 3.6 x 106 J = 3.6 MJ
1 kWyear (1kWy) = 1000 x 3600 x 24 x 365 = 31 536 000 000 J
or 1 J = 31.71 x 10-12 kWy = 31.71 x 10-21 TWy
In the slides that follow energy capacity is usually expressed in GWy or TWy, shortened in
the figures as GW and TW. In some slides energy consumption is expressed in kWh, MWh
or TWh
3
3

4. Fuel
kWh per
kilogram*
Deuterium–tritium 92 400 000
Uranium-235 23 279 200[3]
Hydrogen (compressed
at 70 MPa)
34
Natural gas 15.5
Gasoline (petrol) /
Diesel
~13
Propane (including LPG) 13
Biodiesel 12
Ethanol 8.4
Coal 6.7
Wood 5
Car battery (lead-acid) 0.7
Li-ion battery 0.24
Alkaline battery 0.67
Nickel-metal hydride
battery
0.288
106
Fuel kWh per m3
Liquid hydrogen 2389
Hydrogen, at 690
bar and 15°C
1260
Hydrogen, gas[ 2.8
Natural gas 10.2
Gasoline (petrol) /
Diesel 9600

5. Electricity generation Efficiency
Gas turbine up to 40%
Gas turbine plus steam turbine
(combined cycle)
up to 60%
Hydropower turbine up to 90%
Wind turbine up to 59% (theoretical limit)
Solar cell 6–40% (technology dependent)
Hydrogen Fuel cell up to 85%
Geothermal power 10–23%
Engine/Motor
Combustion engine 10–50%[2]
Electric motors
70–99.99% (above 200W);
50–90% (between 10–200W);
Electrolysis of water 50–70%
Appliances
Incandescent light bulb 0.7–5 %
Electric heater 100 %
Natural process
Photosynthesis up to 6% [3]
Muscle 14–27%
Energy conversion efficiency is
the ratio between the useful
output of an energy conversion
machine and the input, in
energy terms. The useful
output may be electric power,
mechanical work, or heat.
103

6. • Energy returned on energy invested (EROEI); or
energy return on investment (EROI), is the ratio of
the amount of usable energy acquired from a
particular energy resource to the amount of energy
expended to obtain that energy. Determining the
EROEI is often complex, resulting in wide variations in
the data. In the asesment the whole life cycle should
be envisaged.
• The more difficult to extract energy from a source, the
more energy is to be invested to extract it, lowering
the EROEI and increasing the price. For example, when
oil was originally discovered, it took on average one
barrel of oil to find, extract, and process about 100
barrels of oil. That ratio has declined steadily over the
last century to about three barrels gained for one
barrel used up in the U.S.
• If an energy source can flow to different tracks, its
EROEI will increase. For example in Europe rapeseed is
used to produce biodiesel. The EROEI is around 1.5
but a side product, pure plant oil, is used as a protein-
rich animal food, with an EROEI of 16.
105
Energy source ERoEI[1]
Crude oil (per
2007)
10
Oil sands (per
2007)
2 - 4
Natural gas 5 – 10
Coal 1 – 10
Nuclear 2,7 - 4
Hydroelectric 10
Wind 3 – 10
Solar panels 1 – 10
Biofuels
Soy biodiedel 5.5
Sugar cane ethanol 4 - 8
Rapeseed biodiesel 1,5
Corn ethanol 0,8 - 1,5
Maize ethanol 1,1
Biomass 0,8
Hydrogen 0,5

7. • The net capacity factor of a power plant is the ratio of its actual output over a period
of time, to its potential output if it were possible for it to operate at full nameplate
capacity indefinitely. The capacity factor is highest for nuclear and geothermal power
plants and lower for wind and solar energy as the latter are not continuously available.
Fossil energy power stations work at full capacity only during peak hours in the day and
les at night during lower demand.
102
85 87 90 92
83
53
34
25
Capacity(%)
Capacity factor

8. The figure shows the huge differences between energy types, solar and wind facilities
occupying much smaller land area than bio- and fossil fuel facilities. Both low and high
estimates (depending on the study) are given.
3 9 16
1000
900
0
200
400
600
800
1000
1200
Globalhectares/MW
Low
High
110

9. Total
• Total use in billion m3 (bcm)(in 2010 and prospected). Water withdrawal is water that is
taken from the natural environment and after use redistributed in nature, for example to
feed an electric turbine in the form of steam, to cool the reactor in a nuclear power plant
or to irrigate biomass crop land. Often that water is warm and polluted. Consumption is
water that is consumed during energy production, for example water taken up by
biomass crops.
From IEA
111

