Applications & Pathways
Preference Structure on the Design of Hydrogen Refueling Stations to Activate Energy Transition
Aug 2020
Publication
As a countermeasure to the greenhouse gas problem the world is focusing on alternative fuel vehicles (AFVs). The most prominent alternatives are battery electric vehicles (BEV) and fuel cell electric vehicles (FCEVs). This study examines FCEVs especially considering hydrogen refueling stations to fill the gap in the research. Many studies suggest the important impact that infrastructure has on the diffusion of AFVs but they do not provide quantitative preferences for the design of hydrogen refueling stations. This study analyzes and presents a consumer preference structure for hydrogen refueling stations considering the production method distance probability of failure to refuel number of dispensers and fuel costs as core attributes. For the analysis stated preference data are applied to choice experiments and mixed logit is used for the estimation. Results indicate that the supply stability of hydrogen refueling stations is the second most important attribute following fuel price. Consumers are willing to pay more for green hydrogen compared to gray hydrogen which is hydrogen produced by fossil fuels. Driver fuel type and perception of hydrogen energy influence structure preference. Our results suggest a specific design for hydrogen refueling stations based on the characteristics of user groups.
A Combined Heat and Green Hydrogen (CHH) Generator Integrated with a Heat Network
Sep 2021
Publication
Combined heat and power (CHP) systems offer high energy efficiencies as they utilise both the electricity generated and any excess heat by co-suppling to local consumers. This work presents the potential of a combined heat and hydrogen (CHH) system a solution where Proton exchange membrane (PEM) electrolysis systems producing hydrogen at 60–70% efficiency also co-supply the excess heat to local heat networks. This work investigates the method of capture and utilisation of the excess heat from electrolysis. The analysed system was able to capture 312 kW of thermal energy per MW of electricity and can deliver it as heated water at either 75 ◦C or 45 ◦C this appropriate for existing district heat networks and lower temperature heat networks respectively. This yields an overall CHH system efficiency of 94.6%. An economic analysis was conducted based on income generated through revenue sales of both hydrogen and heat which resulted in a significant reduction in the Levelized Cost of Hydrogen.
Hydrogen to Support Electricity Systems
Jan 2020
Publication
The Department of Environment Land Water and Planning (DELWP) engaged GHD Advisory and ACIL Allen to assess the roles opportunities and challenges that hydrogen might play in the future to support Australia’s power systems and to determine whether the relevant electricity system regulatory frameworks are compatible with both enabling an industrial-scale1 hydrogen production capability and the use of hydrogen for power generation.
You can read the full report on the website of the Australian Government at this link
You can read the full report on the website of the Australian Government at this link
Experimental Investigation of the Effect of Hydrogen Addition on Combustion Performance and Emissions Characteristics of a Spark Ignition High Speed Gasoline Engine
Sep 2014
Publication
Considering energy crises and pollution problems today much work has been done for alternative fuels for fossil fuels and lowering the toxic components in the combustion products. Expert studies proved that hydrogen one of the prominent alternative energy source which has many excellent combustion properties that can be used for improving combustion and emissions performance of gasoline-fuelled spark ignition (SI) engines. This article experimentally investigated the performance and emission characteristics of a high speed single cylinder SI engine operating with different hydrogen gasoline blends. For this purpose the conventional carburetted high speed SI engine was modified into an electronically controllable engine with help of electronic control unit (ECU) which dedicatedly used to control the injection timings and injection durations of gasoline. Various hydrogen enrichment levels were selected to investigate the effect of hydrogen addition on engine brake mean effective pressure (Bmep) brake thermal efficiency volumetric efficiency and emission characteristics. The test results demonstrated that combustion performances fuel consumption and brake mean effective pressure were eased with hydrogen enrichment. The experimental results also showed that the brake thermal efficiency was higher than that for the pure gasoline operation. Moreover HC and CO emissions were all reduced after hydrogen enrichment.
