Germany
Concepts for Hydrogen Internal Combustion Engines and Their Implications on the Exhaust Gas Aftertreatment System
Dec 2021
Publication
Hydrogen as carbon-free fuel is a very promising candidate for climate-neutral internal combustion engine operation. In comparison to other renewable fuels hydrogen does obviously not produce CO2 emissions. In this work two concepts of hydrogen internal combustion engines (H2 -ICEs) are investigated experimentally. One approach is the modification of a state-of-the-art gasoline passenger car engine using hydrogen direct injection. It targets gas Read More
Political Economy of Green Hydrogen Rollout: A Global Perspective
Dec 2021
Publication
The present paper dwells on the role of green hydrogen in the transition towards climateneutral economies and reviews the central challenges for its emancipation as an economically viable source of energy. The study shows that countries with a substantial share of renewables in the energy mix advanced natural gas pipeline infrastructure and an advanced level of technological and economic development have a comparative advantage for the wide Read More
Boosting the H2 Production Efficiency via Photocatalytic Organic Reforming: The Role of Additional Hole Scavenging System
Nov 2021
Publication
The simultaneous photocatalytic H2 evolution with environmental remediation over semiconducting metal oxides is a fascinating process for sustainable fuel production. However most of the previously reported photocatalytic reforming showed nonstoichiometric amounts of the evolved H2 when organic substrates were used. To explain the reasons for this phenomenon a careful analysis of the products and intermediates in gas and aqueous phases upon the Read More
Cost-effective Technology Choice in a Decarbonized and Diversified Long-haul Truck Transportation Sector: A U.S. Case Study
Dec 2021
Publication
Achieving net-zero emissions by 2050 will require accelerated efforts that include decarbonizing long-haul truck transportation. In this difficult-to-decarbonize low-margin industry economic transparency on technology options is vital for decision makers seeking to eliminate emissions. Battery electric (BET) and hydrogen fuel cell electric trucks (FCET) can represent emission-free alternatives to diesel-powered trucks (DT). Previous studies focus on cost co Read More
How Flexible Electricity Demand Stabilizes Wind and Solar Market Values: The Case of Hydrogen Electrolyzers
Nov 2021
Publication
Wind and solar energy are often expected to fall victim to their own success: the higher their share in electricity generation the more their revenue in electricity markets (their “market value”) declines. While market values may converge to zero in conventional power systems this study argues that “green” hydrogen production can effectively and permanently halt the decline by adding flexible electricity demand in low-price hours. To support this argu Read More
Liquid Organic Hydrogen Carriers - A Technology to Overcome Common Risks of Hydrogen Storage
Sep 2021
Publication
In transport and storage of hydrogen the risks are mainly seen in its volatile nature its ability to form explosive mixtures with air and the harsh conditions (high pressure or low temperature) for efficient storage. The concept of Liquid Organic Hydrogen Carriers (LOHC) offers a technology to overcome the above mentioned threats. The present submission describes the basics of the LOHC technology. It contains a comparison of a selection of common LOHC Read More
Linking the Power and Transport Sectors—Part 2: Modelling a Sector Coupling Scenario for Germany
Jul 2017
Publication
“Linking the power and transport sectors—Part 1” describes the general principle of “sector coupling” (SC) develops a working definition intended of the concept to be of utility to the international scientific community contains a literature review that provides an overview of relevant scientific papers on this topic and conducts a rudimentary analysis of the linking of the power and transport sectors on a worldwide EU and German level. The aim of this f Read More
Risk Assessment and Mitigation Evaluation for Hydrogen Vehicles in Private Garages. Experiments and Modelling
Sep 2021
Publication
Governments and local authorities introduce new incentives and regulations for cleaner mobility as part of their environmental strategies to address energy challenges. Fuel cell electric vehicles (FCEVs) are becoming increasingly important and will extend beyond captive fleets reaching private users. Research on hydrogen safety issues is currently led in several projects in order to highlight and manage risks of FCEVs in confined spaces such as tunnels unde Read More
Import Options for Chemical Energy Carriers from Renewable Sources to Germany
Feb 2024
Publication
Import and export of fossil energy carriers are cornerstones of energy systems world-wide. If energy systems are to become climate neutral and sustainable fossil carriers need to be substituted with carbon neutral alternatives or electrified if possible. We investigate synthetic chemical energy carriers hydrogen methane methanol ammonia and Fischer-Tropsch fuels produced using electricity from Renewable Energy Source (RES) as fossil substitutes. RES p Read More