10. Per energy unit
• Withdrawal and consumption of water in gallons (Gal) per MWh (1
gallon=3.8 liter)
112

11. Total and by energy type
• World total energy consumption in 2010 was 17.8 terrawatt (TW). Most
is extracted from conventional fossil (coal, oil, natural gas) and nuclear
(uranium) reserves. Renewable energy (wind, solar, hydroelectric,
geothermal and biomass) is growing rapidly in recent years, now reaching
12 % of the world total energy consumption, which is more than double of
nuclear energy consumption (5.3 %).
4.9
5.9
3.9
0.95
2.17
0
1
2
3
4
5
6
7
TW
World energy consumption 2010
coal
28%
oil
33%
gas
22%
nuclear
5%
renewable
12%
4

12. Consumption by energy type and country
5
Coal
19%
Oil
35%
Gas
24%
Nuclear
14%
Renew
ables
8%
EU
Coal
21%
Oil
37%
Gas
25%
Nuclear
9%
Renew
ables
8%
USA 2010 (EIA)
Coal
23%
Oil
43%
Gas
18%
Nuclear
13%
Renew
ables
4%
Japan 2010 (EIA)
Coal
70%
Oil
19%
Gas
4%
Nuclear
1%
Hydro
electric
6%
China 2009 (EIA)
Coal
41%
Oil
23%
Gas
8%
Nuclear
5%
Waste
&
Renew
ables
28%
India 2011 (EIA)
Oil
13% Gas
4%
Hydro
electric
1%
Tradi-
tional
biomass
& waste
82%
Nigeria 2010 (EIA)
Coal
2%
Oil
47%
Gas
28%
Hydro
electric
23%
Venezuela 2010 (EIA)
Coal
3%
Oil &
bioethanol
39%
Gas
7%
Nuclear
1%
Hydro
electric
29%
Biomass
21%
Brazil 2010 (EIA)

13. • Energy consumption per capita is highly variable in different areas of the world,
developing countries consuming much less. Values range between 0.2 kW/person
(Eritrea) and 22 kW/person (Iceland) sustained for 1 year. In Belgium it is 7.4 kW,
ranking 7th highest.
• There are also striking differences between cities in the same country, for example in
electricity consumption in U.S. cities.
6
Per capita electricity use in kWh/capita

14. • The striking differences between developed and developing countries is also reflected
in the number of people (> 1.6 billion) without access to electricity in 2002
and predicted to have only slightly improved in 2030. This is due in part to the strong
population growth in this part of the world. It clearly shows that dealing with energy
issues cannot be disconnected from the inequality problem between people.
7
In India 2009

15. • Energy consumption grew spectacularly, both in total and per capita, since the industrial
revolution, as a consequence of the population explosion (click here to see population
growth animation) and of human scientific and technical development. Since then we have
already consumed about 800 TW of fossil energy. Fossil fuels are still dominant in the global
energy mix, supported by $ 523 billion subsidies in 2011, up almost 30% in 2010 and six
times more than subsidies to the renewable energy sector[4 ., an alarming situation,
considering that the fact that fossil energy combustion is the cause of global warming and
climate change .
8

16. • The dominant energy source changed over time from wood to coal to oil.
At present there is a transition in motion to a renewable energy age,
named by Greenpeace the ‘Energy Revolution’.
9
(1 Quad.Btu (british thermal units) = 33.45 × 10
- 3 TW)

17. • Energy supplies are used for >50 % in industry, for > 25 % in
transportation, and for 22 % in residential and commercial facilities. The
type of energy differs widely among these sectors. Oil is used for 96 % in
transportation, while coal and nuclear energy feed electricity generation.
10
Industry
52%
Transpo
rtation
26%
Residen
tial
14%
Commer
cial
8%
World 2012 (EIA)
0
20
40
60
80
100
120
Percent
Sector energy consumption by energy type
Coal
Oil
Gas
Nuclear
Renewable
World total electricity
production = 2.3 TW
(~20 000 TWh)

18. • Energy type used by sector differs widely among countries
Industry
77%
Transportati
on…
Residenti
al 11%
Commerc
ial 4%
China 2009 (EIA)
Industry
31%
Transpor
tation
28%
Residenti
al
22%
Commercia
l…
U.S. 2008
10b

19. 113
The table underneath shows the number of people killed by electricity generation systems
worldwide per year, as collated by the IEA from different studies (lowest and highest numbers
are given). Coal is responsible for a much higher number of deaths than other energy
sources, while nuclear fatalities are lowest. In the Chernobyl disaster there were 56 direct
deaths and 4000 people died from cancer. Recent estimates on the hazards caused by the
Fukushima nuclear accident predict a total of 130 cancer deaths over lifespan.[22] Some 230
000 people were killed in a dam failure of a hydroelectric power station in China in 1975.
However, it is astonishing to note that the number of people killed in road accidents
worldwide was 1,230,000[2] in 2007.
It is even more astonishing that the annual death toll due to fossil energy-related
climate change is 400 000 and that this will increase to 700 000 by 2030 if a drastic
change in our fossil energy economy is not implemented.
Average number of people killed/year due to
electricity generation
Low estimates High estimates
Coal 2296 26814
Hydroelectric 320 512
Natural gas 126 672
Nuclear 52 312