The Technical and Economic Potential of the H2@Scale Concept within the United States
Oct 2020
Publication
The U.S. energy system is evolving as society and technologies change. Renewable electricity generation—especially from wind and solar—is growing rapidly and alternative energy sources are being developed and implemented across the residential commercial transportation and industrial sectors to take advantage of their cost security and health benefits. Systemic changes present numerous challenges to grid resiliency and energy affordability creating a need for synergistic solutions that satisfy multiple applications while yielding system-wide cost and emissions benefits. One such solution is an integrated hydrogen energy system (Figure ES-1). This is the focus of H2@Scale—a U.S. Department of Energy (DOE) initiative led by the Office of Energy Efficiency and Renewable Energy’s Hydrogen and Fuel Technologies Office. H2@Scale brings together stakeholders to advance affordable hydrogen production transport storage and utilization in multiple energy sectors. The H2@Scale concept involves hydrogen as an energy intermediate. Hydrogen can be produced from various conventional and renewable energy sources including as a responsive load on the electric grid. Hydrogen has many current applications and many more potential applications such as energy for transportation—used directly in fuel cell electric vehicles (FCEVs) as a feedstock for synthetic fuels and to upgrade oil and biomass—feedstock for industry (e.g. for ammonia production metals refining and other end uses) heat for industry and buildings and electricity storage. Owing to its flexibility and fungibility a hydrogen intermediate could link energy sources that have surplus availability to markets that require energy or chemical feedstocks benefiting both. This document builds upon a growing body of analyses of hydrogen as an energy intermediate by reporting the results from our initial analysis of the potential impacts of the H2@Scale vision by the mid-21st century for the 48 contiguous U.S. states. Previous estimates have been based on expert elicitation and focused on hydrogen demands. We build upon them first by estimating hydrogen’s serviceable consumption potential for possible hydrogen applications and the technical potential for producing hydrogen from various resources. We define the serviceable consumption potential as the quantity of hydrogen that would be consumed to serve the portion of the market that could be captured without considering economics (i.e. if the price of hydrogen were $0/kg over an extended period); thus it can be considered an upper bound for the size of the market. We define the technical potential as the resource potential constrained by real-world geography and system performance but not by economics. We then compare the cumulative serviceable consumption potential with the technical potential of a number of possible sources. Second we estimate economic potential: the quantity of hydrogen at an equilibrium price at which suppliers are willing to sell and consumers are willing to buy the same quantity of hydrogen. We believe this method provides a deeper understanding than was available in the previous analyses. We develop economic potentials for multiple scenarios across various market and technology-advancement assumptions.
An Overview of Promising Alternative Fuels for Road, Rail, Air, and Inland Waterway Transport in Germany
Feb 2022
Publication
To solve the challenge of decarbonizing the transport sector a broad variety of alternative fuels based on different concepts including Power-to-Gas and Power-to-Liquid and propulsion systems have been developed. The current research landscape is investigating either a selection of fuel options or a selection of criteria a comprehensive overview is missing so far. This study aims to close this gap by providing a holistic analysis of existing fuel and drivetrain options spanning production to utilization. For this purpose a case study for Germany is performed considering different vehicle classes in road rail inland waterway and air transport. The evaluated criteria on the production side include technical maturity costs as well as environmental impacts whereas on the utilization side possible blending with existing fossil fuels and the satisfaction of the required mission ranges are evaluated. Overall the fuels and propulsion systems Methanol-to-Gasoline Fischer–Tropsch diesel and kerosene hydrogen battery-electric propulsion HVO DME and natural gas are identified as promising future options. All of these promising fuels could reach near-zero greenhouse gas emissions bounded to some mandatory preconditions. However the current research landscape is characterized by high insecurity with regard to fuel costs depending on the predicted range and length of value chains.
Hybrid Hydrogen PEM Fuel Cell and Batteries Without DC–DC Converter
Sep 2013
Publication
Concerns about greenhouse gases as well as the price and security of oil supply have acted as a spur to sustainable automobile development. The hydrogen fuel cells electric vehicle (HFCEV) is generally recognised by leading automobile manufacturers and scientists as one of the optimum technologies for long-term future low carbon vehicle. In a typical HFCEV power train a DC–DC converter is required to balance the voltage difference between the fuel cells (FCs) stack and batteries. However research shows that a considerable amount of energy generated by the hydrogen FCs stack is deplete during this conversion process as heat. This experiment aims to improve the power train efficiency by eliminating the DC–DC converter by finding the best combination of FC stack and batteries matching the size and capacity of the electrical components.