Improving the Efficiency of PEM Electrolyzers through Membrane-Specific Pressure Optimization
Feb 2020
Publication
Hydrogen produced in a polymer electrolyte membrane (PEM) electrolyzer must be stored under high pressure. It is discussed whether the gas should be compressed in subsequent gas compressors or by the electrolyzer. While gas compressor stages can be reduced in the case of electrochemical compression safety problems arise for thin membranes due to the undesired permeation of hydrogen across the membrane to the oxygen side forming an exp Read More
A Policy Review of Green Hydrogen Economy in Southern Africa
Nov 2021
Publication
Renewable energy and clean energy have been on the global agenda for energy transition for quite a long time but recently gained strong momentum especially with the anticipated depletion of fossil fuels alongside increasing environmental degradation from their exploitation and the changing climate caused by their excessive carbon emissions. Despite this Africa’s pursuit to transition to a green economy using renewable energy resources still f Read More
Conceptual Study and Development of an Autonomously Operating, Sailing Renewable Energy Conversion System
Jun 2022
Publication
With little time left for humanity to reduce climate change to a tolerable level a highly scalable and rapidly deployable solution is needed that can be implemented by any country. Offshore wind energy in international waters is an underused resource and could even be harnessed by landlocked countries. In this paper the use of sailing wind turbines operating autonomously in high seas to harvest energy is proposed. The electrical energy that is genera Read More
A Novel Framework for Development and Optimisation of Future Electricity Scenarios with High Penetration of Renewables and Storage
May 2019
Publication
Although electricity supply is still dominated by fossil fuels it is expected that renewable sources will have a much larger contribution in the future due to the need to mitigate climate change. Therefore this paper presents a new framework for developing Future Electricity Scenarios (FuturES) with high penetration of renewables. A multi-period linear programming model has been created for power-system expansion planning. This has been coupled with an e Read More
Law and Policy Review on Green Hydrogen Potential in ECOWAS Countries
Mar 2022
Publication
This paper aims to review existing energy-sector and hydrogen-energy-related legal policy and strategy documents in the ECOWAS region. To achieve this aim current renewable-energyrelated laws acts of parliament executive orders presidential decrees administrative orders and memoranda were analyzed. The study shows that ECOWAS countries have strived to design consistent legal instruments regarding renewable energy in developing comprehe Read More
Review of Hydrogen Production Techniques from Water Using Renewable Energy Sources and Its Storage in Salt Caverns
Feb 2022
Publication
Hydrogen is becoming an increasingly important energy carrier in sector integration for fuel cell transportation heat and electricity. Underground salt caverns are one of the most promising ways to store the hydrogen obtained from water electrolysis using power generation from renewable energy sources (RES). At the same time the production of hydrogen can be used to avoid energy curtailments during times of low electricity demand or low prices. The stor Read More
Hydrogen-powered Aviation and its Reliance on Green Hydrogen Infrastructure - Review and Research Gaps
Oct 2021
Publication
Aircraft powered by green hydrogen (H2) are a lever for the aviation sector to reduce the climate impact. Previous research already focused on evaluations of H2 aircraft technology but analyses on infrastructure related cost factors are rarely undertaken. Therefore this paper aims to provide a holistic overview of previous efforts and introduces an approach to assess the importance of a H2 infrastructure for aviation. A short and a medium-range aircraft are Read More
Cost Benefits of Optimizing Hydrogen Storage and Methanation Capacities for Power-to-Gas Plants in Dynamic Operation
Oct 2019
Publication
Power-to-Gas technologies offer a promising approach for converting renewable electricity into a molecular form (fuel) to serve the energy demands of non-electric energy applications in all end-use sectors. The technologies have been broadly developed and are at the edge of a mass roll-out. The barriers that Power-to-Gas faces are no longer technical but are foremost regulatory and economic. This study focuses on a Power-to-Gas pathway where elect Read More
Study of the Microstructural and First Hydrogenation Properties of TiFe Alloy with Zr, Mn and V as Additives
Jul 2021
Publication
