Publications

Time is rapidly running out to make the crucial planning decisions and secure investment to keep the UK on track to deliver a reliable affordable and decarbonised energy system to meet future emissions regulation enshrined in the 2008 Climate Change Act according to a report published today by the Royal Academy of Engineering.

Prepared for the Prime Minister's Council for Science and Technology A critical time for UK energy policy details the actions needed now to create a secure and affordable low carbon energy system for 2030 and beyond.

The study looks at the future evolution of the UK’s energy system in the short to medium term. It considers how the system is expected to develop across a range of possible trajectories identified through modelling and scenarios.

The following actions for government are identified as a matter of urgency:

• enable local or regional whole-system large scale pilot projects to establish real-world examples of how the future system will work. These must move beyond  current single technology demonstrators and include all aspects of the energy systems along with consumer behaviour and financial mechanisms
• drive forward new capacity in the three main low carbon electricity generating technologies: nuclear carbon capture and storage (CCS) and offshore wind
• develop policies to accelerate demand reduction especially in domestic heating and introduce smarter demand management
• clarify and stabilise market mechanisms and incentives in order to give industry the confidence to invest.

New technologies could become unexpectedly significant – such as solar PV which has recently become much cheaper. But large scale deployment of novel technologies would take decades and the system cannot be planned on promises and aspirations alone. The Academy calls instead for a combination of known technologies to be scaled up to unprecedented levels and integrated in smarter ways.

The report notes that the addition of shale gas or tight oil is unlikely to have a major impact on the evolution of the UK's energy system as we already have secure and diverse supplies of hydrocarbons from multiple sources.

Dr David Clarke FREng who led the group that produced the report says: “Updating the UK energy system to meet the ‘trilemma’ of decarbonisation security and affordability is a massive undertaking. Meeting national targets affordably requires substantial decarbonisation of the electricity system by 2030 through a mix of nuclear power CCS and renewables with gas generation for balancing. Beyond 2030 we must then largely decarbonise heat and transport potentially through electrification but also using other options such as hydrogen and biofuels. We also need to adapt our transmission and distribution networks to become ‘smarter’”.

"Failure to plan the development of the whole energy system carefully will result at best in huge increases in the cost of delivery or at worst a failure to deliver. Substantial investment is needed and current investment capacity is fragile. For example in the last month projects like Carlton’s new Trafford CCGT plant have announced further financing delays and the hoped-for investment by Drax in the White Rose CCS demonstrator has been withdrawn. The UK has also dropped four places to 11th in EY’s renewable energy country attractiveness index.”

Link to document download on Royal Society Website

Low carbon hydrogen could have a significant role to play in meeting the UK’s Net Zero target: the Committee on Climate Change (CCC) estimates that up to 270TWh of low carbon hydrogen could be needed in its ‘Further Ambition’ scenario. However at present there is no large-scale production of low carbon hydrogen in the UK not least as it is more costly than most high carbon alternatives. For hydrogen to be the viable option envisaged by the CCC projects may need to be deployed from the 2020s.<br/>BEIS has commissioned Frontier Economics to develop business models to support low carbon hydrogen production. This report builds on the earlier Carbon Capture Usage and Storage (CCUS) business models consultation2 and develops business models for BEIS to consider further. This report is a milestone in BEIS’ longer term process of developing hydrogen business models. It forms a part of BEIS’ wider research into a range of decarbonisation options across the economy.<br/>Further analysis will be required before a final decision is made.

