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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Probing coherence in nanoscale energy transport with high spatial-temporal resolution. Final Technical Report for DOE Award Number DE-SC0019244

The overarching goal of this project is to understand how the phase coherence of phonons and the interaction of phonons with other microscopic degrees of freedom in nanomaterials, such as 2D materials, can affect the energy transport properties and eventually lead to control of energy transport by manipulating phonon interference and phonon scatterings. On the computational side, we are developing and applying first-principles methods to study emerging phonon properties in nanomaterials, including coherent phonons, resonant bonding and gate-tunable phonon-electron scatterings, which hold the promise of enabling significant tunability of energy transport processes with external fields for a wide range of applications. On the experimental side, we are developing ultrafast transient grating spectroscopy and scanning ultrafast electron microscopy (SUEM) to directly probe the coherent phonon transport and phonon-electron interaction processes in nanomaterials with high combined spatial-temporal resolutions. This program will not only provide new insights into the microscopic transport and interaction processes of fundamental energy carriers, but also open new venue towards energy-relevant applications such as thermal switches and coherent energy harvesters.

42 ENGINEERING↗
DOE OSTI2024

Geochemical and Microbial Dynamics of Hydrogen in a Methane Storage Reservoir

Hydrogen has been identified as a flexible energy carrier with zero or negative emission across multiple energy systems, and existing natural gas infrastructure could be leveraged if hydrogen gas (H2) was blended with methane (CH4). For example, subsurface methane storage reservoirs could be slightly modified to also store hydrogen if a methane/hydrogen blend were injected. However, the compatibility of methane storage reservoirs to include H2 injection has not been fully demonstrated, and this could lead to geochemical and microbiological reactions that alter the reservoir and stored gas content. It is essential that we understand the impact of H2 gas on the biogeochemistry of subsurface storage reservoirs before deploying large-scale H2-CH4 storage, We collected produced fluid from two separate methane storage reservoirs in the Southwestern US. First, we completed a baseline analysis of the biogeochemistry through qPCR, 16S rRNA sequencing, metagenomic sequencing, and geochemical analysis. Each reservoir was found to have unique geochemical conditions and a unique microbial community structure, with Site 1 having a higher TDS and an abundance of Shewanella and Site 2 having a lower TDS and high abundance of Eubacterium and Acetobacterium. Next, we ran a series of high pressure, high temperature reactors under hydrogen storage conditions with the biological sample from one of the storage reservoirs and a 20% H2-80% CH4 gas blend for up to 7 days. Our results show a decrease of hydrogen by 5% in reactors as early as 1-3 days. Previous hydrogen storage work has linked subsurface microorganisms with methanogenesis hydrogen sulfide production, acid production, and microbial corrosion. Our results show minimal change in the fluid chemistry, with the exception of a decrease in dissolved sulfate concentrations. Taxonomic sequencing demonstrated the presence of microorganisms capable of iron redox, acid generation, and hydrogen sulfide production throughout the reactors, suggesting microbial hydrogen consumption may occur through various metabolic pathways. This work demonstrates that site-specific geochemistry and microbiology may impact the efficiency of hydrogen storage in methane storage reservoirs.

environmental microbiology↗
DOE OSTI2025

Potential Challenges of HyBlend Storage in a Methane Reservoir Located in Southwestern United States

Hydrogen has been identified as a flexible energy carrier with zero or negative emissions across multiple energy systems. It is possible to utilize hydrogen by storing Hyblend, or hydrogen gas blended with methane, in existing natural gas infrastructure. However, the compatibility of adapting the current CH4 storage strategies to include H2 injection has not been fully demonstrated. It is essential that we understand the impact of H2 gas on the naturally occurring microbial community of subsurface storage reservoirs before deploying large-scale H2-CH4 storage. We designed a series of experiments that allowed us to identify potential geochemical and microbial challenges of HyBlend Storage in existing methane reservoirs. First, we collected and characterized field fluid samples from a methane reservoir located in southwestern United States. Next, we used these field fluid samples to complete a series of short-term reactor experiments at reservoir conditions (80 °C and ~1,000 psi) for a natural gas (100% CH4) and HyBlend(80% CH4/20% H2) storage environment to measure the transformation of gas content. We conducted both biotic and abiotic (sterilized) measurements to accurately understand and decouple abiotic and microbially driven processes. Overall, we found that our field sample was characterized by a diverse microbial community with the metabolic capacity for sulfur reduction, iron reduction, and acetogenesis. Across our reactors, there was minimal change in geochemistry.

