Publications

Smart energy hubs (Smart Hubs) equipped with Vehicle-to-Grid (V2G) charging photovoltaic (PV) energy generation and hydrogen storage capabilities are an emerging technology with potential to alleviate the impact of electric vehicles (EV) on the electricity grid. Their operation however is characterised by intermittent PV energy generation as well as uncertainties in EV traffic and driver preference. These uncertainties when combined with the need to maximise their financial return while guaranteeing driver satisfaction yields a challenging decision-making problem. This paper presents a novel Monte-Carlo-based modelling and computational framework for simulating the operation of Smart Hubs — providing a means for a holistic assessment of their technical and financial viability. The framework utilises a compact and representative mathematical model accounting for power losses PV module degradation variability in EV uptake price inflation driver preference and diversity in charge points and EVs. It provides a comprehensive approach for dealing with uncertainties and dependencies in EV data while being built on an energy management algorithm that maximises revenue generation ensures driver satisfaction and preserves battery life. The energy management problem is formulated as a mixed-integer linear programming problem constituting a business case that includes an adequate V2G reward model for drivers. To demonstrate its applicability the framework was used to assess the financial viability of a fleet management site for various caps on vehicle stay at the site. From the assessment controlled charging was found to be more financially rewarding in all cases yielding between 1.7% and 3.1% more revenue than uncontrolled charging. The self-consumption of the site was found to be nearly 100% due mainly to local load shifting and dispatchable hydrogen generation. V2G injection was however negligible — suggesting its unattractiveness for sites that do not participate in the demand side response market. Overall the numerical results obtained validate the applicability of the proposed framework as a decision-support tool in the sustainable design and operation of Smart Hubs for EV charging.

Electric trains (ET) and hydrogen trains (HT) are considered zero emission at the point of use. True emissions are dependent upon non-tailpipe sources primarily in energy production. We present UK carbon dioxide (CO₂) operating emission model outputs for conventionally fuelled trains (CFT) ETs and HTs between 2017 and 2050 under four National Grid electricity generation scenarios.



Comparing four service categories (urban regional intercity and high speed) to private conventionally fuelled vehicles (CFV) and electric vehicles considering average distance travelled per trip under different passenger capacity levels (125% 100% 75% 50% and 25%).



Results indicate by 2050 at 100% capacity CFTs produce a fifth of the emissions of CFVs per kilometre per person. Under two degree generation scenario by 2050 ETs produced 14 times and HTs produced five times less emissions than CFTs. Policymakers should encourage shifts away from private vehicles to public transport powered by low carbon electricity.

With the advent of large-scale application of hydrogen transportation becomes crucial. Reusing the existing natural gas transmission system could serve as catalyst for the future hydrogen economy. However a risk analysis of hydrogen transmission in existing pipelines is essential for the deployment of the new energy carrier. This paper focuses on the individual risk (IR) associated with a hazardous hydrogen jet fire and compares it with the natural gas case. The risk analysis adopts a detailed flame model and state of the art computational software to provide an enhanced physical description of flame characteristics.<br/>This analysis concludes that hydrogen jet fires yield lower lethality levels that decrease faster with distance than natural gas jet fires. Consequently for large pipelines hydrogen transmission is accompanied by significant lower IR. Howbeit ignition effects increasingly dominate the IR for decreasing pipeline diameters and cause hydrogen transmission to yield increased IR in the vicinity of the pipeline when compared to natural gas.

Portable H2 sensor was made by using mass spectrometer for the outside monitoring experiment: the leak test the replacement test of gas pipe line the combustion test the explosion experiment the H2 diffusion experiment and the recent issue of the exhaust gas of Fuel Cell Vehicle. In order to check the real time concentration of H2 in various conditions even in the highly humid condition the system volume of the sampling route was minimized with attaching the humidifier. Also to calibrate H2 concentration automatically the specific concentration H2 small cylinder was mounted in the system. In the experiment when H2 gas was introduced in the N2 flow or air in the tube or the high-pressure bottle highly concentrated H2 phases were observed by this sensor without diffusion. This H2 sensor can provide the real time information of the hydrogen molecules and the clouds. The basic characterization of this sensor showed 0-100% H2 concentrations within 2ms. Our observation showed the size of the high concentration phase of H2 and the low concentration phase after mixing process. The mixed and unmixed H2 unintended concentration of cloud gas the high speed small cluster of hydrogen molecules in purged gas were explored by this real time monitoring system.

