Applications & Pathways

The House of Lords Science and Technology Committee will question experts on the role of batteries and fuel cells for decarbonisation and how much they can contribute to meeting the net-zero target.

Tuesday’s evidence session will be the first of the committee’s new decarbonisation inquiry which was launched on Wednesday 3 March and is currently accepting written evidence submissions.

The session will give an overview of battery and fuel cell technologies and their applications in transport and other sectors. The Committee will ask how battery manufacture can be scaled up to meet wide-scale deployment of electric vehicles and whether technical challenges can be overcome to allow batteries and fuel cells to be used in HGVs and trains. The Committee will also investigate the wider use of batteries and fuel cells in various sectors including integration into power grids and heating systems.

Inquiry Role of batteries and fuel cells in achieving Net Zero

Professor Nigel Brandon Dean of the Faculty of Engineering at Imperial College London

Professor Mauro Pasta Associate Professor of Materials at University of Oxford

Professor Pam Thomas CEO at Faraday Institution and Pro Vice Chancellor for Research at University of Warwick

Mr Amer Gaffar Director of Manchester Fuel Cell Innovation Centre at Manchester Metropolitan University



Possible questions

What contribution are battery and fuel cell technologies currently making towards decarbonization in the UK?

What advances do we expect to see in battery and fuel cell technologies and over what timeframes?

How quickly can UK battery and fuel cell manufacture be scaled up to meet electrification demands?

What are the challenges facing technological innovation and deployment in heavy transport?

Are there any sectors where battery and fuel cell technologies are not currently used but could contribute to decarbonisation?

What are the life cycle environmental impacts of batteries and fuel cells?

Parliament TV video of the meeting​​​

This is part one of a three part enquiry.

Part two can be found here and part three can be found here.

Energy requirements push the shipping industry towards more energy-efficient ships while environmental regulations influence the development of environmentally friendly ships by replacing fossil fuels with alternatives. Current mathematical models for ship energy efficiency which set the analysis boundaries at the level of the ship power system are not able to consider alternative fuels as a powering option. In this paper the energy efficiency and emissions index are formulated for ships with alternative power systems considering three different impacts on the environment (global warming acidification and eutrophication) and realistic fuel pathways and workloads. Besides diesel applications of alternative powering options such as electricity methanol liquefied natural gas hydrogen and ammonia are considered. By extending the analysis boundaries from the ship power system to the complete fuel cycle it is possible to compare different ships within the considered fleet or a whole shipping sector from the viewpoint of energy efficiency and environmental friendliness. The applicability of the model is illustrated on the Croatian ro-ro passenger fleet. A technical measure of implementation of alternative fuels in combination with an operational measure of speed reduction results in an even greater emissions reduction and an increase in energy efficiency. Analysis of the impact of voluntary speed reduction for ships with different power systems resulted in the identification of the optimal combination of alternative fuel and speed reduction by a specific percentage from the ship design speed.

A key component of the Government's recently announced ‘Ten Point Plan for a Green Industrial Revolution’ is 'Driving the Growth of Low Carbon Hydrogen'. The plan outlined a range of measures to support the development and adoption of hydrogen including a £240 million 'Net Zero Hydrogen Fund'. Noting this and the further £81 million allocated for hydrogen heating trials in the 2020 Spending Review the House of Commons Science and Technology Committee is today launching a new inquiry into the role of hydrogen in achieving Net Zero.  

Following recommendations from the Committee on Climate Change that the Government develop a strategy for hydrogen use and should aim for largescale hydrogen trials to begin in the early 2020s the Committee seeks to ensure that the Government's intended plan will be suitable and effective. The Committee will also assess the infrastructure required for hydrogen as a Net Zero fuel and examine progress made so far internationally to determine the viability of hydrogen as a significant contributor to achieving Net Zero.

All documents are in the Supplements tab above.

Shipping is one of the largest greenhouse gas (GHG) emitting sectors of the global economy responsible for around 1 Gt of CO₂eq every year. If shipping were a country it would be the 6th biggest GHG emitter. EU related shipping is responsible for about 1/5 of global ship GHG emissions emitting on average 200 Mt/year. This report assesses potential technology pathways for decarbonising EU related shipping through a shift to zero carbon technologies and the impact such a move could have on renewable electricity demand in Europe. It also identifies key policy and sustainability issues that should be considered when analysing and supporting different technology options to decarbonise the maritime sector. The basis of the study is outbound journeys under the geographical scope of the EU ship MRV Regulation.



We have not tried to quantify the emissions reductions that specific regulatory measures to be introduced at the IMO or EU level might contribute towards decarbonisation by 2050 because there are too many uncertainties. We have taken a more limited first approach and investigated how zero carbon propulsion pathways that currently seem feasible to decarbonise shipping would likely affect the future EU renewable energy supply needs.



It is now generally accepted that ship design efficiency requirements while potentially having an important impact on future emissions growth will fall well short of what is needed. Further operational efficiency measures such as capping operational speed will be important to immediately peak energy consumption and emissions but will be insufficient to decarbonise the sector or reduce its growing energy needs. In this context this study assumes that with all the likely immediate measures adopted energy demand for EU related shipping will still grow by 50% by 2050 over 2010 levels. This is within the range of the 20 -1 20% global BAU maritime energy demand growth estimate.



The decarbonisation of shipping will require changes in on -board energy storage and use and the necessary accompanying bunkering infrastructure. This study identifies the technology options for zero emission propulsion that based on current know-how are likely to be adopted. It is not exhaustive nor prescriptive because the ultimate pathways will likely depend on both the requirements of the shipping industry in terms of cost efficiency and safety and on the future renewable electricity sources that the shipping sect or will need to compete for.



Literature is nascent on the different techno-economic options likely to be available to decarbonise shipping and individual ships 4 but almost completely lacking on the possible impacts of maritime decarbonisation on the broader energy system(s). Understanding these impacts is nevertheless essential because it will influence financial and economic decision making by the EU and member states including those related to investment in future renewable energy supplies and new ship bunkering infrastructure. With this in mind the report aims to provide a preliminary first answer to the following question: Under different zero emission technology pathways how much additional renewable electricity would be needed to cater for the needs of EU related shipping in 2050?



Link to Document Download on Transport & Environment website

This short film promotes Geoscience Australia's online and publicly accessible hydrogen data products. The film steps through the functionality of GA's Australian Hydrogen Opportunities Tool (AusH2) and describes the upcoming Hydrogen Economic Fairways Tool which has been created through a collaborative effort with Monash University.

The House of Lords Science and Technology Committee will hear from leading researchers about anticipated developments in batteries and fuel cells over the next ten years that could contribute to meeting the net-zero target.

The Committee continues its inquiry into the Role of batteries and fuel cells in achieving Net Zero. It will ask a panel of experts about batteries hearing about the current state-of-the-art in technologies that are currently in deployment primarily lithium-ion batteries. It will also explore the potential of next generation technologies currently in development and the challenges in scaling them up to manufacture.

