United States

With rising demand for clean energy global focus turns to finding ideal sites for large-scale underground hydrogen storage (UHS) in depleted petroleum reservoirs. A thorough preliminary reservoir evaluation before hydrogen (H2) injection is crucial for UHS success and safety. Recent criteria for UHS often emphasize economics and chemistry neglecting key reservoir attributes. This study introduces a comprehensive framework for the reservoir-scale preliminary assessment specifically tailored for long-term H2 storage within depleted gas reservoirs. The evaluation criteria encompass critical components including reservoir geometry petrophysical properties tectonics and formation fluids. To illustrate the practical application of this approach we assess the Barnett shale play reservoir parameters. The assessment unfolds through three key stages: (1) A systematic evaluation of the reservoir's properties against our comprehensive screening criteria determines its suitability for H2 storage. (2) Using both homogeneous and multilayered gas reservoir models we explore the feasibility and efficiency of H2 storage. This phase involves an in-depth examination of reservoir behavior during the injection stage. (3) To enhance understanding of UHS performance sensitivity analyses investigate the impact of varying reservoir dimensions and injection/production pressures. The findings reveal the following: (a) Despite potential challenges associated with reservoir compaction and aquifer support the reservoir exhibits substantial promise as an H2 storage site. (b) Notably a pronounced increase in reservoir pressure manifests during the injection stage particularly in homogeneous reservoirs. (c) Furthermore optimizing injection-extraction cycle efficiency can be achieved by augmenting reservoir dimensions while maintaining a consistent thickness. To ensure a smooth transition to implementation further comprehensive investigations are advised including experimental and numerical studies to address injectivity concerns and explore storage site development. This evaluation framework is a valuable tool for assessing the potential of depleted gas reservoirs for large-scale hydrogen storage advancing global eco-friendly energy systems.

Hydrogen is increasingly recognized as a pivotal energy storage solution and a transformative alternative to conventional energy sources. This review summarizes the evolving landscape of global H2 production and consumption markets focusing on the crucial role of photothermal catalysts (PTCs) in driving Hydrogen evolution reactions (HER) particularly with regards to oxide selenide and telluride-based PTCs. Within this exploration the mechanisms of PTCs take center stage elucidating the intricacies of light absorption localized heating and catalytic activation. Essential optimization parameters ranging from temperature and irradiance to catalyst composition and pH are detailed for their paramount role in enhancing catalytic efficiency. This work comprehensively explores photothermal catalysts (PTCs) for hydrogen production by assessing their synthesis techniques and highlighting the current research gaps particularly in optimizing catalytic stability light absorption and scalability. The energy-efficient nature of oxide selenide and telluride-based PTCs makes them prime candidates for sustainable H2 production when compared to traditional materials. By analyzing a range of materials we summarize key performance metrics including hydrogen evolution rates ranging from 0.47 mmolh− 1 g− 1 for Ti@TiO2 to 22.50 mmolh− 1 g− 1 for Mn0.2Cd0.8S/NiSe2. The review concludes with a strategic roadmap aimed at enhancing PTC performance to meet the growing demand for renewable hydrogen as well as a critical literature review addressing challenges and prospects in deploying PTCs.

Energy system optimization models offer insights into energy and emissions futures through least-cost optimization. However real-world energy systems often deviate from deterministic scenarios necessitating rigorous uncertainty exploration in macro-energy system modeling. This study uses modeling techniques to generate diverse near cost-optimal net-zero CO2 pathways for the United States’ energy system. Our findings reveal consistent trends across these pathways including rapid expansion of solar and wind power generation substantial petroleum use reductions near elimination of coal combustion and increased end-use electrification. We also observe varying deployment levels for natural gas hydrogen direct air capture of CO2 and synthetic fuels. Notably carbon-captured coal and synthetic fuels exhibit high adoption rates but only in select decarbonization pathways. By analyzing technology adoption correlations we uncover interconnected technologies. These results demonstrate that diverse pathways for decarbonization exist at comparable system-level costs and provide insights into technology portfolios that enable near cost-optimal net-zero CO2 futures.