Hydrogen Double Compression-expansion Engine (H2DCEE): A Sustainable Internal Combustion Engine with 60%+ Brake Thermal Efficiency Potential at 45 Bar BMEP
May 2022
Publication
Hydrogen (H2) internal combustion engines may represent cost-effective and quick solution to the issue of the road transport decarbonization. A major factor limiting their competitiveness relative to fuel cells (FC) is the lower efficiency. The present work aims to demonstrate the feasibility of a H2 engine with FC-like 60%+ brake thermal efficiency (BTE) levels using a double compression-expansion engine (DCEE) concept combined with a high pressure direct injection (HPDI) nonpremixed H2 combustion. Experimentally validated 3D CFD simulations are combined with 1D GT-Power simulations to make the predictions. Several modifications to the system design and operating conditions are systematically implemented and their effects are investigated. Addition of a catalytic burner in the combustor exhaust insulation of the expander dehumidification of the EGR and removal of the intercooling yielded 1.5 1.3 0.8 and 0.5%-point BTE improvements respectively. Raising the peak pressure to 300 bar via a larger compressor further improved the BTE by 1.8%-points but should be accompanied with a higher injector-cylinder differential pressure. The λ of ~1.4 gave the optimum tradeoff between the mechanical and combustion efficiencies. A peak BTE of 60.3% is reported with H2DCEE which is ~5%-points higher than the best diesel-fueled DCEE alternative.
Strategies for the Sampling of Hydrogen at Refuelling Stations for Purity Assessment
Aug 2021
Publication
Hydrogen delivered at hydrogen refuelling station must be compliant with requirements stated in different standards which require specialized sampling device and personnel to operate it. Currently different strategies are implemented in different parts of the world and these strategies have already been used to perform 100s of hydrogen fuel sampling in USA EU and Japan. However these strategies have never been compared on a large systematic study. The purpose of this paper is to describe and compare the different strategies for sampling hydrogen at the nozzle and summarize the key aspects of all the existing hydrogen fuel sampling including discussion on material compatibility with the impurities that must be assessed. This review highlights the fact it is currently difficult to evaluate the impact or the difference these strategies would have on the hydrogen fuel quality assessment. Therefore comparative sampling studies are required to evaluate the equivalence between the different sampling strategies. This is the first step to support the standardization of hydrogen fuel sampling and to identify future research and development area for hydrogen fuel sampling.
The Sector Coupling Concept: A Critical Review
Jun 2020
Publication
Pursued climate goals require reduced greenhouse gas emissions by substituting fossil fuels with energy from renewable sources in all energy-consuming processes. On a large-scale this can mainly be achieved through electricity from wind and sun which are subject to intermittency. To efficiently integrate this variable energy a coupling of the power sector to the residential transport industry and commercial/trade sector is often promoted called sector coupling (SC). Nevertheless our literature review indicates that SC is frequently misinterpreted and its scope varies among available research from exclusively considering the use of excess renewable electricity to a rather holistic view of integrated energy systems including excess heat or even biomass sources. The core objective of this article is to provide a thorough understanding of the SC concept through an analysis of its origin and its main purpose as described in the current literature. We provide a structured categorization of SC derived from our findings and critically discuss its remaining challenges as well as its value for renewable energy systems. We find that SC is rooted in the increasing use of variable renewable energy sources and its main assets are the flexibility it provides for renewable energy systems decarbonization potential for fossil-fuel-based end-consumption sectors and consequently reduced dependency on oil and gas extracting countries. However the enabling technologies face great challenges in their economic feasibility because of the uncertain future development of competing solutions.
Refuelling Infrastructure Requirements for Renewable Hydrogen Road Fuel through the Energy Transition
Nov 2022
Publication
Current commercially available options for decarbonisation of road transport are battery electric vehicles or hydrogen fuel cell electric vehicles. BEVs are increasingly deployed while hydrogen is in its infancy. We examine the infrastructure necessary to support hydrogen fuelling to various degrees of market penetration. Scotland makes a good exemplar of transport transition with a world leading Net-Zero ambition and proven pathways for generating ample renewable energy. We identified essential elements of the new transport systems and the associated capital expenditure. We developed nine scenarios based on the pace of change and the ultimate market share of hydrogen and constructed a model to analyse their infrastructure requirements. This is a multi-period model incorporating Monte Carlo and Markov Chain elements. A “no-regrets” initial action is rapid deployment of enough hydrogen infrastructure to facilitate the early years of a scenario where diesel fuel becomes replaced with hydrogen. Even in a lower demand scenario of only large and heavy goods vehicles using hydrogen the same infrastructure would be required within a further two years. Subsequent investment in infrastructure could be considered in the light of this initial development.