The Committee will then question a second panel about fuel cells hearing about the different types available and their applications. It will explore challenges that need to be overcome in the development of the technology and will consider the UK’s international standing in the sector.

Meeting details

At 10.00am: Oral evidence

Professor Serena Corr Chair in Functional Nanomaterials and Director of Research Department of Chemical and Biological Engineering at University of Sheffield

Professor Paul Shearing Professor in Chemical Engineering at University College London

Dr Jerry Barker Founder and Chief Technology Officer at Faradion Limited

Dr Melanie Loveridge Associate Professor Warwick Manufacturing Group at University of Warwick

At 11.00am: Oral evidence

Professor Andrea Russell Professor of Physical Electrochemistry at University of Southampton

Professor Anthony Kucernak Professor of Physical Chemistry Faculty of Natural Sciences at Imperial College London

Professor John Irvine Professor School of Chemistry at University of St Andrews

Possible questions

• What contribution are battery and fuel cell technologies currently making towards decarbonization in the UK?
• What advances do we expect to see in battery and fuel cell technologies and over what timeframes?
• How quickly can UK battery and fuel cell manufacture be scaled up to meet electrification demands?
• What are the challenges facing technological innovation and deployment in heavy transport?
• Are there any sectors where battery and fuel cell technologies are not currently used but could contribute to decarbonisation?
• What are the life cycle environmental impacts of batteries and fuel cells?

Parliament TV video of the meeting

This is part two of a three part enquiry.

Part one can be found here and part three can be found here.

Continuous developments in Proton Exchange Membrane Fuel Cells (PEMFC) make them a promising technology to achieve zero emissions in multiple applications including mobility. Incremental advancements in fuel cells materials and manufacture processes make them now suitable for commercialization. However the complex operation of fuel cell systems in automotive applications has some open issues yet. This work develops and compares three different controllers for PEMFC systems in automotive applications. All the controllers have a cascade control structure where a generator of setpoints sends references to the subsystems controllers with the objective to maximize operational efficiency. To develop the setpoints generators two techniques are evaluated: off-line optimization and Model Predictive Control (MPC). With the first technique the optimal setpoints are given by a map obtained off-line of the optimal steady state conditions and corresponding setpoints. With the second technique the setpoints time profiles that maximize the efficiency in an incoming time horizon are continuously computed. The proposed MPC architecture divides the fast and slow dynamics in order to reduce the computational cost. Two different MPC solutions have been implemented to deal with this fast/slow dynamics separation. After the integration of the setpoints generators with the subsystems controllers the different control systems are tested and compared using a dynamic detailed model of the automotive system in the INN-BALANCE project running under the New European Driving Cycle.

Solid oxide fuel cells (SOFCs) produce electricity with high electrical efficiency and fuel flexibility without pollution for example CO₂ NO_x SO_x and particles. Still numerous issues hindered the large‐scale commercialization of fuel cell at a large scale such as fuel storage mechanical failure catalytic degradation electrode poisoning from fuel and air for example lifetime in relation to cost. Computational fluid dynamics (CFD) couples various physical fields which is vital to reduce the redundant workload required for SOFC development. Modeling of SOFCs includes the coupling of charge transfer electrochemical reactions fluid flow energy transport and species transport. The Butler‐Volmer equation is frequently used to describe the coupling of electrochemical reactions with current density. The most frequently used is the activation‐ and diffusion‐controlled Butler‐Volmer equation. Three different electrode reaction models are examined in the study which is named case 1 case 2 and case 3 respectively. Case 1 is activation controlled while cases 2 and 3 are diffusion‐controlled which take the concentration of redox species into account. It is shown that case 1 gives the highest reaction rate followed by case 2 and case 3. Case 3 gives the lowest reaction rate and thus has a much lower current density and temperature. The change of activation overpotential does not follow the change of current density and temperature at the interface of the anode and electrolyte and interface of cathode and electrolyte which demonstrates the non‐linearity of the model. This study provides a reference to build electrochemical models of SOFCs and gives a deep understanding of the involved electrochemistry.

Hydrogen is a promising energy carrier in the clean energy systems currently being developed. However its effectiveness in mitigating greenhouse gas (GHG) emissions requires conducting a lifecycle analysis of the process by which hydrogen is produced and supplied. This study focuses on the hydrogen for the transport sector in particular renewable hydrogen that is produced from wind- or solar PV-powered electrolysis. A life cycle inventory analysis is conducted to evaluate the Well-to-Tank (WtT) GHG emissions from various renewable hydrogen supply chains. The stages of the supply chains include hydrogen being produced overseas converted into a transportable hydrogen carrier (liquid hydrogen or methylcyclohexane) imported to Japan by sea distributed to hydrogen filling stations restored from the hydrogen carrier to hydrogen and filled into fuel cell vehicles. For comparison an analysis is also carried out with hydrogen produced by steam reforming of natural gas. Foreground data related to the hydrogen supply chains are collected by literature surveys and the Japanese life cycle inventory database is used as the background data. The analysis results indicate that some of renewable hydrogen supply chains using liquid hydrogen exhibited significantly lower WtT GHG emissions than those of a supply chain of hydrogen produced by reforming of natural gas. A significant piece of the work is to consider the impacts of variations in the energy and material inputs by performing a probabilistic uncertainty analysis. This suggests that the production of renewable hydrogen its liquefaction the dehydrogenation of methylcyclohexane and the compression of hydrogen at the filling station are the GHG-intensive stages in the target supply chains.

The European steel industry is experiencing new challenges related to the market situation and climate policy. Experience from the period of pandemic restrictions and the effects of Russia’s armed invasion of Ukraine has given many countries a basis for including steel along with raw materials (coke iron ore electricity) in economic security products (CRMA). Steel is needed for economic infrastructure and construction development as well as a material for other industries (without steel factories will not produce cars machinery ships washing machines etc.). In 2022 steelmakers faced a deepening energy crisis and economic slowdown. The market situation prompted steelmakers to impose restrictions on production volumes (worldwide production fell by 4% compared to the previous year). Despite the difficult economic situation of the steel industry (production in EU countries fell by 11% in 2022 compared to the previous year) the EU is strengthening its industrial decarbonisation policy (“Fit for 55”). The decarbonisation of steel production is set to accelerate by 2050. To sharply reduce carbon emissions steel mills need new steelmaking technologies. The largest global steelmakers are already investing in new technologies that will use green hydrogen (produced from renewable energy sources). Reducing iron ore with hydrogen plasma will drastically reduce CO2 emissions (steel production using hydrogen could emit up to 95% less CO2 than the current BF + BOF blast furnace + basic oxygen furnace integrated method). Investments in new technologies must be tailored to the steel industry. A net zero strategy (deep decarbonisation goal) may have different scenarios in different EU countries. The purpose of this paper was to introduce the conditions for investing in low-carbon steelmaking technologies in the Polish steel market and to develop (based on expert opinion) scenarios for the decarbonisation of the Polish steel industry.

