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

Future Energy Systems
In some studies, the acceptance of wind
power plants is rated significantly lower
than that of PV, which illustrates the necessary
political effort regarding the involvement
of the population. Politically set targets
alone will not be enough to meet climate
goals. The change must be increasingly
supported by the population.
Regarding the further development of wind
power technologies, almost all studies assume
an increase in full load hours both onshore
and offshore. Thus, on average, the
use of low wind turbines is expected to increase
the onshore yield from about
1,900 ha -1 in 2020 to about 2,300 ha -1 in
2050. Offshore wind turbines are also expected
to increase full load hours from
3,875 ha -1 in 2020 to over 4,200 ha -1 in 2050.
Conventional power plants
A detailed analysis on the demand for conventional
power plants during the energy
transition is published by the authors in
[46]. In summary, based on the considered
system studies, a peak in natural gas consumption
can be identified between 2030
and 2040. Most scenarios expect a natural
gas demand until at least 2040, while simultaneously
more than half of the scenarios
considered meeting Germany’s zero emissions
target in 2050. In summary, the definition
of the respective scenario in particular
is shown to be decisive for the length of
natural gas dependency. While natural gas
demand is eliminated by 2050 on average,
more than 75 % of the evaluated scenarios
assume that the basic need for conventional
power plants will continue well beyond
2050. Increased demand for synthetic energy
carriers will begin in 2040. Based on the
median installed capacities of the developments,
as well as the amounts of energy provided
in each case, a full load maximum of
about 3000 ha -1 results for the period from
2020 to 2050. As power generation decreases
while installed capacities remain unchanged,
the median utilization decreases
to about 1200 ha -1 by 2050. While individual
power plants may be used for medium- or
base-load, the majority will have significantly
fewer operating hours. The main applications
will be, for example, peak load coverage
or back-up for black start events.
Hydrogen
The total demand for hydrogen is given by
the studies with a median of 149 TWh and a
maximum of 450 TWh in 2050. As can be
seen in Ta b l e 4 , an increasingly rising demand
for hydrogen can be observed. Individual
scenarios assume no hydrogen demand
up to 2030. The assumptions of the
German government from the “National
Hydrogen Strategy” are rather in the upper
range with 90 to 110 TWh in 2030 [47].
Both some studies and the strategy paper of
the German government assume that initially
only a small part of the green hydrogen
demand can be provided within Germany.
The majority will come from imports. Regardless
of the hydrogen strategy, the median
of the evaluated scenarios shows a
three-part expansion rate regarding the installed
electrolysis capacities in Germany.
Initially, about 0.8 GWa-1 of new electrolysis
capacity per year is expected by 2030.
The expansion rates increase to 1.5 GWa-1
in the period 2030 to 2040 and to 3.0 GWa-1
in 2040 to 2050. These values are clearly
above the strategy paper.
Due to the high electricity demand of water
electrolysis, the effects on the higher-level
energy system are of particular interest. In
the long term, a purely green hydrogen production
is targeted, which is ultimately accompanied
by a significantly higher demand
for renewable electricity generation. This
effect can be observed by comparing the expected
development of renewable capacities
depending on the consideration of hydrogen
production. Here, a clearly steeper increasing
median of the scenarios with hydrogen
consideration in comparison with those
without hydrogen consideration can be
seen. The sum of renewable capacities is
thus about 40 GW in 2030 and over 70 GW
in 2050 above the scenarios without hydrogen
consideration. The resulting steeper expansion
rates of renewables are comparable
to those of electrolysis and the general hydrogen
demand, respectively.
3,1,3 Future energy carriers
The sectors heat, mobility/transport and industry
are increasingly being considered in
current energy system studies. In addition to
the goals of maximum efficiency increase
and electrification, there is often the question
of providing synthetic energy carriers.
Some industrial processes cannot be electrified
or are considered uneconomical due to
the low energy density of current electricity
storage systems. The following sections
therefore deal in an excursus with the representation
of other sectors than the electricity
sector in current energy system studies. However,
a purely qualitative evaluation is possible
in this section due to the limited data
Tab. 4. Overview of the expected hydrogen demand of the German energy system in the years
from 2020 to 2050.
Unit 2020 2030 2040 2050
Minimum TWh 0.0 0.0 11.4 22.5
Median TWh 4.5 46.0 111.5 149.0
Maximum TWh 16.5 115.0 265.0 450.0
German national hydrogen
strategy
90-110 TWh until 2030
basis and, in particular, the strongly fluctuating
level of detail between the studies.
Heat sector
Due to the different temperature levels required
and the complexity of district heating
network planning, the mapping of the heat
supply is significantly more complex than
the distribution of electrical energy. For this
reason, the level of detail of the studies considered
varies greatly. What the studies have
in common, however, is that overall a decrease
in heat demand is assumed. The reason
for this is the progressive renovation of
existing buildings, as well as the expansion
of district heating networks and more efficient
heat supply technologies. It is also assumed
across all studies that - irrespective of
whether district heating or building-specific
- the use of both electricity-based technologies,
biomass, solar thermal energy and geothermal
energy, but also synthetic energy
carriers will play an important role.
Industrial sector
Industry in particular is seen as the sector in
which the transformation toward climate
neutrality will be among the most difficult.
Both high-temperature processes and chemical
processes can only be electrified to a limited
extent. While the steel industry has
great potential for reducing greenhouse gas
emissions through the use of green hydrogen,
emissions in the cement industry are
fixed due to the process. Here, technologies
for CO 2 capture, as well as CO 2 -negative
technologies, are increasingly being discussed
in order to achieve the emission targets.
Initial studies are therefore already
explicitly addressing the challenges and opportunities
for German industry during the
transformation of the energy system.
Transport sector
The transport sector has the smallest data
base regarding the use of synthetic energy
carriers. Here, the focus is on electromobility,
in particular due to political interest.
However, more recent studies are already
increasingly taking alternative technologies
into account, especially in the transport sector.
Here it is apparent that pure electrification
will probably not be sufficient, but that
non-negligible shares of mobility and transport
will be based on synthetic fuels.
Cross-sector
The demand for synthetic fuels will increase
not only due to the demand in power plants,
but also due to other applications such as
mobility and industry. Since future energy
systems will most likely be based entirely on
renewable power generation through photovoltaics
and wind energy, power-to-X technologies
are expected to meet a large part of
this demand. Taking the median of the studies,
power-to-gas demand in Germany is assumed
to increase from 2.5 GW in 2030 to
over 40 GW in 2050. The corresponding
electricity demand for all power-to-X appli-
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