Comparative Study of Spark-Ignited and Pre-Chamber Hydrogen-Fueled Engine: A Computational Approach
Nov 2022
Publication
Hydrogen is a promising future fuel to enable the transition of transportation sector toward carbon neutrality. The direct utilization of H2 in internal combustion engines (ICEs) faces three major challenges: high NOx emissions severe pressure rise rates and pre-ignition at mid to high loads. In this study the potential of H2 combustion in a truck-size engine operated in spark ignition (SI) and pre-chamber (PC) mode was investigated. To mitigate the high pressure rise rate with the SI configuration the effects of three primary parameters on the engine combustion performance and NOx emissions were evaluated including the compression ratio (CR) the air–fuel ratio and the spark timing. In the simulations the severity of the pressure rise was evaluated based on the maximum pressure rise rate (MPRR). Lower compression ratios were assessed as a means to mitigate the auto-ignition while enabling a wider range of engine operation. The study showed that by lowering CR from 16.5:1 to 12.5:1 an indicated thermal efficiency of 47.5% can be achieved at 9.4 bar indicated mean effective pressure (IMEP) conditions. Aiming to restrain the auto-ignition while maintaining good efficiency growth in λ was examined under different CRs. The simulated data suggested that higher CRs require a higher λ and due to practical limitations of the boosting system λ at 4.0 was set as the limit. At a fixed spark timing using a CR of 13.5 combined with λ at 3.33 resulted in an indicated thermal efficiency of 48.6%. It was found that under such lean conditions the exhaust losses were high. Thus advancing the spark time was assessed as a possible solution. The results demonstrated the advantages of advancing the spark time where an indicated thermal efficiency exceeding 50% was achieved while maintaining a very low NOx level. Finally the optimized case in the SI mode was used to investigate the effect of using the PC. For the current design of the PC the results indicated that even though the mixture is lean the flame speed of H2 is sufficiently high to burn the lean charge without using a PC. In addition the PC design used in the current work induced a high MPRR inside the PC and MC leading to an increased tendency to engine knock. The operation with PC also increased the heat transfer losses in the MC leading to lower thermal efficiency compared to the SI mode. Consequently the PC combustion mode needs further optimizations to be employed in hydrogen engine applications.
Low Temperature Autoignition of Diesel Fuel Under Dual Operation with Hydrogen and Hydrogen-carriers
Mar 2022
Publication
While electrification of light duty vehicles is becoming a real solution to abate local pollutant as well as greenhouse gases emission heavy duty applications (such as long distance freight and maritime transport) will keep requiring fuel-based propulsion systems. In these sectors dominated by compression ignition engines research on alternative biofuels and new combustion modes is still highly necessary. Dual-fuel combustion appears as a very promising concept to replace conventional diesel fuel by sustainable ones. Among the latter hydrogen-derived fuels (the so-called electrofuels or e-fuels) are maybe the most interesting. This work addresses the effect of partial substitution of diesel fuel by hydrogen and hydrogen-carriers (ammonia and methane) on the autoignition process under low temperature conditions. Tests were carried out in a constant volume combustion chamber at different temperatures (535 600 and 650 ◦C) and pressures (11 16 and 21 bar). While the cool flames timing and intensity was only slightly affected by the low reactivity fuel energy content the main ignition was delayed this effect being much more noticeable for ammonia followed by hydrogen and finally methane. Kinetic simulations showed a clear competition for active radicals between both fuels (diesel and low reactivity fuel). The combustion duration also increased with the hydrogen or hydrogen-carrier content which greatly points to the need of modifications in the injection strategy of compression ignition engines operating under dual mode. A correlation was proposed for estimating the autoignition delay time for dual-fuel lean combustion at low temperature.