Natural ventilation is a well-known passive mitigation method to limit hydrogen build-up in confined spaces in case of accidental release [1-3]. In most cases a basic design of H2 infrastructure is adopted and vents installed for natural ventilation are adjusted according to safety targets and constraints of the considered structure. With the growing H2 mobility market the demand for H2 refueling infrastructure in our urban environment is on the rise. In order to meet both safety requirements and societal acceptance the design of such infrastructure is becoming more important. In this study a novel design concept is proposed for the hydrogen refueling station (HRS) by modifying physical structure while keeping safety consideration as the top priority of the concept. In this collaborative project between Air Liquide and the University of Delaware an extensive evaluation was performed on new structures of the processing container and dispenser of HRS by integrating safety protocols via passive means. Through a SWOT analysis combined with the most relevant approaches including analytical engineering models numerical simulations [4] and dedicated experimental trials an optimized design was obtained and its safety enhancement was fully evaluated. A small-scale processing container and an almost full-scale dispenser were built and tested to validate the design concepts by simulating accidental H2 release scenarios and assessing the associated consequences in terms of accumulation and potential flammable volumes formation. A conical dispenser and a V-shaped roof-top processing container which were easy to build and implement were designed and tested for this proof-of-concept study. This unique methodology from conception fundamental analysis investigation and validation through experimental design execution and evaluation is fully described in this study.

Introduction: Several cities in Malaysia have established plans to reduce their CO2 emissions in addition to Malaysia submitting a Nationally Determined Contribution to reduce its carbon intensity (against GDP) by 45% in 2030 compared to 2005. Meeting these emissions reduction goals will require ajoint effort between governments industries and corporations at different scales and across sectors.<br/>Methods: In collaboration with national and sub-national stakeholders we developed and used a global integrated assessment model to explore emissions mitigation pathways in Malaysia and Kuala Lumpur. Guided by current climate action plans we created a suite of scenarios to reflect uncertainties in policy ambition level of adoption and implementation for reaching carbon neutrality. Through iterative engagement with all parties we refined the scenarios and focus of the analysis to best meet the stakeholders’ needs.<br/>Results: We found that Malaysia can reduce its carbon intensity and reach carbon neutrality by 2050 and that action in Kuala Lumpur can play a significant role. Decarbonization of the power sector paired with extensive electrification energy efficiency improvements in buildings transportation and industry and the use of advanced technologies such as hydrogen and carbon capture and storage will be Major drivers to mitigate emissions with carbon dioxide removal strategies being key to eliminate residual emissions.<br/>Discussion: Our results suggest a hopeful future for Malaysia’s ability to meet its climate goals recognizing that there may be technological social and financial challenges along the way. This study highlights the participatory process in which stakeholders contributed to the development of the model and guided the analysis as well as insights into Malaysia’s decarbonization potential and the role of multilevel governance.

Securing decarbonized economies for energy and commodities will requireabundant and widely available green H2. Ubiquitous wastewaters and nontraditional watersources could potentially feed water electrolyzers to produce this green hydrogen withoutcompeting with drinking water sources. Herein we show that the energy and costs of treatingnontraditional water sources such as municipal wastewater industrial and resource extractionwastewater and seawater are negligible with respect to those for water electrolysis. We alsoillustrate that the potential hydrogen energy that could be mined from these sources is vast.Based on these findings we evaluate the implications of small-scale distributed waterelectrolysis using disperse nontraditional water sources. Techno-economic analysis and lifecycle analysis reveal that the significant contribution of H2 transportation to costs and CO2emissions results in an optimal levelized cost of hydrogen at small- to moderate-scale waterelectrolyzer size. The implications of utilizing nontraditional water sources and decentralizedor stranded renewable energy for distributed water electrolysis are highlighted for severalhydrogen energy storage and chemical feedstock applications. Finally we discuss challengesand opportunities for mining H2 from nontraditional water sources to achieve resilient and sustainable economies for water andenergy.

