Publications

Hydrogen is widely recognized as an attractive energy carrier due to its low-level air pollution and its high mass-related energy density. However its wide flammability range and high burning velocity present a potentially significant hazard. A significant fraction of hydrogen is stored and transported as a cryogenic liquid (liquid hydrogen or LH2) as it requires much less volume compared to gaseous hydrogen. In order to exist as a liquid H2 must be cooled to a very low temperature 20.28 K. LH2 is a common liquid fuel for rocket applications. It can also be used as the fuel storage in an internal combustion engine or fuel cell for transport applications. Models for handling liquid releases both two-phase flashing jets and pool spills have been developed in the CFD-model FLACS. The very low normal boiling point of hydrogen (20 K) leads to particular challenges as this is significantly lower than the boiling points of oxygen (90 K) and nitrogen (77 K). Therefore a release of LH2 in the atmosphere may induce partial condensation or even freezing of the oxygen and nitrogen present in the air. A pool model within the CFD software FLACS is used to compute the spreading and vaporization of the liquid hydrogen depositing on the ground where the partial condensation or freezing of the oxygen and nitrogen is also taken into account. In our computations of two-phase jets the dispersed and continuous phases are assumed to be in thermodynamic and kinematic equilibrium. Simulations with the new models are compared against selected experiments performed at the Health and Safety Laboratory (HSL).

Reversible solid oxide cells (r-SOCs) can be operated in either solid oxide fuel cell or solid oxide electrolysis cell mode. They are expected to become important in the support of renewable energy due to their high efficiency for both power generation and hydrogen generation. The exchange current density is one of the most important parameters in the quantification of electrode performance in solid oxide cells. In this study four different fuel electrodes and two different air electrodes are fabricated using different materials and the microstructures are compared. The temperature fuel humidification and oxygen concentration at the air electrode are varied to obtain the apparent exchange current density for the different electrode materials. In contrast to ruthenium-and-gadolinia-doped ceria (Rh-GDC) as well as nickel-and-gadolinia-doped ceria (Ni-GDC) electrodes significant differences in the apparent exchange current density were observed between electrolysis and fuel cell modes for the nickel-scandia-stabilized zirconia (Ni-ScSZ) cermet. Variation of gas concentration revealed that surface adsorption sites were almost completely vacant for all these electrodes. The apparent exchange current densities obtained in this study are useful as a parameter for simulation of the internal properties of r-SOCs.

The HyDeploy project is the UK’s first practical project to demonstrate that hydrogen can be safely blended into the natural-gas distribution system without requiring changes to appliances and the associated disruption. The project is funded under Ofgem’s Network Innovation Competition and is a collaboration between Cadent Gas Northern Gas Networks Progressive Energy Ltd Keele University (Keele) Health & Safety Laboratory and ITM Power. Cadent and Northern Gas Networks are the Gas Distribution Network sponsors of the project. Keele University is the host site providing the gas-distribution network which will receive the hydrogen blend. Keele University is the largest campus university in the UK. Health & Safety Laboratory provides the scientific laboratories and experimental expertise. ITM Power provides the electrolyser that produces the hydrogen. Progressive Energy Ltd is the project developer and project manager. HyDeploy is structured into three distinct phases. The first is an extensive technical programme to establish the necessary detailed evidence base in support of an application to the Health & Safety Executive for Exemption to Schedule 3 of the Gas Safety (Management) Regulations (GS(M)R) to permit the injection of hydrogen at 20 mol%. This is required to allow hydrogen to be blended into a natural-gas supply above the current British limit of 0.1 mol%.



The second phase comprises the construction of the electrolyser and grid entry unit along with the necessary piping and valves to allow hydrogen to be mixed and injected into the Keele University gas-distribution network and to ensure all necessary training of operatives is conducted before injection. The third phase is the trial itself which is due to start in the summer of 2019 and last around 10 months. The trial phase also provides an opportunity to undertake further experimental activities related to the operational network to support the pathway to full deployment of blended gas. The outcome of HyDeploy is principally developing the initial evidence base that hydrogen can be blended into a UK operational natural-gas network without disruption to customers and without prejudicing the safety of end users. If deployed at scale hydrogen blending at 20 mol% would unlock 29 TWh pa of decarbonized heat and provide a route map for deeper savings. The equivalent carbon savings of a national roll-out of a 20-mol% hydrogen blend would be to remove 2.5 million cars from the road.



HyDeploy is a seminal UK project for the decarbonization of the gas grid via hydrogen deployment and will provide the first stepping stone for setting technical operational and regulatory precedents of the hydrogen vector.

In the course towards a safe future hydrogen based society one of the tasks to be considered is the investigation of the conditions under which the use or storage of hydrogen systems inside buildings becomes too dangerous to be accepted. One of the relevant scenarios which is expected to have a relatively high risk is a slow (and long lasting) hydrogen release from a vehicle stored in a closed private garage without any forced ventilation i.e. only with natural ventilation. This scenario has been earlier investigated experimentally (by M. Swain) using He (helium) to simulate the hydrogen behavior. In the present work the CFD code ADREA-HF is used to simulate three of the abovementioned experiments using the standard k-  turbulence model. For each case modeled the predicted concentration (by vol.) time series are compared against the experimental at the given sensor locations. In addition the structure of the flow is investigated by presenting the helium concentration field.

The successful development of hydrogen-energy technologies has several advantages and benefits. Hydrogen energy development could prevent global warming as well as ensure energy security for countries without adequate energy resources. The successful development of hydrogen would provide energy for transportation and electric power. It is a unique energy carrier as it can be produced from various energy sources such as wind fossil fuels and biomass and when it is combusted it emits no CO2 emissions. The other advantage is the wide distribution of resources globally that can be used to produce hydrogen. In Japan the Ministry of Economy Trade and Industry (METI) published a ‘Strategic Roadmap for Hydrogen and Fuel Cells’ in 2014 with a revised update published in March 2016. The goal of the roadmap is to achieve a hydrogen society. The roadmap aims to resolve technical problems and secure economic efficiency. The roadmap has been organized into the following three phases: Phase 1—Installation of fuel cells; Phase 2—Hydrogen power plant/mass supply chain; Phase 3—CO2- free hydrogen. This paper reports on the current status of fuel cells and fuel-cell vehicles in Japan and gives a description and status of the R&D programmes along with the results of global energy model study towards 2050.