hydrogen storage↗
DOE OSTI2021

Chalkboard 2 - How to Make Clean Hydrogen

Clean hydrogen is a carbon-free energy carrier that can be produced from water and sustainable energy sources such as wind, solar, and nuclear. Therefore, clean hydrogen is one of the best ways to not only decarbonize the energy supply system, but also address the zero-emission challenges specific to large-carbon emitting industries that are difficult to separate from fossil fuels. To help achieve the Biden Administration's goal of a 100% clean energy economy and net-zero emissions by 2050, several tens of millions of metric tons of clean, low-cost hydrogen will be needed annually. The HydroGEN Advanced Water Splitting Materials (AWSM) Consortium was established in 2016 as part of the Energy Materials Network (EMN) under the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office to enhance the performance, improve the durability, and reduce the cost of clean hydrogen production technologies, and it is helping to advance the H2@Scale vision.

08 HYDROGEN↗
DOE OSTI2024

Biogeochemical Responses and Microbial Community Dynamics Responding to Experimental Hydrogen Storage Conditions

Hydrogen has been identified as a flexible energy carrier with zero or negative carbon emission across multiple energy sectors. There is tremendous capacity for deep geologic storage of H2 but many aspects of feasibility, reliability, safety and the potential for unintended consequences need to be examined. As part of a larger programmatic effort to address the knowledge gaps, we aim to gain a better understanding of reservoir microbial communities and their metabolic and biogeochemical responses to hydrogen storage conditions. In this study we collected and characterized reservoir brine from candidate hydrogen storage sites in the southwestern U.S. for use in a temporal reactor series under blended storage conditions (40% H2, 40% CH4, 20% CO2) at reservoir temperature (60°C).

hydrogen storage↗
DOE OSTI2022

System and technoeconomic analysis of solar thermochemical hydrogen production

Hydrogen is a promising energy carrier that can be obtained from various feedstocks using renewable energy sources. Direct solar thermochemical hydrogen (STCH) production by water splitting can utilize the full spectrum of solar radiation and has the potential to achieve high solar energy conversion efficiencies. Currently STCH research areas focus on material discovery. This paper evaluates the performance of various STCH materials in the context of a system platform to assess techno-economic benefits and gaps in the path to STCH scale-up. Additionally, to analyze the hydrogen production cost, a concentrating solar thermal (CST) system is introduced as a platform for integrating STCH materials and accommodating generalized thermochemical processes. The thermochemical process is based on a two-step STCH cycle using metal oxide that consists of a high temperature step for metal oxide reduction, followed by an oxidation step for water splitting at a lower temperature. A preferred configuration is to have the high temperature step occurring in a directly irradiated solar receiver reactor. To this end, we conceptualized a receiver design and associated solar field layout and investigated STCH operational boundaries, component costs and sensitivity parameters on the $2/kgH 2 goal of hydrogen production. The study explored system-related variables and factors associated with scaling up. The CST platform allows more comprehensive studies that encompass aspects of STCH materials and systems such as cost, hydrogen productivity and replacement frequency, alongside other system components like heliostat field, tower, and potential receiver costs.

08 HYDROGEN↗
DOE OSTI2020

Photocarrier Dynamics in TlGaS 2 Nanoflakes and van der Waals Heterostructures with Hexagonal Boron Nitride and WS 2 Nanoflakes: Implications for Optoelectronic Applications

