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At least 451 records · Page 25

Report on General Hydrogen Safety

Hydrogen is an important resource for many different industries throughout the world, including refining, manufacturing, and as a direct energy source. Hydrogen production, through methods such as steam methane reforming, has been developed over several decades. There is a large global demand for hydrogen from these industries and safe production and distribution are paramount for hydrogen systems. Codes and standards have been developed to reduce the risk associated with hydrogen accidents to the public. These codes and standards are similar to those in other industries in which there is inherent risk to the public, such as gasoline and natural gas production and distribution. Although there will always be a risk to the public in these types of fuels, the codes and standards are developed to reduce the likelihood of an accident occurring and reduce the severity of impact, should one occur. This report reviews the current state of hydrogen in the United States and outlines the codes and standards that ensure safe operation of hydrogen systems. The total hydrogen demand and use in different industries is identified. Additionally, the current landscape of hydrogen production and fueling stations in the United States is outlined. The safety of hydrogen systems is discussed through an overview of the purpose, methods, and content included in codes and standards. As outlined in this safety overview, the risk to the public in operation of hydrogen generation facilities and fueling stations is reduced through implementation of appropriate measures. Codes, such as NFPA 2, ensure that the risk associated with a hydrogen system is no greater than the risk presented by gasoline refueling stations.

08 HYDROGEN↗

Short-Run Marginal Emission Factors Neglect Impactful Phenomena and are Unsuitable for Assessing the Power Sector Emissions Impacts of Hydrogen Electrolysis

This comment reacts to Ruhnau and Schiele's (2023) assessment of the cost and emissions impacts of electrolytic hydrogen production operating under different green hydrogen certification requirements in the EU. We critique the paper's use of short-run marginal emissions rates to estimate emissions impacts, a methodology which the literature has shown to be inadequate for assessing the full lifecycle emissions impacts of electricity sector interventions. We hope that our response clarifies the need to consider induced structural change when assessing the greenhouse gas emissions impacts of electricity sector decisions at all scales.

electricity↗

Overview of Integrated Pathway Analyses to Meet the Hydrogen Energy Earthshot Goal

This slide deck was presented at the 2021 DOE Hydrogen Shot Summit on Aug. 31, 2021. The presentation describes two ongoing NETL system analysis efforts: "Comparison of Commercial, State-of-the-Art, Fossil-Based Hydrogen Production Technologies" (nearing completion), and "Hydrogen Energy Earthshot Initiative Screening Analysis" (which has recently started). The former study will detail costs and greenhouse gas emissions profiles of current commercial technologies (e.g., reforming and gasification routes). The latter will focus on our efforts to identify pathways that may meet the goal of the DOE Hydrogen Energy Earthshot Initiative (i.e., $1/kg H2 by 2030) as well as low carbon emissions.

Lewis, Eric↗

Trace levels of PtRu on NiMo foam electrodes towards hydrogen evolution reaction

Electrochemical water splitting plays a critical role in high purity hydrogen production. To lower capital cost and energy consumption, efficient catalysts are required to boost the hydrogen evolution reaction (HER), especially in alkaline media. Although PtRu alloy materials are still considered the state-of-the-art catalyst for the HER under alkaline media, large-scale application is hindered by its scarcity and high cost. NiMo alloy catalysts can be potential Pt-free alternatives to drive the sluggish kinetics of the HER under alkaline media, but their HER activity is still not ideal due to the limitation of Volmer step. Herein, we investigated the impact of trace levels of PtRu catalysts on NiMo electrodes towards the HER by incorporating advantages of both PtRu and NiMo catalysts to minimize cost and maintain a promising HER activity. Trace levels of PtRu catalysts from 0.0173 to 0.2648 mg cm −2 were loaded on commercial NiMo foam electrodes by a facile electrodeposition technique utilizing ppm concentration levels of PtRu in electrolyte. The results show that 0.0173 mg cm −2 PtRu loading on NiMo electrode can significantly enhance HER activity compared to the pristine NiMo foam electrode (Tafel slopes drop from ∼170 to ∼60 mV dec −1 ) due to the remarkable decline of energy barriers towards water dissociation and hydrogen adsorption. Meanwhile, the rate determining step (RDS) switches from the Volmer step to the Heyrovsky step when the PtRu loading increases to 0.0675 mg cm −2 . Promising catalytic stability is observed at 100 mA cm −2 over the course of 50 h with a PtRu loading of 0.1198 mg cm −2 . In conclusion, this work demonstrates a potential strategy to decrease the cost and simultaneously maintain superior HER performance by integrating trace levels of PtRu catalyst with NiMo foam electrodes.