Permeation Tests in Type-approval Regulations for Hydrogen Fuelled Vehicles: Analysis and Testing Experiences at the JRC-GASTEF Facility
Jan 2023
Publication
This article presents an analysis of the permeation tests established in the current regulations for the type-approval of on board tanks in hydrogen vehicles. The analysis is done from the point of view of a test maker regarding the preparation for the execution of a permeation test. The article contains a description of the required instrumentation and set-up to carry out a permeation test according to the applicable standards and regulations. Tank conditions at the beginning of the test configuration of permeation chamber duration of the test or permeation rate to be reported are aspects that are not well-defined in regulations. In this paper we examine the challenges when carrying out a permeation test and propose possible solutions to overcome them with the intention of supporting test makers and helping the development of permeation test guidelines.
Planetary Boundaries Assessment of Deep Decarbonisation Options for Building Heating in the European Union
Jan 2023
Publication
Building heating is one of the sectors for which multiple decarbonisation options exist and current geopolitical tensions provide urgency to design adequate regional policies. Heat pumps and hydrogen boilers alongside alternative district heating systems are the most promising alternatives. Although a host of city or country-level studies exist it remains controversial what role hydrogen should play for building heating in the European Union compared with electrification and how blue and green hydrogen differ in terms of costs and environmental impacts. This works assesses the optimal technology mix for staying within planetary boundaries and the influence of international cooperation and political restrictions. To perform the analysis a bottom-up optimisation model was developed incorporating life cycle assessment constraints and covering production storage transport of energy and carbon dioxide as well as grid and non-grid connected end-users of heat. It was found that a building heating system within planetary boundaries is feasible through large-scale electrification via heat pumps although at a higher cost than the current system with abatement costs of around 200 €/ton CO2. Increasing interconnector capacity or onshore wind energy is found to be vital to staying within boundaries. A strong trade-off for hydrogen was identified with blue hydrogen being cost-competitive but vastly unsustainable (when applied to heating) and green hydrogen being 2–3 times more expensive than electrification while still transgressing several planetary boundaries. The insights from this work indicate that heat pumps and renewable electricity should be prioritised over hydrogen-based heating in most cases and grid-stability and storage aspects explored further while revealing a need for policy instruments to mitigate increased costs for consumers.
Hydrogen Technology for Supply Chain Sustainability: The Mexican Transportation Impacts on Society
Mar 2022
Publication
This study sheds light on the Hydrogen technology in transportation for reaching the sustainability goals of societies illustrated by the case of Mexico. In terms of the affected supply chains the study explores how the packaging and distribution of a fuel-saving tool that allows the adoption of hydrogen as complementary energy for maritime transportation to improve economic and environmental performance in Mexico. This exploratory study performs interviews observations simulations and tests involving producers suppliers and users at 26 ports in Mexico. The study shows that environmental and economic performance are related to key processes in Supply Chain Management (SCM) in which packaging and distribution are critical for achieving logistics and transportation sustainability goals. Reusable packaging and the distribution of a fuel-saving tool can help decrease costs - of transport and downstream/upstream processes in SCM while at the same time increasing the environmental performance.
Investigations on Pressure Dependence of Coriolis Mass Flow Meters Used at Hydrogen Refueling Stations
Sep 2020
Publication
In the framework of the ongoing EMPIR JRP 16ENG01 ‘‘Metrology for Hydrogen Vehicles’’ a main task is to investigate the influence of pressure on the measurement accuracy of Coriolis Mass Flow Meters (CFM) used at Hydrogen Refueling Stations (HRS). At a HRS hydrogen is transferred at very high and changing pressures with simultaneously varying flow rates and temperatures. It is clearly very difficult for CFMs to achieve the current legal requirements with respect to mass flow measurement accuracy at these measurement conditions. As a result of the very dynamic filling process it was observed that the accuracy of mass flow measurement at different pressure ranges is not sufficient. At higher pressures it was found that particularly short refueling times cause significant measurement deviations. On this background it may be concluded that pressure has a great impact on the accuracy of mass flow measurement. To gain a deeper understanding of this matter RISE has built a unique high-pressure test facility. With the aid of this newly developed test rig it is possible to calibrate CFMs over a wide pressure and flow range with water or base oils as test medium. The test rig allows calibration measurements under the conditions prevailing at a 70 MPa HRS regarding mass flows (up to 3.6 kg min−1) and pressures (up to 87.5 MPa).