We present an experimental investigation on photocarrier dynamics in a TlGaS 2 bulk crystal and its heterostructures with hexagonal BN and WS 2 . The samples were obtained by mechanical exfoliation and dry transfer techniques. The photocarrier dynamics was monitored by a transient absorption technique. We observed a direct optical transition of about 555 nm in the TlGaS 2 crystal. By utilizing transient absorption of that transition, we obtained a hot-carrier energy relaxation time of less than 1 ps and a carrier lifetime of about 300 ps in TlGaS 2 at room temperature. In the hexagonal-BN-TlGaS 2 heterostructure, the photocarrier dynamics was similar to that in TlGaS 2 , indicating the type-I band alignment of this structure with both band extremes located in TlGaS 2 . In the monolayer WS 2 -TlGaS 2 heterostructure, we observed charge transfer from TlGaS 2 to WS 2 and an extended lifetime of the transferred carriers in WS 2 . Here, these results introduce TlGaS 2 as a promising layered material for developing two-dimensional van der Waals materials that can be combined with other two-dimensional materials for various optoelectronic devices.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Preliminary Evidence of Gas-Phase Water Splitting on Holmium Nitrogen Oxide Clusters

Preliminary Evidence of Gas-Phase Water Splitting on Holmium Nitrogen Oxide Clusters Christopher A. Zarzana1, Makayla R. Baxter , Introduction: Molecular hydrogen is a potential energy carrier that could be used to help implement a clean energy economy if it is generated from splitting of water. Improvements in the efficiencies of water-splitting electrolyzers relies on development of novel materials with enhanced performance. However, research in this area is slowed due to underdeveloped understanding of the mechanisms of device performance due to challenges interrogating the fundamental chemical reactions at play in bulk materials. Studies of the intrinsic reactivity of clusters that are representative of the reactive sites of these materials can increase understanding of the fundamental reaction mechanisms involved in hydrogen production, allowing for more efficient development of new water-splitting materials. Methods: Holmium tetranitrato ([Ho(NO3)4]-) clusters were generated in gas-phase using the electrospray ionization source of a Bruker (Billerica, MA, USA) micrOTOF-Q II quadrupole time-of-flight mass spectrometer. Spray solutions consisted of aqueous holmium (Ho) nitrate solutions (at nominally 3 mM) diluted to 30 µM in acetonitrile. The holmium (Ho) tetranitrato clusters were isolated using the quadrupole and were subsequently activated and allowed to react with background water in the collision cell. High resolution, high mass accuracy spectra were recorded using the time-of-flight. Mass accuracy was ensured using external calibration with Agilent (Santa Clara, CA, USA) ESI-L Low Concentration tuning mix. Preliminary data: Collisional activation of the holmium tetranitrato complexes ([Ln(NO3)4]-) resulted in an expected series of ions resulting from the loss of ·NO and ·NO2. This included an ion at m/z = 382.885 assigned as [HoO2(NO3)3]- (theoretical m/z=382.884, error=-1.2 ppm), resulting from loss of ·NO, and an ion at m/z=366.890 assigned as [HoO(NO3)3]- (theorical m/z=366.889, error=-1.8 ppm), resulting from loss of ·NO2. Additional ions were detected that would result from more complicated losses from [Ho(NO3)4]-, including ions at m/z=320.898 assigned as [HoO2(NO3)2]- (theoretical m/z=320.896, error=-4.9 ppm), at m/z=304.904 assigned as [HoO(NO3)2]- (theoretical m/z=304.901, error=-8.1 ppm, very low signal), and at m/z=288.908 assigned as [Ho(NO3)2]- (theoretical m/z=288.907, error=-3.4 ppm). This ion series would arise from loss of some combination of ·NO, ·NO2, and ·NO3, although it is not known whether these losses occur sequentially (e.g. loss of ·NO and ·NO3 to yield [HoO2(NO3)2]-) or as a single species (e.g. direct loss of N2O4). These ions were accompanied by a complementary series representing addition of a single water molecule. This included an ion at m/z=338.908 assigned as [HoO2(NO3)2H2O]- (theoretical m/z=338.907, error=-4.1 ppm), an ion at m/z=322.912 assigned as [HoO(NO3)2H2O]- (theoretical m/z=322.912, error=1.2 ppm), and an ion at m/z=306.918 assigned as [Ho(NO3)2H2O]-, (theoretical m/z=306.918, error=-3.7 ppm). An additional hydrated ion was observed at m/z=276.921 assigned as [HoO2(NO3) H2O]- (theoretical m/z=276.919, error=-7.3 ppm), although corresponding dehydrated ion was not observed. An additional ion was observed at m/z=367.898 that has been assigned as [Ho(NO3)3OH]- (theoretical m/z=367.897, error=-2.5 ppm). It is hypothesized that this ion arises from addition of water to [Ho(NO3)3]- followed by elimination of a hydrogen radical. Neither [Ho(NO3)3]- nor [Ho(NO3)3H2O]- were detected, suggesting that, if the hypothesis is correct, addition of water to [Ho(NO3)3]- and its subsequent splitting is rapid. Elimination of HNO3 from [Ho(NO3)4H2O]- could also yield [Ho(NO3)3OH]-; however, no [Ho(NO3)4H2O]- ions were observed. Novelty: Potential evidence of water splitting on gas-phase lanthanide clusters offers a way to study the intrinsic reactivity of hydrogen-generation materials.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Ten questions concerning energy flexibility in buildings