This report responds to a request from the Governments of the UK Wales and Scotland asking the Committee to reassess the UK’s long-term emissions targets. Our new emissions scenarios draw on ten new research projects three expert advisory groups and reviews of the work of the IPCC and others.<br/>The conclusions are supported by detailed analysis published in the Net Zero Technical Report that has been carried out for each sector of the economy plus consideration of F-gas emissions and greenhouse gas removals.

Hydrogen production from butanol is a promising alternative when it is obtained from bio-butanol or bio-oil due to the higher hydrogen content compared to other oxygenates such as methanol ethanol or propanol. Catalysts and operating conditions play a crucial role in hydrogen production. Ni and Rh are metals mainly used for butanol steam reforming oxidative steam reforming and partial oxidation. Additives such as Cu can improve catalytic activity in many folds. Moreover support–metal interaction and catalyst preparation technique also play a decisive role in the stability and hydrogen production capacity of catalyst. Steam reforming technique as an option is more frequently researched due to higher hydrogen production capability in comparison to other thermochemical techniques despite its endothermic nature. The use of the oxidative steam reforming and partial oxidation has the advantages of requiring less energy and longer stability of catalysts. However the hydrogen yield is less. This article brings together and examines the latest research on hydrogen production from butanol via steam reforming oxidative steam reforming and partial oxidation reactions. In addition the review examines a few thermodynamic studies based on sorption-enhanced steam reforming and dry reforming where there is potential for hydrogen extraction.  

Hydrogen is considered a secondary source of energy commonly referred to as an energy carrier. It has the highest energy content when compared to other common fuels by weight having great potential for further development. Hydrogen can be produced from various domestic resources but based on the fossil resource conditions in China coal-based hydrogen energy is considered to be the most valuable because it is not only an effective way to develop clean energy but also a proactive exploration of the clean usage of traditional coal resources. In this article the sorption-enhanced water–gas shift technology in the coal-to-hydrogen section and the hydrogen-storage and transport technology with liquid aromatics are introduced and basic mechanisms technical advantages latest progress and future R&D focuses of hydrogen-production and storage processes are listed and discussed. As a conclusion after considering the development frame and the business characteristics of CHN Energy Group a conceptual architecture for developing coal-based hydrogen energy and the corresponding supply chain is proposed.

Hydrogen is recognized as a promising and attractive energy carrier to decarbonize the sectors responsible for global warming such as electricity production industry and transportation. However although hydrogen releases only water as a result of its reaction with oxygen through a fuel cell the hydrogen production pathway is currently a challenging issue since hydrogen is produced mainly from thermochemical processes (natural gas reforming coal gasification). On the other hand hydrogen production through water electrolysis has attracted a lot of attention as a means to reduce greenhouse gas emissions by using low-carbon sources such as renewable energy (solar wind hydro) and nuclear energy. In this context by providing an environmentally-friendly fuel instead of the currently-used fuels (unleaded petrol gasoline kerosene) hydrogen can be used in various applications such as transportation (aircraft boat vehicle and train) energy storage industry medicine and power-to-gas. This article aims to provide an overview of the main hydrogen applications (including present and future) while examining funding and barriers to building a prosperous future for the nation by addressing all the critical challenges met in all energy sectors.

The Reactive Discrete Equation Method (RDEM) was recently introduced in [12] adapted to combustion modelling in [3] and implemented in the TONUS code [4]. The method has two major features: the combustion constant having velocity dimension is the fundamental flame speed and the combustion wave now is an integral part of the Reactive Riemann Problem. In the present report the RDEM method is applied to the simulation of the combustion Test 13H performed in the ENACCEF facility. Two types of computations have been considered: one with a constant fundamental flame speed the other with time dependent fundamental flame speed. It is shown that by using the latter technique we can reproduce the experimental visible flame velocity. The ratio between the fundamental flame speed and the laminar flame speed takes however very large values compared to the experimental data based on the tests performed in spherical bombs or cruciform burner.

This is the eighth annual Progress Report to the Scottish Parliament required by Scottish Ministers under the Climate Change (Scotland) Act 2009. It assesses Scotland’s progress in achieving its legislated targets to reduce greenhouse gas emissions.<br/>Overall greenhouse gas emissions reduced by 3% in 2017 compared to a 10% fall in 2016. The fall was again led by the power sector due in large part to Scotland’s first full year of coal-free electricity generation. Recent performance in other sectors shows only incremental improvement at best and unless emissions reductions are delivered economy-wide Scotland is at risk of missing its new interim target of a 56% reduction in emissions by 2020. Setting a net-zero greenhouse gas emissions target for 2045 represents a step-change in ambition for Scotland. The Scottish Parliament’s 2030 target to reduce emissions by 75% will be extremely challenging to meet. It must be backed up by steps to drive meaningful emissions reductions immediately.<br/>Scotland’s Programme for Government 2019-20 alongside other recent policies sent a clear signal that the Scottish Government is taking its more ambitious targets seriously but there is much more to do.Scotland’s ability to deliver its net-zero target is contingent on action taken in the UK and vice versa.

In this report the Committee sets out how Northern Ireland can reduce its greenhouse gas emissions between now and 2030 in order to meet UK-wide climate change targets.

The report’s key findings are:

• Existing policies are not enough to deliver this reduction
• There are excellent opportunities to close this gap and go beyond 35%
• Meeting the cost-effective path to decarbonisation in Northern Ireland will require action across all sectors of the economy and a more joined-up approach

Overall Northern Ireland’s fair contribution to the UK’s fifth carbon budget requires emissions reductions of at least 35% against 1990 levels by 2030.