Electrochemical water splitting↗

Overview of Integrated Pathway Analyses to Meet the Hydrogen Energy Earthshot Goal

This presentation was given at the 2022 Bulk Storage of Gaseous Hydrogen Workshop sponsored by the U.S. Department of Energy's (DOE) Hydrogen and Fuel Cell Technology Office (HFTO). The presentation topics cover the current status of an upcoming NETL publication titled "Comparison of Commercial, State-of-the-Art, Fossil-Based Hydrogen Production Technologies." The study will publicize plant performance, life cycle environmental performance, and the levelized cost of hydrogen (LCOH) production from six fossil-based pathways. The presentation provides preliminary results pending finalization of the study. In addition, the presentation provides an overview of NETL analysis efforts to support the DOE Hydrogen Shot targets.

Lewis, Eric↗

Production of Renewable Natural Gas from Waste Carbon Dioxide Sources (CRADA Final Report)

This CRADA provides new funding from SoCalGas and DOE's BETO and FCTO Offices focused hydrogen mass transfer limitations in H2@Scale processes. The project leverages the existing hydrogen production capabilities at the Energy Systems Integration Facility (ESIF) and SoCalGas' 700 L bioreactor system designed, built, and delivered to NLR under the first phase of this CRADA. This Joint Work Statement will cover new hardware modifications between NLR's electorlyzer stack and the SoCalGas bioreactor located outdoors. The new hardware and controls will provide researchers with the tools needed to obtain preliminary experimental data for a non-provisional application due in July 2019. The IP being developed is expected to improve the productivity of the bioreactor and would have wider impacts on other end-use processes using pressurized hydrogen (H2). In addition, this new funding enhances an existing BETO Biopower award by developing a 10-15 kW electrolyzer that is scalable to the MW-class with reduced capital cost and higher efficiency aimed at improving H2 mass transfer to downstream processes, like biomethanation. Finally due to the close-coupling between the electrolyzer stack and bioreactor, R&D will focus on cell retention, nutrient maintenance, optimal water management and process controls.

08 HYDROGEN↗

Efficient Screening of Bi–Metallic Electrocatalysts for Glycerol Valorization

Glycerol is a byproduct of biodiesel production and, as such, it is of limited economic value. By means of electrooxidation, glycerol can be used as a feedstock for scalable hydrogen production, in addition to conversion to value-added products. The development of novel and efficient catalytic electrode materials for the anodic side of the reaction is a key towards a hydrogen-based energy economy. In the present study, a computational screening protocol combining DFT, scaling relations, and microkinetic modeling allows for a rational selection of novel catalysts that can deliver efficient glycerol electrooxidation, low cost of production, and environmental sustainability. Activity and chemical selectivity towards hydrogen production on pure metal catalysts is discussed in terms of volcano-shaped plots. We find that the selectivity in the glycerol oxidation reaction is influenced by a different energy landscape when in the presence of water and best classified by a comparison of O—H and C—H bond-breaking barriers. In addition, we screened 3570 bi-metallic catalysts in the AB (L1 0 ) and A 3 B (L1 2 ) ordered structures for activity, stability, price, and toxicity. By filtering based on the criteria for toxicity, resistance to oxidation, miscibility, and price, we have identified 5 L1 0 structured catalysts (AgPd, AuPd, PtSb, CuPt, and AgPt) and 20 L1 2 catalysts (Ga 3 Ta, In 3 Ta, Ir 3 W, Ir 3 Mo, Cu 3 Pt, Ir 3 Ta, Ir 3 Re, Pd 3 Bi, Pd 3 Cu, Pd 3 W, Pd 3 Co, Pd 3 Sn, Pd 3 Mo, Pd 3 Ag, Pd 3 Ga, Pd 3 Ta, Au 3 Ru, Pd 3 In, Au 3 Ir, and Pd 3 Au) that are all predicted to show high activity. We also identify an additional 37 L1 0 and 92 L1 2 structured electrocatalysts with an anticipated medium-high activity.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Effect of Support on Iron-Based Catalyst Toward CO2-Free H2 Production From Methane Pyrolysis