The deployment of diverse energy storage technologies with the combination of daily weekly and seasonal storage dynamics allows for the reduction of carbon dioxide (CO₂) emissions per unit energy provided. In particular the production storage and re-utilization of hydrogen starting from renewable energy has proven to be one of the most promising solutions for offsetting seasonal mismatch between energy generation and consumption. A realistic possibility for large-scale hydrogen storage suitable for long-term storage dynamics is presented by salt caverns. In this contribution we provide a framework for modelling underground hydrogen storage with a focus on salt caverns and we evaluate its potential for reducing the CO₂ emissions within an integrated energy systems context. To this end we develop a first-principle model which accounts for the transport phenomena within the rock and describes the dynamics of the stored energy when injecting and withdrawing hydrogen. Then we derive a linear reduced order model that can be used for mixed-integer linear program optimization while retaining an accurate description of the storage dynamics under a variety of operating conditions. Using this new framework we determine the minimum-emissions design and operation of a multi-energy system with H₂ storage. Ultimately we assess the potential of hydrogen storage for reducing CO₂ emissions when different capacities for renewable energy production and energy storage are available mapping emissions regions on a plane defined by storage capacity and renewable generation. We extend the analysis for solar- and wind-based energy generation and for different energy demands representing typical profiles of electrical and thermal demands and different CO₂ emissions associated with the electric grid.

Fuel cell electric vehicles (FCEV) currently have the challenge of high CAPEX mainly associated to the fuel cell. This study investigates strategies to promote FCEV deployment and overcome this initial high cost by combining a detailed simulation model of the passenger transport sector with an energy system model. The focus is on an energy system with 95% CO2 reduction by 2050. Soft-linking by taking the powertrain shares by country from the simulation model is preferred because it considers aspects such as car performance reliability and safety while keeping the cost optimization to evaluate the impact on the rest of the system. This caused a 14% increase in total cost of car ownership compared to the cost before soft-linking. Gas reforming combined with CO₂ storage can provide a low-cost hydrogen source for FCEV in the first years of deployment. Once a lower CAPEX for FCEV is achieved a higher hydrogen cost from electrolysis can be afforded. The policy with the largest impact on FCEV was a purchase subsidy of 5 k€ per vehicle in the 2030–2034 period resulting in 24.3 million FCEV (on top of 67 million without policy) sold up to 2050 with total subsidies of 84 bln€. 5 bln€ of R&D incentives in the 2020–2024 period increased the cumulative sales up to 2050 by 10.5 million FCEV. Combining these two policies with infrastructure and fuel subsidies for 2030–2034 can result in 76 million FCEV on the road by 2050 representing more than 25% of the total car stock. Country specific incentives split of demand by distance or shift across modes of transport were not included in this study.

Citizens’ emotional responses to energy technology projects influence the success of the technology’s implementation. Contrary to popular belief these emotions can have a systematic base. Bringing together insights from appraisal theory and from technology acceptance studies this study develops and tests hypotheses regarding antecedents of anger fear joy and pride about a local hydrogen fuel station (HFS). A questionnaire study was conducted among 271 citizens living near the first publicly accessible HFS in the Netherlands around the time of its implementation. The results show that anger is significantly explained by (from stronger to weaker effects) perceived procedural and distributive unfairness and fear by distributive unfairness perceived safety procedural unfairness gender and prior awareness. Joy is significantly explained by perceived environmental outcomes and perceived usefulness and pride by prior awareness perceived risks trust in industry and perceived usefulness. The study concludes that these predictors are understandable practical and moral considerations which can and should be taken into account when developing and executing a project.

Offshore renewable energy – including offshore wind and solar power as well as emerging ocean energy technologies – could support sustainable long-term development and drive a vibrant blue economy. For countries and communities around the world offshore renewables can provide reliable stable electricity as well as support water desalination and aquaculture.

This report from the International Renewable Energy Agency (IRENA) considers the status and prospects of offshore renewable sources and recommends key actions to accelerate their uptake.

The development of renewable sources and technologies at sea promises to spur new industries and create jobs in line with the global energy transition. Offshore wind towers with either fixed or floating foundations and floating solar photovoltaic (PV) arrays offer clear technological and logistical synergies with the existing offshore oil and gas industry.

Offshore renewables could provide clean power and ensure energy security for small island developing states (SIDS) and many of the least-developed countries (LDCs).