Until recently electrified aircraft propulsion (EAP) technology development has been driven by the dual objectives of reducing greenhouse gas (GHG) emissions and addressing the depletion of fossil fuels. However the increasing severity of climate change posing a significant threat to all life forms has resulted in the global consensus of achieving net-zero GHG emissions by 2050. This major shift has alerted the aviation electrification industry to consider the following: What is the clear path forward for EAP technology development to support the net-zero GHG goals for large commercial transport aviation? The purpose of this paper is to answer this question. After identifying four types of GHG emissions that should be used as metrics to measure the effectiveness of each technology for GHG reduction the paper presents three significant categories of GHG reduction efforts regarding the engine evaluates the potential of EAP technologies within each category as well as combinations of technologies among the different categories using the identified metrics and thus determines the path forward to support the net-zero GHG objective. Specifically the paper underscores the need for the aviation electrification industry to adapt adjust and integrate its EAP technology development into the emerging new engine classes. These innovations and collaborations are crucial to accelerate net-zero GHG efforts effectively.

The depletion of fossil fuels in the current world has been a major concern due to their role as a primary source of energy for many countries. As non-renewable sources continue to deplete there is a need for more research and initiatives to reduce reliance on these sources and explore better alternatives such as renewable energy. Hydrogen is one of the most intriguing energy sources for producing power from fuel cells and heat engines without releasing carbon dioxide or other pollutants. The production of hydrogen via the electrolysis of water using renewable energy sources such as solar energy is one of the possible uses for solid oxide electrolysis cells (SOECs). SOECs can be classified as either oxygen-ion conducting or proton-conducting depending on the electrolyte materials used. This article aims to highlight broad and important aspects of the hybrid SOEC-based solar hydrogen-generating technology which utilizes a mixed-ion conductor capable of transporting both oxygen ions and protons simultaneously. In addition to providing useful information on the technological efficiency of hydrogen production in SOEC this review aims to make hydrogen production more efficient than any other water electrolysis system.

The NREL Hydrogen Sensor Laboratory is comprised of researchers dedicated to furthering hydrogen sensor technology and detection methodology. NREL has teamed up with researchers at Environment and Climate Change Canada (ECCC) and Transport Canada (TC) to conduct research to quantify hydrogen emissions from Fuel Cell Electric Vehicles (FCEV). Test protocols will have a large effect on monitoring and regulating the hydrogen emissions from FCEVs. How emissions are tested will play an important role when understanding the safety and environmental implications of using FCEVs. NREL Sensor Laboratory personnel have partnered with other entities to conduct multiple variations of emissions testing for FCEVs. This experimentation includes testing different models of FCEVs under various driving conditions while monitoring the hydrogen concentration of the exhaust using several different test methods and apparatus. Researchers look to support regulatory bodies by providing useful data that can support more consistent and relevant safety and environmental standards. We plan to present on the current test methods and results from recent emissions measurements at ECCC.

Industrial and public interest in hydrogen technologies has risen strongly recently as hydrogen is the ideal means for medium to long term energy storage transport and usage in combination with renewable and green energy supply. In a future energy system the production storage and usage of green hydrogen is a key technology. Hydrogen is and will in future be even more used for industrial production processes as a reduction agent or for the production of synthetic hydrocarbons especially in the chemical industry and in refineries. Under certain conditions material based systems for hydrogen storage and compression offer advantages over the classical systems based on gaseous or liquid hydrogen. This includes in particular lower maintenance costs higher reliability and safety. Hydrogen storage is possible at pressures and temperatures much closer to ambient conditions. Hydrogen compression is possible without any moving parts and only by using waste heat. In this paper we summarize the newest developments of hydrogen carriers for storage and compression and in addition give an overview of the different research activities in this field.