Hydrogen is one of the most promising power sources for meeting the aviation sector’s long-term decarbonization goals. Although on-board hydrogen systems namely fuel cells are extensively researched the maintenance repair and overhaul (MRO) perspective remains mostly unaddressed. This paper analyzes fuel cells from an MRO standpoint based on a literature review and comparison with the automotive sector. It also examines how well the business models and key resources of MRO providers are currently suited to provide future MRO services. It is shown that fuel cells require extensive MRO activities and that these are needed to meet the aviation sector’s requirements for price safety and especially durability. To some extent experience from the automotive sector can be built upon particularly with respect to facility requirements and qualification of personnel. Yet MRO providers’ existing resources only partially allow them to provide these services. MRO providers’ underlying business models must adapt to the implementation of fuel cells in the aviation sector. MRO providers and services should therefore be considered and act as enablers for the introduction of fuel cells in the aviation industry.

The green hydrogen–electric coupling system can consume locally generated renewable energy thereby improving energy utilization and enabling zero-carbon power supply within a certain range. This study focuses on a green hydrogen–electric coupling system that integrates photovoltaic energy storage and proton exchange membrane electrolysis (PEME). Firstly the impact of operating temperature power quality and grid auxiliary services on the characteristics of the electrolysis cell is analyzed and a voltage model and energy model for the cell are established. Secondly a multi-operating conditions adaptability experiment for PEME grid-connected operation is designed. A test platform consisting of a grid simulator simulated photovoltaic power generation system lithium battery energy storage system PEME and measurement and acquisition device is then built. Finally experiments are conducted to simulate multi-operating conditions such as temperature changes voltage fluctuations frequency offsets harmonic pollution and current adjustment speed. The energy efficiency and consumption is calculated based on the recorded data and the results are helpful to guide the operation of the system.

A new integrated energy system (IES) framework is created in order to encourage the consumption of renewable energy which is represented by wind and solar energy and lower carbon emissions. The connection between the units in the composite system is examined in this research. In-depth analysis is done on how energy is transferred between electricity heat gas and hydrogen. The system model and constraints are used to build an objective function with the lowest total operating cost. The calculation of carbon trading includes the ladder carbon trading method. And set up 6 cases for analysis which verifies the effectiveness of the participation of the concentrated solar power plant (CSPP) in the heat supply and power to hydrogen system (P2HS) in reducing the total operating cost of the system reducing wind curtailment and light curtailment and reducing carbon emissions. Under the model considered in this paper reduces the total operating cost reduces by 27.04% when the concentrated solar power plant is involved in the supply of thermal load. And the carbon emission is reduced by 14.529%. Compared with the traditional power to gas considers the power to hydrogen system in this paper which reduces the total operating cost by 4.79%.

Current commercially available options for decarbonisation of road transport are battery electric vehicles or hydrogen fuel cell electric vehicles. BEVs are increasingly deployed while hydrogen is in its infancy. We examine the infrastructure necessary to support hydrogen fuelling to various degrees of market penetration. Scotland makes a good exemplar of transport transition with a world leading Net-Zero ambition and proven pathways for generating ample renewable energy. We identified essential elements of the new transport systems and the associated capital expenditure. We developed nine scenarios based on the pace of change and the ultimate market share of hydrogen and constructed a model to analyse their infrastructure requirements. This is a multi-period model incorporating Monte Carlo and Markov Chain elements. A “no-regrets” initial action is rapid deployment of enough hydrogen infrastructure to facilitate the early years of a scenario where diesel fuel becomes replaced with hydrogen. Even in a lower demand scenario of only large and heavy goods vehicles using hydrogen the same infrastructure would be required within a further two years. Subsequent investment in infrastructure could be considered in the light of this initial development.

Studies on the prospects of the use of alternative fuels in the maritime industry have rarely been assessed in the context of developing countries. This study assesses seven energy sources for shipping in the context of Bangladesh with a view to ranking their prospects based on sustainability as well as identifying the energy transition criteria. Data were collected from maritime industry experts including seafarers shipping company executives government representatives and academics. The Bayesian Best-Worst Method (BWM) was used for ranking nine criteria related to the suitability and viability of the considered alternative energy sources. Next the PROMETHEE-GAIA method is applied for priority analysis of the seven energy alternatives. The findings reveal that capital cost alternative energy price and safety are the most important factors for alternative energy transition in Bangladesh. Apart from the benchmark HFO Liquified Natural Gas (LNG) HFO-Wind and LNG-Wind hybrids are considered the most viable alternatives. The findings of the study can guide policymakers in Bangladesh in terms of promoting viable energy sources for sustainable shipping.

This review focuses on the reduction of iron oxides using hydrogen as a reducing agent. Due to increasing requirements from environmental issues a change of process concepts in the iron and steel industry is necessary within the next few years. Currently crude steel production is mainly based on fossil fuels and emitting of the climate-relevant gas carbon dioxide is integral. One opportunity to avoid or reduce greenhouse gas emissions is substituting hydrogen for carbon as an energy source and reducing agent. Hydrogen produced via renewable energies allows carbon-free reduction and avoids forming harmful greenhouse gases during the reduction process. The thermodynamic and kinetic behaviors of reduction with hydrogen are summarized and discussed in this review. The effects of influencing parameters such as temperature type of iron oxide grain size etc. are shown and compared with the reduction behavior of iron oxides with carbon monoxide. Different methods to describe the kinetics of the reduction progress and the role of the apparent activation energy are shown and proofed regarding their plausibility.

Road transport is one of the most energy-consuming and greenhouse gas (GHG) emitting sectors. Progressive decarbonisation of electricity generation could support the ambitious target of road vehicle climate neutrality in two different ways: direct electrification with onboard electro-chemical storage or a change of energy vector with e-fuels. The most promising state-of-the-art electrochemical storages for road transport have been analysed considering current and future technologies (the most promising ones) whose use is assumed to occur within the next 10–15 years. Different e-fuels (e-hydrogen e-methanol e-diesel e-ammonia E-DME and e-methane) and their production pathways have been reviewed and compared in terms of energy density synthesis efficiency and technology readiness level. A final energetic comparison between electrochemical storages and e-fuels has been carried out considering different powertrain architectures highlighting the huge difference in efficiency for these competing solutions. E-fuels require 3–5 times more input energy and cause 3–5 times higher equivalent vehicle CO2 emissions if the electricity is not entirely decarbonised.

The deployment of hydrogen fuel cell electric vehicles (FCEVs) is critical to achieve zero emissions. A key parameter influencing FCEV performance and durability is hydrogen fuel quality. The real impact of contaminants on FCEV performance is not well understood and requires reliable measurements from real-life events (e.g. hydrogen fuel in poor-performing FCEVs) and controlled studies on the impact of synthetic hydrogen fuel on FCEV performance. This paper presents a novel methodology to flow traceable hydrogen synthetic fuel directly into the FCEV tank. Four different synthetic fuels containing N2 (90–200 µmol/mol) CO (0.14–5 µmol/mol) and H2S (4–11 nmol/mol) were supplied to an FCEV and subsequently sampled and analyzed. The synthetic fuels containing known contaminants powered the FCEV and provided real-life performance testing of the fuel cell system. The results showed for the first time that synthetic hydrogen fuel can be used in FCEVs without the requirement of a large infrastructure. In addition this study carried out a traceable H2 contamination impact study with an FCEV. The impact of CO and H2S at ISO 14687:2019 threshold levels on FCEV performance showed that small exceedances of the threshold levels had a significant impact even for short exposures. The methodology proposed can be deployed to evaluate the composition of any hydrogen fuel.