The global demand for low-emission hydrogen production is increasing rapidly due to the potential for hydrogen to substitute conventional fossil fuels in energy related applications. Among all the current practical technologies – Steam Reforming of Methane (SMR), Water Electrolysis, and Methane Pyrolysis – methane pyrolysis has the potential to produce economical- and near-zero-emission hydrogen because the reaction produces a solid carbon by-product that can be monetized to offset production costs. However, this route is not without research challenges, and the selective formation of high-value carbon remains a critical issue. Supported nickel, iron, and cobalt, have been widely investigated for methane pyrolysis. Although iron-based catalysts are less active than Ni, iron catalysts offer less resistance to coke formation, are inexpensive, and have a longer lifetime. One area not sufficiently explored is the effect of support materials other than Al2O3 for the iron-based catalysts. Therefore, in this study we investigated a detailed variation of support material to study their influence on the catalytic performance. Moreover, this study offers a fair comparison because all catalytic materials were synthesized and studied under identical conditions, allowing a direct comparison of the obtained results; this is important because results reported in different publications in literature are often not comparable, due to very different reaction conditions.

Aireddy, Divakar Reddy↗

Effect of Support on Iron-Based Catalyst Toward CO2-Free H2 Production From Methane Pyrolysis

The global demand for low-emission hydrogen production is increasing rapidly due to the potential for hydrogen to substitute conventional fossil fuels in energy-related applications. Among practical technologies such as steam reforming of methane (SMR), water electrolysis, and methane pyrolysis, methane pyrolysis has the most potential to produce economical- and near-zero-emission hydrogen. The reaction during methane pyrolysis produces a solid carbon by-product that can be monetized to offset production costs. However, this route is not without research challenges, and the selective formation of high-value carbon remains a critical issue. Supported nickel, iron, and cobalt, have been widely investigated for methane pyrolysis. Although iron-based catalysts are less active than Ni, iron catalysts offer less resistance to coke formation, are inexpensive, and have a longer lifetime. One area not sufficiently explored is the effect of support materials other than Al2O3 for the iron-based catalysts. Therefore, we investigated a detailed variation of support materials to study their influence on the catalytic performance. Moreover, this study offers a fair and direct comparison among all catalytic materials which were synthesized and studied under identical conditions. This direct comparison of the obtained results is important because results reported in different publications are often not comparable due to very different reaction conditions.

Gull, Nathan↗

Observation of molecular hydrogen produced from bridging hydroxyls on anatase TiO2(101)

Anatase TiO2 is used extensively in a wide range of catalytic and photocatalytic processes and is a promising catalyst for hydrogen production. Here, we show that molecular hydrogen was produced from bridging hydroxyls, HOb, on the (101) surface of single crystal anatase (a-TiO2(101)). Electron bombardment at 30 K produced bridging oxygen vacancies in the surface. Deuterated bridging hydroxyls, DOb, were subsequently formed via dissociation of adsorbed D2O and confirmed by infrared reflection-absorption spectroscopy. During temperature programmed desorption (TPD) spectroscopy, D2 desorption was observed at 520 K. Density functional theory calculations show that both H2 and H2O production from HOb are endothermic at 0 K on a-TiO2(101), but H2 (H2O) desorption is entropically driven above 230 K (800 K). The calculated activation barrier for H2 desorption is 1.40 eV, which is similar to the desorption energy obtained from analysis of the D2 TPD spectra. The H2 desorption likely proceeds in two steps: H atom diffusion on the surface and then recombination. The calculations indicate that diffusion of the hydrogen atoms into the subsurface could also be an important process. We thank Drs. Z. Dohnalek and R. Rousseau for stimulating discussions. This work was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, & Biosciences and performed in EMSL, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is a multiprogram national laboratory operated for DOE by Battelle. We also acknowledge the WPI computational facilities for providing resources to perform the DFT studies.

Deskins, N A.↗

Potential for large-scale deployment of offshore wind-to-hydrogen systems in the United States

This study explores the role of producing low-carbon hydrogen using water electrolysis powered by offshore wind in facilitating the United States’ transition to a net-zero emissions economy by 2050. This research introduces an open-source scenario analysis tool for offshore wind-to-hydrogen systems, aiming to assess the impact of technology, regional considerations, and policy incentives on the cost of producing low-carbon hydrogen through offshore wind. Conducting a regional techno-economic analysis at four U.S. coastal sites, the study evaluates two energy transmission configurations and examines associated costs for the years 2025, 2030, and 2035. The results highlight that locations using fixed-bottom technology may achieve cost-competitive water electrolysis hydrogen production by 2030 through leveraging geologic hydrogen storage and federal policy incentives. Furthermore, floating technology locations are expected to see an average 38% reduction in the levelized cost of hydrogen from 2025 to 2035.

