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Necessity and Impact of Power-to-gas on Energy Transition in Germany

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  • Ingenieurbüro Thema
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Necessity and Impact of Power-to-gas on Energy Transition in Germany

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The present paper gives an outlook on a bandwidth of required installed power-to-gas capacity in the German power sector fed by 100% renewable generation until 2050. Two scenarios were simulated to quantify cost effects of power-to-gas on the electricity system: once with, once without additional short-term flexibility options to a system using fossil natural gas as sole flexibility option instead. As a result, at latest in 2035, power-to-gas capacity expansion has to take place to reach required installed capacities of up to 89-134 GW in 2050. Application of power-to-gas as long-term flexibility leads to cost savings of up to 11,7-19 bn Euro enabling a fully renewable system in 2050.
Content may be subject to copyright.
1876-6102 © 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/).
Peer-review under responsibility of EUROSOLAR - The European Association for Renewable Energy
doi: 10.1016/j.egypro.2016.10.129
Energy Procedia 99 ( 2016 ) 392 400
ScienceDirect
10th International Renewable Energy Storage Conference, IRES 2016, 15-17 March 2016,
Düsseldorf, Germany
Necessity and impact of power-to-gas on energy transition in
Germany
Martin Themaa
*
, Michael Sternera, Thorsten Lenckb, Philipp Götzb
aTechnical University of Applied Sciences Regensburg, Research Center on Energy Transmission and Energy Storage (FENES),
Seybothstraße 2, D-93059 Regensburg, Germany
bEnergy Brainpool GmbH & Co. KG, Brandenburgische Straße 86/87, D-10713 Berlin
Abstract
The present paper gives an outlook on a bandwidth of required installed power-to-gas capacity in the German power
sector fed by 100 % renewable generation until 2050. Two scenarios were simulated to quantify cost effects of
power-to-gas on the electricity system: once with, once without additional short-term flexibility options to a system
using fossil natural gas as sole flexibility option instead.
As a result, at latest in 2035, power-to-gas capacity expansion has to take place to reach required installed capacities
of up to 89-134 GW in 2050. Application of power-to-gas as long-term flexibility leads to cost savings of up to
11,7-19 bn Euro enabling a fully renewable system in 2050.
© 2016 The Authors. Published by Elsevier Ltd.
Peer-review under responsibility of EUROSOLAR - The European Association for Renewable Energy.
Keywords: power-to-gas; energy storage; renewable energy; system costs; surplus energy; supply security; energy transition; decarbonization.
1. Introduction
Facing climate change, the German federal government made a commitment to own energy policy objectives within
their coalition agreement and energy concept in 2010: greenhouse gas emissions in Germany shall be reduced by 40 %
* Corresponding author: Martin Thema. Tel.: +49-941-943-9200; fax: +49-941-943-1424.
E-mail address: martin.thema@oth-regensburg.de
Available online at www.sciencedirect.com
© 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/).
Peer-review under responsibility of EUROSOLAR - The European Association for Renewable Energy
Martin Thema et al. / Energy Procedia 99 ( 2016 ) 392 – 400 393
until 2020 and by 80-95 % until 2050 compared to the amount of 1990. Power consumption is supposed to decline by
one quarter in the same period of time (10 % until 2020, 25 % until 2050) while shares of renewable energy generation
ought to rise up to 80 % in 2050 (40-45 % in 2025, 55-60 % in 2035). Furthermore, the aim is to reduce the final
energy consumption in the heat sector by -80 %, the one in the transport sector -40 % until 2050.
To avert dangerous consequences of climate change, these aims are not sufficient. A fully renewable power supply
in the year 2050 is required and feasible [1]. Because of highest potentials and lowest costs, the main supporting
columns of energy transition in Germany will be wind and solar power (photovoltaics). Therefore, one of the major
tasks will be balancing the fluctuating, weather-dependent generation of wind and solar power at contemporary high-
level security of supply. For this, amongst different flexibility options, energy storage becomes increasingly important.
In the following, necessity and impact of power-to-gas (PtG) for energy transition in Germany [2-4] will be introduced.
2. Methodology
The need for renewable energy storage options is depending on a variety of aspects such as upcoming extensions
in renewable power plant capacity, national and international grid expansion or demand side integration. Today, there
are no final and reliable answers to tell how exactly the future energy system will look like. For this reason, evidence
at which point of time power-to-gas is needed, only can be given throughout a range of time.
2.1. Assumptions
To determine the role of power-to-gas as energy storage option, a simplified approach is introduced: the German
power supply at 100 % renewable generation in 2050 outgoing from a trend-scenario set up by the environmental
organization Greenpeace e.V. (Table 1). To turn out the effect of power-to-gas on the system, its costs are calculated
once with and once without power-to-gas as a flexibility and storage option while alternative flexibility options are
not considered. At assumed CO2-costs of 100 €/t CO2 [5], coal is not profitable anymore. For this, maximum balancing
costs for fluctuations in power generation (with the use of power-to-gas) become clear as a ‘worst-case-scenario’ [2]
and can be compared to a system whose supply security is assured only by fossil natural gas. In reality, a renewable
power system gets cheaper because of other flexibility options get into market which are at lower price for specific
situations. This is the reason why in an extended analysis of Götz et al. [3], the effect of short-term storage respectively
flexibility options were examined. There, fluctuations below two days get balanced through short-term options, for
cycles above this benchmark, power-to-gas gets into action.
Table 1. Trend-scenario for a 100 % renewable power supply system in Germany on specifications of the environmental organization
Greenpeace e.V. Assumptions made for generation capacity to be installed in GW, gross electricity production in TWh and full load hours (VLH)
of different renewable generation capacities. As a basis of this expansion phase, the real German generation situation in 2013 is taken from AG
Energiebilanzen1) [6] and German Ministry for Economic Affairs and Energy2) [7]. * Including not-appearing other sources e.g. domestic waste
(difference: 5,2 TWh).