Among other findings:

• The predictability of power generation from ocean energy technologies complements the variable character solar PV and wind.
• Desalination of seawater using renewable energy sources – including solar and wind power but also direct solar and geothermal heat – can further enhance the sustainable blue economy.
• Renewable-based shipping powered with advanced biofuels hydrogen or synthetic fuels as alternatives to oil offer further synergies with offshore renewable energy.
• Islands and coastal territories could adopt renewable-based electric propulsion for short-distance (< 100 km) sea transport.
• Two reports released concurrently examine the potential for offshore renewables:

Press hardening steel (PHS) is widely applied in current automotive body design. The trend of using PHS grades with strengths above 1500 MPa raises concerns about sensitivity to hydrogen embrittlement. This study investigates the hydrogen delayed fracture sensitivity of steel alloy 32MnB5 with a 2000 MPa tensile strength and that of several alloy variants involving molybdenum and niobium. It is shown that the delayed cracking resistance can be largely enhanced by using a combination of these alloying elements. The observed improvement appears to mainly originate from the obstruction of hydrogen-induced damage incubation mechanisms by the solutes as well as the precipitates of these alloying elements.

Nowadays nearly 50% of the hydrogen produced worldwide comes from Steam Methane Reforming (SMR) at an environmental burden of 10.5 t_CO2 eq/t_H2 accelerating the consequences of global warming. One way to produce clean hydrogen is via methane pyrolysis using melts of metals and salts. Compared to SMR significant less CO₂ is produced due to conversion of methane into hydrogen and carbon making this route more sustainable to generate hydrogen. Hydrogen is produced with high purity and solid carbon is segregated and deposited on the molten bath. Carbon may be sold as valuable co-product making industrial scale promising. In this work methane pyrolysis was performed in a quartz bubble column using molten gallium as heat transfer agent and catalyst. A maximum conversion of 91% was achieved at 1119 °C and ambient pressure with a residence time of the bubbles in the liquid of 0.5 s. Based on in-depth analysis of the carbon it can be characterized as carbon black. Techno-economic and sensitivity analyses of the industrial concept were done for different scenarios. The results showed that if co-product carbon is saleable and a CO₂ tax of 50 euro per tonne is imposed to the processes the molten metal technology can be competitive with SMR.

This paper analyzes using the theory of critical distances the environmentally assisted cracking behaviour of two steels (S420 and API X80) subjected to two different aggressive environments. The propagation threshold for environmentally assisted cracking (i.e. the stress intensity factor above which crack propagation initiates) in cracked and notched specimens (KIEAC and KNIEAC) has been experimentally obtained under different environmental conditions. Cathodic polarization has been employed to generate the aggressive environments at 1 and 5 mA/cm² causing hydrogen embrittlement on the steels. The point method and the line method both belonging to the theory of critical distances have been applied to verify their capacity to predict the initiation of crack propagation. The results demonstrate the capacity of the theory of critical distances to predict the crack propagation onset under the different combinations of material and aggressive environments.

Catalytic hydrogen-oxygen recombination is a non-traditional method to limit hydrogen accumulation and prevent combustion in the hydrogen industry. Outside of conventional use in the nuclear power industry this hydrogen safety technology can be applied when traditional hydrogen mitigation methods (i.e. active and natural ventilation) are not appropriate or when a back-up system is required. In many of these cases it is desirable for hydrogen to be removed without the use of power or other services which makes catalytic hydrogen recombination attractive. Instances where catalytic recombination of hydrogen can be utilized as a stand-alone or back-up measure to prevent hydrogen accumulation include radioactive waste storage (hydrogen generated from water radiolysis or material corrosion) battery rooms hydrogen-cooled generators hydrogen equipment enclosures etc.<br/>Water tolerant hydrogen-oxygen recombiner catalysts for non-nuclear applications have been developed at Canadian Nuclear Laboratories (CNL) through a program in which catalyst materials were selected prepared and initially tested in a spinning-basket type reactor to benchmark the catalyst’s performance with respect to hydrogen recombination in dry and humid conditions. Catalysts demonstrating high activity for hydrogen recombination were then selected and tested in trickle-bed and gas phase recombiner systems to determine their performance in more typical deployment conditions. Future plans include testing of selected catalysts after exposure to specific poisons to determine the catalysts’ tolerance for such poisons.

