29 March 2017
Purposefor
of this
talk
Feeling
Energy
What is 1
MJ in real
life ?
Rinke Wijngaarden
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5.6 MJ = YOU up the Kilimanjaro
560 kJ/100 g
5700 m
=5.6 MJ/kg
E = mgh 100 kg up a
mountain of 5708 m
=5.6 MJ/kg
1 jar = 1 kg
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How much energy do you need for a bath?
Comparison of energy densities
1 jar = 1 kg
Jam 6 MJ/kg
High explosive 12 MJ/kg
Gasoline 44 MJ/kg
300 liter
Methane 50 MJ/kg
7 x 5.6 MJ
Natural gas 42 MJ/kg
37.8 MJ
Hydrogen 120 MJ/kg
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29 March 2017
Natural gas (Groningen)
energy content
MJ/m3
kWh/m3
lower heating value (LHV)
31.65
8.8
35.17
9.8
Jo Hermans’ guide
flame
gas stove
Central heating
TGV
Boeing 747
Electricity plant
onderwaarde
higher heating value (HHV)
bovenwaarde
100 W
2 kW
20 kW
10 MW
100 MW
1000 MW
includes heat of condensation
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Air plane energy
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General Conversion Factors for Energy
For example:
1 toe is equal to 41.868 GJ or 11.630 MWh or 11630 kWh
About 70 airplanes x 50 MW = 3.5 GW
Total electricity plants NL = 20 GW verbruik 2009: 13 GW
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1 GJ=109 J
1 TJ=1012 J
1 PJ=1015 J
1 EJ=1018 J
1 N  1 kg x 1
[Energy]= Joule
1J  1 N x 1m
J
s
[Power]= Watt
1 kW  1 000
[Energy]= Joule
1 kWh  1
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Heating: 50 – 100 W
m
s2
[Force]= Newton
1W  1
Primary energy consumption NL: 3 EJ
Power per person NL: 6 kW
Human power
Energy and Power
[Power]= Watt
giga
tera
peta
exa
Mechanical:
J
kJ
1
s
s
kJ
 3600s  3.6MJ
s
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P  E/t  mgh/t
P  70 kg  9. 8 m s −2  300 m/3600 s  60 W
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29 March 2017
Energy per € in NL
Man-equivalent of energy
Electricity
Gas
1 kWh costs: 0.21 €
1 m3 gas costs: 0.55 €
1 m3 = 35.17 MJ
4900 W /60 W person −1  82 person
(Groningen-gas-equivalent)
1 kWh electricity (Nuon) costs 0.21 €
1 kWh=3.6 MJ
3.6 MJ
0.21€
 17
MJ
€
36.17 MJ
0.55€
European energy use 4900 W
 66
25 €/day
MJ
€
Gas is cheaper
Electricity can be converted into
mechanical energy with ~ 100% efficiency
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paid 0.29 €/day
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