Content uploaded by Martin Robinius
Author content
All content in this area was uploaded by Martin Robinius on Aug 12, 2020
Content may be subject to copyright.
A preview of the PDF is not available
WEGE FÜR DIE ENERGIEWENDE Kosteneffiziente und klimagerechte Transformationsstrategien für das deutsche Energiesystem bis zum Jahr 2050
Abstract
Deutschland hat sich zum Ziel gesetzt, die Treibhausgasemissionen bis zum Jahr 2050 um 80 bis 95 % gegenüber dem Emissionsniveau von 1990 zu reduzieren. Die hierfür festgelegten Treibhausgasreduktionspfade werden durch eine Vielzahl von weiteren zum Teil sehr detaillierten Zielsetzungen (z. B. Anteil erneuerbarer Energien an der Stromerzeugung) flankiert, die von der Bundesregierung als notwendig gesehen werden, um die übergeordneten Treibhausgasreduktionsziele zu erreichen. Dieser Zielekanon wurde im Laufe der letzten Dekade sukzessive entwickelt und erweitert. Viele vorliegende Studien, in denen Transformationspfade vorgeschlagen werden, integrieren diesen Zielkanon durch exogene Annahmen und schränken damit das Technikportfolio ein. Dies widerspricht einem Lösungsansatz, der sich vor allem durch Technologieoffenheit auszeichnen sollte. Die Frage, ob es sich bei den vorgeschlagenen Transformationspfaden um kostenoptimale Strategien handelt, bleibt in aller Regel unbeantwortet.
Ziel der vorliegenden Studie ist es daher, die kosteneffizientesten CO2 Minderungsstrategien zur Erreichung der Klimaschutzziele Deutschlands bis zum Jahr 2050 zu identifizieren. Hierzu werden zwei CO2-Reduktionsszenarien analysiert, die sich ausschließlich an den Minderungszielen für das Jahr 2050 von -80 % (Szenario 80) und -95 % (Szenario 95) orientieren. Für die Analyse wird eine neuartige Modellfamilie eingesetzt, die am Forschungszentrum Jülich entwickelt wurde. Diese ermöglicht es, die nationale Energieversorgung in all ihren Wechselwirkungen und Pfaden abzubilden. Unter der Randbedingung der Einhaltung der Reduktionsziele lassen sich die kosteneffizientesten Maßnahmen bzw. Treibhausgasminderungsstrategien ermitteln. Die Kombination der verschiedenen eingesetzten Modelle, die sich durch unterschiedliche methodische Vorgehensweisen auszeichnen, erlaubt eine fundierte und tiefgehende Analyse von Treibhausgasminderungsstrategien. Die hohe zeitliche und räumliche Auflösung ermöglicht Aussagen zur Konzeption von zukünftigen Energieinfrastrukturen (Strom, Erdgas und Wasserstoff) sowie detaillierte Regionalanalysen eines möglichen Windkraft- sowie PV-Ausbaus. Darüber hinaus können zukünftige globale Energiemärkte (z. B. synthetische Kraftstoffe, synthetisches Methan, Wasserstoff) simuliert und mögliche Energieimporte und -exporte im Kontext der Energiewende abgeschätzt werden.
Hydrogen is seen as a promising energy carrier due to its multifarious fields of possible application within climate change mitigation. Particularly, hard-to-abate sectors like aviation, shipping, steel production, and back up electricity supply can be promising applications for this energy carrier in its elementary form or as a derivative. In this context, different hydrogen supply chains are introduced, analyzed and discussed. While compressed gaseous hydrogen supply via pipeline networks offer cost advantages for shorter distances, seaborne transportation of liquid hydrogen can be a viable option for longer-distance transportation, leveraging regions with abundant renewable sources of energy. Material-based carriers like ammonia, methanol, and to some extend LOHCs are considered short-term solutions due to their established infrastructure, although they pose higher energy demands and costs for hydrogen release at the consumption site.
