Harald Heinrichs · Pim Martens Gerd Michelsen · Arnim Wiek Editors

Final energy (EJ/a)
2010
2020
Fossil and nuclear energy
Renewable heat and fuels
Renewable power
Baseline: ~520 EJ/a
Ambitious
end-use energy
savings and
electrification
Remaining
fossil fuels
Substitution of
conventional by
renewable
energy sources
ECOFYS
Fig. 19.5
Key developments of the transition to a fully sustainable energy system (Source: 
Deng 
et al. 2012
, 119)
S. Lechtenböhmer and L.J. Nilsson

---

243
other aspects but would need to strongly emphasise energy efficiency and renewable 
energies which make up for the bulk of future sustainable energy technologies that 
are needed for the transformation towards a sustainable energy system.
This transformation of global, national and local energy systems is, however, not 
only a technical question. It implies also major social, institutional and economic 
changes as well as local acceptance. It is also linked to social norms and individual 
consumption patterns (“sufficiency”). The implementation of energy-efficient tech-
nologies and solutions often takes place at the local level. Also, with renewable 
energies such as wind and solar energy, production becomes more decentralised and 
local converting the role of energy consumers to so-called prosumers which are 
simultaneously producers (of, e.g. renewable electricity) and consumers. In this 
context particularly community levels are important. Consequently, there are
numerous scenarios, targets and plans in many cities and communities which try to 
figure out the local challenges and potentials for action. Cities have (re)acquired
their energy supply companies, and, for example, people in rural areas have started 
renewable energy cooperatives (DGRV 
2013
).