This report assesses the potential of hydrogen (H2) propulsion to reduce aviation’s climate impact. To reduce climate impact the industry will have to introduce further levers such as radically new technology significantly scale sustainable aviation fuels (SAF) such as synthetic fuel (synfuel) temporarily rely on offsets in large quantities or rely on a combination thereof. H2 propulsion is one such technology and this report assesses its potential in aviation. Developed with input from leading companies and research institutes it projects the technological development of H2 combustion and fuel cell-powered propulsion evaluates their technical and economic feasibility compares them to synfuel and considers implications on aircraft design airport infrastructure and fuel supply chains.

Among several candidates of hydrogen storage liquid hydrogen methylcyclohexane (MCH) and ammonia are considered as potential hydrogen carriers in terms of their characteristics application feasibility and economic performance. In addition as a main motor in the hydrogen introduction Japan has focused and summarized the storage methods for hydrogen into these three methods. Each of them has advantages and disadvantages compared to each other. This study focuses on the effort to analyze and clarify the potential of these three hydrogen storages especially in terms of physical characteristics energy efficiency and economic cost. Liquid hydrogen faces challenges in huge energy consumption during liquefaction and boil-off during storage. MCH has main obstacles in largely required energy in dehydrogenation. Lastly ammonia encounters high energy demand in both synthesis and decomposition (if required). In terms of energy efficiency ammonia is predicted to have the highest total energy efficiency (34–37%) followed by liquid hydrogen (30–33%) and MCH (about 25%). In addition from cost calculation ammonia with direct utilization (without decomposition) is considered to have the highest feasibility for being massively adopted as it shows the lowest cost (20–22 JPY/Nm3-H2 in 2050). However in case that highly pure hydrogen (such as for fuel cell) is demanded liquid hydrogen looks to be promising (24–25 JPY/Nm3-H2 in 2050) compared to MCH and ammonia with decomposition and purification.

We at Kawasaki have proposed a “CO2 free H2 chain” using the abundant brown coal of Australia as a hydrogen source. We developed the basic design package and finished the Front End Engineering Design (FEED) in 2014. There are not only the hazards of the processing plant system but also the characteristic hazards of a hydrogen plant system. We considered and carried out Hazard Identification (HAZID) as the most appropriate approach for safety design in this stage. This paper describes the safety design and HAZID which we practiced for the CO2-Free Hydrogen Supply Chain FEED.

Transitioning German road transport partially to hydrogen energy is among the possibilities being discussed to help meet national climate targets. This study investigates impacts of a hypothetical complete transition from conventionally-fuelled to hydrogen-powered German transport through representative scenarios. Our results show that German emissions change between −179 and +95 MtCO₂eq annually depending on the scenario with renewable-powered electrolysis leading to the greatest emissions reduction while electrolysis using the fossil-intense current electricity mix leads to the greatest increase. German energy emissions of regulated pollutants decrease significantly indicating the potential for simultaneous air quality improvements. Vehicular hydrogen demand is 1000 PJ annually requiring 446–525 TWh for electrolysis hydrogen transport and storage which could be supplied by future German renewable generation supporting the potential for CO₂-free hydrogen traffic and increased energy security. Thus hydrogen-powered transport could contribute significantly to climate and air quality goals warranting further research and political discussion about this possibility.

