United States

The viability and public acceptance of the hydrogen and fuel cell (HFC) systems and infrastructure depends on their robust safety engineering design education and training of the workforce regulators and other stakeholders in the state-of-the-art in the field. This can be provided only through building up and maturity of the hydrogen safety engineering (HSE) profession. HSE is defined as an application of scientific and engineering principles to the protection of life property and environment from adverse effects of incidents/accidents involving hydrogen. This paper describes a design framework and overviews a structure and contents of technical sub-systems for carrying out HSE. The approach is similar to British standard BS7974 for application of fire safety engineering to the design of buildings and expanded to reflect on specific for hydrogen safety related phenomena including but not limited to high pressure under-expanded leaks and dispersion spontaneous ignition of sudden hydrogen releases to air deflagrations and detonations etc. The HSE process includes three main steps. Firstly a qualitative design review is undertaken by a team that can incorporate owner hydrogen safety engineer architect representatives of authorities having jurisdiction e.g. fire services and other stakeholders. The team defines accident scenarios suggests trial safety designs and formulates acceptance criteria. Secondly a quantitative safety analysis of selected scenarios and trial designs is carried out by qualified hydrogen safety engineer(s) using the state-of-the-art knowledge in hydrogen safety science and engineering and validated models and tools. Finally the performance of a HFC system and/or infrastructure under the trial safety designs is assessed against predefined by the team acceptance criteria. This performance-based methodology offers the flexibility to assess trial safety designs using separately or simultaneously three approaches: deterministic comparative or combined probabilistic/deterministic.

In July 2020 the European Union unveiled its new Hydrogen Strategy a visionary plan to accelerate the adoption of green hydrogen to meet the EU’s net-zero emissions goal by 2050. Combined with smaller-scale plans in South Korea and Japan IEEFA believes this could form the beginnings of a global green hydrogen economy.

Green hydrogen produced exclusively with renewable energy has been acclaimed for decades but ever lower solar electricity costs mean this time really is different.

We expect the EU’s initiative to find strong support as the proposed investment of €430bn by 2030 places it in pole position to develop a world-class green energy manufacturing industry and provides a vital bridge for energy transition by repurposing existing ‘natural’ gas pipelines and fossil-fuel dependent ports.

In the past year numerous green hydrogen projects have been proposed primarily in Asia Europe Australia.

We estimate there are 50 viable projects globally announced in the past year with a total hydrogen production capacity of 4 million tons per annum and renewable power capacity of 50 gigawatts (GW) requiring capex of US$75bn.

The paper can be download on the IEEFA website

The possibility of using hydrogen as a reliable energy carrier for both stationary and mobile applications has gained renewed interest in recent years due to improvements in high temperature fuel cells and a reduction in hydrogen production costs. However a number of challenges remain and new media are needed that are capable of safely storing hydrogen with high gravimetric and volumetric densities. Metal hydrides and complex metal hydrides offer some hope of overcoming these challenges; however many of the high capacity “reversible” hydrides exhibit a large endothermic decomposition enthalpy making it difficult to release the hydrogen at low temperatures. On the other hand the metastable hydrides are characterized by a low reaction enthalpy and a decomposition reaction that is thermodynamically favorable under ambient conditions. The rapid low temperature hydrogen evolution rates that can be achieved with these materials offer much promise for mobile PEM fuel cell applications. However a critical challenge exists to develop new methods to regenerate these hydrides directly from the reactants and hydrogen gas. This spotlight paper presents an overview of some of the metastable metal hydrides for hydrogen storage and a few new approaches being investigated to address the key challenges associated with these materials.

