vgbe energy journal 11 (2022) - International Journal for Generation and Storage of Electricity and Heat

Future Energy Systems
1.0
Historical Median Range lnterquartile
n sum = 97; n min = 45
0.8
Renewable share of power
generation
0.6
0.4
0.2
0.0
1990 2000 2010 2020 2030 2040 2050
n sum = 87; n min = 50 n sum = 98; n min = 46
800
(B) - Photovoltaics
(C) - Wind turbines
Installed capacities in GW
600
400
200
0
2020 2025 2030 2035 2040 2045 2050 2020 2025 2030 2035 2040 2045 2050
Fig. 2. Expected share of renewable power generation on overall power demand (A) and installed capacities of photovoltaics (B) and wind turbines (C).
Most of the electricity generated by renewables
is provided by photovoltaics and onshore
and offshore wind turbines. In addition,
the German power system has hydropower
plants and biomass-based technologies,
as well as small capacities of geothermal
power plants. F i g u r e 2 (A) shows
the expected share of renewables in total
electricity generation. As can already be deduced
from the expected decrease in greenhouse
gas emissions, the share increases to
almost 100 % by 2050. As photovoltaics and
wind turbines are expected to cover the biggest
share of future power generation, the
following two sections will discuss the expected
demand on photovoltaic and wind
turbine capacities in more detail. For hydro-,
biomass- and geothermal power plants a
more or less constant installed capacity is assumed
until 2050.
Photovoltaic
First of all, it is noticeable that the interquartile
range of the expected development of
installed photovoltaic capacities covers only
a comparatively small corridor compared to
the entire range (F i g u r e 2 (B)). For example,
half of all scenarios expect photovoltaic
capacity in 2050 to be between 100 and
200 GW, while the maximum is close to
800 GW. The extremely high installed capacities
are based, for example, on scenarios
from the [44]. Here, a maximum electrification,
respectively a one-to-one replacement
of fossil feedstocks by power-to-X products is
assumed, leading to installed photovoltaic
capacities of 810 GW in 2050. Besides [44],
other studies with high electrification or
high share of intra-German power-to-X application
and self-supply also show a large
demand for renewables. Exemplary are scenarios
from the studies [14], [12] and [21].
While the latter include only individual scenarios
with above-average expansion needs,
all scenarios from [14] are in the upper
quarter of the range. The highest requirements
come from the scenarios with the
lowest ambition, or the greatest societal resistance
to new technologies, large infrastructure
projects or energy-saving measures.
The same climate targets, represented
here by meeting CO 2 emission targets, lead
to higher demand for installed capacity and
thus to higher costs.
The other extreme of low photovoltaic capacities
in 2050 is based on scenarios such
as the reference or low restriction scenario
from [32]. Here, no or minimal climate targets
are specified. As a result, cost-optimal
and without consideration of possible emissions,
the expansion of renewable energies
is only used to a limited extent and the energy
system further relies on fossil technologies.
Looking at the plans of the current federal
government regarding the new expansion
plan for renewable energies, it becomes
apparent that the median, as well as the entire
interquartile range, is still below the ambitious
targets from [45]. Here, over 100 GW
of additional photovoltaic capacity is targeted
by the end of 2030.
Wind turbines
F i g u r e 2 (C) summarizes the expected development
of installed wind turbine capacities
onshore and offshore. The known stagnating
expansion of the last years is used in
most studies as the actual state for 2020.
The whole range shows a much narrower
course compared to the photovoltaic expansion,
whereby the extreme values are based
on the same studies. Compared to the new
expansion targets, especially the year 2030
shows the ambition level of the German government
[45]. Thus, by 2030, 30 GW and by
2045, 70 GW of offshore wind turbines are
to be installed, whereas within the system
studies, only 15 GW and 55 GW, respectively,
are expected in the median. For 2045, the
expansion target is even outside the entire
range. For onshore wind power, the new expansion
targets are also in the upper quarter
of the range expected by the studies. The
planned annual addition of up to 10 GWa -1
by 2035 contrasts sharply with an expected
addition of 2 to 3 GWa -1 , based on the median
of the studies. Especially the lowest installed
capacities of wind turbines originate
from scenarios in which the social resistance
against wind turbine expansion, or in general
against construction measures in one’s
own environment, is strongly pronounced.
36 | vgbe energy journal 11 · 2022