Installed Capacity GW
Gross electricity production in TWh
Full load hours
Trend-Scenario
100 %
(2013)
(2013)
Trend-Scenario
100 %
Wind Onshore
131
33,662)
49,81)
2000
Wind Offshore
30
0,522)
4000
Photovoltaics
135
35,92)
28,31)
1000
Hydro power
5,6
5,62)
21,21)
4000
Biomass
8,1
8,12)
42,61)
6000
Geothermal
3
0,0312)
0,042)
6000
Sum renewable energy generation
147,11)*
Shares of renewable energy on gross electricity consumption in Germany
23,4 % 1)
Gross electricity consumption/demand
629 TWh 1)
394 Martin Thema et al. / Energy Procedia 99 ( 2016 ) 392 – 400
The trend scenario (Table 1) particularly passes forward the expansion of wind and photovoltaic generation. For
ecological reasons, biomass and hydropower generation is not and geothermal generation is build up only limited. It
is valid that throughout Germany, grid expansion entirely follows network development plans. Additionally, energy
exchange at cross-border interconnections is permitted for balanced imports and exports in an annual average. Further
substantially assumptions for the simulations are summarized in Table 2.
Table 2. Additional assumptions for the simulation of the German energy system.
Indication
Assumed value
Costs natural gas
30 €/MWh
Costs emission certificates
100 €/tCO2
Efficiency gas-fired power plants and their
emission factor
60 %
0,2 tCO2/MWh thermal energy
Efficiency power-to-gas [10]
2015: 49-54 %
2020: 58-70 %
2030: 68-75 %
2050: 77-84 %
Costs power-to-gas
2015: 1000-4000 €/kW, 0,1-0,6 €/kWh
2023: 800-1300 €/kW, 0,1-0,5 €/kWh
2033: 400-900 €/kW, 0,05-0,4 €/kWh
2050: 250-700 €/kW, 0,05-0,3 €/kWh
Power purchase for power-to-gas plants
0-35 €/MWh
All surpluses get stored in, only differing costs are considered in the comparison of the two systems with and without power-to-gas (for more
information, see Fig. 5).
2.2. Simulation model: Power2Sim
The hourly coverage of power consumption throughout the years and electricity prices were simulated with the
fundamental model Power2Sim by Energy Brainpool. The model falls back to established and, if possible, public and
independent data sources like Eurostat, ENTSO-E or highly respected surveys such as Capros et al. [5]. It consists out
of a number of modules in which different component models are implemented, simulating various components of the
energy market such as electricity demand, particular controllable loads, fossil and renewable power generation or
import- and exportation of electricity. An overview of the different modules of Power2Sim is given in Fig. 1.
Fig. 1. Functional diagram and structure of the different modules of the fundamental model Power2Sim (Energy Brainpool GmbH).
Martin Thema et al. / Energy Procedia 99 ( 2016 ) 392 – 400 395
2.3. Storage capacity
With 88 %, the main part of the German demand for natural gas is imported from which 40 % comes from Russia,
the rest mainly from European countries like Norway and the Netherlands. Supply security in the gas sector is
guaranteed by big underground storage facilities which can theoretically cover the demand for 37 days [8] and
compensate over- and undersupply. Originating from this underground storage capacity, estimations for power-to-gas
storage capacity are based in this survey. The maximal feasible receptivity of the caverns and aquifers is determined
for hydrogen and methane production.
3. Results
3.1. Surplus energy and demand for power-to-gas capacity at rising shares of renewable energy
It was calculated, that energy surpluses of 154 TWh with power peaks up to 134 GW are to be expected until 2050.
This corresponds to about 20 % of the German gross electricity production in 2012. Other studies as well predict
energy surpluses of 80-100 TWh per year and more at high shares of renewable power generation (Fig. 2).
To take up every surplus production peak (Table 2) and transform it into renewable gas, resulting from the
simulations, an installed power-to-gas-capacity of 89-134 GW (Fig. 3) is required until 2050. The worst-case scenario
(high demand for power-to-gas, no alternative flexibility) calculated, sets the upper benchmark [2], the lower one is
set by Götz et al. [3] where at latest in 2035 expansion of power-to-gas capacity in a gigawatt-scale has to occur to
reach the needed level of at least 89 GW in 2050.
Fig. 2. Surplus electricity at increasing shares of fluctuating renewable power generation until 2050 [1, 9-20].
0
20
40
60
80
100
120
140
0
10
20
30
40
50
60
70
80
90
100
2013/15 2020 2025 2030 2035 2040 2045 2050
TWh/a
Percent
Year
Surplus electricity (mean value from literature) in TWh/a
Share of renewable energy (RE) in the trend-scenario in %
Share of RE (simulation results in a system with power-to-gas) in %
Share of RE (simulation results in a system without power-to-gas) in %
Share of RE on power generation (goals of German federal government) in %
Surplus electricity (simulation results) in TWh/a
396 Martin Thema et al. / Energy Procedia 99 ( 2016 ) 392 – 400
3.2. German storage capacity for power-to-gas
Based on the long-term-available storage capacity of about 30,6 billion m³(Vn) [8] for natural gas in German storage
facilities, a storage potential for hydrogen of 612 million m³(Vn) results from volumetric feed-in limits of at maximum
2 Vol.-% hydrogen (H2) in natural gas. This is equal to a stored energy of about 2,2 TWh (Table 3). At a rise of the
feed-in limitation to 10 Vol.-% H2, 3,06 billion m³(Vn) or about 11 TWh of hydrogen could be stored in the German
gas storage infrastructure.