Synthetic fuels or e-fuels produced from captured CO2 and renewable hydrogen are envisaged as a feasible path towards a climate-neutral transportation in medium/heavy-duty and maritime sectors. EU is presently debating energy targets by 2030 for these fuels. As their production involves chemical processing of hydrogen it must be evaluated if the extra cost is worthy at least in applications where hydrogen use is possible. This manuscript focuses on the performance and environmental impact when hydrogen and methanol are fed to a heavy-duty compression-ignition engine working under dual-fuel combustion. The trade-off thermal efficiency-NOx emissions is primary considered in the assessment by combining both variables in an own defined function. During the work engine operating settings were adjusted to exploit the potential of methanol and hydrogen. Compared to conventional combustion methanol required centering the combustion towards TDC and doubling the EGR rate resulting in a low temperature highly premixed combustion almost soot-free and with extremely low NOx emissions. The best settings for hydrogen were in the middle of those for methanol and conventional combustion. Results showed great dependance with the engine load but methanol proved superior to hydrogen for all conditions. At high load 20–60 % methanol even improved the efficiency and reduced the NOx emissions obtained by conventional combustion. However at low load hydrogen could substitute 90 % of the diesel fuel while methanol failed at substitutions higher than 55 %.

The presented work concerns experimental research of a spark-ignition engine with variable compression ratio (VCR) adapted to dual-fuel operation in which co-combustion of ammonia with hydrogen was conducted and the energy share of hydrogen varied from 0% to 70%. The research was aimed at assessing the impact of the energy share of hydrogen co-combusted with ammonia on the performance stability and emissions of an engine operating at a compression ratio of 8 (CR 8) and 10 (CR 10). The operation of the engine powered by ammonia alone for both CR 8 and CR 10 is associated with either a complete lack of ignition in a significant number of cycles or with significantly delayed ignition and the related low value of the maximum pressure pmax. Increasing the energy share of hydrogen in the fuel to 12% allows to completely eliminate the instability of the ignition process in the combustible mixture which is confirmed by a decrease in the IMEP uniqueness and a much lower pmax dispersion. For 12% of the energy share of hydrogen co-combusted with ammonia the most favorable course of the combustion process was obtained the highest engine efficiency and the highest IMEP value were recorded. The conducted research shows that increasing the H2 share causes an increase in NO emissions for both analyzed compression ratios

National Implementation Plans (NIP) in regard hydrogenation motor transport are in place in European Union (EU) countries e.g.Germany France or Belgium Denmark Netherlands. Motor transport hydrogenization plans exist in the Japan and USA. In Poland the methodology deployment Hydrogen Refuelling Stations (HRS) developed in Motor Transport Institute is of multi-stage character are as follows: Stage I: Method allowing to identify regions in which HRS should be located. Stage II: Method allowing to identify urban centres in which should be located the said stations. Stage III: Method for determining the area of the station location. The presentation of the aforesaid NIPS and based on that and the mentioned methodology the conditions for hydrogenization of motor transport in Poland is the purpose of this article which constitutes its novelty. The scope of the article concerns the hydrogenization of motor transport in the abovementioned countries. With the above criteria the order the construction in Poland of a HRS in the order of their creation along the TEN-T corridors is as follows: 1 - Poznan 2 - Warsaw 3 - Bialystok 4 - Szczecin 5 - the Lodz region 6 - the Tri-City region 7 - Wrocław 8 - the Katowice region 9 – Krakow. The concluding discussion sets out the status of deployment HRS and FCEVs in the analysed countries.

The freight sector is expected to keep or even increase its fundamental role for the major modern economies and therefore actions to limit the growing pressure on the environment are urgent. The use of electricity is a major option for the decarbonization of transports; in the heavy-duty segment it can be implemented in different ways: besides full electric-battery powertrains electricity can be used to supply catenary roads or can be chemically stored in liquid or gaseous fuels (e-fuels). While the current EU legislation adopts a tailpipe Tank-To-Wheels approach which results in zero emissions for all direct uses of electricity a Well-To-Wheels (WTW) method would allow accounting for the potential benefits of using sustainable fuels such as e-fuels. In this article we have performed a WTW-based comparison and modelling of the options for using electricity to supply heavy-duty vehicles: e-fuels eLNG eDiesel and liquid Hydrogen. Results showed that the direct use of electricity can provide high Greenhouse Gas (GHG) savings and also in the case of the e-fuels when low-carbonintensity electricity is used for their production. While most studies exclusively focus on absolute GHG savings potential considerations of the need for new infrastructures and the technological maturity of some options are fundamental to compare the different technologies. In this paper an assessment of such technological and non-technological barriers has been conducted in order to compare alternative pathways for the heavy-duty sector. Among the available options the flexibility of using drop-in energy-dense liquid fuels represents a clear and substantial immediate advantage for decarbonization. Additionally the novel approach adopted in this paper allows us to quantify the potential benefits of using e-fuels as chemical storage able to accumulate electricity from the production peaks of variable renewable energies which would otherwise be wasted due to grid limitations.

This paper investigates conversion of a Nordic oil-heated townhouse into carbon-neutral by different energy efficiency (EE) improvements and an off-grid system including solar photovoltaics (PV) wind power and battery and hydrogen energy storage systems (BESS and HESS). A heat-pump-based heating system including waste heat recovery (WHR) from the HESS and an off-grid electrical system are dimensioned for the building by applying models developed in MATLAB and Microsoft Excel to study the life cycle costs (LCC). The work uses a measured electrical load profile and the heat generation of the new heating system and the power generation are simulated by commercial software. It is shown that the EE improvements and WHR from the HESS have a positive effect on the dimensioning of the off-grid system and the LCC can be reduced by up to €2 million. With the EE improvements and WHR the component dimensioning can be reduced by 22%–41% and 13%–51% on average respectively. WHR can cover up to 57% of the building's annual heat demand and full-power dimensioning of the heat pump is not reasonable when WHR is applied. Wind power was found to be very relevant in the Nordic conditions reducing the LCC by 32%.

In this paper by using a large eddy simulation we study the combustion process in the HyShot II scramjet combustor. By conducting a detailed analysis of the mass-fraction distributions of the main species such as H2 H2O and the radicals OH and HO2 of the mass source terms of these main species and of the chemical source term of the energy equation we detect the regions where chemical reactions occur through a diffusion process and the regions where auto-ignition and premixed combustion may develop. The analysis indicates that the combustion process is mainly of diffusive type along a thin shear layer enveloping the hydrogen plume whereas there could be some auto-ignition and/or premixed combustion cores inside the plume.