In this paper we report the effect of adding Zr + V or Zr + V + Mn to TiFe alloy on microstructure and hydrogen storage properties. The addition of only V was not enough to produce a minimum amount of secondary phase and therefore the first hydrogenation at room temperature under a hydrogen pressure of 20 bars was impossible. When 2 wt.% Zr + 2 wt.% V or 2 wt.% Zr + 2 wt.% V + 2 wt.% Mn is added to TiFe the alloy shows a finely distributed Ti Read More
Decarbonizing China’s Energy System – Modeling the Transformation of the Electricity, Transportation, Heat, and Industrial Sectors
Nov 2019
Publication
Growing prosperity among its population and an inherent increasing demand for energy complicate China’s target of combating climate change while maintaining its economic growth. This paper therefore describes three potential decarbonization pathways to analyze different effects for the electricity transport heating and industrial sectors until 2050. Using an enhanced version of the multi-sectoral open-source Global Energy System Model ena Read More
Hydrogen Supply Chain Scenarios for the Decarbonisation of a German Multi-modal Energy System
Sep 2021
Publication
Analysing hydrogen supply chains is of utmost importance to adequately understand future energy systems with a high degree of sector coupling. Here a multi-modal energy system model is set up as linear programme incorporating electricity natural gas as well as hydrogen transportation options for Germany in 2050. Further different hydrogen import routes and optimised inland electrolysis are included. In a sensitivity analysis hydrogen demands are va Read More
SimSES: A Holistic Simulation Framework for Modeling and Analyzing Stationary Energy Storage Systems
Feb 2022
Publication
The increasing feed-in of intermittent renewable energy sources into the electricity grids worldwide is currently leading to technical challenges. Stationary energy storage systems provide a cost-effective and efficient solution in order to facilitate the growing penetration of renewable energy sources. Major technical and economical challenges for energy storage systems are related to lifetime efficiency and monetary returns. Holistic simulation tools a Read More
Optimization of Hydrogen Cost and Transport Technology in France and Germany for Various Production and Demand Scenarios
Jan 2021
Publication
Green hydrogen for mobility represents an alternative to conventional fuel to decarbonize the transportation sector. Nevertheless the thermodynamic properties make the transport and the storage of this energy carrier at standard conditions inefficient. Therefore this study deploys a georeferenced optimal transport infrastructure for four base case scenarios in France and Germany that differs by production distribution based on wind power potential Read More
Technologies and Policies to Decarbonize Global Industry: Review and Assessment of Mitigation Drivers Through 2070
Mar 2020
Publication
Jeffrey Rissman,
Chris Bataille,
Eric Masanet,
Nate Aden,
William R. Morrow III,
Nan Zhou,
Neal Elliott,
Rebecca Dell,
Niko Heeren,
Brigitta Huckestein,
Joe Cresko,
Sabbie A. Miller,
Joyashree Roy,
Paul Fennell,
Betty Cremmins,
Thomas Koch Blank,
David Hone,
Ellen D. Williams,
Stephane de la Rue du Can,
Bill Sisson,
Mike Williams,
John Katzenberger,
Dallas Burtraw,
Girish Sethi,
He Ping,
David Danielson,
Hongyou Lu,
Tom Lorber,
Jens Dinkel and
Jonas Helseth
Fully decarbonizing global industry is essential to achieving climate stabilization and reaching net zero greenhouse gas emissions by 2050–2070 is necessary to limit global warming to 2 °C. This paper assembles and evaluates technical and policy interventions both on the supply side and on the demand side. It identifies measures that employed together can achieve net zero industrial emissions in the required timeframe. Key supply-side technologies incl Read More
Transient Reversible Solid Oxide Cell Reactor Operation – Experimentally Validated Modeling and Analysis
Oct 2018
Publication
A reversible solid oxide cell (rSOC) reactor can operate efficiently in both electrolysis mode and in fuel cell mode. The bidirectional operability enables rSOC reactors to play a central role as an efficient energy conversion system for energy storage and sector coupling for a renewable energy driven society. A combined system for electrolysis and fuel cell operation can result in complex system configurations that should be able to switch between the tw Read More
System Analysis and Requirements Derivation of a Hydrogen-electric Aircraft Powertrain
Sep 2022
Publication
In contrast to sustainable aviation fuels for use in conventional combustion engines hydrogen-electric powertrains constitute a fundamentally novel approach that requires extensive effort from various engineering disciplines. A transient system analysis has been applied to a 500 kW shaft-power-class powertrain. The model was fed with high-level system requirements to gain a fundamental understanding of the interaction between sub-systems and compo Read More
Decentral Production of Green Hydrogen for Energy Systems: An Economically and Environmentally Viable Solution for Surplus Self-Generated Energy in Manufacturing Companies?