The ORKG has opened a new era in the way scholarly knowledge is curated, managed, and disseminated. By transforming vast arrays of unstructured narrative text
into structured, machine-processable knowledge, the ORKG has emerged as an
essential service with sophisticated functionalities. Over the past five years, our
team has developed the ORKG into a vibrant platform that enhances the accessibility and visibility of scientific research. This book serves as a non-technical guide
and a comprehensive reference for new and existing users that outlines the
ORKG's approach, technologies, and its role in revolutionizing scholarly communication. By elucidating how the ORKG facilitates the collection, enhancement, and
sharing of knowledge, we invite readers to appreciate the value and potential of
this groundbreaking digital tool presented in a tangible form.
Prior research suggests that energy demand-side interventions have a large potential in climate change mitigation, connected to co-benefits in human well-being and several Sustainable Development Goals. However, it is challenging to translate such strategies into local and sectoral realities. We explore sufficiency futures for German passenger transport, a sector that is assumed to further grow in most studies, to analyse demand reduction potentials. In an interdisciplinary research design, we collect 133 diverse drivers of change of which we construct three sufficiency storylines. We translate them into parameters of the aggregated transport model quetzal\_germany and quantify it through an expert survey. Results indicate that passenger transport energy demand can be lowered by up to 73~\%, while pointing at the various cultural, political, economic, technological, and organisational developments that are responsible for this change and show co-benefits for well-being. The comparison to global low energy demand studies suggests that our results lie between two boundaries: the absolute minimum for decent living standards and the most ambitious illustrative modelling pathway in the IPCC Sixth Assessment Report. This work bridges the gap between ambitious climate targets from a global perspective and corresponding system design requirements in the local context.
The role of hydrogen in a future energy system with a high share of variable renewable energy sources (VRES) is regarded as crucial in order to balance fluctuations in electricity generation. These fluctuations can be compensated for by flexibility measures such as the expansion of transmission, flexible generation, larger back-up capacity and storage. Salt cavern storage is the most promising technology due to its large storage capacity, followed by pumped hydro storage. For the underground storage of chemical energy carriers such as hydrogen, salt caverns offer the most promising option owing to their low investment cost, high sealing potential and low cushion gas requirement. This paper provides a suitability assessment of European subsurface salt structures in terms of size, land eligibility and storage capacity. Two distinct cavern volumes of 500,000 m³ and 750,000 m³ are considered, with preference being given for salt caverns over bedded salt deposits and salt domes. The storage capacities of individual caverns are estimated on the basis of thermodynamic considerations based on site-specific data. The results are analyzed using three different scenarios: onshore and offshore salt caverns, only onshore salt caverns and only onshore caverns within 50 km of the shore. The overall technical storage potential across Europe is estimated at 84.8 PWhH2, 27% of which constitutes only onshore locations. Furthermore, this capacity decreases to 7.3 PWhH2 with a limitation of 50 km distance from shore. In all cases, Germany has the highest technical storage potential, with a value of 9.4 PWhH2, located onshore only in salt domes in the north of the country. Moreover, Norway has 7.5 PWhH2 of storage potential for offshore caverns, which are all located in the subsurface of the North Sea Basin.
The technological lock-in of the transportation and industrial sector can be largely attributed to the limited availability of alternative fuel infrastructures. Herein, a countrywide supply chain analysis of Germany, spanning until 2050, is applied to investigate promising infrastructure development pathways and associated hydrogen distribution costs for each analyzed hydrogen market. Analyzed supply chain pathways include seasonal storage to balance fluctuating renewable power generation with necessary purification, as well as trailer- and pipeline-based hydrogen delivery. The analysis encompasses green hydrogen feedstock in the chemical industry and fuel cell-based mobility applications, such as local buses, non-electrified regional trains, material handling vehicles, and trucks, as well as passenger cars. Our results indicate that the utilization of low-cost, long-term storage and improved refueling station utilization have the highest impact during the market introduction phase. We find that public transport and captive fleets offer a cost-efficient countrywide renewable hydrogen supply roll-out option. Furthermore, we show that, at comparable effective carbon tax resulting from the current energy tax rates in Germany, hydrogen is cost-competitive in the transportation sector by the year 2025. Moreover, we show that sector-specific CO2 taxes are required to provide a cost-competitive green hydrogen supply in both the transportation and industrial sectors.