Hydrogen jet flames resulting from ignition of unintended releases can be extensive in length and pose significant radiation and impingement hazards. One possible mitigation strategy to reduce exposure to jet flames is to incorporate barriers around hydrogen storage and delivery equipment. While reducing the extent of unacceptable consequences the walls may introduce other hazards if not properly configured. This paper describes experiments carried out to characterize the effectiveness of different barrier wall configurations at reducing the hazards created by jet fires. The hazards that are evaluated are the generation of overpressure during ignition the thermal radiation produced by the jet flame and the effectiveness of the wall at deflecting the flame.<br/>The tests were conducted against a vertical wall (1-wall configuration) and two “3-wall” configurations that consisted of the same vertical wall with two side walls of the same dimensions angled at 135° and 90°. The hydrogen jet impinged on the center of the central wall in all cases. In terms of reducing the radiation heat flux behind the wall the 1-wall configuration performed best followed by the 3-wall 135° configuration and the 3-wall 90°. The reduced shielding efficiency of the three-wall configurations was probably due to the additional confinement created by the side walls that limited the escape of hot gases to the sides of the wall and forced the hot gases to travel over the top of the wall.<br/>The 3-wall barrier with 135° side walls exhibited the best overall performance. Overpressures produced on the release side of the wall were similar to those produced in the 1-wall configuration. The attenuation of overpressure and impulse behind the wall was comparable to that of the three-wall configuration with 90° side walls. The 3-wall 135° configuration’s ability to shield the back side of the wall from the heat flux emitted from the jet flame was comparable to the 1-wall and better than the 3-wall 90° configuration. The ratio of peak overpressure (from in front of the wall and from behind the wall) showed that the 3-wall 135° configuration and the 3-wall 90° configuration had a similar effectiveness. In terms of the pressure mitigation the 3-wall configurations performed significantly better than the 1-wall configuration

Hydrogen embrittlement (HE) has been extensively studied in bulk materials. However little is known about the role of H on the plastic deformation and fracture mechanisms of nanoscale materials such as nanowires. In this study molecular dynamics simulations are employed to study the influence of H segregation on the behavior of intergranular cracks in bicrystalline α-Fe nanowires. The results demonstrate that segregated H atoms have weak embrittling effects on the predicted ductile cracks along the GBs but favor the cleavage process of intergranular cracks in the theoretically brittle directions. Furthermore it is revealed that cyclic loading can promote the H accumulation into the GB region ahead of the crack tip and overcome crack trapping thus inducing a ductile-to-brittle transformation. This information will deepen our understanding on the experimentally-observed H-assisted brittle cleavage failure and have implications for designing new nanocrystalline materials with high resistance to HE.

The Committee’s report ‘The compatibility of UK onshore petroleum with meeting the UK’s carbon budgets’ is the result of a new duty under the Infrastructure Act 2015. This duty requires the CCC to advise the Secretary of State for Energy and Climate Change about the implications of exploitation of onshore petroleum including shale gas for meeting UK carbon budgets.<br/>The CCC’s report finds that the implications of UK shale gas exploitation for greenhouse gas emissions are subject to considerable uncertainty – from the size of any future industry to the potential emissions footprint of shale gas production. It also finds that exploitation of shale gas on a significant scale is not compatible with UK carbon budgets or the 2050 commitment to reduce emissions by at least 80% unless three tests are satisfied.

Fuel cell based micro-combined heat and power (CHP) units used for domestic applications can provide significant cost and environmental benefits for end users and contribute to the UK’s 2050 emissions target by reducing primary energy consumption in dwellings. Lately there has been increased interest in the development of systematic methods for the design of such systems and their smoother integration with domestic building services. Several models in the literature whether they use a simulation or an optimisation approach ignore the dwelling side of the system and optimise the efficiency or delivered power of the unit. However the design of the building services is linked to the choice of heating plant and its characteristics. Adding the dwelling’s energy demand and temperature constraints in a model can produce more general results that can optimise the whole system not only the micro-CHP unit. The fuel cell has various heat streams that can be harvested to satisfy heat demand in a dwelling and the design can vary depending on the proportion of heat needed from each heat stream to serve the energy demand. A mixed integer non-linear programming model (MINLP) that can handle multiple heat sources and demands is presented in this paper. The methodology utilises a process systems engineering approach. The model can provide a design that integrates the temperature and water flow constraints of a dwelling’s heating system with the heat streams within the fuel cell processes while optimising total CO₂ emissions. The model is demonstrated through different case studies that attempt to capture the variability of the housing stock. The predicted CO₂ emissions reduction compared to a conventionally designed building vary from 27% to 30% and the optimum capacity of the fuel cell ranges between 1.9 kW and 3.6 kW. This research represents a significant step towards an integrated fuel cell micro-CHP and dwelling design.

Hydrogen and renewable electricity-based microgrid is considered to be a promising way to reduce carbon emissions promote the consumption of renewable energies and improve the sustainability of the energy system. In view of the fact that the existing day-ahead optimal operation model ignores the uncertainties and fluctuations of renewable energies and loads a two-stage energy management model is proposed for the sustainable wind-PV-hydrogen-storage microgrid based on receding horizon optimization to eliminate the adverse effects of their uncertainties and fluctuations. In the first stage the day-ahead optimization is performed based on the predicted outpower of WT and PV the predicted demands of power and hydrogen loads. In the second stage the intra-day optimization is performed based on the actual data to trace the day-ahead operation schemes. Since the intra-day optimization can update the operation scheme based on the latest data of renewable energies and loads the proposed two-stage management model is effective in eliminating the uncertain factors and maintaining the stability of the whole system. Simulations show that the proposed two-stage energy management model is robust and effective in coordinating the operation of the wind-PV-hydrogen-storage microgrid and eliminating the uncertainties and fluctuations of WT PV and loads. In addition the battery storage can reduce the operation cost alleviate the fluctuations of the exchanged power with the power grid and improve the performance of the energy management model.

In the transition to a hydrogen economy it is likely that hydrogen will be used or stored in close proximity to other flammable fuels and gases. Accidents can occur that result in the release of two or more fuels such as hydrogen and natural gas that can mix and form a hazard. A series of five medium-scale semi-open-space deflagration experiments have been conducted with hydrogen natural gas and air mixtures. The natural gas consisted of 90% methane 6% ethane 3% propane and 1% butane by volume. Mixtures of hydrogen and natural gas were created with the hydrogen mole fraction in the fuel varying from 1.000 to 0.897 and the natural gas mole fraction varying from 0.000 to 0.103. The hydrogen and natural gas mixture was then released inside a 5.27-m³ thin plastic tent. The stoichiometric fuel-air mixtures were ignited with a 40-J spark located at the bottom center of the tent. Overpressure and impulse data were collected using pressure transducers located within the mixture volume and in the free field. Flame front time-of-arrival was measured using fast response thermocouples and infrared video. Flame speeds relative to a fixed observer were measured between 36.2 m/s and 19.7 m/s. Average peak overpressures were measured between 2.0 kPa and 0.3 kPa. The addition of natural gas inhibited the combustion when the hydrogen mole fraction was less than or equal to 0.949. For these mixtures there was a significant decrease in overpressures. When the hydrogen mole fraction in the fuel was between 0.999 and 0.990 the overpressures were slightly higher than for the case of hydrogen alone. This could be due to experimental scatter or there may be a slight enhancement of the combustion when a very small amount of natural gas was present. From a safety standpoint variation in overpressure was small and should have little effect on safety considerations.