Feb 2023
Publication
Power-to-X processes where renewable energy is converted into storable liquids or gases are considered to be one of the key approaches for decarbonizing energy systems and compensating for the volatility involved in generating electricity from renewable sources. In this context the production of “green” hydrogen and hydrogen-based derivatives is being discussed and tested as a possible solution for the energy-intensive industry sector in particular Read More
Solar Hydrogen Fuel Generation from Wastewater—Beyond Photoelectrochemical Water Splitting: A Perspective
Oct 2022
Publication
Green hydrogen—a carbon-free renewable fuel—has the capability to decarbonise a variety of sectors. The generation of green hydrogen is currently restricted to water electrolysers. The use of freshwater resources and critical raw materials however limits their use. Alternative water splitting methods for green hydrogen generation via photocatalysis and photoelectrocatalysis (PEC) have been explored in the past few decades; however their comme Read More
Carbon-negative Hydrogen from Biomass Using Gas Switching Integrated Gasification: Techno-economic Assessment
Sep 2022
Publication
Ambitious decarbonization pathways to limit the global temperature rise to well below 2 ◦C will require largescale CO2 removal from the atmosphere. One promising avenue for achieving this goal is hydrogen production from biomass with CO2 capture. The present study investigates the techno-economic prospects of a novel biomass-to-hydrogen process configuration based on the gas switching integrated gasification (GSIG) concept. GSIG applies t Read More
A Model for Cost- and Greenhouse Gas Optimal Material and Energy Allocation of Biomass and Hydrogen
Nov 2022
Publication
BENOPT an optimal material and energy allocation model is presented which is used to assess cost-optimal and/or greenhouse gas abatement optimal allocation of renewable energy carriers across power heat and transport sectors. A high level of detail on the processes from source to end service enables detailed life-cycle greenhouse gas and cost assessments. Pareto analyses can be performed as well as thorough sensitivity analyses. The model is Read More
Knowledge and Technology Transfer via Publications, Patents, Standards: Exploring the Hydrogen Technological Innovation System
Nov 2022
Publication
Clean technologies play a crucial role in reducing greenhouse gas emissions and protecting the climate. Hydrogen is a promising energy carrier and fuel that can be used in many applications. We explore the global hydrogen technological innovation system (TIS) by analyzing the three knowledge and technology transfer channels of publications patents and standards. Since the adoption of hydrogen technologies requires trust in their safety this study specif Read More
Hydrogen in Aviation: A Simulation of Demand, Price Dynamics, and CO2 Emission Reduction Potentials
Mar 2024
Publication
Aviation contributes to anthropogenic climate change by emitting both carbon dioxide (CO2) and non-CO2 emissions through the combustion of fossil fuels. One approach to reduce the climate impact of aviation is the use of hydrogen as an alternative fuel. Two distinct technological options are presently under consideration for the implementation of hydrogen in aviation: hydrogen fuel cell architectures and the direct combustion of hydrogen. In this stud Read More
Implementation of Fuel Cells in Aviation from a Maintenance, Repair and Overhaul Perspective
Dec 2022
Publication
Hydrogen is one of the most promising power sources for meeting the aviation sector’s long-term decarbonization goals. Although on-board hydrogen systems namely fuel cells are extensively researched the maintenance repair and overhaul (MRO) perspective remains mostly unaddressed. This paper analyzes fuel cells from an MRO standpoint based on a literature review and comparison with the automotive sector. It also examines how well the Read More
Quantification of Hydrogen in Nanostructured Hydrogenated Passivating Contacts for Silicon Photovoltaics Combining SIMS-APT-TEM: A Multiscale Correlative Approach
Mar 2021
Publication
Multiscale characterization of the hydrogenation process of silicon solar cell contacts based on c-Si/SiOx/nc-SiCx(p) has been performed by combining dynamic secondary ion mass-spectrometry (D-SIMS) atom probe tomography (APT) and transmission electron microscopy (TEM). These contacts are formed by high-temperature firing which triggers the crystallization of SiCx followed by a hydrogenation process to passivate remaining interfacial defects Read More
Is Iridium Demand a Potential Bottleneck in the Realization of Large-Scale PEM Water Electrolysis?