Following the Paris Agreement in 2015 the worldwide focus on global warming countermeasures has intensified. The Japanese government has declared its aim at achieving carbon neutrality by 2050. The concept of zero-energy buildings (ZEBs) is based on measures to reduce energy consumption in buildings the prospects of which are gradually increasing. This study investigated the annual primary energy consumption; as well as evaluated renewed and renovated buildings that had a solar power generation system and utilized solar and geothermal heat. It further examines the prospects of hydrogen production from on-site surplus electricity and the use of hydrogen fuel cells. A considerable difference was observed between the actual energy consumption (213 MJ/m2 ) and the energy consumption estimated using an energy simulation program (386 MJ/m2 ). Considerable savings of energy were achieved when evaluated based on the actual annual primary energy consumption of a building. The building attained a near net zero-energy consumption considering the power generated from the photovoltaic system. The study showed potential energy savings in the building by producing hydrogen using surplus electricity from on-site power generation and introducing hydrogen fuel cells. It is projected that a building’s energy consumption will be lowered by employing the electricity generated by the hydrogen fuel cell for standby power water heating and regenerating heat from the desiccant system.

Hydrogen energy applications often require that systems are used indoors (e.g. industrial trucks for materials handling in a warehouse facility fuel cells located in a room or hydrogen stored and distributed from a gas cabinet). It may also be necessary or desirable to locate some hydrogen system components/equipment inside indoor or outdoor enclosures for security or safety reasons to isolate them from the end-user and the public or from weather conditions.<br/>Using of hydrogen in confined environments requires detailed assessments of hazards and associated risks including potential risk prevention and mitigation features. The release of hydrogen can potentially lead to the accumulation of hydrogen and the formation of a flammable hydrogen-air mixture or can result in jet-fires. Within Hyindoor European Project carried out for the EU Fuel Cells and Hydrogen Joint Undertaking safety design guidelines and engineering tools have been developed to prevent and mitigate hazardous consequences of hydrogen release in confined environments. Three main areas are considered: Hydrogen release conditions and accumulation vented deflagrations jet fires and including under-ventilated flame regimes (e.g. extinguishment or oscillating flames and steady burns). Potential RCS recommendations are also identified.

Heating and cooling accounts for almost half of global energy consumption. With most of this relying fossil fuels however it contributes heavily to greenhouse gas emissions and air pollution. In parts of the world lacking modern energy access meanwhile inefficient biomass use for cooking also harms people’s health damages the environment and reduces social well-being.



The transition to renewable-based energy-efficient heating and cooling could follow several possible pathways depending on energy demand resource availability and the needs and priorities of each country or region. Broad options include electrification with renewable power renewable-based gases (including “green” hydrogen) sustainable bioenergy use and the direct use of solar and geothermal heat.



This report developed jointly by the International Renewable Energy Agency (IRENA) the International Energy Agency (IEA) and the Renewable Energy Policy Network for the 21st Century (REN21) outlines the infrastructure and policies needed with each transition pathway. This edition focused on renewable-based heating and cooling follows a broader initial study Renewable Energy Policies in a Time of Transition (IRENA IEA and REN21 2018).



The shift to renewables for heating and cooling requires enabling infrastructure (e.g. gas grids district heating and cooling networks) as well as various combinations of deployment integrating and enabling policies. The policy framework can demonstrate a country’s commitment to the energy transition level the playing field with fossil fuels and create the necessary enabling conditions to attract investments.



Along with highlighting country experiences and best practices the study identifies barriers and highlights policy options for renewable heating and cooling.



Key recommendations include:

• Setting specific targets and developing an integrated long-term plan for the decarbonisation of heating and cooling in all end-uses including buildings industry and cooking and productive uses in areas with limited energy access.
• Creating a level playing field by phasing out fossil-fuel subsidies and introducing other fiscal policies to internalise environmental and socio-economic costs.
• Combining the electrification of heating and cooling with increasingly cost-competitive renewable power generation scaling up solar and wind use and boosting system flexibility via energy storage heat pumps and efficient electric appliances.
• Harnessing existing gas networks to accommodate renewable gases such as biogas and green hydrogen.
• Introducing standards certification and testing policies to promote the sustainable use of biomass combining efficient systems and bioenergy solutions such as pellets briquettes bioethanol or anaerobic digestion.
• Reducing investment risks for geothermal exploration and scaling up direct use of geothermal heat.
• Improving district heating and cooling networks through energy efficiency measures and the integration of low-temperature solar thermal geothermal and other renewable-based heat sources.
• Supporting clean cooking and introducing renewable-based food drying in areas lacking energy access with a combination of financing mechanisms capacity building and quality standards aimed at improving livelihoods and maximising socio-economic benefits.