Development of efficient and affordable photocatalysts is of great significance for energy production and environmental sustainability. Transition metal chalcogenides (TMCs) with particle sizes in the 1–100 nm have been used for various applications such as photocatalysis photovoltaic and energy storage due to their quantum confinement effect optoelectronic behavior and their stability. In particular TMCs and their heterostructures have great potential as an emerging inexpensive and sustainable alternative to metal-based catalysts for hydrogen evolution. Herein the methods used for the fabrication of TMCs characterization techniques employed and the different methods of solar hydrogen production by using different TMCs as photocatalyst are reviewed. This review provides a summary of TMC photocatalysts for hydrogen production.

We present results from hydrogen dispersion simulations from a pressurized reservoir at constant flow rate in the presence and absence of a wall. The dispersion simulations are performed using a commercial finite volume solver. Validation of the approach is discussed. Constant concentration envelopes corresponding to the 2% 4% and 15% hydrogen concentration in air are calculated for a subcritical vertical jet and for an equivalent subcritical horizontal jet from a high pressure reservoir. The consequences of ignition and the resulting overpressure are calculated for subcritical horizontal and vertical hydrogen jets and in the latter case compared to available experimental data.

Many advanced steels are based on tempered martensitic microstructures. Their mechanical strength is characterized by fine sub-grain structures with a high density of free dislocations and metallic carbides and/or nitrides. However the strength for practical use has been limited mostly to below 1400 MPa owing to delayed fractures that are caused by hydrogen. A literature survey suggests that ε-carbide in the tempered martensite is effective for strengthening. A preliminary experimental survey of the hydrogen absorption and hydrogen embrittlement of a tempered martensitic steel with ε-carbide precipitates suggested that the proper use of carbides in steels can promote a high resistance to hydrogen embrittlement. Based on the surveys martensitic steels that are highly resistant to hydrogen embrittlement and that have high strength and toughness are proposed. The heuristic design of the steels includes alloying elements necessary to stabilize the ε-carbide and procedures to introduce inoculants for the controlled nucleation of ε-carbide.

The CCC has established a variety of viable scenarios in which UK decarbonisation targets can be met. Each has consequences for the way in which the UK’s gas network infrastructure is utilised. This report considers the implications of decarbonisation for the future regulation of the gas grid.<br/>The CCC’s 5th Carbon Budget envisaged different scenarios that would enable the UK to meet its emissions targets for 2050. These scenarios represent holistic analyses based on internally consistent combinations of different technologies which could deliver carbon reductions across different sectors of the economy.<br/>The CCC’s scenarios incorporate projections of the demand for natural gas to 2050. The scenarios imply that the volume of throughput on the gas networks1 and the nature and location of network usage is likely to change significantly to meet emissions targets. They are also characterised by significant uncertainty.<br/>Under some decarbonisation scenarios gas networks could be re-purposed to supply hydrogen instead of natural gas meaning there would be ongoing need for network infrastructure.<br/>In other scenarios gas demand in buildings is largely replaced by electric alternatives meaning portions of the low pressure gas distribution networks could be decommissioned.<br/>Patchwork scenarios are also possible in which there is a mixture of these outcomes across the country.<br/>In this project the CCC wished to assess the potential implications for gas networks under these different demand scenarios; and evaluate the associated challenges for Government and regulatory policy. The challenge for BEIS and Ofgem is how to regulate in a way that keeps options open while uncertainty persists about the best solution for the UK; and at the same time how best to make policy and regulatory decisions which would serve to reduce this uncertainty. Both Government and Ofgem have policy and regulatory levers that they can use – and we identify and evaluate such levers in this report.

In this report Quantifying Greenhouse Gas Emissions the Committee on Climate Change assesses how the UK’s greenhouse gas emissions are quantified where uncertainties lie and the implications for setting carbon budgets and measuring progress against climate change targets. The report finds that:

• The methodology for constructing the UK’s greenhouse gas inventory is rigorous but the process for identifying improvements could be strengthened.
• There is high confidence over large parts of the inventory. A small number of sectors contribute most to uncertainty and research efforts should be directed at improving these estimates.
• UK greenhouse gas emissions for 2014 were within ±3% of the estimated level with 95% confidence which is a low level of uncertainty by international standards.
• Methodology revisions in recent years have tended to increase estimated emissions but these changes have been within uncertainty margins.
• Statistical uncertainty in the current greenhouse gas inventory is low but could rise in future.
• Uncertainty also arises from sources of emissions not currently included in the inventory and from potential changes to IPCC guidelines.
• Independent external validation of greenhouse gas emissions is important and new monitoring techniques should be encouraged.
• Government should continue to monitor consumption-based greenhouse gas estimates and support continued research to improve methodology and reduce uncertainty in these estimates.

For the evaluation of hydrogen and fuel cell vehicle safety a new comprehensive facility was constructed in our institute. The new facility includes an explosion resistant indoor vehicle fire test building and high pressure hydrogen tank safety evaluation equipment. The indoor vehicle fire test building has sufficient strength to withstand even an explosion of a high pressure hydrogen tank of 260 liter capacity and 70 MPa pressure. It also has enough space to observe vehicle fire flames of not only hydrogen but also other conventional fuels such as gasoline or compressed natural gas. The inside dimensions of the building are a 16 meter height and 18 meter diameter. The walls are made of 1.2 meter thick reinforced concrete covered at the insides with steel plate. This paper shows examples of hydrogen vehicle fires compared with other fuel fires and hydrogen high pressure tank fire tests utilizing several kinds of fire sources. Another facility for evaluation of high pressure hydrogen tank safety includes a 110 MPa hydrogen compressor with a capacity of 200 Nm3/h a 300 MPa hydraulic compressor for burst tests of 70 MPa and higher pressure tanks and so on. This facility will be used for not only the safety evaluation of hydrogen and fuel cell vehicles but also the establishment of domestic/international regulations codes and standards.

