Solar Energy Perspectives - IEA

Chapter 3: Solar electricity
Figure 3.5 Share of variable renewables in global electricity generation by 2050
Solar CSP
Solar PV
Wind
Biomass
+CCS
Biomass
and waste
Hydro
Nuclear
Natural gas
+CCS
Natural gas
Oil
Coal+CCS
Coal
50
45
40
35
30
25
20
15
10
5
0
PWh
18%
2007 Baseline 2050 BLUE
Map 2050
31%
BLUE High
Renewables 2050
Source: IEA, 2011c.
Key point
Variable renewables could represent one-third of total electricity generation by 2050.
Grids will need to evolve considerably to handle new tasks, such as managing more variable
supply, sending appropriate and timely price signals to producers and customers, and
managing demand loads. This is already seen in the evolution towards so-called smart grids.
Increased interconnection between electric systems and countries will also help exploit all
the benefits of the variable sources of electricity.
The challenges this variability raises in integrating renewable electricity sources should,
however, not be overestimated, a recent IEA study suggests (see Box: Harnessing variable
renewables). The capacity of electric grids to integrate variable renewables depend on
their flexibility, i.e.: the capability of the power system as a whole to ramp electricity
supply or demand up or down, in response to variability and uncertainty in either. The
need for flexibility is not introduced by the deployment of variable renewables, as all
electric systems already have flexibility to meet variable demand, and the contingencies
that may affect all generating sources and transmission capacities. Flexibility can be
provided by dispatch-able generating devices (whether fossil-fuelled or renewable),
storage capacities when they exist (mostly pumped-hydropower stations), interconnection
among systems, and demand-side management. Variability of individual devices or
technologies is dampened by geographical spread, as well as technology or resource
versatility: for example, if there is no wind in one area, there might be some in another
area; if the sun does not shine one day, the wind may blow instead; and if clouds in one
region reduce solar electricity generation to a minimum, other roofs or regions might enjoy
better weather, and so forth.
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© OECD/IEA, 2011