The H2@Scale program of the U.S. Department of Energy (DOE) Fuel Cell Technologies Office is supporting work on the hydrogen compatibility of polymers to improve the durability and reliability of materials for hydrogen infrastructure. The hydrogen compatibility program (H-Mat) seeks “to address the challenges of hydrogen degradation by elucidating the mechanisms of hydrogen-materials interactions with the goal of providing science-based strategies to design materials (micro)structures and morphology with improved resistance to hydrogen degradation.” This research has found hydrogen and pressure interactions with model rubber-material compounds demonstrating volume change and compression-set differences in the materials. The research leverages state-of-the-art capabilities of the DOE national labs. The materials were investigated using helium-ion microscopy which revealed significant morphological changes in the plasticizer incorporating compounds after exposure as evidenced by time-of-flight secondary ion mass spectrometry. Additional studies using transmission electron microscopy and nuclear magnetic resonance revealed that nanosized inclusions developed after gas decompression in rubber- and plasticizer-only materials; this is an indication of void formation at the nanometer level.

Today electricity & heat generation transportation and industrial sectors together produce more than 80% of energy-related CO₂ emissions. Hydrogen may be used as an energy carrier and an alternative fuel in the industrial residential and transportation sectors for either heating energy production from fuel cells or direct fueling of vehicles. In particular the use of hydrogen fuel cell vehicles (HFCVs) has the potential to virtually eliminate CO₂ emissions from tailpipes and considerably reduce overall emissions from the transportation sector. Although steam methane reforming (SMR) is the dominant industrial process for hydrogen production environmental concerns associated with CO₂ emissions along with the process intensification and energy optimization are areas that still require improvement. Metallic membrane reactors (MRs) have the potential to address both challenges. MRs operate at significantly lower pressures and temperatures compared with the conventional reactors. Hence the capital and operating expenses could be considerably lower compared with the conventional reactors. Moreover metallic membranes specifically Pd and its alloys inherently allow for only hydrogen permeation making it possible to produce a stream of up to 99.999+% purity.

For smaller and emerging hydrogen markets such as the semiconductor and fuel cell industries Pd-based membranes may be an appropriate technology based on the scales and purity requirements. In particular at lower hydrogen production rates in small-scale plants MRs with CCUS could be competitive compared to centralized H₂ production. On-site hydrogen production would also provide a self-sufficient supply and further circumvent delivery delays as well as issues with storage safety. In addition hydrogen-producing MRs are a potential avenue to alleviate carbon emissions. However material availability Pd cost and scale-up potential on the order of 1.5 million m3/day may be limiting factors preventing wider application of Pd-based membranes.

Regarding the economic production of hydrogen the benchmark by the year 2020 has been determined and set in place by the U.S. DOE at less than $2.00 per kg of produced hydrogen. While the established SMR process can easily meet the set limit by DOE other carbon-free processes such as water electrolysis electron beam radiolysis and gliding arc technologies do not presently meet this requirement. In particular it is expected that the cost of hydrogen produced from natural gas without CCUS will remain the lowest among all of the technologies while the hydrogen cost produced from an SMR plant with solvent-based carbon capture could be twice as expensive as the conventional SMR without carbon capture. Pd-based MRs have the potential to produce hydrogen at competitive prices with SMR plants equipped with carbon capture.

Despite the significant improvements in the electrolysis technologies the cost of hydrogen produced by electrolysis may remain significantly higher in most geographical locations compared with the hydrogen produced from fossil fuels. The cost of hydrogen via electrolysis may vary up to a factor of ten depending on the location and the electricity source. Nevertheless due to its modular nature the electrolysis process will likely play a significant role in the hydrogen economy when implemented in suitable geographical locations and powered by renewable electricity.

This review provides a critical overview of the opportunities and challenges associated with the use of the MRs to produce high-purity hydrogen with low carbon emissions. Moreover a technoeconomic review of the potential methods for hydrogen production is provided and the drawbacks and advantages of each method are presented and discussed.