Table 3: Long-term-available power-to-gas storage capacity in German aquifers (pore storage) and caverns (without gas grid). Calculations based
on gross calorific values of hydrogen 3,55 kWh/m³(Vn) and methane 11,0 kWh/m³(Vn) [8].
Storage technology
Storeable volume (long-term)
Containing
Storage capacity for
hydrogen in TWh
Storage capacity for
methane in TWh
Pore storage/aquifers
10,8 bn m³(Vn)
--
119
Caverns
19,8 bn m³(Vn)
70,3
218
Sum
30,6 bn m³(Vn)
337
Gas storage total
2 Vol.-%-hydrogen
612 m m³(Vn)
2,17
Gas storage total
10 Vol.-%-hydrogen
3,06 bn m³(Vn)
10,9
A distinction has to be made between power-to-gas producing either hydrogen or methane: caverns, in general can
be charged with both renewable gases hydrogen and methane. But aquifers, to present knowledge, only can uptake
methane at very low shares of hydrogen.
0
100
200
300
400
500
600
0
50
100
150
200
250
300
2013/15 2020 2025 2030 2035 2040 2045 2050
TWh/a
GW
Year
Range for needed power-to-gas capacity in GW
Installed power-to-gas capacity in GW without short-therm flexibility
Installed power-to-gas capacity in GW incl. 48-h-short-term flexibility
Installed renewable generation capacity in GW
Power generation from renewable energy in TWh/a
Fig. 3. Required power-to-gas capacity for uptaking of renewable surpluses compared to cumulated built up capacity of fluctuating renewable
generation (wind and photovoltaics).
Martin Thema et al. / Energy Procedia 99 ( 2016 ) 392 – 400 397
If renewable hydrogen is further converted into methane, because of the higher volumetric energy density of
methane and more ascertainable storage potential (no feed-in limits), 337 TWh could get stored in.
3.3. Cost development of the power-to-gas-technology
At present, investment costs of power-to-gas are so high, that viable operation only is possible in niches [2, 21].
Investment costs for power-to-gas will basically fall with scale and amount of built up facilities. Upcoming cost
development will mainly base on learning effects, improvement in efficiency and new, cost-cutting progress due to
research and development for market introduction. Based on present investment costs (see Table 2 for cost-
development) of 1000-3000 €/kW for power-to-gas with hydrogen production and 2000-4000 €/kW with methane
production, with a realistic decreasing trend in costs of 13 % per doubling of the installed power-to-gas capacity [22],
investment costs for both technologies will even out at around 500 €/kW (Fig. 4).
3.4. Impact of power-to-gas on energy system costs in Germany
In evidence, the effect of power-to-gas on the German electricity system simulated with Power2Sim in this survey
is cost-cutting in comparison to a system without power-to-gas: Initially, system costs will decrease in both scenarios
(with and without power-to-gas) because of rising renewable generation replacing expensive production from gas fired
power plants. Between 2020 and 2035, expansion of power-to-gas storage infrastructure causes higher costs in relation
to the system without power-to-gas (Fig. 5). From 2035 on, the variant without power-to-gas starts to cost-increase
due to significantly rising expenditures for remunerated curtailment. In addition, residual gaps have to be filled with
costly gas power to guarantee supply security. Meanwhile, in the system with power-to-gas, investment costs get
overcompensated by the use of surpluses. In 2040, annual savings sum up to 2-6 billion € and rise up to 18 billion
in 2050. The considerably lower-priced system with power-to-gas is able to reach full renewable supply in 2050 while
only 86 % are reached without power-to-gas.
Fig. 4. Learning curve. Comparison of cost development for power-to-gas producing hydrogen (H2) and methane (CH4) at decreasing trend in
costs of 13 % per doubling of the installed power-to-gas capacity.
398 Martin Thema et al. / Energy Procedia 99 ( 2016 ) 392 – 400
4. Discussion
4.1. The need for power-to-gas capacity
The large range of power-to-gas demand examined (Fig. 3) is to be understood as guideline. The upper benchmark
stands for the unlikely case that no alternative flexibility options than power-to-gas get carried out. Nonetheless, the
calculations show that even with assumed short-term options and scheduled grid expansion, there is a need for at least
89 GW of power-to-gas until 2050 by only considering the power sector.
Throughout the decarbonization, even if this high power-to-gas capacity is not necessary for the conventional
electricity sector alone, the other energy sectors mobility, chemistry and heat will have considerably a high demand
on renewable gas for which building up power-to-gas capacities seems to be meaningful in any case.
4.2. Storage capacity, allocation and use
Most of the existing gas storages are former crude oil and natural gas reservoirs. Since the commissioning of the
German gas grid in 1955, their working gas volume is steadily increasing until today to one of the biggest in the world.
Most of the more flexible and latter built facilities are, for geological reasons, located in the northern half of the country
in favourable proximity to prior wind sites [23]. There, they can directly collect surpluses at the origin of bottlenecks
and minimize losses.
At determined storage capacities of 2,2-11 TWh for renewable hydrogen and up to 337 TWh for renewable
methane, after reconversion into electricity in a combined-cycle gas turbine power plant with an efficiency of 60 %
results an electricity-to-electricity storage capacity of 1,3-6,6 TWh (hydrogen) and 202 TWh (methane). Thereby, a
complete renewable supply with a backup capacity of 66 GW gas power plants run by the renewable gas could be
Fig. 5. Surplus assimilation cost development for a German power supply system levelling fluctuating renewable feed-in at power purchase for
power-to-gas plants between zero and 35 €/MWh. The figure shows costs for a system once using power-to-gas with, once without additional
short-term flexibility and the other using conventional gas-fired power plants for production balance. The spread between both variants is shown
as well as shares of renewable generation achievable. In the comparison, only differing costs are considered. These are electricity costs for gas
power plants and curtailment of wind and pv generation in the system without power-to-gas. In the system with power-to-gas, costs for invest
and operation of power-to-gas accrue. Prices for alternative short-term flexibility are not included to emphasize the effect of power-to-gas [2, 3].