Jul 2021
Publication
Proton exchange membrane water electrolysis (PEMWE) is a key technology for future sustainable energy systems. Proton exchange membrane (PEM) electrolysis cells use iridium one of the scarcest elements on earth as catalyst for the oxygen evolution reaction. In the present study the expected iridium demand and potential bottlenecks in the realization of PEMWE for hydrogen production in the targeted GW a−1 scale are assessed in a model buil Read More
Solar Thermochemical Hydrogen Production in the USA
Jul 2021
Publication
Hydrogen produced from renewable energy has the potential to decarbonize parts of the transport sector and many other industries. For a sustainable replacement of fossil energy carriers both the environmental and economic performance of its production are important. Here the solar thermochemical hydrogen pathway is characterized with a techno-economic and life-cycle analysis. Assuming a further increase of conversion efficiency and a red Read More
Underground Hydrogen Storage to Balance Seasonal Variations in Energy Demand: Impact of Well Configuration on Storage Performance in Deep Saline Aquifers
Mar 2023
Publication
Grid-scale underground hydrogen storage (UHS) is essential for the decarbonization of energy supply systems on the path towards a zero-emissions future. This study presents the feasibility of UHS in an actual saline aquifer with a typical dome-shaped anticline structure to balance the potential seasonal mismatches between energy supply and demand in the UK domestic heating sector. As a main requirement for UHS in saline aquifers we investig Read More
Hydrogen Micro-Systems: Households’ Preferences and Economic Futility
Mar 2024
Publication
This study examines the potential market for residential hydrogen systems in light of the trends towards digitalisation and environmental awareness. Based on a survey of 350 participants the results indicate that although energy experts are sceptical about the benefits of residential hydrogen systems due to their high costs households are highly interested in this technology. The sample shows a willingness to invest in hydrogen applications with some househ Read More
Study on the Use of Fuel Cells in Shipping
Jan 2017
Publication
Fuel Cells are a promising technology in the context of clean power sustainability and alternative fuels for shipping. Different specific developments on Fuel Cells are available today with research and pilot projects under evaluation that have revealed strong potential for further scaled up implementation. The EMSA Study on the use of Fuel Cells in Shipping has been the result of this Agency’s initiative under the agreement of the Commission and in supp Read More
Multi-Objective Optimization-Based Health-Conscious Predictive Energy Management Strategy for Fuel Cell Hybrid Electric Vehicles
Feb 2022
Publication
The Energy Management Strategy (EMS) in Fuel Cell Hybrid Electric Vehicles (FCHEVs) is the key part to enhance optimal power distribution. Indeed the most recent works are focusing on optimizing hydrogen consumption without taking into consideration the degradation of embedded energy sources. In order to overcome this lack of knowledge this paper describes a new health-conscious EMS algorithm based on Model Predictive Control (MPC) which aims Read More
Derivation and Validation of a Reference Data-based Real Gas Model for Hydrogen
Mar 2023
Publication
Hydrogen plays an important role for the decarbonization of the energy sector. In its gaseous form it is stored at pressures of up to 1000 bar at which real gas effects become relevant. To capture these effects in numerical simulations accurate real gas models are required. In this work new correlation equations for relevant hydrogen properties are developed based on the Reference Fluid Thermodynamic and Transport Properties Database (REFPROP). Wit Read More
Hydrogen-powered Aviation in Germany: A Macroeconomic Perspective and Methodological Approach of Fuel Supply Chain Integration into an Economy-wide Dataset
Oct 2022
Publication
The hydrogen (H2) momentum affects the aviation sector. However a macroeconomic consideration is currently missing. To address this research gap the paper derives a methodology for evaluating macroeconomic effects of H2 in aviation and applies this approach to Germany. Three goals are addressed: (1) Construction of a German macroeconomic database. (2) Translation of H2 supply chains to the system of national accounts. (3) Implementation of Read More
Towards Climate-neutral Aviation: Assessment of Maintenance Requirements for Airborne Hydrogen Storage and Distribution Systems
Apr 2023
Publication
Airlines are faced with the challenge of reducing their environmental footprint in an effort to push for climate-neutral initiatives that comply with international regulations. In the past the aviation industry has followed the approach of incremental improvement of fuel efficiency while simultaneously experiencing significant growth in annual air traffic. With the increase in air traffic negating any reduction in Greenhouse Gas (GHG) emissions more disruptive t Read More
