Energy in a Globalised World - Energy and Climate: How to Achieve a Successful Energy Transition - page 3

coefficient based on 0.33 efficiency (0.261 toe for 1 MWh of nuclear
electricity).
Primary energy is then converted into secondary energy, into a form
which can be used by the consumer (production of fuels in the refineries
and electricity in the power stations).
The final energy is consumed by the user after the transport and
distribution process.
Currently, fossil energies are by far themostwidely used, providing a little
over 80%of the world supply of primary energy [2]. Oil still represents the
most important share (34%), followed by coal (26%), natural gas (21%),
renewable energies (13%) and lastly nuclear power (6%).
Most of the renewable energy supply comes from biomass (nearly
80%). Hydroelectricity represents only 16% of this supply and the other
forms of renewable energy (including wind and solar) just 4%, i.e. about
0.5% of the total primary energy consumed.
After a fast development phase in the 1970s, the proportion of nuclear
power stagnated and even dropped, following the concerns raised by the
accidents at Three Mile Island and especially Chernobyl, which exacer-
bated public distrust. This trend was amplified by the oil counter crisis,
which reduced the financial attraction of nuclear power for a long period
of time.
At the same time, extensive development in road and air transport
generated a high demand for oil, virtually the only source of the fuels
used for which there is no immediate substitute at the required scale.
In this context, the share of fossil energies usedhas remainedmore or
less stable. The share of oil has dropped slightly, with a corresponding
increase first in natural gas and more recently coal, which has made a
remarkable come-back over the last five years. Although 'post-oil' is
oftenmentioned, making substantial changes to the distribution of the
various primary energy sources will involve considerable time and
effort.
Uses of energy
Consumption of final energy worldwide is distributed as follows between
the main sectors of activity (Figure 1.2):
- The residential (dwellings), tertiary (offices and service activities)
and agricultural sectors represent 36% of the global energy
demand.