This is our sixth statutory report to Parliament on progress towards meeting carbon budgets. In it we consider the latest data on emissions and their drivers. This year the report also includes a full assessment of how the first carbon budget (2008-2012) was met drawing out policy lessons and setting out what is required for the future to stay on track for the legislated carbon budgets and the 2050 target. The report includes assessment at the level of the economy the non-traded and traded sectors the key emitting sectors and the devolved administrations. Whilst the first carbon budget has been met and progress made on development and implementation of some policies the main conclusion is that strengthening of policies will be needed to meet future budgets.

As governments focus on dealing with the Covid-19 health emergency they are increasingly turning their attention to the impact of shutting down their economies and how to revive them quickly through stimulus measures. Economic recovery packages offer a unique opportunity to create jobs while supporting clean energy transitions around the world.

Energy efficiency and renewable energy like wind and solar PV – the cornerstones of any clean energy transition – are good places to start. Those industries employ millions of people across their value chains and offer environmentally sustainable ways to create jobs and help revitalise the global economy.

But more than just renewables and efficiency will be required to put the world on track to meet climate goals and other sustainability objectives. IEA analysis has repeatedly shown that a broad portfolio of clean energy technologies will be needed to decarbonise all parts of the economy. Batteries and hydrogen-producing electrolysers stand out as two important technologies thanks to their ability to convert electricity into chemical energy and vice versa. This is why they also deserve a place in any economic stimulus packages being discussed today.

Link to Document on IEA Website

Clarification of questions of safety represents a decisive contribution to the successful introduction of vehicles fuelled by hydrogen. At the moment the safety of hydrogen is being discussed and investigated by various bodies. The primary focus is on fuel-cell vehicles with hydrogen stored in gaseous form. This paper looks at the safety of hydrogen-fuelled vehicles with an internal combustion engine and liquefied hydrogen storage. The safety concept of BMW’s hydrogen vehicles is described and the specific aspects of the propulsion and storage concepts discussed. The main discussion emphasis is on the utilization of boil-off parking of the vehicles in an enclosed space and their crash behaviour. Theoretical safety observations are complemented by the latest experimental and test results. Finally reference is made to the topic-areas in the field of hydrogen safety in which cooperative research work could make a valuable contribution to the future of the hydrogen-powered vehicle.

It is expected that hydrogen will serve as a nonpolluting carrier of energy for the next generation of vehicles and guidelines for its safe use are required. Hydrogen-gas service stations for supplying fuel cell vehicles will have to handle high-pressure hydrogen gas but safety regulations for such installations have not received much investigation. In this study we experimentally investigated the flame characteristics of a rapid leakage of high-pressure hydrogen gas. A hydrogen jet diffusion flame was injected horizontally from convergent nozzles of various diameters between 0.1 and 4 mm at reservoir over pressures of between 0.01 and 40 MPa. The sizes of the flame were measured and experimental equations were obtained for the length and the width of the flame. Flame sizes depend not only on the nozzle diameter but also on the spouting pressure. Blow-off limits exists and are determined by the nozzle diameter and the spouting pressure. Furthermore the radiation from a hydrogen flame can be predicted from the flow rate of the gas and the distance from the flame.

This report forms part of the Committee’s advice on the level of the fifth carbon budget.<br/>The report describes the scenarios used by the Committee to inform its judgements over the cost-effective path to meeting the UK’s greenhouse reduction targets in the period 2028-2032.

The first part of the present work is to validate a detailed kinetic mechanism for the oxidation of hydrogen – methane – air mixtures in a detonation waves. A series of experiments on auto-ignition delay times have been performed by shock tube technique coupled with emission spectrometry for H2 / CH4 / O2 mixtures highly diluted in argon. The CH4/H2 ratio was varied from 0 to 4 and the equivalence ratio from 0.4 up to 1. The temperature range was from 1250 K to 2000 K and the pressure behind reflected shock waves was between 0.15 and 1.6 MPa. A correlation was proposed between temperature (K) concentration of chemical species (mol m-3) and ignition delay times. The experimental auto-ignition delay times were compared to the modelled ones using four different mechanisms from the literature: GRI [22] Marinov et al. [23] Hughes et al. [24] Konnov [25]. A large discrepancy was generally found between the different models. The Konnov’s model that predicted auto-ignition delay times close to the measured ones has been selected to calculate the ignition delay time in the detonation waves. The second part of the study concerned the experimental determination of the detonation properties namely the detonation velocity and the cell size. The effect of the initial composition hydrogen to methane ratio and the amount of oxygen in the mixture as well as the initial pressure on the detonation velocity and on the cell size were investigated. The ratio of methane / (methane + hydrogen) varied between 0 and 0.6 for 2 different equivalence ratio (0.75 and 1) while the initial pressure was fixed to 10 kPa. A correlation was established between the characteristic cell size and the ignition delay time behind the leading shock of the detonation. It was clearly showed that methane has an important inhibitor effect on the detonation of these combustible mixtures.

This is the Committee’s fifth report on Scotland’s progress towards meeting emission reduction targets as requested by Scottish Ministers under the Climate Change (Scotland) Act 2009.<br/>The Scottish Act sets a long-term target to reduce emissions of greenhouse gases (GHGs) by at least 80% in 2050 relative to 1990 with an interim target to reduce emissions by 42% in 2020. Secondary legislation passed in October 2010 and October 2011 also set a series of annual emission reduction targets for 2010 to 2022 and 2023 to 2027 respectively. We advised the Scottish Government on annual targets for the period 2028 to 2032 in March 2016 and July 2016.<br/>The report reveals that Scotland’s annual emissions reduction target for 2014 was met with gross Scottish greenhouse gas emissions including international aviation and shipping falling by 8.6% in 2014. This compares to a 7.3% fall for the UK as a whole. Since 1990 gross Scottish emissions have fallen nearly 40% compared to nearly 33% at a UK level.