Martin Thema et al. / Energy Procedia 99 ( 2016 ) 392 – 400 399
guaranteed for a duration of over three months. Present existing pumped hydro storage in Germany only can render
about a tenth of this service for an average of six hours. The gas storage disposes the 33-5.000-fold of the storage
capacity of all German pumped hydro storage.
4.3. Cost development and cost benefits of power-to-gas and its impact on system costs
If costs for storage capacity will fall mainly because of learning effects like explained in Fig. 4 and prices for
emissions certificates, and with it for fossil fuels, will rise as assumed in [24], power-to-gas can exist at procurement
costs for electricity between 4-7 ct/kWh at rising full load hours. With power-to-gas, electricity surpluses which get
lost in the comparative simulation without power-to-gas, can be used to fill the gaps in supply.
As shown in this examinations, power-to-gas will achieve system relevance as storage and flexibility option at
shares of about 70 % renewable power generation in about 2035. From then on, a system with power-to-gas gets more
cost effective as a comparative system using only natural gas as flexibility option and saves several billions of Euros
every year (Fig. 5). If consequently thought to the end, even under adverse conditions, power-to-gas effects cost-
cutting on a supply system with high shares of renewable energy generation.
If necessary grid expansion ought to be retarded, massive bottlenecks and surpluses are predicted already from
2020 onwards. In this case and at constant building up of renewable generation capacity, energy storage capacity is
needed on an earlier occasion.
For optional implemented methanation, CO2-sources are adequate. Especially if the CO2 is taken from the
atmosphere, it is not relevant for the climate footprint of power-to-gas technology. As for every other flexibility option
in energy transition, it is important for power-to-gas to take stored-in electricity only from renewable generation.
Benndorf et al. [25] assume fuels made from power-to-gas with an energy content of 360 TWh/a in 2050 only for
the mobility sector. Moreover it is postulated that the chemical industry needs to substitute feedstocks with an energy
equivalent of about 293 TWh/a. This indicates, that a decarbonization beyond the electricity sector without renewable
gas as raw material for present mineral oil and chemical industry is barely not possible. Electricity as high-quality
primary energy is today still often regarded separated from the other energy sectors. But as an intersectoral connecting
element, power-to-gas will play a key-role in energy transition not only in Germany.
5. Conclusion
To sum up, power-to-gas on the long run effects cost-efficient on energy transition in the electricity system. It
allows higher shares of renewable electricity generation in the power system and is the only present storage option
with significant large long-term capacities. At least, power-to-gas and its derivates power-to-liquid and power-to-
chemicals enable a comprehensive decarbonization of mobility and chemistry sectors as well.
There is a dilemma which needs to be resolved: from an economical point of view, power-to-gas is a prospective
required technology which is not worthwhile to operate today mainly because of an unsuitable framework. To reach
the technically required power-to-gas capacity at the right point of time, we have to start building up the necessary
infrastructure now.
Acknowledgements
Hereby, we express our appreciation to all colleagues involved during the process leading to this paper: Fabian
Eckert from FENES in Regensburg, Fabian Huneke and Carlos Linkenheil from Energy Brainpool in Berlin and last
but not least to Marcel Keiffenheim and Michael Friedrich from Greenpeace Energy who initiated the work done on
this topic.
400 Martin Thema et al. / Energy Procedia 99 ( 2016 ) 392 – 400
References
[1] Klaus T, Vollmer C, Werner K et al. Energieziel 2050: 100 % Strom aus erneuerbaren Quellen. Dessau-Roßlau; 2010.
[2] Thema M, Sterner M, Eckert F et al. Bedeutung und Notwendigkeit von Windgas für die Energiewende in Deutschland.
Hamburg, Regensburg, Berlin; 2015.
[3] Götz P, Huneke F, Lenck T et al. Minimaler Bedarf an langfristiger Flexibilität im Stromsystem bis 2050:
Studienerweiterung. Hamburg, Berlin; 2016.
[4] Sterner M. Bioenergy and renewable power methane in integrated 100 % renewable energy systems Limiting global
warming by transforming energy systems. Thesis, Kassel University; 2009.
[5] Capros P, De Vita A, Tasios N et al. Trends to 2050: Reference Scenario 2013. EU Energy, Transport and GHG Emissions.
Bruxelles; 2013.
[6] Arbeitsgemeinschaft Energiebilanzen e.V. Auswertungstabellen zur Energiebilanz Deutschland: 1990 bis 2013; 2014.
[7] Arbeitsgruppe Erneuerbare Energien-Statistik (AGEE-Stat). Erneuerbare Energien im Jahr 2013: Erste vorläufige Daten
zur Entwicklung der erneuerbaren Energien in Deutschland, Berlin; 2014.
[8] Sedlacek R. Underground Gas Storage in Germany. Erdgasspeicherung. Erdöl Erdgas Kohle 129(11); 2013. p. 378-388.
[9] Sterner M, Stadler I. Energiespeicher: Bedarf, Technologien, Integration. Springer Vieweg, Heidelberg, Dordrecht, London,
New York; 2014.
[10] Bauknecht D, Koch T, Tröster E et al. Systematischer Vergleich von Flexibilitäts- und Speicheroptionen im deutschen
Energiesystem zur Integration der erneuerbaren Energien und Analyse entsprechender Rahmenbedingungen. Berlin; 2013
[11] Breuer C, Drees T, Echternacht D et al. Identification of Potentials and Locations for Power-to-Gas in Germany. 6th
International Renewable Energy Storage Conference. Eurosolar. Berlin; 2011.