China has plenty of renewable energy like wind power and solar energy especially in the northwest part of the country. Due to the volatile and intermittent characters of the green powers high penetration level of renewable resources could arise grid stabilization problem. Therefore electricity storage is considered as a solution and hydrogen energy storage is proposed. Instead of storing the electricity directly it converts electricity into hydrogen and the energy in hydrogen will be released as needed from gas to electricity and heat. The transformed green power can be fed to the power grid and heat supply network. State Grid Corporation of China carried out its first hydrogen demonstration project. In the demonstration project an alkaline electrolyzer and a PEM hydrogen fuel cell stack are decided as the hydrogen producer and consumer respectively. Hydrogen safety issue is always of significant importance to secure the property. In order to develop a dedicated safety analysis method for hydrogen energy storage system in power industry the risk analysis for the power-to-gas-topower&heat facility was made. The hazard and operability (HAZOP) study and the failure mode and effects analysis (FMEA) are performed sequentially to the installation to identify the most problematic parts of the system in view of hydrogen safety and possible failure modes and consequences. At the third step the typical hydrogen leak accident scenarios are simulated by using computational fluid dynamics (CFD) computer code. The resulted pressure loads of the possibly ignited hydrogen-air mixture in the facility container are estimated conservatively. Important safeguards and mitigation measures are proposed based on the three-stage risk and safety studies.

Extensive energy consumption has become a major concern due to increase of greenhouse gas emissions and global warming. Hence hydrogen has attracted attention as a green fuel with zero carbon emission for green transportation through production of electric vehicles with hydrogen fuel cells. South Korea has launched a hydrogen society policy with the objective of expanding production of hydrogen from renewable energy sources. The hydrogen economy will play a critical role in reducing atmospheric pollution and global  arming. However new development of infrastructure for hydrogen refuelling and increasing awareness of the hydrogen economy is required together with reduced prices of hydrogen-driven vehicles that are promising options for a sustainable green  hydrogen economy.

The Fuel Cells and Hydrogen Joint Undertaking (FCH JU) has supported a range of initiatives in recent years designed to develop hydrogen fuel cell buses to a point where they can fulfil their promise as a mainstream zero emission vehicle for public transport.<br/>Within this study 90 different European cities and regions have been supported in understanding the business case of fuel cell bus deployment and across these locations. The study analyses the funding and financing for fuel cell bus deployment to make them become a mainstream zero emission choice for public transport providers in cities and regions across Europe. It also outlines possible solutions for further deployment of FC buses beyond the subsidised phase.<br/>In the light of the experience of the joint tender process in the UK and in Germany the study highlights best practices for ordering fuel cell buses. Other innovative instruments explored in other countries for the orders of large quantities of fuel cells buses are presented: Special Purpose Vehicles and centralised purchase office. Finally the study deeply analyses the funding and financing for fuel cell bus deployment to make them become a mainstream zero emission choice for public transport providers in cities and regions across Europe.

Power-to-Power is a process whereby the surplus of renewable power is stored as chemical energy in the form of hydrogen. Hydrogen can be used in situ or transported to the consumption node. When power is needed again hydrogen can be consumed for power generation. Each of these processes incurs energy losses leading to a certain round-trip efficiency (Energy Out/Energy In). Round-trip efficiency is calculated considering the following processes; water electrolysis for hydrogen production compressed liquefied or metal-hydride for hydrogen storage fuel-cell-electric-truck for hydrogen distribution and micro-gas turbine for hydrogen power generation. The maximum achievable round-trip efficiency is of 29% when considering solid oxide electrolysis along with metal hydride storage. This number goes sharply down when using either alkaline or proton exchange membrane electrolyzers 22.2% and 21.8% respectively. Round-trip efficiency is further reduced if considering other storage media such as compressed- or liquefied-H2. However the aim of the paper is to highlight there is still a large margin to increase Power-to-Power round-trip efficiency mainly from the hydrogen production and power generation blocks which could lead to round-trip efficiencies of around 40%e42% in the next decade for Power-to-Power energy storage systems with micro-gas turbines.