17 WIND ENERGY↗

Towards a standard approach to the analysis of carbon products generated from Natural Gas pyrolysis

Conference presentation for the work entitled “A standard approach to the analysis of carbon products generated from Natural Gas pyrolysis”. Pyrolysis of natural gas (NGP) has been proposed as a near term solution for the production of direct CO2 free (turquoise) hydrogen, to help fuel a more sustainable energy future. NGP can serve as a bridging technology while other (green) hydrogen production technologies mature. In order for NGP to be successful, the management of the generated carbon products needs to be carefully considered. Necessary markets need to be considered to incorporate the (turquoise) carbon products that are generated. A large hurdle in addressing the channeling of carbon products into desired markets is determining exactly what is manufactured from the NGP process. In this work an analysis method is presented that combines a suite of techniques for the assessment of the carbon product from Natural Gas Pyrolysis for appropriate identification and quality control.

Riley, Jarrett↗

Perovskite/Perovskite Tandem Photoelectrodes for Low-Cost Unassisted Photoelectrochemical Water Splitting

In this project, we aim to address the challenges of achieving efficient and cost-effective unassisted photoelectrochemical water splitting using perovskite/perovskite tandem photoelectrodes. We utilized the following unique approaches to advance our innovation. (1) We developed stable and efficient low-E g (1.2 – 1.4 eV) perovskites as the bottom electrodes. We demonstrated approaches to improve the photovoltaic performance and photothermal stability of low-E g Sn-Pb iodide perovskite solar cells. (2) We developed a low-temperature synthesis route to fabricate wide-E g (>1.8 eV) perovskite top electrodes. By combining theoretical and experimental investigation, we found methods to reduce the formation of defects and dislocations in the wide-E g mixed halide perovskites and suppress halide segregation. (3) We developed a robust metal oxide-based interconnecting layer to integrate two perovskite layers into tandem photoelectrodes. Our monolithically integrated tandem devices feature a high V OC of more than 2 V and a high J SC of more than 15 mA/cm 2 . We showed the new design of the tandem photoelectrodes that is critical to the stable operation of tandem photoelectrodes for unassisted PV/PEC water splitting. (4) We demonstrated a water-impermeable barrier of carbon paste/epoxy/metal foil composite, which can prevent photocorrosion and water ingress of perovskite active layers. This surface protection enabled the operation of perovskite photoelectrodes in water and significantly enhanced the long-term stability of our tandem devices. (5) We conducted standardized PEC characterization in collaboration with NREL and reported accurate determination of solar-to-hydrogen conversion efficiencies of perovskite/perovskite tandem photoelectrodes. At the end of the project, we demonstrated perovskite/perovskite tandem photoelectrodes with STH efficiencies of up to 18% and less than 20% efficiency loss after continuous operation for more than 500 hours in water. Our results demonstrate the potential to develop a low-cost, durable, and efficient water-splitting system that meets the DOE 2026 and 2031 cost targets for hydrogen production.

08 HYDROGEN↗

NX Fuels H2 Shot Incubator Phase I (CRADA Final Report)

NX Fuels will work with NREL to perform Life-Cycle Analysis (LCA) and Techno-Economic Analysis (TEA) for NX Fuels' solar H 2 system. TEA/LCA modeling developed early on will provide insight on the most critical parameters related to the green H 2 cost and environmental impacts and help us create the business case at scale. This project will advance the Nation’s decarbonization goals by demonstrating the economic feasibility of NX Fuels clean hydrogen production pathway and evaluate its impact on CO 2 emissions.

08 HYDROGEN↗

H2A-Lite (Hydrogen Analysis Lite Production Model) [SWR-24-69]

Within H2A-Lite, users can provide a minimal number of inputs—such as hydrogen production technology of choice —to produce estimates about characteristic scale, capital, and operations. Price projections for energy and feedstock are based on the Energy Information Administration's Annual Energy Outlook 2022, AEO2022 Reference case. The model additionally allows users to override technology default values to adapt to specific technology scales or regional energy prices. As output, H2A-Lite provides cost breakdown from rigorous financial analysis as well as greenhouse gas and criteria pollutant emissions characteristics.