[12] Breuer C et al. Standorte und Potenziale für Power-to-Gas. e/m/w Zeitschrift für Energie, Markt, Wettbewerb 2012(4);
2012.
[13] Gerhard N, Sandau F, Zimmermann B et al. Geschäftsmodell Energiewende: Eine Antwort auf das „Die Kosten-der-
Energiewende“-Argument. Kassel; 2014.
[14] Henning H, Palzer A. A comprehensive model for the German electricity and heat sector in a future energy system with a
dominant contribution from renewable energy technologies Part I Methodology. In: Renewable and Sustainable Energy
Reviews; 2014. p. 1003-1018.
[15] Nitsch J, Pregger T, Naegler T et al. Leitstudie 2011: Langfristszenarien und Strategien für den Ausbau der erneuerbaren
Energien in Deutschland bei Berücksichtigung der Entwicklung in Europa und global. Berlin; 2012.
[16] Palzer A, Henning H. A Future German Energy System with a Dominating Contribution from Renewable Energies: A
Holistic Model Based on Hourly Simulation. Energy Technology 2(1); 2014. p. 13-28.
[17] Schill W. Stromspeicher als zentrales Element der Integration von Strom aus erneuerbaren Energien (StoRES Storage for
Renewable Energy Sources). In: DIW Wochenbericht 34. Berlin; 2013.
[18] Schlesinger M, Lindenberger D, Lutz C. Energieszenarien für ein Energiekonzept der Bundesregierung. Projekt Nr. 12/10.
Basel, Köln, Osnabrück, Berlin; 2010.
[19] Stolzenburg K. Large Wind-Hydrogen Plants in Germany: The Potential for Success. Results from the study „Integration
von Wind-Wasserstoffsystemen in das Energiesystem“. Berlin; 2013.
[20] Adamek F, Aundrup T, Glaunsinger W et al. Energiespeicher für die Energiewende: Speicherungsbedarf und Auswirkungen
auf das Übertragungsnetz für Szenarien bis 2050. Frankfurt am Main; 2012.
[21] Sterner M, Jentsch M, Holzhammer U. Energiewirtschaftliche und ökologische Bewertung eines Windgas-Angebotes:
Gutachten. Hamburg, Kassel; 2011.
[22] Wirth H Aktuelle Fakten zur Photovoltaik in Deutschland. Fraunhofer-Institut für Solare Energiesysteme (ISE). Freiburg;
2014.
[23] Jentsch M. Potenziale von Power-to-Gas Energiespeichern: Modellbasierte Analyse des markt- und netzseitigen Einsatzes
im zukünftigen Stromversorgungssystem. Thesis, Universität Kassel; 2014.
[24] Sterner M, Thema M, Eckert F et al. Stromspeicher in der Energiewende: Untersuchung zum Bedarf an neuen Stromspeichern
in Deutschland für den Erzeugungsausgleich, Systemdienstleistungen und im Verteilnetz. Studie, Berlin; 2014.
[25] Benndorf R, Bernicke M, Bertram A et al. Treibhausgasneutrales Deutschland im Jahr 2050. THGND 2050. Dessau-Roßlau;
2014.
... In this study, the efficiency of the transformation to synthetic natural gas was in the range provided in Figure 5. These data have been obtained from [25] and extended from 2030 up to 2055. The economic impact of the implementation of the PtG infrastructure to manage such energy surplus is provided in the next sections. ...
... In this study, the efficiency of the transformation to synthetic natural gas was in the range provided in Figure 5. These data have been obtained from [25] and extended from 2030 up to 2055. ...
... The economic impact of the implementation of the PtG infrastructure to manage such energy surplus is provided in the next sections. A similar analysis has been reported by [24,25] in Germany. PtG infrastructure is under development, and the costs may be estimated according to classical learning curves to account for the maturity and cost of different electrolysis technologies and methanation facilities versus installed capacity [26]. ...
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... In sectors like shipping, road transport, and iron/steel, it is expected to have share rates between 20 % and 25 %. In the chemical industry, the share of hydrogen is predicted as approximately 40 % by 2050 [47]. ...
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Hydrogen fuel cells (HFCs), which have shown significant technological developments in recent years, are promising alternative energy sources with high electrical efficiency and zero-emission in the coming years. Currently, these alternative sources are employed as energy units in many areas. The existing studies show that HFCs are structurally and operationally more efficient, durable, and usable year after year. However, a detailed study is needed showing the forthcoming structures, future socio-economic impacts, and production/cost prospects for the future vision of HFCs. To this end, this work aims to contribute a considerable view on the future vision of utilization and prediction in the HFC field. In this context, the forthcoming HFC structures basis fuel types and the future of hydrogen production are first presented. Further, the future applications of HFCs are detailed for potential areas like stationary, portable, transportation, and space applications. Subsequently, the expected socio-economic impacts like new job opportunities, environmental improvement, and health issues are detailed and explained for the following years. Implementation trends in several sectors like transportation, heating, industry heat, industry feedstock, and power generation are clarified for the 2050 vision. Finally, the production/cost forecasting values are demonstrated for the future vision of HFC technologies.
... Methane is studied as an energy vector in the context of Power-to-Gas (PtG) concepts, transitional technologies where CO 2 from anthropogenic sources can be utilized to reduce greenhouse effect emissions, and the produced methane can be exploited by employing the currently existing natural gas infrastructure [15,16]. Given the highly exothermic nature of the reaction, one of the main challenges regarding catalytic CO 2 methanation is the management of the generated reaction heat, which can easily lead to important hot-spots and thermal runaway of the reactor. ...