Renewable electricity can be converted into hydrogen via electrolysis also known as power-to-H2 (P2H) which when injected in the gas network pipelines provides a potential solution for the storage and transport of this green energy. Because of the variable renewable electricity production the electricity end-user’s demand for “power when required” distribution and transmission power grid constrains the availability of renewable energy for P2H can be difficult to predict. The evaluation of any potential P2H investment while taking into account this consideration should also examine the effects of incorporating the produced green hydrogen in the gas network. Parameters including pipeline pressure drop flowrate velocity and most importantly composition and calorific content are crucial for gas network management. A simplified representation of the Irish gas transmission network is created and used as a case study to investigate the impact on gas network operation of hydrogen generated from curtailed wind power. The variability in wind speed and gas network demands that occur over a 24 h period and with network location are all incorporated into a case study to determine how the inclusion of green hydrogen will affect gas network parameters. This work demonstrates that when using only curtailed renewable electricity during a period with excess renewable power generation despite using multiple injection points significant variation in gas quality can occur in the gas network. Hydrogen concentrations of up to 15.8% occur which exceed the recommended permitted limits for the blending of hydrogen in a natural gas network. These results highlight the importance of modelling both the gas and electricity systems when investigating any potential P2H installation. It is concluded that for gas networks that decarbonise through the inclusion of blended hydrogen active management of gas quality is required for all but the smallest of installations.

Hydrogen is one of the most suitable solutions to replace hydrocarbons in the future. Hydrogen consumption is expected to grow in the next years. Hydrogen liquefaction is one of the processes that allows for increase of hydrogen density and it is suggested when a large amount of substance must be stored or transported. Despite being a clean fuel its chemical and physical properties often arise concerns about the safety of the hydrogen technologies. A potentially critical scenario for the liquid hydrogen (LH2) tanks is the catastrophic rupture causing a consequent boiling liquid expanding vapour explosion (BLEVE) with consequent overpressure fragments projection and eventually a fireball. In this work all the BLEVE consequence typologies are evaluated through theoretical and analytical models. These models are validated with the experimental results provided by the BMW care manufacturer safety tests conducted during the 1990’s. After the validation the most suitable methods are selected to perform a blind prediction study of the forthcoming LH2 BLEVE experiments of the Safe Hydrogen fuel handling and Use for Efficient Implementation (SH2IFT) project. The models drawbacks together with the uncertainties and the knowledge gap in LH2 physical explosions are highlighted. Finally future works on the modelling activity of the LH2 BLEVE are suggested.

The permanent introduction of green hydrogen into the energy economy would require that a discriminating selection be made of its use in the sectors where its value is optimal in terms of relative cost and life cycle reduction in carbon dioxide emissions. Consequently hydrogen can be used as an energy storage medium when intermittent wind and solar power exceed certain penetration in the grid likely above 40% and in road transportation right away to begin displacing gasoline and diesel fuels. To this end the proposed approach is to utilize current technologies represented by PHEV in light-duty and HEV in heavy-duty vehicles where a high-performance internal combustion engine is used with a fuel comprised of 15–20% green hydrogen and 85–89% green methane depending on vehicle type. This fuel designated as RHYME takes advantage of the best attributes of hydrogen and methane results in lower life cycle carbon dioxide emissions than BEVs or FCEVs and offers a cost-effective and pragmatic approach both locally as well as globally in establishing hydrogen as part of the energy economy over the next ten to thirty years.