Demand side energy flexibility is increasingly being viewed as an essential enabler for the swift transition to a low-carbon energy system that displaces conventional fossil fuels with renewable energy sources while maintaining, if not improving, the operation of the energy system. Building energy flexibility may address several challenges facing energy systems and electricity consumers as society transitions to a low-carbon energy system characterized by distributed and intermittent energy resources. For example, by changing the timing and amount of building energy consumption through advanced building technologies, electricity demand and supply balance can be improved to enable greater integration of variable renewable energy. Although the benefits of utilizing energy flexibility from the built environment are generally recognized, solutions that reflect diversity in building stocks, customer behavior, and market rules and regulations need to be developed for successful implementation. In this paper, we pose and answer ten questions covering technological, social, commercial, and regulatory aspects to enable the utilization of energy flexibility of buildings in practice. In particular, we provide a critical overview of techniques and methods for quantifying and harnessing energy flexibility. We discuss the concepts of resilience and multi-carrier energy systems and their relation to energy flexibility. We argue the importance of balancing stakeholder engagement and technology deployment. Finally, we highlight the crucial roles of standardization, regulation, and policy in advancing the deployment of energy flexible buildings.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2023

Opportunities for green hydrogen production with land-based wind in the United States

Hydrogen (H 2 ) is an efficient energy carrier and storage mechanism that can supply both stationary and transport energy demand. Rapidly declining renewable energy generation costs; technology innovations in wind, solar, battery storage, and electrolysis; and a global push for more sustainable and secure energy have driven increased interest in green H 2 production. In this study, we develop an H 2 scenario analysis tool to assist in rapid, high-resolution insights into future, green H 2 pathways to achieve policy goals and market competitiveness. Using this tool, we estimate H 2 production and costs for U.S., off-grid scenarios given varying policy and cost scenarios from 2025–2035. Results indicate that achieving economically competitive green H 2 production (below $\$$2/kg) is possible in 2030 with no policy incentives (one site achieves this target), while increasing policy support to include wind and green H 2 production tax credits enables widespread economic viability sooner, with sub-$\$$2/kg LCOH targets achieved by 2025 and 51.7% of sites achieving this target by 2035. Maximizing policy support through prevailing wage and apprenticeship credit multipliers enable widespread economic viability, including sub-$\$$2/kg of green H 2 by 2025 and even negative pricing by 2035. Regions with lowest LCOH values correspond to high wind resource areas and capacity factors. Achieving decarbonization goals with green H 2 depends on technology cost reductions and policy support, with a maximum average LCOH reduction of $\$$23.10 between no and maximum policy support scenarios, and a maximum average LCOH reduction of $\$$25.86 between current, conservative technology costs and 2035 projected technology cost assumptions.