Hydrogen technologies maintained strong momentum in 2019 awakening keen interest among policy makers. It was a record year for electrolysis capacity becoming operational and several significant announcements were made for upcoming years. The fuel cell electric vehicle market almost doubled owing to outstanding expansion in China Japan and Korea. However low-carbon production capacity remained relatively constant and is still off track with the SDS. More efforts are needed to: scale up to reduce costs; replace high-carbon with low-carbon hydrogen in current applications; and expand hydrogen use to new applications.

Link to Document on IEA Website

This research introduces a ‘Hydrogen Interconnector System’ (HIS) as a novel method 7 for transporting electrical energy over long distances. The system takes electricity from 8 stranded renewable energy assets converts it to hydrogen in an electrolyser plant transports 9 hydrogen to the demand centre via pipeline where it is reconverted to electricity in either a 10 gas turbine or fuel cell plant. This paper evaluates the competitiveness of the technology with 11 High Voltage Direct Current (HVDC) systems calculating the following techno-economic 12 indicators; Levelised Cost Of Electricity (LCOE) and Levelised Cost Of Storage (LCOS). The 13 results suggest that the LCOE of the HIS is competitive with HVDC for construction in 2050 14 with distance beyond 350km in case of all scenarios for a 1GW system. The LCOS is lower 15 than an HVDC system using large scale hydrogen storage in 6 out of 12 scenarios analysed 16 including for construction from 2025. The HIS was also applied to three case studies with 17 the results showing that the system outperforms HVDC from LCOS perspectives in all cases 18 and has 15-20% lower investment costs in 2 studies analysed.

Hydrogen is not more dangerous than current fossil energy carriers but it behaves differently. Therefore hydrogen specific analyses and countermeasures will be needed to support the development of safe hydrogen technologies. A systematic step-by-step procedure for the mechanistic analysis of hydrogen behaviour and mitigation in accidents is presented. The procedure can be subdivided into four main parts:<br/>1) 3D modelling of the H2-air mixture generation<br/>2) hazard evaluation for this mixture based on specifically developed criteria for flammability flame acceleration and detonation on-set<br/>3) numerical simulation of the appropriate combustion regime using verified 3D-CFD codes and<br/>4) consequence analysis based on the calculated pressure and temperature loads.

Vanadium (V) has higher hydrogen permeability than Pd-based alloy membranes but exhibits poor resistance to hydrogen-induced embrittlement. The alloy elements are added to reduce hydrogen solubility and prevent hydrogen-induced embrittlement. To enhance hydrogen permeability the alloy elements which improve hydrogen diffusivity in V are more suitable. In the present study hydrogen diffusivity in V-Cr V-Al and V-Pd alloy membranes was investigated in view of the hydrogen chemical potential and compared with the previously reported results of V-Fe alloy membranes. The additions of Cr and Fe to V improved the mobility of hydrogen atoms. In contrast those of Al and Pd decreased hydrogen diffusivity. The first principle calculations revealed that the hydrogen atoms cannot occupy the first-nearest neighbour T sites (T1 sites) of Al and Pd in the V crystal lattice. These blocking effects will be a dominant contributor to decreasing hydrogen diffusivity by the additions of Al and Pd. For V-based alloy membranes Fe and Cr are more suitable alloy elements compared with Al and Pd in view of hydrogen diffusivity.

In this paper comparison studies of the hydrogen effect on the structural and phase state deformation behavior and mechanical properties of the fine- (average grain size 4 µm) and ultrafine-grained (average element size 0.3 and 0.4 µm) Zr–1wt.%Nb (hereinafter Zr–1Nb) alloy under tension at temperatures in the range of 293–873 K were conducted. The formation of an ultrafine-grained structure is established to increase the strength characteristics of the Zr–1Nb alloy by a factor of 1.5–2 with a simultaneous reduction of its resistance to the localization of plastic deformation at the macro level and the value of deformation to failure. The presence of hydrogen in the Zr–1Nb alloy in the form of a solid solution and hydride precipitates increases its resistance to the localization of plastic deformation at the macro level if the alloy has an ultrafine-grained structure and decreases if the structure of the alloy is fine-grained. In the studied temperature range the Zr–1Nb alloy in the ultrafine-grained state has a higher resistance to hydrogen embrittlement than the alloy in the fine-grained state.

Recent research efforts to develop advanced–/ultrahigh–strength medium-Mn steels have led to the development of a variety of alloying concepts thermo-mechanical processing routes and microstructural variants for these steel grades. However certain grades of advanced–/ultrahigh–strength steels (A/UHSS) are known to be highly susceptible to hydrogen embrittlement due to their high strength levels. Hydrogen embrittlement characteristics of medium–Mn steels are less understood compared to other classes of A/UHSS such as high Mn twinning–induced plasticity steel because of the relatively short history of the development of this steel class and the complex nature of multiphase fine-grained microstructures that are present in medium–Mn steels. The motivation of this paper is to review the current understanding of the hydrogen embrittlement characteristics of medium or intermediate Mn (4 to 15 wt pct) multiphase steels and to address various alloying and processing strategies that are available to enhance the hydrogen-resistance of these steel grades.

The rise in hydrogen fuel cell electric vehicles (FCEVs) is expected to pose a variety of hazards on the road. Vehicles using hydrogen could cause significant damage owing to hydrogen vapor cloud explosions jet fires caused by leakage or hydrogen tank explosions. This risk is expected to further increase in semi-enclosed spaces such as underground parking lots and road tunnels. Therefore it is necessary to study the fire safety of hydrogen vehicles in semi-enclosed spaces. In this study an experiment on hydrogen tank explosion was performed. In addition the CFD numerical model was verified using the experimental results and the damaging effect due to pressure propagation during hydrogen tank explosions in underground parking lots and road tunnels was analyzed using numerical analysis. From the experiment results the hydrogen tank exploded at about 80 Mpa a maximum incident pressure is generated 267 kPa at a distance of 1.9 m. As a result of numerical analysis based on the experimental results the limit distance that can cause serious injury due to the explosion of a hydrogen tank in a road tunnel or underground parking lot was analyzed up to about 20 m from the point of explosion.