Hybrid renewable hydrogen energy systems could play a key role in delivering sustainable solutions for enabling the Net Zero ambition; however the lack of exact computational modelling tools for sizing the integrated system components and simulating their real-world dynamic behaviour remains a key technical challenge against their widespread adoption. This paper addresses this challenge by developing a precise dynamic model that allows sizing the rated capacity of the hybrid system components and accurately simulating their real-world dynamic behaviour while considering effective energy management between the grid-integrated system components to ensure that the maximum possible proportion of energy demand is supplied from clean sources rather than the grid. The proposed hybrid system components involve a solar PV system electrolyser pressurised hydrogen storage tank and fuel cell. The developed hybrid system model incorporates a set of mathematical models for the individual system components. The developed precise dynamic model allows identifying the electrolyser’s real-world hydrogen production levels in response to the input intermittent solar energy production while also simulating the electrochemical behaviour of the fuel cell and precisely quantifying its real-world output power and hydrogen consumption in response to load demand variations. Using a university campus case study building in Scotland the effectiveness of the developed model has been assessed by benchmarking comparison between its results versus those obtained from a generic model in which the electrochemical characteristics of the electrolyser and fuel cell systems were not taken into consideration. Results from this comparison have demonstrated the potential of the developed model in simulating the real-world dynamic operation of hybrid solar hydrogen energy systems for grid-connected buildings while sizing the exact capacity of system components avoiding oversizing associated with underutilisation costs and inaccurate simulation.

In recent years growing awareness about environmental issues is pushing humankind to explore innovative technologies to reduce the anthropogenic sources of pollutants. Among these sources internal combustion engines in non-road mobile machinery (NRMM) such as agricultural tractors are one of the most important. The aim of this work is to explore the possibility of replacing the conventional diesel engine with an electric powertrain powered by a hybrid storage system consisting of a small battery pack and a fuel-cell system. The battery pack (BP) is necessary to help the fuel cell manage sudden peaks in power demands. Numerical models of the conventional powertrain and a fuel-cell tractor were carried out. To compare the two powertrains work cycles derived from data collected during real operative conditions were exploited and simulated. For the fuel-cell tractor a control strategy to split the electric power between the battery pack and the fuel cell was explored. The powertrains were compared in terms of greenhouse gas emissions (GHG) according to well-to-wheel (WTW) equivalent CO2 emission factors available in the literature. Considering the actual state-of-the-art hydrogen production methods the simulation results showed that the fuel-cell/battery powertrain was able to accomplish the tasks with a reduction of about 50% of the equivalent CO2 emissions compared to traditional diesel-powered vehicles.

The steel sector currently accounts for 7% of global energy-related CO2 emissions and requires deep reform to disconnect from fossil fuels. Here we investigate the market competitiveness of one of the widely considered decarbonisation routes for primary steel production: green hydrogen-based direct reduction of iron ore followed by electric arc furnace steelmaking. Through analysing over 300 locations by combined use of optimisation and machine learning we show that competitive renewables-based steel production is located nearby the tropic of Capricorn and Cancer characterised by superior solar with supplementary onshore wind in addition to high-quality iron ore and low steelworker wages. If coking coal prices remain high fossil-free steel could attain competitiveness in favourable locations from 2030 further improving towards 2050. Large-scale implementation requires attention to the abundance of suitable iron ore and other resources such as land and water technical challenges associated with direct reduction and future supply chain configuration.

Business-as-usual (BAU) cement production is associated with a linear model that contributes significantly to global warming and is dependent on volatile energy markets. A novel circular model is proposed by adding three power-to-gas system components to current production systems: a calcium-looping (CaL) CO2 capture unit; water electrolysis for hydrogen and oxygen generation; and a methanation unit for synthetic natural gas (SNG) production. The paper presents the first analysis of the combined industrial-scale operation of these components in a closed loop where the SNG fuels the cement kiln and the CaL unit while the O2 produced feeds it. The circular hybrid and BAU models are compared in three feasibility scenarios. It is concluded that the circular model outperforms the other alternatives environmentally opening a potential pathway for the cement industry to achieve near net-zero CO2 emissions reduce energy dependence and improve economic efficiency.

Molecular hydrogen (H2 ) is a low-molecular-weight non-polar and electrochemically neutral substance that acts as an effective antioxidant and cytoprotective agent with research into the effects of H2 incorporation into the food chain at various stages rapidly gaining momentum. H2 can be delivered throughout the food growth production delivery and storage systems in numerous ways including as a gas as hydrogen-rich water (HRW) or with hydrogen-donating food supplements such as calcium (Ca) or magnesium (Mg). In plants H2 can be exploited as a seedpriming agent during seed germination and planting during the latter stages of plant development and reproduction as a post-harvest treatment and as a food additive. Adding H2 during plant growth and developmental stages is noted to improve the yield and quality of plant produce through modulating antioxidant pathways and stimulating tolerance to such environmental stress factors as drought stress enhanced tolerance to herbicides (paraquat) and increased salinity and metal toxicity. The benefits of pre- and post-harvest application of H2 include reductions in natural senescence and microbial spoilage which contribute to extending the shelf-life of animal products fruits grains and vegetables. This review collates empirical findings pertaining to the use of H2 in the agri-food industry and evaluates the potential impact of this emerging technology.

This work evaluates the effectiveness of chemical-based solutions for storing large amounts of renewable electricity. Four “Power-to-X-to-Power” pathways are examined comprising hydrogen methane methanol and ammonia as energy carriers. The pathways are assessed using a model scenario where they are produced with electricity from an onshore wind farm stored in suitable facilities and then reconverted to electricity to meet the energy demand of a chemical site. An energy management and storage capacity estimation tool is used to calculate the annual load coverage resulting from each pathway. All four pathways offer a significant increase in load coverage compared to a scenario without storage solution (56.19%). The hydrogen-based pathway has the highest load coverage (71.88%) and round-trip efficiency (36.93%) followed by the ammonia-based (69.62% 31.37%) methanol-based (67.85% 27.00%) and methane-based (67.64% 26.47% respectively) pathways. The substantially larger storage capacity required for gaseous energy carriers to ensure a steady supply to the consumer could be a decisive factor. The hydrogen pathway requires a storage volume up to 10.93 times larger than ammonia and 16.87 times larger than methanol. Notably ammonia and methanol whose load coverages are only 2.26 and 4.03 percentage points lower than that of hydrogen offer the possibility of implementing site-specific storage solutions avoiding potential bottlenecks due to limited pipeline and cavern capacities.

This report from the WP5 “Mitigation” provides information and test results regarding perturbations that hydrogen could cause to gas appliances when blended to natural gas especially on anatural draught for exhaust fumes or acidity for the condensates. The important topic of on-site adjustment is also studied with test results on alternative technologies and proposals of mitigation approaches.