Global Hydrogen and Synfuel Exchanges in an Emission-Free Energy System
Apr 2023
Publication
This study investigates the global allocation of hydrogen and synfuels in order to achieve the well below 2 ◦C preferably 1.5 ◦C target set in the Paris Agreement. For this purpose TIMES Integrated Assessment Model (TIAM) a global energy system model is used. In order to investigate global hydrogen and synfuel flows cost potential curves are aggregated and implemented into TIAM as well as demand technologies for the end use sectors. Furthermo Read More
A Review of the Role of Hydrogen in the Heat Decarbonization of Future Energy Systems: Insights and Perspectives
Apr 2024
Publication
Hydrogen is an emerging technology changing the context of heating with cleaner combustion than traditional fossil fuels. Studies indicate the potential to repurpose the existing natural gas infrastructure offering consumers a sustainable economically viable option in the future. The integration of hydrogen in combined heat and power systems could provide residential energy demand and reduce environmental emissions. However the widespread adopt Read More
Technical Reliability of Shipboard Technologies for the Application of Alternative Fuels
Jul 2022
Publication
Background: Naval trafc is highly dependent on depleting fossil resources and causes signifcant greenhouse gas emissions. At the same time marine transportation is a major backbone of world trade. Thus alternative fuel concepts are highly needed. Diferent fuels such as ammonia methanol liquefed natural gas and hydrogen have been proposed. For some of them frst prototype vessels have been in operation. However practical experience is s Read More
Ecological and Economic Evaluation of Hydrogen Production by Different Water Electrolysis Technologies
Jul 2020
Publication
The economic and ecological production of green hydrogen by water electrolysis is one of the major challenges within Carbon2Chem and other power-to-X projects. This paper presents an evaluation of the different water electrolysis technologies with respect to their specific energy demand carbon footprint and the forecast production costs in 2030. From a current perspective alkaline water electrolysis is evaluated as the most favorable technology for the Read More
Positioning Germany in an International Hydrogen Economy: A Policy Review
Apr 2024
Publication
Germany the European Union member state with the largest fiscal space and its leading manufacturer of industrial goods is pursuing an ambitious hydrogen strategy aiming at establishing itself as a major technology provider and importer of green hydrogen. The success of its hydrogen strategy represents not only a key element in realizing the European vision of climate neutrality but also a central driver of an emerging global hydrogen economy. This ar Read More
Socio-environmental and Technical Factors Assessment of Photovoltaic Hydrogen Production in Antofagasta, Chile
Apr 2024
Publication
This study introduces a method for identifying territories ideal for establishing photovoltaic (PV) plants for green hydrogen (GH2 ) production in the Antofagasta region of northern Chile a location celebrated for its outstanding solar energy potential. Assessing the viability of PV plant installation necessitates a balanced consideration of technical aspects and socio-environmental constraints such as the proximity to areas of ecological impor Read More
The More the Merrier? Actors and Ideas in the Evolution of Germany Hydrogen Policy Discourse
Feb 2023
Publication
Hydrogen has set high hopes for decarbonization due to its flexibility and ability to decarbonize sectors of the economy where direct electrification appears unviable. Broad hydrogen policies have therefore started to emerge. Nevertheless it is still a rather niche technology not integrated or adopted at scale and not regulated through particular policy provisions. The involved stakeholders are thus still rushing to set the agenda over the issue. All this plays ou Read More
Blast Wave Generated by Delayed Ignition of Under-Expanded Hydrogen Free Jet at Ambient and Cryogenic Temperatures
Nov 2022
Publication
An under-expanded hydrogen jet from high-pressure equipment or storage tank is a potential incident scenario. Experiments demonstrated that the delayed ignition of a highly turbulent under-expanded hydrogen jet generates a blast wave able to harm people and damage property. There is a need for engineering tools to predict the pressure effects during such incidents to define hazard distances. The similitude analysis is applied to build a correlation using Read More
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