Introduction and Structure - Renewable Energy: Technology, Economics and Environment - page 3

space heating, food preparation, information, transportation). It is produced
from final energy carrier or final energy, reduced by losses of this last conver-
sion (e.g. losses due to heat dissipation by a light bulb to generate light, losses
of wood chip fired stove to provide heat).
The entire energy quantity available to humans is referred to as energy basis. It is
composed by the energy of the (predominantly exhaustible) energy resources and
the (largely renewable) energy sources.

Primary energy
(e. g. hard coal, lignite, crude oil, natural
gas, uranium, hydropower, solar
radiation, forest wood)

- Conversion losses
- Distribution losses
- Self consumption
- Non-energetic
consumption

- Conversion losses
- Distribution losses
- Self consumption
- Non-energetic
consumption

Secondary energy
(e. g. coke, briquettes, gas, biodiesel,
heating oil, power, wood logs, district
heating)

- Conversion losses
- Distribution losses
- Self consumption
- Non-energetic
consumption

Final energy
(e. g. briquettes, gas, heating oil,
natural gas, power, wood chips,
district heating)

Useful energy

Consumer
losses

(e. g. heat, power, light)

Fig. 1.1 Energy conversion chain (see /1-1/)

In terms of energy resources, generally fossil and recent resources are distin-
guished.
− Fossil energy resources are stocks of energy that have formed during ancient
geologic ages by biologic and/or geologic processes. They are further subdi-
vided into fossil biogenous energy resources (i.e. stocks of energy carrier of
biological origin) and fossil mineral energy resources (i.e. stocks of energy car-
rier of mineral origin or non-biological origin). The former include among oth-
ers hard coal, natural gas and crude oil deposits, whereas the latter comprise for
instance the energy contents of uranium deposits and resources to be used for
nuclear fusion processes.
− Recent resources are energy resources that are currently generated, for in-
stance, by biological processes. They include, among others, the energy con-
tents of biomass and the potential energy of a natural reservoir.
Energy sources, by contrast, provide energy streams over a long period of time;
they are thus regarded as almost "inexhaustible" in terms of human (time) dimen-
sions. But these energy flows are released by natural and technically uncontrolla-
ble processes from exhaustible fossil energy resources (like fusion process within
the sun). Even if such processes take place within very long time periods - and