Environmental Engineering Reference
In-Depth Information
A drawback of using biomass as a direct source for electricity production would
be that useful work (exergy) is destroyed. It might be more efficient from an
energy system
s point of view to use biomass as a primary source for (petro)
chemical synthesis.
'
Figure 1.6 presents the forecasted energy demand per energy resource and the role
of different strategies to mitigate the CO
2
emissions according to recent IEA scenarios
(OECD/IEA, 2012). The 6DS scenario is characterized by the absence of efforts to
reduce GHG emissions, leading to a projected 6
C increase of the global mean tem-
perature. The 4DS scenario includes pledges that countries have made to reduce such
emissions as well as to increase efforts to improve energy efficiency. It is consistent
with the World Energy Outlook
s New Policies Scenario through 2035 (IEA, 2011)
and would lead to an expected global mean temperature increase of 4
C. The 2DS
scenario, projecting a long-term global temperature rise of 2
C, is targeted by IEA
in their Energy Technology Perspectives 2012 (OECD/IEA, 2012) and comprises a
cut of energy-associated CO
2
emissions by more than 50% in 2050, as compared
'
900
800
700
600
500
400
Other renewables
Biomass and waste
Hydro
Nuclear
Gas
Oil
Coal
300
200
100
0
6DS
4DS
2DS
2009
2050
60
6DS
Nuclear 8%
Power generation efficiency and fuel switching 3%
Renewables 29%
End-use fuel switching 9%
CCS 20%
End-use fuel and electricity efficiency 31%
50
40
30
20
10
2009
2020
2030
2040
2050
FIGURE 1.6
IEA scenarios for primary energy use and mitigation of CO
2
. World total
primary energy supply per energy source in 2009 and in three scenarios for 2050, with DS
being
C global temperature increase perspective (top). Key technologies for reducing CO
2
emissions (bottom); note that percentages in the legend represent cumulative contributions
to emission reductions relative to the 4DS scenario. (Source: Reproduced with permission
from OECD/IEA (2012). © IEA.)
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