08 HYDROGEN↗
DOE OSTI2024

Oxidation of Ammonia Catalyzed by a Molecular Iron Complex: Translating Chemical Catalysis to Mediated Electrocatalysis

Abstract Ammonia is a promising candidate in the quest for sustainable, clean energy. With its capacity to serve as an energy carrier, the oxidation of ammonia opens avenues for carbon‐neutral approaches to address worldwide growing energy needs. We report the catalytic chemical oxidation of ammonia by an Earth‐abundant transition metal complex, trans ‐ [LFe II (MeCN) 2 ][PF 6 ] 2 , where L is a macrocyclic ligand bearing four N ‐heterocyclic carbene (NHC) donors. Using triarylaminium radical cations in MeCN, up to 182 turnovers of N 2 per Fe were obtained from chemical catalysis with an extremely low loading of the Fe catalyst (0.043 mM, 0.004 mol % catalyst). This chemical catalysis was successfully transitioned to mediated electrocatalysis for the oxidation of ammonia. Molecular electrocatalysis by the Fe catalyst and the mediator ( p ‐MeOC 6 H 4 ) 3 N exhibited a catalytic half‐wave potential ( E cat/2 ) of 0.18 V vs [Cp 2 Fe] +/0 in MeCN, and achieved 9.3 turnovers of N 2 at an applied potential of 0.20 V vs [Cp 2 Fe] +/0 at −20 °C in controlled‐potential electrolysis, with a Faradaic efficiency of 75 %. Based on computational results, the catalyst undergoes sequential oxidation and deprotonation steps to form [LFe IV (NH 2 ) 2 ] 2+ , and thereafter bimetallic coupling to form an N−N bond.

Liu, Liang↗
DOE OSTI2024

Oxidation of Ammonia Catalyzed by a Molecular Iron Complex: Translating Chemical Catalysis to Mediated Electrocatalysis

Abstract Ammonia is a promising candidate in the quest for sustainable, clean energy. With its capacity to serve as an energy carrier, the oxidation of ammonia opens avenues for carbon‐neutral approaches to address worldwide growing energy needs. We report the catalytic chemical oxidation of ammonia by an Earth‐abundant transition metal complex, trans ‐ [LFe II (MeCN) 2 ][PF 6 ] 2 , where L is a macrocyclic ligand bearing four N ‐heterocyclic carbene (NHC) donors. Using triarylaminium radical cations in MeCN, up to 182 turnovers of N 2 per Fe were obtained from chemical catalysis with an extremely low loading of the Fe catalyst (0.043 mM, 0.004 mol % catalyst). This chemical catalysis was successfully transitioned to mediated electrocatalysis for the oxidation of ammonia. Molecular electrocatalysis by the Fe catalyst and the mediator ( p ‐MeOC 6 H 4 ) 3 N exhibited a catalytic half‐wave potential ( E cat/2 ) of 0.18 V vs [Cp 2 Fe] +/0 in MeCN, and achieved 9.3 turnovers of N 2 at an applied potential of 0.20 V vs [Cp 2 Fe] +/0 at −20 °C in controlled‐potential electrolysis, with a Faradaic efficiency of 75 %. Based on computational results, the catalyst undergoes sequential oxidation and deprotonation steps to form [LFe IV (NH 2 ) 2 ] 2+ , and thereafter bimetallic coupling to form an N−N bond.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Effect of hydrogen on tensile properties of 304L stainless steel at cryogenic temperatures

Safe and efficient hydrogen storage and distribution are key attributes to realizing hydrogen as an alternative energy carrier. To this end, cryogenic liquid and cryo-compressed gaseous hydrogen are considered high energy density alternatives to ambient temperature gas. However, these alternatives have significant material demands to overcome extreme temperature (20 K) and pressure (700 bar) as well as hydrogen effects. Austenitic stainless steels are widely used for cryogenic pressure vessels owing to relatively high ductility even at 4 K. However, the influence of hydrogen on mechanical properties at cryogenic temperatures has rarely been studied. In this study, the tensile properties of 304L austenitic stainless steel with internal hydrogen were evaluated at 20 K, 77 K, and 113 K. Test specimens were saturated with internal hydrogen to concentration of 140 wtppm in a high pressure environment at elevated temperature, a process called thermal precharging. While lower temperature in known to increase strength properties and reduced elongation at fracture, the presence of internal hydrogen increased both strength and elongation at fracture, but reduced ductility. Magnetic evaluation of the uniformly strained region of the test specimens suggest that hydrogen mitigates the strain-induced transformation to a’-martensite. Brittle fracture features and secondary cracking indicative of hydrogen embrittlement were observed on the fracture surfaces of hydrogen-precharged specimens, which is consistent with the loss of ductility.