Modernising Australia’s old truck fleet and adopting a more stringent standard to reduce emissions and air pollutants is a primary objective for the Australian truck sector. Various strategies worldwide have been introduced to cut emissions and pollutants in the truck sector such as a low-emission strategy supported by strict diesel standards and a zero-emission strategy to shift to battery-electric or hydrogen trucks. The paper focuses on emissions and local air pollutants of trucks under various transition scenarios at both the tailpipe and the wider supply chain including domestic power generation and hydrogen production. In contrast for diesel we focus on tailpipe outputs following fuel standards in Australia given diesel is imported other than in some limited refineries. We compare and recommend actions that government and truck operators may take in the near to longer term in transitioning to cleaner energy. We tested a number of scenarios using a decision support system incorporating all the latest information on costs and emissions for all truck classes using diesel electric or hydrogen. A key finding from our scenario tests is that the current electricity mix has high carbon emissions and air pollutants due to fossil fuel-fired sources for power generation. Without improvement in using renewable energy sources in the future transitioning to electric trucks implies more carbon emissions and air pollutants in the atmosphere from power plants even though electric trucks generate zero tailpipe emissions. The main motivation for switching to zero-emission trucks is energy cost savings. We urge the government to decide on a clear roadmap for the truck sector before the sector is in a position to take action to shift to low or zero-emission trucks without totally relying on the likely reduction of emission intensity in electricity and renewable energy production.

The hydrogen supply system is one of the important components of a hydrogen fuel cell engine and its performance has an important impact on the economy and power of the engine system. In this paper a hydrogen supply system based on cyclic mode is designed for a hydrogen fuel cell stack with a full load power of 150 kW and the corresponding hydrogen fuel cell engine simulation model is built and validated. The control strategy of the fuel cell hydrogen supply system is developed and its effect is verified through bench tests. The results show that the developed control strategy can keep the volume fraction of nitrogen below 6% the hydrogen excess ratio does not exceed 1.5 under medium and high operating conditions the anode pressure is relatively stable and the stack can operate efficiently and reliably.

The importance of hydrogen in the effort to decarbonize the power sector has grown immensely in recent years. Previous studies have investigated the effects of mixing hydrogen into natural gas for gas turbine combustors but limited studies have examined the resulting effects hydrogen addition has on the entire system. In this work a thermodynamic model of a gas turbine with combustion chemical kinetics integrated is created and the effects hydrogen addition (0-100 volume percent addition) has on the system performance emissions and combustion kinetics are analyzed. The maximum system performance is achieved when the maximum turbine inlet temperature is reached and the resulting optimal fuel/air equivalence ratio is determined. As hydrogen is added to the fuel mixture the optimal equivalence ratio shifts leaner causing non-linearity in emissions and system performance at optimal conditions. An analysis of variance is conducted and it is shown that isentropic efficiencies of the turbine and compressor influences the system performance the most out of any system parameter. While isentropic efficiencies of the turbine and compressor increase towards 100% an operating regime where the optimal system efficiency cannot be achieved is discovered due to the lower flammability limit of the fuel being reached. This can be overcome by mixing hydrogen into the fuel.

This paper introduces a Techno-Economic Assessment (TEA) on present and future scenarios of different energy storage technologies comprising hydrogen and batteries: Battery Energy Storage System (BESS) Hydrogen Energy Storage System (H2ESS) and Hybrid Energy Storage System (HESS). These three configurations were assessed for different time horizons: 2019 2022 and 2030 under both on-grid and off-grid conditions. For 2030 a sensitivity analysis under different energy scenarios was performed covering other trends in on-grid electric consumption and prices CO2 taxation and the evolution of hydrogen technology prices from 2019 until 2030. The selected case study is the Research Park Zellik (RPZ) a CO2- neutral sustainable Local Energy Community (LEC) in Zellik Belgium. The software HOMER (Hybrid Optimisation Model for Electric Renewable) has been selected to design model and optimise the defined case study. The results showed that BESS was the most competitive when the electric grid was available among the three possible storage options. Additionally HESS was overall more competitive than H2ESS-only regardless of the grid connection mode. Finally as per HESS hydrogen was proved to play a complementary role when combined with batteries enhancing the flexibility of the microgrid and enabling deeper decarbonisation by reducing the electricity bought from the grid increasing renewable energy production and balancing toward an island operating mode.

The investment in hydrogen-refueling stations (HRS) is key to the development of a hydrogen economy. This paper focuses on the decision-making for potential investors faced with the thought-provoking question of when the optimal timing to invest in HRS is. To fill the gap that exists due to the fact that few studies explain why HRS investment timing is critical we expound that earlier investment in HRS could induce the first mover advantages of the technology diffusion theory. Additionally differently from the previous research that only considered that HRS investment is just made by one individual firm we innovatively examine the HRS co-investment made by two different firms. Accordingly we compare these two optional investment modes and determine which is better considering either independent investment or co-operative investment. We then explore how the optimal HRS investment timing could be figured out under conditions of uncertainty with the real options approach. Given the Chinese HRS case under the condition of demand uncertainty the hydrogen demand required for triggering investment is viewed as the proxy for investment timing. Based on analytical and numerical results we conclude that one-firm independent investment is better than two-firm cooperative investment to develop HRS not only in terms of the earlier investment timing but also in terms of the attribute for dealing with the uncertainty. Finally we offer recommendations including stabilizing the hydrogen demand for decreasing uncertainty and accelerating firms’ innovation from both technological and strategic perspectives in order to ensure firms can make HRS investments on their own.

Efficiently predicting and understanding refuelling patterns in the context of HFVs is paramount for optimising fuelling processes infrastructure planning and facilitating vehicle operation. This study evaluates several supervised machine learning methodologies for predicting the refuelling behaviour of HFVs. The LightGBM model emerged as the most effective predictive model due to its ability to handle time series and seasonal data. The selected model integrates various input variables encompassing refuelling metrics day of the week and weather conditions (e.g. temperature precipitation) to capture intricate patterns and relationships within the data set. Empirical testing and validation against real-world refuelling data underscore the efficacy of the LightGBM model demonstrating a minimal deviation from actual data given limited data and thereby showcasing its potential to offer valuable insights to fuelling station operators vehicle manufacturers and policymakers. Overall this study highlights the potential of sustainable predictive modelling for optimising fuelling processes infrastructure planning and facilitating vehicle operation in the context of HFVs.

This article investigates the potential of renewable and low-carbon fuel production for the maritime shipping sector using Sweden as a case in focus. Techno-economic modelling and socio-technical transition studies are combined to explore the conditions opportunities and barriers to decarbonising the maritime shipping industry. A set of scenarios have been developed considering demand assumptions and potential instruments such as carbon price energy tax and blending mandate. The study finds that there are opportunities for decarbonising the maritime shipping industry by using renewable marine fuels such as advanced biofuels (e.g. biomethanol) electrofuels (e.g. e-methanol) and hydrogen. Sweden has tremendous resource potential for bio-based and hydrogen-based renewable liquid fuel production. In the evaluated system boundary biomethanol presents the cheapest technology option while e-ammonia is the most expensive one. Green electricity plays an important role in the decarbonisation of the maritime sector. The results of the supply chain optimisation identify the location sites and technology in Sweden as well as the trade flows to bring the fuels to where the bunker facilities are potentially located. Biomethanol and hydrogen-based marine fuels are cost-effective at a carbon price beyond 100 €/tCO2 and 200 €/tCO2 respectively. Linking back to the socio-technical transition pathways the study finds that some shipping companies are in the process of transitioning towards using renewable marine fuels thereby enabling niche innovations to break through the carbon lock-in and eventually alter the socio-technical regime while other shipping companies are more resistant. Overall there is increasing pressure from (inter)national energy and climate policy-making to decarbonise the maritime shipping industry.