Achieving the UK's net zero target by 2050 will be a challenge. Hydrogen can make a substantial contribution but it needs investment and policy support to establish demand increase the scale of deployment and reduce costs. The Ten Point Plan for a Green Industrial Revolution confirms the government’s commitment to drive the growth of low carbon hydrogen in the UK through a range of measures. This includes publishing its hydrogen strategy and setting out revenue mechanisms to attract private investment as well as allocating further support for hydrogen production and hydrogen applications in heating.

We have created a bespoke model to help understand the cost of hydrogen in the UK across the value chain under different pathways. Our analysis highlights areas for cost reduction and identifies factors that could make hydrogen more attractive to investors.

You can read the full report on the Deloitte website at this link

Environmental regulations have always been an essential component in the natural gas supply chain with recent and greater emphasis on shipping operations. Recently more stringent regulations have been imposed by the International Maritime Organization on global maritime shipping operations. This review explores the challenges and opportunities associated with substituting heavy fuel oils used for maritime transportation with relatively cleaner fuels. First the review considers the feasibility and environmental dimensions of different bunker fuels including liquefied natural gas hydrogen and ammonia. Also the operational viability and optimal conditions for these fuels are examined. Secondly the review considers the entire supply chain with an emphasis on how liquefied natural gas exporters can establish synergies across the supply chain to also deliver the end-product required by customers instead of delivering only liquefied natural gas. Finally measures that can support ship operators to comply with environmental regulations are suggested. The outcomes of this review supports the notion that the demand for alternative fuels will continue to increase as the transportation sector moves towards integrating cleaner fuels to comply with increasing environmental regulations.

In order to reduce global greenhouse gas emissions renewable energy technologies such as wind power and solar photovoltaic power systems have recently become more widespread. However Japan as a nation faces high reliance on imported fossil fuels for electricity generation despite having great potential for further renewable energy development. The focus of this study examines untapped geographical locations in Japan’s northern most prefecture Hokkaido that possess large wind power potential. The possibility of exploiting this potential for the purpose of producing green hydrogen is explored. In particular its integration with a year-round conversion of Kraft lignin into bio-oil from nearby paper pulp mills through a near critical water depolymerization process is examined. The proposed bio-oil and aromatic chemical production as well as the process’ economics are calculated based upon the total available Kraft lignin in Hokkaido including the magnitude of wind power capacity that would be required for producing the necessary hydrogen for such a large-scale process. Green hydrogen integration with other processes in Japan and in other regions is also discussed. Finally the potential benefits and challenges are outlined from an energy policy point-of-view.

This paper offers a numerical approach to the problem of hydrogen embrittlement and notch tensile strength of sharply notched specimens of high-strength pearlitic steel supplied in the form of hot rolled bars by using the finite element method in order to determine how the notch depth influences the concentration of hydrogen in the steady-state regime for different loading values. Numerical results show that the point of maximum hydrostatic stress (towards which hydrogen is transported by a mechanism of stress-assisted diffusion) shifts from the notch tip to the inner points of the specimen under increasing load with numerical evidence of an elevated inwards gradient of hydrostatic stress “pumping” hydrogen inside the sample.

High hydrogen content fuels can be used in gas turbine for power generation with CO₂ capture IGCC plants or with hydrogen from renewables. The challenge for the engine is the high reactive combustion properties making dilution necessary to mitigate NO_x emissions at the expense of a significant energy cost. In the concept analysed in this study high Exhaust Gas Recirculation (EGR) rate is applied to the gas turbine to generate oxygen depleted air. As a result combustion temperature is inherently limited keeping NO_x emissions low without the need for dilution or unsafe premixing. The concept is analysed by process simulation based on a reference IGCC plant with CO₂ Capture. Results with dry and wet EGR options are presented as a function EGR rate. Efficiency performance is assessed against the reference power cycle with nitrogen dilution. All EGR options are shown to represent an efficiency improvement. Nitrogen dilution is found to have a 1.3% efficiency cost. Although all EGR options investigated offer an improvement dry EGR is considered as the preferred option despite the need for higher EGR rate as compared with the wet EGR. The efficiency gain is calculated to be of 1% compared with the reference case.

