IEEE Power & Energy Magazine - July/August 2018 - 26

ieee power & energy magazine

2050

2045

2040

2035

2030

2025

2020

2015

2010

2005

2000

1995

1990

GHG Emission, Million Ton CO2-eq.

resource share of gross electricity generation in germany is con1,400
stantly growing, starting from 6%
Energy-Related CO2 Emission
Other
in 2000 to approximately 31.6%
1,200
in 2015.
still, even if the power-supply
1,000
-20 %
sector fundamentally transforms,
800
this alone will not be sufficient to
-40 %
achieve the ambitious climate pro600
tection targets shown in figure 1.
-55 %
The present situation shows that,
400
-70 %
while the power sector is progressively changing, the goals for other
-80 %
200
sectors will most likely be missed
-95 %
(for example, doubling the annual
0
renovation rate of buildings from 1
to 2%). To reduce ghg emissions
by at least 80% and, wherever
figure 1. GHG emissions in Germany from 1990 to 2015, and target values to 2050
possible, 95% below 1990 levels,
(blue dots). The green bars represent energy-related CO2 emissions and the red bars
each one of the illustrated sectors
other GHG emissions. Percentage reductions refer to the 1990 value. (Source:
(figure 2) will have to undergo
Henning and Palzer, 2015.)
a substantial transformation itself,
i.e., follow a strict decarbonizing
strategy.
To
properly
assess
the transition of the energy sysis responsible for approximately 44% of the total energy-related
Co2 emissions as power generation in germany relies heavily tem toward a climate friendly, reliable, and affordable supply
on fossil fuel-fired plants. in 2015, 71% of the gross electricity of energy, it is necessary to consider all sectors as well as
generation was provided by coal (42%), nuclear power (14%), their interactions.
natural gas (10%), and petroleum products and other fuels (5%),
while only 29% came from renewable energy resources. in Methodology
2015, the specific emission Co2 factor for electricity amounted The remod-D model is a bottom-up energy system model
to 535 g/kWh as a result of the extensive use of lignite and developed at the fraunhofer institute for solar energy systems
hard coal, with fuel Co2 emission factors of 337 g/kWhcoal and assesses the transformation of national energy systems to
and 407 g/kWhcoal, respectively, and overall power plant a more environmentally friendly and low-carbon economy.
efficiency below 40%. on the other hand, the share of final The fundamental idea behind the model is the identification
energy consumption for the supply of low-temperature heat of a cost-optimized system structure in line with the set Co2
in 2015 amounted to 30%, yet yielding only 18% of the total reduction targets by taking into account the highly complex
energy-related Co2 emissions. in this sector, gas boilers, not dependencies occurring between different energy carriers and
coal, are the dominant technology. The emission factor for sectors (sector coupling model). The objective is to dimension
natural gas amounts to 201 g/kWhgas, leading to lower emis- all system-relevant technologies in a cost-effective way, starting from 2015 until the target year 2050.
sions when compared to the electricity sector.
The model calculations are based on a comprehensive
in this context, the changes in sources of electricity production have been a central topic for the last few years. for exam- database in which weather data as well as technological and
ple, in July 2011, the german federal government declared a economic parameters are specified for each year from 1990
progressive reduction of nuclear power plants until a complete to 2050. The first part of the database, from 1990 to 2014,
shutdown of all reactors by 2022. similarly, in october 2017, describes technical parameters for all relevant components
germany's environment minister declared that a withdrawal of the energy system. This includes installed capacities of
from coal-fired power is not a question of whether it should be power plants, storage facilities, heating technologies in builddone but, rather, when and how it will be accomplished. While ings, building stock (as well as its physical characteristics),
the phase out from nuclear power is final, the retirement of number of vehicles, and transportation technologies. The seccoal-fired resources has not yet been legally embodied and is ond part, from 2015 to 2050, deals with assumptions regardthe subject of controversial debate. at the same time, a further ing cost or performance projections of individual technoloincrease in installed capacity of renewable energy resources is gies, technical restrictions (capacity limits per year), and other
expected. The government aims for a share of renewable elec- time-dependent characteristics. This information is essentricity generation of 40-45% in 2025 and 55-60% in 2035. tial to determine the mix of generators, energy converters, and
The current development shows that the renewable energy consumers that meet environmental goals at minimal cost.
july/august 2018

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