Merkel, Daniel R.↗
DOE OSTI2022

Hydrogen 101: Frequently Asked Questions About Hydrogen for Decarbonization

Hydrogen is emerging across the world as a potential low-carbon energy carrier that can provide an alternative to fossil fuels. With the increasing deployment of renewable energy, the role of low-carbon power generation in hydrogen production through electrolysis is expected to increase. Hydrogen can also play a role in reducing carbon emissions in several strategic sectors such as chemicals, iron, steel, and long-haul transport like heavy-duty trucks and shipping. As a result of these possibilities, many countries have included hydrogen as a central part of their energy strategies. This growing interest has led to many questions among various stakeholders, including policymakers, planners, regulators, system operators, utilities, and investors. This fact sheet provides answers to some of the most frequently asked questions related to hydrogen production, transportation, storage, cross-sectoral utilization, and its role in power sector decarbonization.

08 HYDROGEN↗
DOE OSTI2024

The hydrogen economy can reduce costs of climate change mitigation by up to 22%

In response to the urgent need to mitigate climate change via net-zero targets, many nations are renewing their interest in clean hydrogen as a net-zero energy carrier. Although clean hydrogen can be directly used in various sectors for deep decarbonization, the relatively low energy density and high production costs have raised doubts as to whether clean hydrogen development is worthwhile. Here, we improve on the GCAM model by including a more comprehensive and detailed representation of clean hydrogen production, distribution, and demand in all sectors of the global economy and simulate 25 scenarios to explore the cost-effectiveness of integrating clean hydrogen into the global energy system. We show that, due to costly technical obstacles, clean hydrogen can only provide 3%–9% of the 2050 global final energy use. Nevertheless, clean hydrogen deployment can reduce overall energy decarbonization costs by 15%–22%, mainly via powering “hard-to-electrify” sectors that would otherwise face high decarbonization expenditures. Our work provides practical references for cost-effective clean hydrogen planning.

08 HYDROGEN↗
DOE OSTI2022

Demonstrating Advanced Nuclear Energy Solutions for Net Zero

Background/Objectives. The aggressive goals being set by nation states, communities, and private industry for decarbonization of grid electricity, industrial heat sources, and transportation around the world are imperative to mitigating the devastating effects that we are seeing from climate change. Although many of these goals focus on accomplishments by 2035 or 2050, the decisions that we make today won’t just impact the landscape of energy systems for the next 20 or 30 years—they will shape the world’s environment for centuries to come. That means that we can’t just focus on technologies that will get us to 2050, but technologies that will withstand our energy demands over that long-ranging future. Success will require us to utilize all of the clean energy resources that we have available to meet demands for electricity, heat, and steam, and we will need energy carriers such as hydrogen that do not emit additional greenhouse gases at the point of use. Nuclear energy, ranging from technologies in service today to advanced, higher temperature and modular systems that will be in service this decade, will provide a robust complement to renewable energy resources that operate variably. Researchers across the U.S. Department of Energy laboratory complex are working to advance multiple aspects of these clean energy solutions, with many focusing on integrated energy system solutions that leverage all available clean energy assets to meet wide-ranging energy demands. Approach/Activities. Nuclear energy is a proven, zero-emission option during operation that can provide consistent, dispatchable power to meet electricity demands while also providing high-quality heat that can meet energy demands beyond the electricity sector. Energy system design should seek to maximize these assets. As a dispatchable energy source with a small land utilization footprint, nuclear energy can be collocated with renewable resources, and the smaller systems that will be deployed this decade (ranging from a few megawatts to hundreds of megawatts) can be installed right where that energy is needed. Integrated nuclear and renewable systems will enhance power grid reliability and resilience, and they will help stabilize the grid through their increasingly flexible operation. Licensing, installation, and broad adoption of these advanced nuclear energy systems are expected to progress significantly in the 2020s, but this may be longer than desired by some stakeholders wishing to implement impactful clean energy decisions today. However, one must recall that nuclear energy systems will operate for 80 or more years, as is being demonstrated by current fleet nuclear systems. The nuclear community is extremely thorough in reviewing these systems with regard to safety and security; these efforts ensure that the deployed systems will continue to provide reliable, resilient energy over that operational lifetime. That investment of time up front will ensure that we can support energy demands over the centuries to come. While advanced nuclear technologies move through this process, communities and private industry may choose to install renewable generation systems that can later be coupled to the complementary nuclear systems as they become available—thus moving closer to the net zero goals in the near term. Choosing technologies and deployment configurations that allow small modular nuclear powerhouses to be added to these “energy parks” as they become available will ensure that advanced technologies can be readily adopted to support growing demands for clean energy. Results/Lessons Learned. The primary focus of integrated energy systems (IES) research is to assess the technical and economic potential of novel multi-input, multioutput solutions that are expected to enhance energy system flexibility, reliability, and resilience as we pursue a clean energy transition. Various energy applications and product streams beyond electricity are being evaluated, ranging from generation of potable water to production of hydrogen, fertilizers, synthetic fuels, and various chemicals. In early FY23 Idaho National Laboratory (INL) will commission thermal energy generation systems that emulate nuclear fission energy input using electric heating and will allow for integrated system testing with thermal energy storage, hydrogen production via high temperature electrolysis (HTE), and power systems hardware to demonstrate operation of a clean energy park within a microgrid or larger grid infrastructure, supporting up to 450 kW of heat input via electric heating and demonstrating operation of HTE systems at the multi-hundred kW scale. This presentation will highlight the wide array of RD&D being conducted at INL and partner laboratories to develop and deploy nuclear and renewable-based IES that will be key to achieving our net zero goals, including both computational and experimental demonstrations. By working with key collaborators in industry, analytical st