Iron oxide has been widely used as an oxygen carrier material (OCM) for hydrogen production by chemical looping due to its favourable thermodynamic properties. In spite of this iron oxide loses much of its activity after redox cycling mainly due to sintering and agglomeration. Perovskites such as La_0.7Sr_0.3FeO_3-d (LSF731) have been suggested as potential candidate OCMs for hydrogen production due to their excellent oxygen transport properties and stability under cycling. However hydrogen production per cycle for a similar carrier weight is lower than with iron oxide. This work proposes the use of composite OCMs made of iron oxide clusters embedded in an LSF731 matrix. The perovskite matrix facilitates oxygen transport to the iron oxide clusters while preventing agglomeration. Two preparation methods mechanical mixing and a modified Pechini method were used to obtain composite materials with different iron oxide weight fractions 11 and 30 wt.%. The reactivity of these OCMs was studied in a thermogravimetric analyser. Hydrogen production and carrier stability were investigated in a microreactor over 25 redox cycles while periodically feeding carbon monoxide and water in order to produce carbon dioxide and hydrogen in separate streams. Hydrogen production was stable over 25 cycles for LSF731 and the composite OCM with 30 wt.% iron oxide produced by the modified Pechini method but iron oxide particles alone underwent a decrease in the hydrogen production with cycling. The hydrogen production during the 25th cycle was eight times higher for the composite material than for iron oxide alone and four times higher than for LSF731. The hydrogen production was therefore also higher than that expected from a simple combination of the iron oxide and LSF731 alone indicating a synergetic effect whereby the LSF731 may have a higher effective oxygen capacity when in the form of the composite material.

The CEP (Clean Energy Partnership) – Berlin is one of the most diversified hydrogen demonstration projects at present. The first hydrogen fuelling station serving 16 cars is fully integrated in an ordinary highly frequented Aral service station centrally located at Messedamm in Berlin. Hydro has supplied and is the owner of the electrolyser with ancillary systems. This unit produces gaseous hydrogen at 12 bar with use of renewable energy presently serving 13 of the cars involved. The CEP project is planned to run for a period of five years and is supported by the German Federal Government and is part of the German sustainability strategy. During the planning and design phase there have been done several safety related assessments and analyses:

• Hydro has carried out a HAZOP (HAZard and OPerability) analysis of the electrolyser and ancillary systems delivered by Hydro Electrolysers.
• Hydro arranged with support from the partners a HAZOP analysis of the interface between the electrolyser and the compressor an interface with two different suppliers on each side.
• A QRA (Quantitative Risk Assessment) of the entire fuelling station has been carried out.
• Hydro has carried out a quantitative explosion risk analysis of the electrolyser container supplied by Hydro Electrolysers.

The aim in the CEP-Berlin project was to follow the guidelines from the European Integrated Hydrogen Project phase 2 (EIHP2) [1] when planning and designing a new hydrogen fuelling station. These guidelines focus on installation and operation of hydrogen refuelling stations and were based upon best practice and knowledge from the industrial partners in EIHP 2. The explosion risk analysis for the CEP-Berlin facility demonstrated that the safety risk was acceptable if certain design modifications were carried out. Both Aral/BP and Hydro accepted the results from the quantitative risk assessments. These companies have also their own standards regarding safety acceptance criteria which have to be complied with. The fuelling station was opened November 12 2004 and was put in normal operation during winter 2005.

This study outlines an approach to identifying the difficulties associated with the bench-marking of alkaline single cells under real electrolyzer conditions. A challenging task in the testing and comparison of different catalysts is obtaining reliable and meaningful benchmarks for these conditions. Negative effects on reproducibility were observed due to the reduction in conditioning time. On the anode side a stable passivation layer of NiO can be formed by annealing of the Ni foams which is even stable during long-term operation. Electrical contact resistance and impedance measurements showed that most of the contact resistance derived from the annealed Ni foam. Additionally analysis of various overvoltages indicated that most of the total overvoltage comes from the anode and cathode activation overpotential. Different morphologies of the substrate material exhibited an influence on the performance of the alkaline single cell based on an increase in the ohmic resistance.

In automotive applications the operational parameters for fuel cell (FC) systems can vary over a wide range. To analyze their impact on fuel cell degradation an automotive size single cell was operated under realistic working conditions. The parameter sets were extracted from the FC system modelling based on on-road customer data. The parameter variation included simultaneous variation of the FC load gas pressures cell temperature stoichiometries and relative humidity. Current density distributions and the overall cell voltage were recorded in real time during the tests. The current densities were low at the geometric anode gas outlet and high at the anode gas inlet. After electrochemical tests post mortem analysis was conducted on the membrane electrode assemblies using scanning electron microscopy. The ex-situ analysis showed significant cathode carbon corrosion in areas associated with low current densities. This suggests that fuel starvation close to the anode outlet is the origin of the cathode electrode degradation. The results of the numerical simulations reveal high relative humidity at that region and therefore water flooding is assumed to cause local anode fuel starvation. Even though the hydrogen oxidation reaction has low kinetic overpotentials “local availability” of H₂ plays a significant role in maintaining a homogeneous current density distribution and thereby in local degradation of the cathode catalyst layer. The described phenomena occurred while the overall cell voltage remained above 0.3 V. This indicates that only voltage monitoring of fuel cell systems does not contain straightforward information about this type of degradation.

The cost reduction of hydrogen refueling stations (HRSs) is very important for the popularization of hydrogen vehicles. This paper proposes an optimized operation algorithm based on hydrogen energy demand estimation for on-site hydrogen refueling stations. Firstly the user’s hydrogen demand was estimated based on the simulation of their hydrogenation behavior. Secondly mixed integer linear programming method was used to optimize the operation of the hydrogen refueling station to minimize the unit hydrogen energy cost by using the peak–valley difference of the electricity price. We then used three typical scenario cases to evaluate the optimized operation method. The results show that the optimized operation method proposed in this paper can effectively reduce the rated configuration of electrolyzer and storage tank for HRS and can significantly reduce the unit hydrogen energy cost considering the construction cost compared with the traditional method. Therefore the optimization operation method of a local hydrogen production and hydrogen refueling station proposed in this paper can reduce the cost of a hydrogen refueling station and accelerate the popularization of hydrogen energy vehicles. Finally the scope of application of the proposed optimization method and the influence of the variation of the electricity price curve and the unit cost of the electrolyzer are discussed.