Designing the future energy supply in accordance with ambitious climate change mitigation goals is a challenging issue. Common tools for planning and calculating future investments in renewable and sustainable technologies are often linear energy system models based on cost optimization. However, input data and the underlying assumptions of future developments are subject to uncertainties that negatively affect the robustness of results. This paper introduces a quadratic programming approach to modifying linear, bottom-up energy system optimization models to take cost uncertainties into account. This is accomplished by implementing specific investment costs as a function of the installed capacity of each technology. In contrast to established approaches such as stochastic programming or Monte Carlo simulation, the computation time of the quadratic programming approach is only slightly higher than that of linear programming. The model’s outcomes were found to show a wider range as well as a more robust allocation of the considered technologies than the linear model equivalent.
The share of global CO2 emissions deriving from the cement industry is about 5%. More than 50% of these are process-related and cannot be avoided. This paper addresses the application of CO2 capture technology to the cement industry. Analyses focusing on post-combustion technology for cement plants are carried out on the basis of detailed model calculations. Different heat supply variants for the regeneration of loaded wash solution were investigated. CO2 avoidance costs are in a range of 77 to 115 EUR/tCO2. The achievable CO2 avoidance rate for the investigated cases was determined to be 70% to 90%. CO2 reduction potentials were identified using CCS technology, focusing on the German cement industry as a case study. The results show that adopting carbon capture technology could lead to a significant reduction in CO2 emissions.
Renewable energy sources will play a central role in the sustainable energy systems of the future. Scenario analyses of such hypothesized energy systems require sound knowledge of the techno-economic potential of renewable energy technologies. Although there have been various studies concerning the potential of offshore wind energy, higher spatial resolution, as well as the future design concepts of offshore wind turbines, has not yet been addressed in sufficient detail. Here, we aim to overcome this gap by applying a high spatial resolution to the three main aspects of offshore wind potential analysis, namely ocean suitability, the simulation of wind turbines and cost estimation. A set of constraints is determined that reveal the available areas for turbine placement across Europe’s maritime boundaries. Then, turbine designs specific to each location are selected by identifying turbines with the cheapest levelized cost of electricity (LCOE), restricted to capacities, hub heights and rotor diameters of between 3-20 MW, 80-200 m and 80-280 m, respectively. Ocean eligibility and turbine design are then combined to distribute turbines across the available areas. Finally, LCOE trends are calculated from the individual turbine costs, as well as the corresponding capacity factor obtained by hourly simulation with wind speeds from 1980 to 2017. The results of cost-optimal turbine design reveal that the overall potential for offshore wind energy across Europe will constitute nearly 8.6 TW and 40.0 PWh at roughly 7 €ct kWh-1 average LCOE by 2050. Averaged design parameters at national level are provided in an appendix.
The uncertain role of the natural gas infrastructure in the decarbonized energy system and the limitations of hydrogen blending raise the question of whether natural gas pipelines can be economically utilized for the transport of hydrogen. To investigate this question, this study derives cost functions for the selected pipeline reassignment methods. By applying geospatial hydrogen supply chain modeling, the technical and economic potential of natural gas pipeline reassignment during a hydrogen market introduction is assessed.
The results of this study show a technically viable potential of more than 80% of the analyzed representative German pipeline network. By comparing the derived pipeline cost functions, it could be derived that pipeline reassignment can reduce the hydrogen transmission costs by more than 60%. Finally, a countrywide analysis of pipeline availability constraints for the year 2030 shows a cost reduction of the transmission system by 30% in comparison to a newly built hydrogen pipeline system.
Common energy system models that integrate hydrogen transport in pipelines typically simplify fluid flow models and reduce the network size in order to achieve solutions quickly. This contribution analyzes two different types of pipeline network topologies (namely, star and tree networks) and two different fluid flow models (linear and nonlinear) for a given hydrogen capacity scenario of electrical reconversion in Germany to analyze the impact of these simplifications. For each network topology, robust demand and supply scenarios are generated. The results show that a simplified topology, as well as the consideration of detailed fluid flow, could heavily influence the total pipeline investment costs. For the given capacity scenario, an overall cost reduction of the pipeline costs of 37% is observed for the star network with linear cost compared to the tree network with nonlinear fluid flow. The impact of these improvements regarding the total electricity reconversion costs has led to a cost reduction of 1.4%, which is fairly small. Therefore, the integration of nonlinearities into energy system optimization models is not recommended due to their high computational burden. However, the applied method for generating robust demand and supply scenarios improved the credibility and robustness of the network topology, while the simplified fluid flow consideration can lead to infeasibilities. Thus, we suggest the utilization of the nonlinear model for post-processing to prove the feasibility of the results and strengthen their credibility, while retaining the computational performance of linear modeling.