08 HYDROGEN↗
DOE OSTI2022

Ammonia eurefstics: Electrolytes for liquid energy storage and conversion at room temperature and ambient pressure

Herein we report the transformation of gaseous ammonia to a liquid at room temperature and ambient pressure through mixing with simple solid ammonium salts. The resulting liquids, named eurefstics, are potentially advantageous for the storage and electrochemical conversion of ammonia and the realization of a green ammonia energy economy. Physical properties of these eurefstics, including the temperature-dependent composition and composition-dependent densities, are reported to glean initial insight into the formation and behavior of this intriguing liquid. Preliminary electrochemical investigations of the eurefstics were also performed. We have found that these eurefstics formed are conductive and can be used directly as electrolytes for ammonia electrolysis reactions to produce hydrogen on demand. Open-circuit potential measurements were also made to determine the formal potential of the hydrogen evolution and corresponding overpotentials. Finally, safety concerns of the eurefstics are discussed in comparison with other liquid phase energy carriers.

25 ENERGY STORAGE↗
DOE OSTI2023

Local-Scale Framework for Techno-Economic Analysis of Subsurface Hydrogen Storage

The energy sector is evolving toward increased reliance on renewable energy technologies to meet state, national, and organization decarbonization goals. This trend is creating challenges and opportunities with meeting current and future energy demand under the variable supply conditions that most renewables provide. Hydrogen (H 2 ) is a promising energy carrier that may meet the need for both on-demand and long-duration storage to maintain energy security and resilience. Underground hydrogen storage (UHS) is a method of storing H 2 in subsurface geological systems, such as depleted hydrocarbon reservoirs, salt caverns, saline aquifers, hard rock, and other engineered systems. UHS has the potential to store large quantities of H 2 over time, providing a reliable source of energy while minimizing surface footprints at a lower investment cost compared to surface storage. Earlier work estimated that, if converted and retrofitted, existing underground natural gas storage (UGS) facilities in the U.S. can store approximately 327 TWh, or 9.8 million metric tons, of pure H 2 . However, a shift to pure H 2 would decrease the collective working-gas energy of the UGS facilities by approximately 75% due to physical and chemical differences between natural gas and hydrogen. The same work also suggests that almost 75% of the existing UGS facilities in the U.S. could maintain current energy demand buffering using a blend of only 20% H 2 to 80% natural gas, by volume at surface conditions. If we can take advantage of the suite of mature technologies of existing UGS facilities and natural gas utility systems to accelerate the transition to a hydrogen economy in the U.S., a 20% H 2 blend could lead to a 6-7% reduction of greenhouse gas emissions for energy delivered through natural gas utility systems.

03 NATURAL GAS↗