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Fibrous catalysts have shown to enhance mass and heat transfer for fast and exothermic reactions. However, these catalysts can be limited by the pressure drop and achievable productivity, due to the flow rates that can be processed and the catalyst content in the reactor. This paper studies the effect of the geometry of fibrous catalysts on reactor performance by applying them to the reaction of CO2 methanation. A fixed-bed reactor model was used to simulate and study variations in fiber diameter and catalyst coating thickness, and their influence on pressure drop, productivity and reactor efficiency. A comparison basis to traditional pellet catalysts with different reactor configurations is established. Fibrous catalysts show superior reaction heat removal and temperature management, higher catalyst utilization, and smaller catalyst fractions to achieve the intended conversions. Smaller, more compact reactors can be designed thanks to their higher global efficiency. The results show the advantages and versatility of structured ceramic fibrous catalysts, as alternatives for process intensification, and to improve overall reactor performance.
... In a literature research for electrolysis, different learning rates between 8 % [16] and 18±13 % [17] were identified. For CM only one publication with same learning rates (13 %) for methanation and electrolysis was found [18]. A trend was observed that highest values are given in publications of the distant past of the last century, when the technologies were less mature. ...
Conference Paper
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Power-to-Gas technologies enable the integration of non-dispatchable renewable energy sources into several sectors and help decarbonize and transform them. This study investigates to which extent an increase in Power-toGas technology applications affects their prospective environmental and economic performance. A first combined prospective LCA and LCC for different Power-toGas technologies based on the learning curve concept is presented. For the considered case study of future electrolysis and methanation, the applicability of the concept is demonstrated and prospective LCA and LCC results are obtained. Under assumed conditions, highest decreases in environmental impacts and costs occur between the years 2025 and 2030. Polymer electrolyte membrane electrolysis shows prospective advantages over alkaline water electrolysis. All results indicate that an extension of Power-toGas deployment and accompanying learning effects until the year 2050 can lead to significant reductions of more than 70 % in terms of environmental impacts and life cycle costs.
... Ultimately, in a market-based economy, this means adjustment to price signals and economic optimization thereof. Further, the shift to RE creates the need for long term energy storage (Jentsch et al., 2014;Thema et al., 2016). Powerto-Gas (PtG), meaning here the production of Synthetic Natural Gas (SNG) by catalytic methanation of hydrogen and carbon dioxide, is a technology which is currently tested at pilot and demonstration scale for energy storage systems. ...
Article
Hydrogen generated by power input from renewable energies can be produced in volatile patterns. Thus, methanation plants as part of Power-to-Gas processes using hydrogen as input stream are subject to high flexibility requirements. Flexibility of methanation plants is a growing topic, however, often limited to theoretical considerations and single reactors. Thus, in this study, we investigate the operating window of a lab-scale plant by means of experiment and simulation. Using experimental data of a two-stage plant, a plant model with detailed 1D reactor models is validated and the process is simulated. Comprehensive investigations are performed regarding operating parameters, such as plant load or coolant temperature. The operating window of the plant is investigated with focus on capacity and feedstock flexibility. A CFD simulation of the cooled fixed-bed reactor reveals insight in flow distribution and heat transfer. Results show a large operating window and thus a high flexibility of the plant.
... Green hydrogen is then stored and distributed for a wide range of end uses (hydrogen to power). Different cost-benefit studies have concluded that green hydrogen will be a feasible and competitive energy carrier in the coming years, optimising the use of natural resources [4][5][6]. ...
Article
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Considering a simple regenerative Brayton cycle, the impact of using different fuel blends containing a variable volumetric percentage of hydrogen in methane was analysed. Due to the potential of hydrogen combustion in gas turbines to reduce the overall CO2 emissions and the dependency on natural gas, further research is needed to understand the impact on the overall thermodynamic cycle. For that purpose, a qualitative thermodynamic analysis was carried out to assess the exergetic and energetic efficiencies of the cycle as well as the irreversibilities associated to a subsystem. A single step reaction was considered in the hypothesis of complete combustion of a generic H2/CH4 mixture, where the volumetric H2 percentage was represented by fH2, which was varied from 0 to 1, defining the amount of hydrogen in the fuel mixture. Energy and entropy balances were solved through the Engineering Equation Solver (EES) code. Results showed that global exergetic and energetic efficiencies increased by 5% and 2%, respectively, varying fH2 from 0 to 1. Higher hydrogen percentages resulted in lower exergy destruction in the chamber despite the higher air-excess levels. It was also observed that higher values of fH2 led to lower fuel mass flow rates in the chamber, showing that hydrogen can still be competitive even though its cost per unit mass is twice that of natural gas.
Article
Large-scale energy storage plants based on power-to-gas-to-power (PtG-GtP) technologies incorporating high temperature electrolysis, catalytic methanation for the provision of synthetic natural gas (SNG) and novel, highly efficient SNG-fired Allam reconversion...
Article
Trickle bed reactors are one of the world’s most employed technologies for multiphase processing, and they have been scrutinized for decades. However, accurate prediction and scale-up of trickle bed reactors are still challenging owing to complex interactions of multiphase flow, interfacial mass transfer, and reaction kinetics. The present computational model provides an insight into process phenomena on the basis of Eulerian–Eulerian methodology. It captures all parts of a trickle bed reactor─packing, head, and sump─which enables simulation of co- and countercurrent flow, gas or liquid recycle, and arbitrary retention time. Applying this model, hydrodynamic simulations reveal an improved prediction of liquid holdup, liquid dispersion, and pressure drop compared to CFD models of only the trickle bed. Furthermore, the interfacial surface area is analyzed and validated on account of a literature correlation. Exemplifying the entire approach with chemical absorption and reaction, the simulation of biological methanation presents methane concentration and productivity which are of the same order of magnitude as experimental data for an operating pressure of p_op = 0.1–1 MPa_abs.