Considering the need to reduce greenhouse gas emissions, onshore wind energy is certain to play a major role in future energy systems. This topic has received significant attention from the research community, producing many estimations of Europe's onshore wind potential for capacity and generation. Despite this focus, previous estimates appear to have underpredicted both the amount of available future wind capacity as well as its performance. Foremost in this regard is the common use of contemporary, or at least near-future, turbine designs which are not fitting for a far-future context. In response to this, an improved, transparent, and fully reproducible work flow is presented here, and applied to determine a future-oriented onshore wind energy potential for Europe. Within a scenario of turbine cost and design in 2050, 13.4 TW of capacity is found to be available, allowing for 34.3 PWh of average generation per year. By sorting the explicitly-placed potential installation locations by their expected generation cost, national relationships between cost and performance versus installed capacity are found, and it is also seen that all countries possess some potential for onshore wind energy generation below 4 ct€ kWh-1. Furthermore, it is unlikely for these costs to exceed 6 ct€ kWh-1 in any future capacity scenario.
HIGHLIGHTS:
- Techno-economic analysis of Power-to-Fuel processes from a comparative perspective.
- Chemical plant design in Aspen Plus® for Power-to-Fuel pathways.
- All simulations with the same assumptions and under the same boundary conditions.
- Flowsheet–based, component-specific cost calculation.
- Production-specific advantages and disadvantages of various e-fuels.
ABSTRACT: Electricity-based fuels are one promising option to achieve the transition of the energy system, and especially the transport sector, in order to minimize the role of fossil energy carriers. One major problem is the lacking compatibility between different techno-economic assessments, such that recommendations regarding the most promising Power-to-Fuel technology are difficult to make. This work provides a technically sound comparison of various Power-to-Fuel options regarding technological maturity and efficiency, as well as cost. The investigated options include methanol, ethanol, butanol, octanol, DME, OME3-5 and hydrocarbons. To guarantee the comparability, all necessary chemical plants were designed in Aspen Plus® to determine material and energy consumption, as well as investment costs within the same boundary conditions and assumptions in all simulations and calculations. Individual technical aspects of the various synthesis routes, as well as their advantages and disadvantages, are highlighted.
With an assumed electrolysis efficiency of 70% and considering the energy demand for the CO2 supply and the energy and operating material demand of the chemical plants, depending on the selected electrofuel, 30–60% of the primary energy in renewable electricity can be stored in the lower heating value of the electrofuel. In the presented results, the costs of H2 supply are responsible for 58–83% of the total manufacturing costs and thus have the greatest potential to reduce the latter. For the base case (4.6 €/kgH2), various electrofuels will have costs of manufacturing of between 1.85 and 3.96 €/lDE, with DME being the cheapest.
Hydrogen could play a key role in future energy systems by enabling the storage of excess electricity from renewable power sources, like solar and wind, and fueling emission-free fuel cell electric vehicles. Nevertheless, the temporal and spatial gap between the fluctuating production in electrolysis plants and the demand at fueling stations necessitates the construction of infrastructures. Different technologies are available for storing and transporting hydrogen in its gaseous or liquid states, or even via liquid organic hydrogen carriers. To select and compare these different infrastructure options on a nationwide scale in Germany for an energy system 2050, we carried out an infrastructure assessment with spatial resolution to analyze the resulting costs and CO 2 emissions, as well as the primary energy demand. To do so, methods for designing a spatially-resolved infrastructure are presented. In particular, the setup of a transmission pipeline with gaseous trailer distribution has not been well represented and investigated in the literature so far. The results show that salt caverns, as well as transmission pipelines, are key technologies for future hydrogen infrastructure systems. The distribution should be handled for low penetration of fuel cell vehicles rates with gaseous compressed trailers and replaced by distribution pipelines in areas with high fueling station densities. This ensures the cost-effective supply during the transition to higher fuel cell vehicle fleets.