The realization of a carbon-neutral civilization which has been set as a goal for the coming decades goes directly hand-in-hand with the need for an energy system based on renewable energies (REs). Due to the strong weather-related daily and seasonal fluctuations in supply of REs suitable energy storage devices must be included for such energy systems. For this purpose an energy system model featuring hybrid energy storage consisting of a hydrogen unit (for long-term storage) and a lithium-ion storage device (for short-term storage) was developed. With a proper design such a system can ensure a year-round energy supply by using electricity generated by photovoltaics (PVs). In the energy system that was investigated hydrogen (H2) was produced by using an electrolyser (ELY) with a PV surplus during the summer months and then stored in an H2 tank. During the winter due to the lack of PV power the H2 is converted back into electricity and heat by a fuel cell (FC). While the components of such a system are expensive a resource- and cost-efficient layout is important. For this purpose a Matlab/Simulink model that enabled an energy balance analysis and a component lifetime forecast was developed. With this model the results of extensive parameter studies allowed an optimized system layout to be created for specific applications. The parameter studies covered different focal points. Several ELY and FC layouts different load characteristics different system scales different weather conditions and different load levels—especially in winter with variations in heating demand—were investigated.

The goals of the long-term tests were to see the impact of blends of hydrogen and natural gas on the technical condition of the appliances and their performance after several hours of operation. To do so they were run through an accelerated test program amounting to more than 3000 testing hours for the boilers and more than 2500 testing hours for the cookers. The percentage of hydrogen in the test gas was 30% by volume. Three boilers and two cookers were tested by DGC and two boilers by GWI. This report describes the test protocol the results and analysis on the seven appliances tested.

The demand for fossil fuels is rising rapidly leading to increased greenhouse gas emissions. Hydrogen has emerged as a promising clean energy alternative that could help meet future demands way sustainably especially if produced using renewable methods. For hydrogen to meaningfully contribute to energy transitions it needs more integration into sectors like transportation buildings and power that currently have minimal hydrogen usage. This requires developing extensive cross-sector hydrogen infrastructure. This review examines hydrogen combustion as a fuel by exploring and comparing production techniques enriching ammonia with hydrogen as a CO2-free option and hydrogen applications in engines. Additionally a techno-economic environmental risk analysis is discussed. Results showed steam methane reforming is the most established and cost-effective production method at $1.3–1.5/kg H2 and 70–85% efficiency but generates CO2. Biomass gasification costs $1.25–2.20/kg H2 and pyrolysis $1.77–2.05/kg H2 offering renewable options. However bio-photolysis currently has high costs of $1.42–2.13/kg H2 due to low conversion rates requiring large reactors. Blending H2/NH3 could enable carbon-free combustion aiding carbon neutrality pursuits but minimizing resultant NOx is crucial. Hydrogen’s wide uses from transportation to power underline its potential as a transformational energy carrier.

Hydrogen-based multi-microgrid systems (HBMMSs) are beneficial for energy saving and emission reductions. However the optimal sizing of HBMMSs lacks a practical configuration optimization model and a reasonable solution method. To address these problems we designed a novel structure of HBMMSs that combines conventional energy renewable energy and a hydrogen energy subsystem. Then we established a bi-level multi-objective capacity optimization model while considering electricity market trading and different hydrogen production strategies. The objective of the inner model which is the minimum annual operation cost and the three objectives of the outer model which are the minimum total annual cost (TAC); the annual carbon emission (ACE); and the maximum self-sufficiency rate (SSR) are researched simultaneously. To solve the above optimization model a two-stage solution method which considers the conflicts between objectives and the objectivity of objective weights is proposed. Finally a case study is performed. The results show that when green hydrogen production strategies are adopted the three objectives of the best configuration optimization scheme are USD 404.987 million 1.106 million tons and 0.486 respectively.

Investing in green hydrogen systems has become a global objective to achieve the net-zero emission goal. Therefore it is seen as the primary force behind efforts to restructure the world’s energy lessen our reliance on gas attain carbon neutrality and combat climate change. This paper proposes a power management for a net zero emission PV microgrid-based decentralized green hydrogen system. The hybrid microgrid combines a fuel cell battery PV electrolyzer and compressed hydrogen storage (CHSU) unit aimed at power sharing between the total components of the islanded DC microgrid and minimizing the equivalent hydrogen consumption (EHC) by the fuel cell and the battery. In order to minimize the EHC and maintain the battery SOC an optimization-based approach known as the Equivalent Consumption Minimization Strategy (ECMS) is used. A rulebased management is used to manage the power consumed by the electrolyzer and the CHSU by the PV system in case of excess power. The battery is controlled by an inverse droop control to regulate the dc bus voltage and the output power of the PV system is maximized by the fuzzy logic controller-based MPPT. As the hybrid microgrid works in the islanded mode a two-level hierarchical control is applied in order to generate the voltage and the frequency references. The suggested energy management approach establishes the operating point for each system component in order to enhance the system’s efficiency. It allows the hybrid system to use less hydrogen while managing energy more efficiently.

This is a summary report of a study which aimed to understand the safety feasibility cost and impacts for 7 industrial sites to switch from natural gas to 100% hydrogen for heating. The volunteer industrial sites:<br/>♦ are located away from industrial clusters<br/>♦ use natural gas to meet most of their energy demand<br/>♦ will likely be most impacted by decisions on the future of the natural gas grid<br/>We have published the report in order to share its findings with other industrial sites and wider industry in particular those considering hydrogen as an option for decarbonisation.<br/>Note that:<br/>♦ some work was carried out on a non-hydrogen alternative energy source but to a lesser level of detail and not to determine the optimal decarbonisation solution<br/>♦ the findings do not apply to other end user environments because of differences between these environments and the consumption of gas<br/>The study was commissioned in 2022 by the former Department for Business and Energy and undertaken by AECOM and their safety sub-contractor ESR.<br/>The evidence will inform strategic decisions in 2026 on the role of low carbon hydrogen as a replacement for natural gas heating.