In the transition to a climate neutral future the transportation sector needs to be sustainably decarbonized. Producing advanced fuels (such as biomethane) and bio-based valorised products (such as pyrochar) may offer a solution to significantly reduce greenhouse gas (GHG) emissions associated with energy and agricultural circular economy systems. Biological and thermochemical bioenergy technologies together with power to gas (P2G) systems can generate green renewable gas which is essential to reduce the GHG footprint of industry. However each technology faces challenges with respect to sustainability and conversion efficiency. Here this study identifies an optimal pathway leading to a sustainable bioenergy system where the carbon released in the fuel is offset by the GHG savings of the circular bio-based system. It provides a state-of-the-art review of individual technologies and proposes a bespoke circular cascading bio-based system with anaerobic digestion as the key platform integrating electro-fuels via P2G systems and value-added pyrochar via pyrolysis of solid digestate. The mass and energy analysis suggests that a reduction of 11% in digestate mass flow with the production of pyrochar bio-oil and syngas and an increase of 70% in biomethane production with the utilization of curtailed or constrained electricity can be achieved in the proposed bio-based system enabling a 70% increase in net energy output as compared with a conventional biomethane system. However the carbon footprint of the electricity from which the hydrogen is sourced is shown to be a critical parameter in assessing the GHG balance of the bespoke system.

Hydrogen enhanced decohesion is expected to play a major role in ferritic steels especially at grain boundaries. Here we address the effects of some common alloying elements C V Cr and Mn on the H segregation behaviour and the decohesion mechanism at a Σ5(310)[001] 36.9∘ grain boundary in bcc Fe using spin polarized density functional theory calculations. We find that V Cr and Mn enhance grain boundary cohesion. Furthermore all elements have an influence on the segregation energies of the interstitial elements as well as on these elements’ impact on grain boundary cohesion. V slightly promotes segregation of the cohesion enhancing element C. However none of the elements increase the cohesion enhancing effect of C and reduce the detrimental effect of H on interfacial cohesion at the same time. At an interface which is co-segregated with C H and a substitutional element C and H show only weak interaction and the highest work of separation is obtained when the substitute is Mn.

For a green economy to be possible in the near future hydrogen production from water is a sought-after alternative to fossil fuels. It is however important to put things into context with respect to global CO2 emission and the role of hydrogen in curbing it. The present world annual production of hydrogen is about 70 million metric tons of which almost 50% is used to make ammonia NH3 (that is mostly used for fertilizers) and about 15% is used for other chemicals [1]. The hydrogen produced worldwide is largely made by steam CH4 reforming (SMR) which is one of the most energy-intensive processes in the chemical industry [2]. It releases based on reaction stoichiometry 5.5 kg of CO2 per 1 kg of H2 (CH4+ 2 H2O → CO2 + 4 H2). When the process itself is taken into account in addition the production [3] becomes about 9 kg of CO2 per kg of H2 and this ratio can be as high as 12 [4]. This results in the production of about one billion tons/year of CO2. The world annual CO2 emission from fossil fuels is however much larger: it is about 36 billion tons of which roughly 25% is emitted while generating electricity and heat 20% due to transport activity and 20% from other industrial processes. Because of the link between global warming and CO2 emissions there is an increasing move towards finding alternative approaches for energy vectors and their applications.

Efficient and robust control strategies can greatly contribute to the reliability of fuel cell systems and a stable output voltage is a key criterion for evaluating a fuel cell system's reliability as a power source. In this study a polymer electrolyte fuel cell (PEFC) system model is developed and its performances under different operating conditions are studied. Then two different novel controllers—a proportional integral derivative (PID) controller and a model predictive control (MPC) controller—are proposed and applied in the PEFC system to control its output voltage at a desired value by regulating the hydrogen and air flow rates at the same time which features a multi‐input and single‐output control problem. Simulation results demonstrate that the developed PEFC system model is qualified to capture the system's behaviour. And both the developed PID and MPC controllers are effective at controlling the PEFC system's output voltage. While the MPC controller presents superior performance with faster response and smaller overshoot. The proposed MPC controller can be easily employed in various control applications for fuel cell systems.