A series of molecular rotors was designed to study and measure the rate accelerating effects of an intramolecular hydrogen bond. The rotors form a weak neutral O–H⋯O[double bond length as m-dash]C hydrogen bond in the planar transition state (TS) of the bond rotation process. The rotational barrier of the hydrogen bonding rotors was dramatically lower (9.9 kcal mol⁻¹) than control rotors which could not form hydrogen bonds. The magnitude of the stabilization was significantly larger than predicted based on the independently measured strength of a similar O–H⋯O[double bond length as m-dash]C hydrogen bond (1.5 kcal mol⁻¹). The origins of the large transition state stabilization were studied via experimental substituent effect and computational perturbation analyses. Energy decomposition analysis of the hydrogen bonding interaction revealed a significant reduction in the repulsive component of the hydrogen bonding interaction. The rigid framework of the molecular rotors positions and preorganizes the interacting groups in the transition state. This study demonstrates that with proper design a single hydrogen bond can lead to a TS stabilization that is greater than the intrinsic interaction energy which has applications in catalyst design and in the study of enzyme mechanisms.

Carbon capture and storage (CCS) is broadly recognised as having the potential to play a key role in meeting climate change targets delivering low carbon heat and power decarbonising industry and more recently its ability to facilitate the net removal of CO₂ from the atmosphere. However despite this broad consensus and its technical maturity CCS has not yet been deployed on a scale commensurate with the ambitions articulated a decade ago. Thus in this paper we review the current state-of-the-art of CO₂ capture transport utilisation and storage from a multi-scale perspective moving from the global to molecular scales. In light of the COP21 commitments to limit warming to less than 2 °C we extend the remit of this study to include the key negative emissions technologies (NETs) of bioenergy with CCS (BECCS) and direct air capture (DAC). Cognisant of the non-technical barriers to deploying CCS we reflect on recent experience from the UK's CCS commercialisation programme and consider the commercial and political barriers to the large-scale deployment of CCS. In all areas we focus on identifying and clearly articulating the key research challenges that could usefully be addressed in the coming decade.

The U.S. transportation sector accounts for 37% of total energy consumption. Automobiles are a primary application of polymer electrolyte membrane (PEM) fuel cells which operate under low temperature and high efficiency to reduce fossil fuel consumption and CO2 emissions. Using hydrogen fuel PEM fuel cells can reach a practical efficiency as high as 65% with water as the only byproduct. Almost all the major automakers are involved in fuel cell electric vehicle (FCEV) development. Toyota and Hyundai introduced FCEVs (the Mirai and NEXO respectively) to consumers in recent years with a driving range between 312 and 402 miles and cold-start capacity from -30 °C. About 50 fuel cell electric buses (FCEB) are operating in California and most of them have achieved the durability target i.e. 25000 h in real-world driving conditions. As of September 2020 over 8573 FCEVs have been sold or leased in the U.S. More than 3521 FCEVs and 22 FCEBs have been sold or leased in Japan as of September 2019. An extensive hydrogen station network is required for the successful deployment of FCEVs and FCEBs. The U.S. currently has over 44 hydrogen fuelling stations (HFSs) nearly all located in California. Europe has over 139 HFSs with ~1500 more stations planned by 2025. This review has three primary objectives: 1) to present the current status of FCEV/FCEB commercialization and HFS development; 2) to describe the PEM fuel cell research/development in automobile applications and the significance of HFS networks; and 3) to outline major challenges and opportunities.