Penev, Michael [National Laboratory of the Rockies↗

Maximizing long-term biohydrogen production with Clostridium thermocellum for high solids conversion of lignocellulosic biomass

Biological hydrogen production from lignocellulosic biomass sustainably couples organic waste reduction with renewable energy generation. Efficient conversion is challenged by the structural complexity of lignocellulose and resulting recalcitrance to enzymatic degradation. Clostridium thermocellum natively breaks down biomass with highly effective hemi-/cellulases systems (i.e., cellulosomes) and generates hydrogen in anaerobic cultivation, creating a compelling platform for lignocellulosic biohydrogen production. Achieving commercially viable production rates requires balancing high biomass loading and throughput against uniform mixing conditions required for enzyme dispersion, pH and temperature control, and efficient hydrogen and metabolite removal in continuous operation. To address these barriers to process intensification, we implemented novel reactor and process designs for high-solids lignocellulosic biomass fermentations using the C. thermocellum KJC19-9 strain, genetically engineered for co-utilization of cellulose and hemicellulose sugars (i.e., xylose). Via computational fluid dynamics (CFD) modeling and experimental validation, we achieved a >50% improvement in biohydrogen production with an improved anchor-type impeller morphology, coupled to a threefold reduction in agitation rate. To further reduce rheological constraints and accumulation of toxic metabolites, we then transitioned the process to sequencing fed-batch operation. The resulting process generated 24.87 L H 2 L −1 from 160 g L −1 of deacetylated and mechanically refined (DMR)-pretreated corn stover biomass over 16 days while solubilizing >95% of influent cellulose and hemicellulose, setting a new performance benchmark for continuous production of biohydrogen from lignocellulose.

08 HYDROGEN↗

Operational Limits of Redox Metal Oxides Performing Thermochemical Water Splitting

Solar thermochemical hydrogen production is an attractive technology that stores intermittent solar energy in the form of chemical bonds. Efficient operation requires the identification of a redox-active metal oxide (MO x ) material that can achieve high conversion of water to hydrogen at minimal energy input. Water splitting occurs by consecutive reduction and reoxidation reactions of MO x . MO x is reduced to MO x-δ and, in the second step, is reoxidized by water recovering the initial MO x and generate H 2 . The material must reduce at temperatures achievable in concentrated solar receiver/reactors, while maintaining a thermodynamic driving force to split water. At equilibrium, extent of reduction depends on temperature and oxygen partial pressure, and in this analysis, a set of thermodynamic properties, namely, enthalpy and entropy of oxygen vacancy formation, is sufficient to represent MO x . Herein, a method to easily classify materials based on these thermodynamic properties under any condition of oxygen partial pressure and temperature is presented. This method is based on fundamental thermodynamic principles and is applicable for any redox material with known thermodynamic properties. Despite the simplicity of the method, it is believed that this analysis will support future research in targeting thermodynamic properties of redox-active metal oxides.

water splitting↗

Multi-Scale Modeling for Plasma-Enhanced Ammonia Decomposition over Carbides and Nitrides

Ammonia is a carbon-free hydrogen carrier, but its decomposition typically requires high temperatures over costly Ru-based catalysts due to the large barrier for N≡N bond formation. We develop a multiscale framework combining density functional theory, zero-dimensional plasma kinetics, and microkinetic modeling to elucidate how non-thermal plasma (NTP) enables low-temperature NH 3 decomposition over Co-based carbides and nitrides, benchmarked against Ru and Co. Under thermal conditions, all catalysts are limited by N≡N bond formation, with Co 3 C(001) most active owing to its negatively charged surface, strong N* binding, and low activation barriers of N≡N bond formation. Plasma-induced vibrational excitation of NH 3 and its reactive radicals promotes a radical-driven •NH 2 –N* coupling pathway that dominates on Co 3 C(001) and Co 3 N(001), shifting the rate-limiting step to NH 3 (v1) dissociation, increasing turnover frequencies by up to 6 orders of magnitude, and reducing the temperature needed to reach a turnover frequency of 5 s –1 from >680 °C (Ru and Co under thermal condition) to 267 °C (Co 3 C) and 415 °C (Co 3 N). These results identify Co-based carbides and nitrides as promising plasma-active catalysts for energy-efficient hydrogen production from ammonia.

ammonia decomposition↗