Economic Evaluation of Renewable Hydrogen Integration into Steelworks for the Production of Methanol and Methane
Jun 2022
Publication
This work investigates the cost-efficient integration of renewable hydrogen into steelworks for the production of methane and methanol as an efficient way to decarbonize the steel industry. Three case studies that utilize a mixture of steelworks off-gases (blast furnace gas coke oven gas and basic oxygen furnace gas) which differ on the amount of used off-gases as well as on the end product (methane and/or methanol) are analyzed and evaluated in terms of their economic performance. The most influential cost factors are identified and sensitivity analyses are conducted for different operating and economic parameters. Renewable hydrogen produced by PEM electrolysis is the most expensive component in this scheme and responsible for over 80% of the total costs. Progress in the hydrogen economy (lower electrolyzer capital costs improved electrolyzer efficiency and lower electricity prices) is necessary to establish this technology in the future.
Optimal Design of Photovoltaic, Biomass, Fuel Cell, Hydrogen Tank Units and Electrolyzer Hybrid System for a Remote Area in Egypt
Jul 2022
Publication
In this paper a new isolated hybrid system is simulated and analyzed to obtain the optimal sizing and meet the electricity demand with cost improvement for servicing a small remote area with a peak load of 420 kW. The major configuration of this hybrid system is Photovoltaic (PV) modules Biomass gasifier (BG) Electrolyzer units Hydrogen Tank units (HT) and Fuel Cell (FC) system. A recent optimization algorithm namely Mayfly Optimization Algorithm (MOA) is utilized to ensure that all load demand is met at the lowest energy cost (EC) and minimize the greenhouse gas (GHG) emissions of the proposed system. The MOA is selected as it collects the main merits of swarm intelligence and evolutionary algorithms; hence it has good convergence characteristics. To ensure the superiority of the selected MOA the obtained results are compared with other well-known optimization algorithms namely Sooty Tern Optimization Algorithm (STOA) Whale Optimization Algorithm (WOA) and Sine Cosine Algorithm (SCA). The results reveal that the suggested MOA achieves the best system design achieving a stable convergence characteristic after 44 iterations. MOA yielded the best EC with 0.2106533 $/kWh the net present cost (NPC) with 6170134 $ the loss of power supply probability (LPSP) with 0.05993% and GHG with 792.534 t/y.
Refueling of LH2 Aircraft—Assessment of Turnaround Procedures and Aircraft Design Implication
Mar 2022
Publication
Green liquid hydrogen (LH2) could play an essential role as a zero-carbon aircraft fuel to reach long-term sustainable aviation. Excluding challenges such as electrolysis transportation and use of renewable energy in setting up hydrogen (H2) fuel infrastructure this paper investigates the interface between refueling systems and aircraft and the impacts on fuel distribution at the airport. Furthermore it provides an overview of key technology design decisions for LH2 refueling procedures and their effects on the turnaround times as well as on aircraft design. Based on a comparison to Jet A-1 refueling new LH2 refueling procedures are described and evaluated. Process steps under consideration are connecting/disconnecting purging chill-down and refueling. The actual refueling flow of LH2 is limited to a simplified Reynolds term of v · d = 2.35 m2/s. A mass flow rate of 20 kg/s is reached with an inner hose diameter of 152.4 mm. The previous and subsequent processes (without refueling) require 9 min with purging and 6 min without purging. For the assessment of impacts on LH2 aircraft operation process changes on the level of ground support equipment are compared to current procedures with Jet A-1. The technical challenges at the airport for refueling trucks as well as pipeline systems and dispensers are presented. In addition to the technological solutions explosion protection as applicable safety regulations are analyzed and the overall refueling process is validated. The thermodynamic properties of LH2 as a real compressible fluid are considered to derive implications for airport-side infrastructure. The advantages and disadvantages of a subcooled liquid are evaluated and cost impacts are elaborated. Behind the airport storage tank LH2 must be cooled to at least 19 K to prevent two-phase phenomena and a mass flow reduction during distribution. Implications on LH2 aircraft design are investigated by understanding the thermodynamic properties including calculation methods for the aircraft tank volume and problems such as cavitation and two-phase flows. In conclusion the work presented shows that LH2 refueling procedure is feasible compliant with the applicable explosion protection standards and hence does not impact the turnaround procedure. A turnaround time comparison shows that refueling with LH2 in most cases takes less time than with Jet A-1. The turnaround at the airport can be performed by a fuel truck or a pipeline dispenser system without generating direct losses i.e. venting to the atmosphere.
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