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Due to the increasing share of renewable energy sources in the electrical network, the focus on decarbonization has extended into other energy sectors. The gas sector is of special interest because it can offer seasonal storage capacity and additional flexibility to the electricity sector. In this paper, we present a new simulation method designed for hydrogen-enriched natural gas network simulation. It can handle different gas compositions and is thus able to accurately analyze the impact of hydrogen injections into natural gas pipelines. After describing the newly defined simulation method, we demonstrate how the simulation tool can be used to analyze a hydrogen-enriched gas pipeline network. An exemplary co-simulation of coupled power and gas networks shows that hydrogen injections are severely constrained by the gas pipeline network, highlighting the importance and necessity of considering different gas compositions in the simulation.
Technical Report
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In dieser Studie wurde die notwendige Speicherkapazität von Kurz- und Langzeitspeichern zur Integration erneuerbarer Energien betrachtet. Untersucht wurde auch der Einfluss der Energiespeicher auf den notwendigen Ausbau des Übertragungsnetzes und der Speicherstandorte. Eine ausführliche Beschreibung der unterschiedlichen Speichertechnologien ist bereits in einer VDE-Studie aus 2009 enthalten. Eine Kurzfassung ist hier öffentlich verfügbar (public), die vollständige Studie nur auf Anfrage (privat).
Research
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Bitte zitieren als Sterner, M.; Thema, M.; Eckert, F.; Lenck, T.; Götz, P. (2015): Bedeutung und Notwendigkeit von Windgas für die Energiewende in Deutschland, Forschungsstelle Energienetze und Energiespeicher (FENES) OTH Regensburg, Energy Brainpool, Studie im Auftrag von Greenpeace Energy, Regensburg/Hamburg/Berlin. 1508/OE1
Research
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Wie groß ist der Speicherbedarf in Deutschland in der weiteren Umsetzung der Energiewende? Welche Rolle spielen Batteriespeicher, Pumpspeicher, Power-to-Gas etc. im Kontext anderer Flexibilitätsoptionen auf den verschiedenen Netzebenen? Wie entwickelt sich der Markt für Batterien und Wasserstoff? In unserer Agora-Speicherstudie haben wir auch erstmalig den Begriff Power-to-X definiert und damit die bis dato entstandenen Begriffe Power-to-Gas, Power-to-Liquids, Power-to-Products, Power-to-Chemicals etc. zusammengefasst.
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Als Schlussbericht des BMU-Vorhabens "Langfristszenarien und Strategien für den Ausbau der Erneuerbaren Energien in Deutschland bei Berücksichtigung der Entwicklung in Eu-ropa und global" wurde die neueste und umfassendste Sze-narienanalyse unter Koordination von DLR-STB mit For-schungspartnern veröffentlicht. Die Studie steht in einer Reihe mit den von DLR-STB in den letzten Jahren durchgeführten BMU-Leitstudien. Mit fünf detaillierten Szenarien wird gezeigt, dass der zügige weitere Ausbau der erneuerbaren Energien (EE) bis zum Jahr 2050 über 80 Prozent des in Deutschland verbrauchten Stroms und über 50 Prozent der Wärmeversorgung und der Primärenergie decken kann. Der zweite Pfeiler für das Erreichen dieser Ziele ist die stärkere Realisierung von Effizienzpotenzialen in allen Bereichen der Sektoren Strom, Wärme und Verkehr. Hierzu müssen wesentlich konsequenter als bislang entsprechende politische Maßnahmen auf den Weg gebracht werden. In der Studie wird gezeigt, dass eine grundlegende Voraussetzung für beide Strategien (EE und Effizienz) eine Ausweitung des Stromeinsatzes darstellt, einerseits zur Wärmeversorgung (Wärmepumpen, Prozesswärme Industrie u. a.) und andererseits im Verkehr (Elektromobilität). Wo Strom nicht direkt eingesetzt werden kann, ermöglicht eine chemische Speicherung in Form von Wasserstoff oder synthetischem Methan weitere Einsatzbereiche für die „Primärenergie“ erneuerbarer Strom. Durch zeitlich aufgelöste Untersuchungen der Stromversorgung in Deutschland einschließlich des europäischen Stromverbunds konnte in Kooperation mit dem Fraunhofer IWES gezeigt werden, dass auch bei über 80 Prozent Erneuerbaren der Strombedarf in jeder Stunde eines Jahres gedeckt werden kann. Ökonomische Analysen der Szenarien zeigen, dass die positiven volkswirtschaftlichen Wirkungen des Ausbaus der erneuerbaren Energien ab dem Jahr 2025 zum Tragen kommen. Die Bereitstellung von Energie aus erneuerbaren Quellen hat zu diesem Zeitpunkt etwa den gleichen Preis, wie der Einsatz, von Steinkohle, Öl und Erdgas. Kurz nach 2035 kann bereits so viel an teurer werdenden fossilen Energieträgern eingespart sein, dass sämtliche Vorleistungen für die Investitionen getilgt wurden. Zur Jahrhundertmitte hat in den Szenarien die Versorgung mit erneuerbaren Energien der Volkswirtschaft dann bereits rund 570 Milliarden Euro gegenüber der Weiterführung einer fossilen Energieversorgung eingespart.