The transition to hydrogen as a fuel source presents several challenges. One of the major hurdles is the cost-effective production of hydrogen in small quantities (less than 1MMscf/month). In the early demonstration phase hydrogen can be provided by bulk distribution of liquid or compressed gas from central production plants; however the next phase to fostering the hydrogen economy will likely include onsite generation and extensive pipeline networks to help effect a pervasive infrastructure. Providing inexpensive hydrogen at a fleet operator’s garage or local fuelling station is a key enabling technology for direct hydrogen Fuel Cell Vehicles (FCVs). The objective of this project was to develop a comprehensive turnkey stand-alone commercial hydrogen fuelling station for FCVs with state-of-the-art technology that is cost-competitive with current hydrocarbon fuels. Such a station would promote the advent of the hydrogen fuel economy for buses fleet vehicles and ultimately personal vehicles. Air Products partnering with the U.S. Department of Energy (DOE) The Pennsylvania State University Harvest Energy Technology and QuestAir developed a turnkey hydrogen fuelling station on the Penn State campus. Air Products aimed at designing a station that would have 65% overall station efficiency 82% PSA (pressure swing adsorption) efficiency and the capability of producing hydrogen at $3.00/kg (gge) H₂ at mass production rates. Air Products designed a fuelling station at Penn State from the ground up. This project was implemented in three phases. The first phase evaluated the various technologies available in hydrogen generation compression storage and gas dispensing. In the second phase Air Products designed the components chosen from the technologies examined. Finally phase three entailed a several-month period of data collection full-scale operation maintenance of the station and optimization of system reliability and performance. Based on field data analysis it was determined by a proprietary hydrogen-analysis model that hydrogen produced from the station at a rate of 1500 kg/day and when produced at 1000 stations per year would be able to deliver hydrogen at a price of $3.03/kg (gge) H₂. The station’s efficiency was measured to be 65.1% and the PSA was tested and ran at an efficiency of 82.1% thus meeting the project targets. From the study it was determined that more research was needed in the area of hydrogen fuelling. The overall cost of the hydrogen energy station when combined with the required plot size for scaled-up hydrogen demands demonstrated that a station using steam methane reforming technology as a means to produce on–site hydrogen would have limited utility in the marketplace. Alternative hydrogen supplies such as liquid or pipeline delivery to a refuelling station need to be included in the exploration of alternative energy site layouts. These avenues need to be explored before a definitive refuelling station configuration and commercialization pathway can be determined.

Hydrogen Fuelling Infrastructure Research and Station Technology (H2FIRST) is a project initiated by the DOE in 2015 and executed by Sandia National Laboratories and the National Renewable Energy Laboratory to address R&D barriers to the deployment of hydrogen fuelling infrastructure. One key barrier to the deployment of fuelling stations is the land area they require (i.e. ""footprint""). Space is particularly a constraint in dense urban areas where hydrogen demand is high but space for fuelling stations is limited. This work presents current fire code requirements that inform station footprint then identifies and quantifies opportunities to reduce footprint without altering the safety profile of fuelling stations. Opportunities analyzed include potential new methods of hydrogen delivery as well as alternative placements of station technologies (i.e. rooftop/underground fuel storage). As interest in heavy-duty fuelling stations and other markets for hydrogen grows this study can inform techniques to reduce the footprint of heavy-duty stations as well.



This work characterizes generic designs for stations with a capacity of 600 kg/day hydrogen dispensed and 4 dispenser hoses. Three base case designs (delivered gas delivered liquid and on-site electrolysis production) have been modified in 5 different ways to study the impacts of recently released fire code changes colocation with gasoline refuelling alternate delivery assumptions underground storage of hydrogen and rooftop storage of hydrogen resulting in a total of 32 different station designs. The footprints of the base case stations range from 13000 to 21000 ft².



A significant focus of this study is the NFPA 2 requirements especially the prescribed setback distances for bulk gaseous or liquid hydrogen storage. While the prescribed distances are large in some cases these setback distances are found to have a nuanced impact on station lot size; considerations of the delivery truck path traffic flow parking and convenience store location are also important. Station designs that utilize underground and rooftop storage can reduce footprint but may not be practical or economical. For example burying hydrogen storage tanks underground can reduce footprint but the cost savings they enable depend on the cost of burial and the cost land. Siting and economic analysis of station lot sizes illustrate the benefit of smaller station footprints in the flexibility and cost savings they can provide. This study can be used as a reference that provides examples of the key design differences that fuelling stations can incorporate the approximate sizes of generic station lots and considerations that might be unique to particular designs.