Hydrogen-powered mobility is believed to be crucial in the future as hydrogen constitutes a promising solution to make up for the non-programmable character of the renewable energy sources. In this context the hydrogen-fueled internal combustion engine represents one of the suitable technical solutions for the future of sustainable mobility. As a matter of fact hydrogen engines suffer from limitations in volumetric efficiency due to the very low density of the fuel. Consequently hydrogen-fueled ICEs can reach sufficient torque and power density only if suitable supercharging solutions are developed. Moreover gaseous-engine performance can be improved to a great extent if direct injection is applied. In this perspective a remarkable know-how has been developed in the last two decades on NG engines which can be successfully exploited in this context. The objective of this paper is twofold. In the first part a feasibility study has been carried out with reference to a typical 2000cc SI engine by means of 1D simulations. This study was aimed at characterizing the performance on the full load curve with respect to a baseline PFI engine fueled by NG. In this phase the turbocharging/supercharging device has not been included in the model in order to quantify the attainable benefits in the absence of any limitation coming from the turbocharger. In the second part of this paper the conversion of a prototype 1400cc direct injection NG engine running with stoichiometric mixture to run on a lean hydrogen combustion mode has been investigated via 1D simulations. The matching between engine and turbocharger has been included in the model and the effects of two different turbomatching choices have been presented and discussed.

Fuel cell electric buses (FCBs) have proven to be a technically viable solution for transportation owing to various advantages such as reliability simplicity better energy efficiency and quietness of operation. However largescale adoption of FCBs is hindered by the lack of extensive and structured infrastructure and the high cost of clean hydrogen. Many studies agree that one of the significant contributors to the lack of competitiveness of green hydrogen is the cost of electricity for its production followed by transportation costs. On the one hand to reduce the investment cost of the electrolyzer high operating hours should be achieved; on the other as the number of operating hours decreases the impact of the electricity costs declines. This paper presents an innovative algorithm for a scalable hydrogen refuelling station (HRS) capable of successfully matching and identifying the most cost-efficient levelized cost of hydrogen (LCOH) produced via electrolysis and connected to the grid based on the HRS components’ cost curves and the hourly average electricity price profile. The objective is to identify the least-cost range of LCOH by considering both the electric energy and the investment costs associated with a hydrogen demand given by different FCB sizes and electrolyzer rated powers. In addition sensitivity analyses have been conducted to quantify the technology cost margins and a cost comparison between the refuelling of an FCB fleet and the recharging infrastructure required for an equivalent fleet of Battery Electric Buse (BEB) has been performed. An LCOH of around 10.5 €/kg varying from 12 €/kg (2 FCB) to 10.2 €/kg (30 FCB) has been found for the best-optimized configurations. The final major conclusion of this paper is that FCB technology is currently not economically competitive. Still a cost contraction of the electric energy price and the electrolyzer capital investment would lead to a 50% decrease in the LCOH. Furthermore increasing renewable energies into the grid may shift the electricity cost curve resulting in higher prices when the BEB recharging demand is more significant. This impact in addition to the peak power load and longer recharging times might contribute to bridging the gap with FCBs.

This paper provides an in-depth review of the current state and future potential of hydrogen fuel cell vehicles (HFCVs). The urgency for more eco-friendly and efficient alternatives to fossilfuel-powered vehicles underlines the necessity of HFCVs which utilize hydrogen gas to power an onboard electric motor producing only water vapor and heat. Despite their impressive energy efficiency ratio (EER) higher power-to-weight ratio and substantial emissions reduction potential the widespread implementation of HFCVs is presently hindered by several technical and infrastructural challenges. These include high manufacturing costs the relatively low energy density of hydrogen safety concerns fuel cell durability issues insufficient hydrogen refueling infrastructure and the complexities of hydrogen storage and transportation. Nevertheless technological advancements and potential policy interventions offer promising prospects for HFCVs suggesting they could become a vital component of sustainable transportation in the future.

In order to eliminate the local CO2 emissions from vehicles and to combat the associated climate change the classic internal combustion engine can be replaced by an electric motor. The two most advantageous variants for the necessary electrical energy storage in the vehicle are currently the purely electrochemical storage in batteries and the chemical storage in hydrogen with subsequent conversion into electrical energy by means of a fuel cell stack. The two variants can also be combined in a battery electric vehicle with a fuel cell range extender so that the vehicle can be refuelled either purely electrically or using hydrogen. The air compressor a key component of a PEM fuel cell system can be operated at different air excess and pressure ratios which influence the stack as well as the system efficiency. To asses the steady state behaviour of a PEM fuel cell range extender system a system test bench utilising a commercially available 30 kW stack (96 cells 409 cm2 cell area) was developed. The influences of the operating parameters (air excess ratio 1.3 to 1.7 stack temperature 20 °C–60 °C air compressor pressure ratio up to 1.67 load point 122 mA/cm2 to 978 mA/cm2) on the fuel cell stack voltage level (constant ambient relative humidity of 45%) and the corresponding system efficiency were measured by utilising current voltage mass flow temperature and pressure sensors. A fuel cell stack model was presented which correlates closely with the experimental data (0.861% relative error). The air supply components were modelled utilising a surface fit. Subsequently the system efficiency of the validated model was optimised by varying the air mass flow and air pressure. It is shown that higher air pressures and lower air excess ratios increase the system efficiency at high loads. The maximum achieved system efficiency is 55.21% at the lowest continuous load point and 43.74% at the highest continuous load point. Future work can utilise the test bench or the validated model for component design studies to further improve the system efficiency.

This paper addresses the energy management of a standalone renewable energy system. The system is configured as a microgrid including photovoltaic generation a lead-acid battery as a short term energy storage system hydrogen production and several loads. In this microgrid an energy management strategy has been incorporated that pursues several objectives. On the one hand it aims to minimize the amount of energy cycled in the battery in order to reduce the associated losses and battery size. On the other hand it seeks to take advantage of the long-term surplus energy producing hydrogen and extracting it from the system to be used in a fuel cell hybrid electric vehicle. A crucial factor in this approach is to accommodate the energy consumption to the energy demand and to achieve this a model predictive control (MPC) scheme is proposed. In this context proper models for solar estimation hydrogen production and battery energy storage will be presented. Moreover the controller is capable of advancing or delaying the deferrable loads from its prescheduled time. As a result a stable and efficient supply with a relatively small battery is obtained. Finally the proposed control scheme has been validated on a real case scenario.

In order to effectively combat the effects of global warming all sectors must actively reduce greenhouse gas emissions in a sustainable and substantial manner. Sector coupling has emerged as a critical technology that can integrate energy systems and address the temporal imbalances created by intermittent renewable energy sources. Despite its potential current sector coupling capabilities remain underutilized and energy modeling approaches face challenges in understanding the intricacies of sector coupling and in selecting appropriate modeling tools. This paper presents a comprehensive review of sector coupling technologies and their role in the energy transition with a specific focus on the integration of electricity heat/cooling and transportation as well as the importance of hydrogen in sector coupling. Additionally we conducted an analysis of 27 sector coupling models based on renewable energy sources with the goal of aiding deciders in identifying the most appropriate model for their specific modeling needs. Finally the paper highlights the importance of sector coupling in achieving climate protection goals while emphasizing the need for technological openness and market-driven conditions to ensure economically efficient implementation.