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Im Kontext der Energiewende sind Energiespeicher ein zentrales technisches, wirtschaftliches und energiepolitisches Thema.Die Autoren dieses kompakten Werkes geben einen umfassenden Uberblick Uber die verschiedenen Aspekte der Energiespeicherung. Sie beschreiben zunachst die Bedeutung von Energiespeichern in der Energieversorgung und definieren ihre Rolle darin. Dann gehen sie auf den Speicherbedarf in der Strom-, Warme- und Kraftstoffversorgung im Kontext der Energiewende ein. Im Hauptteil werden die verschiedenen Speichertechnologien ausfUhrlich vorgestellt sowie ihre Vor- und Nachteile diskutiert. Praktische Anwendungsbeispiele und die Integration von Speichern Uber alle Energiesektoren hinweg runden das Buch ab. Zahlreiche Grafiken und Beispiele veranschaulichen das gesamte Feld der Energiespeicher und sind als Erganzung samt Animationen online in Farbe verfUgbar.Die ZielgruppenDas Lehr- und Fachbuch wendet sich an Ingenieure, Wissenschaftler, Energieplaner und Energiewirtschaftler in Forschung und Industrie sowie an Studierende an Hochschulen und Universitaten in den Bereichen Maschinenbau, Verfahrenstechnik, Elektrotechnik und Energietechnik.Die AutorenProf. Dr.-Ing. Michael Sterner erforscht und lehrt an der Technischen Hochschule Regensburg in der Fakultat Elektro- und Informationstechnik die Bereiche Energiespeicher, Energiewirtschaft und Integration erneuerbarer Energien. Zuvor war er am Fraunhofer IWES in leitender Funktion verantwortlich fUr die Bereiche Systemanalyse und Energiewirtschaft und hat mit Kollegen die Speichertechnologie Power-to-Gas entwickelt. Der Ingenieur arbeitet ehrenamtlich in der Energietechnischen Gesellschaft des VDE, dem bayerischen Wirtschaftsministerium und dem Weltklimarat (IPCC), leitet Speicherkonferenzen von VDI und OTTI, ist beratend fUr die Bundesregierung tatig und im wissenschaftlichen Beirat der International Renewable Energy Storage Conference der Eurosolar sowie der Energy Storage Düsseldorf. Prof. Dr.-Ing. habil. Ingo Stadler forscht und lehrt an der Fachhochschule Köln und ist dort für die Erneuerbaren Energien und Energiewirtschaft verantwortlich. Er habilitierte an der Universität Kassel. Seine Arbeiten umfassen die Netzintegration Erneuerbarer Energien und Energiesysteme mit hohen Anteilen an Erneuerbaren Energien und konzentriert sich auf die über die Elektrizität hinausgehenden, nichtelektrischen Speicher und das Lastmanagement. Er ist Mitglied des Beirats der International Renewable Energy Storage Conference sowie des International Centre for Sustainable Development of Energy, Water and Environment Systems. Über ein Jahrzehnt arbeitete er im Photovoltaik-Programm der Internationalen Energieagentur IEA.
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A survey covers the status of 39 underground gas storage facilities in operation and 17 planned projects for underground gas storage in Germany. New developments are also reported. The survey also includes data and locations for subsurface storage of liquid hydrocarbons. Because of the upgrading of existing and start of new storage facilities, the working gas volume in Germany has increased to 18.3 billion cu m. In the near future, some 23 billion cu m are expected when all of the presently planned projects will have been carried out. Based on the European Standard EN 1918 from the year 1998 new projects are designed according to this standard. EN 1918 is used by the Geological Survey of Lower Saxony relative to the subsurface geological safety of storage facilities in porous rock storage. A map of Germany shows the location of porous rock and cavity underground storages in operation and planned or under construction. The data are also tabulated. The survey includes topics such as the increasing use of the natural gas fraction of primary energy use; and future developments.
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A clear consensus exists in German society that renewable energy resources have to play a dominant role in the future German energy supply system. However, many questions are still under discussion; for instance the relevance of the different technologies such as photovoltaic systems and wind energy converters installed offshore in the North Sea and the Baltic Sea. Concerns also exist about the cost of a future energy system mainly based on renewable energy. In the work presented here we tried to answer some of those questions. Guiding questions for this study were: (1) is it possible to meet the German energy demand with 100% renewable energy, considering the available technical potential of the main renewable energy resources? (2) what is the overall annual cost of such an energy system once it has been implemented? (3) what is the best combination of renewable energy converters, storage units, energy converters and energy-saving measures? In order to answer these questions, we carried out many simulation calculations using REMod-D, a model we developed for this purpose. This model is described in Part I of this publication. To date this model covers only part of the energy system, namely the electricity and heat sectors, which correspond to about 62% of Germany's current energy demand. The main findings of our work indicate that it is possible to meet the total electricity and heat demand (space heating, hot water) of the entire building sector with 100% renewable energy within the given technical limits. This is based on the assumption that the heat demand of the building sector is significantly reduced by at least 60% or more compared to today's demand. Another major result of our analysis shows that - once the transformation of the energy system has been completed - supplying electricity and heat only from renewables is no more expensive than the existing energy supply.
Article
A clear consensus exists in German society that it is necessary to achieve ambitious greenhouse-gas emission reduction targets and that renewable energies have to play a dominant role in the future German energy-supply system. However, many questions are still under discussion, for instance about the relevance of the different technologies such as photovoltaic systems or wind energy converters installed offshore in the North Sea and the Baltic Sea. Concerns are often expressed regarding the cost of a future energy system mainly based on renewable energies. To be able to address the raised issues on a scientifically sound basis we have set up a new simulation model REMod-D (Renewable Energy Model–Deutschland) that models a possible future German energy system for all sectors, including all renewable energy converters, storage components, secondary energy converters, and loads for an entire year based upon an hourly simulation. Moreover, the model includes retrofitting of buildings for energy efficiency as a measure to reduce the future heat loads of the building sector. A generic optimizer is applied to identify system compositions with minimal overall annual cost. After a short introduction about the modeling approach, the results of parameter studies are presented.