In response to the exceptional circumstances stemming from the coronavirus pandemic the annual IEA Global Energy Review has expanded its coverage to include real-time analysis of developments to date in 2020 and possible directions for the rest of the year. In addition to reviewing 2019 energy and CO2 emissions data by fuel and country for this section of the Global Energy Review we have tracked energy use by country and fuel over the past three months and in some cases – such as electricity – in real time. Some tracking will continue on a weekly basis. The uncertainty surrounding public health the economy and hence energy over the rest of 2020 is unprecedented. This analysis therefore not only charts a possible path for energy use and CO2 emissions in 2020 but also highlights the many factors that could lead to differing outcomes. We draw key lessons on how to navigate this once-in-a-century crisis.

Link to Document on IEA websitte

The paper presents an experimental investigation of hydrogen-diesel fuel co-combustion carried out on a naturally aspirated direct injection diesel engine. The engine was supplied with a range of hydrogen-diesel fuel mixture proportions to study the effect of hydrogen addition (aspirated with the intake air) on combustion and exhaust emissions. The tests were performed at fixed diesel injection periods with hydrogen added to vary the engine load between 0 and 6 bar IMEP. In addition a novel inecylinder gas sampling technique was employed to measure species concentrations in the engine cylinder at two inecylinder locations and at various instants during the combustion process. The results showed a decrease in the particulates CO and THC emissions and a slight increase in CO2 emissions with the addition of hydrogen with fixed diesel fuel injection periods. NOx emissions increased steeply with hydrogen addition but only when the combined diesel and hydrogen co-combustion temperatures exceeded the threshold temperature for NOx formation. The inecylinder gas sampling results showed higher NOx levels between adjacent spray cones in comparison to sampling within an individual spray cone.

Tailpipe emissions from vehicles consist of CO2 and other greenhouse gases which con‐ tribute immensely to the rise in global temperatures. Green hydrogen produced from the gasification of biomass can reduce the amount of CO2 emissions to zero. This study aims to provide a modelling framework to optimize the production of hydrogen from biomass waste obtained from different cities for use in the road transport sector in Nigeria. A gasification model with post‐treatment shift conversion and CO2 removal by adsorption is proposed. In this study six cities are simulated based on technical and environmental considerations using the Aspen Plus software package. The results revealed that Kaduna has the highest hydrogen generation potential of 0.148 million metric tons per year which could reduce CO2 emissions to 1.60 and 1.524 million metric tons by the dis‐ placement of an equivalent volume of gasoline and diesel. This amounts to cost savings of NGN 116 and 161.8 billion for gasoline and diesel respectively. In addition the results of the sensitivity analysis revealed that the steam‐to‐biomass ratio and the temperature of gasification are positively correlated with the amount of avoided CO2 emissions while the equivalence ratio shows a negative correlation.

With the rapid development of hydrogen production by water electrolysis the coupling between the electricity-hydrogen system has become closer providing an effective way to consume surplus new energy generation. As a form of centralized management of distributed energy resources virtual power plants can aggregate the integrated energy production and consumption segments in a certain region and participate in electricity market transactions as a single entity to enhance overall revenue. Based on this this paper proposes an optimal scheduling model of an electricity-hydrogen coupling virtual power plant (EHC-VPP) considering hydrogen load response relying on hydrogen to ammonia as a flexibly adjustable load-side resource in the EHC-VPP to enable the VPP to participate in the day-ahead energy market to maximize benefits. In addition this paper also considers the impact of the carbon emission penalty to practice the green development concept of energy saving and emission reduction. To validate the economy of the proposed optimization scheduling method in this paper the optimization scheduling results under three different operation scenarios are compared and analyzed. The results show that considering the hydrogen load response and fully exploiting the flexibility resources of the EHC-VPP can further reduce the system operating cost and improve the overall operating efficiency.

This technical report accompanies the ‘Net Zero’ advice report which is the Committee’s recommendation to the UK Government and Devolved Administrations on the date for a net-zero emissions target in the UK and revised long-term targets in Scotland and Wales.<br/>The conclusions in our advice report are supported by detailed analysis that has been carried out for each sector of the economy plus consideration of F-gas emissions and greenhouse gas removals. The purpose of this technical report is to lay out that analysis.

Computational Fluid Dynamics codes are increasingly being considered for safety assessment demonstrations in many industrial fields as tools to model accidental phenomena and to design mitigation (risk reducing) systems. Thus they naturally complement experimental programmes which may be expensive to run or difficult to set up. However to trust numerical simulations the validity of the codes must be firmly established and a certain number of error sources (user effect modelling errors discretization errors etc) reduced to the minimum. Code validation and establishment of “best practice guidelines” in the application of simulation tools to hydrogen safety assessment are some of the objectives pursued by the HYSAFE Network of Excellence. This paper will contribute to these goals by describing some of the validation efforts that CEA is making in the areas of release dispersion combustion and mitigation thereby proposing the outline of a validation matrix for hydrogen safety problems.

As Europe is gradually moving towards a hydrogen based society it has been acknowledged that adding certain amount of hydrogen as a clean energy carrier to the existing natural gas pipeline will help reduce the CO2 emissions which contribute to the greenhouse effect. On the other hand hydrogen has been demonstrated to be able to change the behaviour of the pipeline steel such as lower toughness and faster crack growth due to hydrogen embrittlement. Therefore it is necessary that the risks associated with the failure of the pipeline carrying mixtures of natural gas and hydrogen be assessed.<br/>The study reported in this paper is part of European NATURALHY project whose aim is to investigate the possibility of using the existing natural gas transmission pipelines to convey natural gas/hydrogen mixtures. According to the EGIG database the most common cause of failure for the existing natural gas pipelines is third party damage which mainly refers to a gouge a dent/gouge combination of known geometry. Among third party damage failures 90% are the result of immediate failure i.e. leakage or rupture of the pipeline and only 10% of them are the result of delayed failure. While its not expected that hydrogen will impact the immediate failure it could increase the vulnerability of the pipe to delayed failure through the initiation or activation of crack like defects.<br/>This paper will present a methodology to predict the probability of increased failures and describe a software tool that has been developed to perform the calculations.