Harald Heinrichs · Pim Martens Gerd Michelsen · Arnim Wiek Editors

2 Types, Structures and Characteristics of Energy Systems
Our current and unsustainable energy systems are dominated by fossil fuels as 
energy sources which today supply almost 80 % of all energy globally. They are 
also characterised by losses of more than two thirds along the supply chains from 
primary energy source to final energy services delivered (Fig. 
19.1
and BP 
2013
). 
Energy systems can be looked upon as national or global energy systems, including 
all energy sources and conversion routes as depicted in Fig. 
19.1
. They can also be 
looked upon in smaller scales and scopes, e.g. the energy system of a single town 
(Fig. 
19.2
) or down to the heating system of a building (cp. Everett et al. 
2012
, 1ff).
Global and national energy systems are large, complex and capital intensive 
although their ultimate purpose is to provide relatively simple energy services such 
as heating, cooking, motive power and powering the Internet. Energy is also needed 
as an input in the production of important basic materials (e.g. metals, cement, 
paper, glass, insulation materials, etc.). It is important to remember that energy (e.g. 
a kWh or litre of fuel) is not an end in itself but the means to an end, namely, the 
delivery of end-use energy services that people and society need. That distinction 
shifts our focus to the demand for energy services and how they can be efficiently 
delivered, rather than how supply can continue to expand (cp. Lovins 
2004
, 
2011
; 
IEA 
2012
, 267ff).
Energy systems involve expensive and long-lived infrastructures in production, 
transports (e.g. power grids) and end uses (e.g. buildings). These characteristics cre-
S. Lechtenböhmer and L.J. Nilsson

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233
86.4
0.8
0.4
2.9
0.9
22.7 1.2 6.3
14.1
22.0
17.6
27.3 7.2
20.3 4.8 24.0
37.2 0.4 33.2
6.8
Trans-
mission
losses
12.3
75.9 1.9 30.1 37.3 28.5 2.0
Central Electricity
&Heat Generation
78.9
Refneries
155.8
154.2
ALS/OTF*
11.6
Loss
1.6
ALS/OTF
10.9
ALS/OTF
18.0
ALS/
OTF
6.7
ALS/
OTF
3.1
Crudeoil
167.4
Coal
122.2
Natural
gas
99.0
New
renewables
2.3
Hydro-
power
30.1
Nuclear
power
28.5
Biomass
46.3
25.0
Feedstocks
21.7
Transportation
62.2
Industry
59.6
Residential& commercial
Loss
5.2
Loss
69.7
Loss
26.0
Loss
60.3
Services
32 10
12 
pass-km
46 10
12 
ton-km
Structural materials
(volume x strength)
15 10
9 
MPa
2/3
m
3
Sustenance 28 EJ (food)
Hygiene 1.5 10
12 
m
3
K(hot water)
Work 2.8 10
18
Nm
Thermal comfort 30 10
15
m
3
K(air)
Illumination 480 10
18 
lum-seconds
Communication 280 10
18 
bytes
*ALS = Auto consumption, losses, stock changes
OTF = Other transformation to secondary fuels
30.2
91.4
88.2
119.9
Conversion loss
107.1