Fuel cell electric vehicles (FCEVs) are zero tailpipe emission vehicles. Their large-scale deployment is expected to play a major role in the de-carbonization of transportation in the European Union (EU) and is therefore an important policy element at EU and Member State level.<br/>For FCEVs to be introduced to the market a network of hydrogen refuelling stations (HRS) first has to exist. From a technological point of view FCEVs are ready for serial production already: Hyundaiand Toyota plan to introduce FCEVs into key markets from 2015 and Daimler Ford and Nissan plan to launch mass-market FCEVs in 2017.<br/>At the moment raising funds for building the hydrogen refuelling infrastructure appears to be challenging.<br/>This study explores options for financing the HRS rollout which facilitate the involvement of private lenders and investors. It  presents a number of different financing options involving public-sector bank loans funding from private-sector strategic equity investors commercial bank loans private equity and funding from infrastructure investors. The options outline the various requirements forn accessing these sources of funding with regard to project structure incentives and risk mitigation. The financing options were developed on the basis of discussions with stakeholders in the HRS rollout from industry and with financiers.<br/>This study was prepared by Roland Berger in close contact with European Investment banks and a series of private banks.<br/>This study explores in details the business cases for HRS in Germany and UK. The conclusion can be easily extrapolate to other countries.

This report provides an outlook for jointly achieving a commercialisation pathway.<br/>Building on the findings of the 2012 FCH JU technology study on alternative powertrains for urban buses this report provides an assessment of the commercialisation pathway from an operational perspective. It reflects the actual situation in which operators deploy large scale demonstration projects in the next years from a rather conservative angle and argues why it makes sense to deploy FC buses now. The insights are based on first-hand data and assessments of the coalition members from the hydrogen and fuel cell industry as well as local governments and public transport operators in Europe.

This brochure offers an overview of the main applications of fuel cell and hydrogen technologies and how they work and provides insights into our programme and our accomplishments.

If Hydrogen is expected to be highly valuable some improvements should be conducted mainly regarding the storage safety. To prevent from high pressure hydrogen composite tanks bursting the comprehension of the thermo-mechanics phenomena in the case of fire should be improved. To understand the kinetic of strength loss the heat flux produced by fire of various intensities should be assessed. This is the objective of this real scale experimental campaign which will allow studying in future works the strength loss of composite high-pressure vessels in similar fire conditions to the ones determined in this study. Fire calibration tests were performed on metallic cylinder vessels. These tests with metallic cylinders are critical in the characterization of the thermal load of various fire sources (pool fire propane gas fire hydrogen gas fire) so as to evaluate differences related to different thermal load. Radiant panels were also used as thermal source for reference of pure radiation heat transfer. The retained thermal load might be representative of accidental situations in worst case scenarios and relevant for a standardized testing protocol. The tests performed show that hydrogen gas fires and heptane pool fire allow reaching the target in terms of absorbed energy regarding the results of risk analysis performed previously. Other considerations can be taken into account that will led to retain an hydrogen gas fire for further works. Firstly hydrogen gas fire is the more realistic scenario: Hydrogen is the combustible that we every time find near an hydrogen storage. Secondly as one of the objectives of the project is to make recommendations for standardization issues it’s important to note that gas fires are not too complex to calibrate control and reproduce. Finally due to previous considerations Hydrogen gas fire will be retained for thermal load of composite cylinders in future works.

The non-interconnected islands of Greece can benefit from the comprehensive use of RES to avoid water droughts and ensure energy autonomy. The present paper analyzes an HRES with two possible operating scenarios. Both of them include a wind park of 27.5 MW capacity an 1175 m3/day desalination plant and a 490000 m3/day water tank in Lemnos Greece. Regarding the wind power 70% is used in the HRES while the rest is channeled directly to the grid. The main difference comes down to how the wind energy is stored either in the form of hydraulic energy or in the form of hydrogen. The lifespan of the system is 25 years such as the produced stochastic series of rainfall temperature and wind of the area. Through the comparison of the operating scenarios the following results arise: (i) the water needs of the island are fully covered and the irrigation needs have a reliability of 66% in both scenarios. (ii) Considering the energy needs the pumping storage seems to be the most reliable solution. (iii) However depending on the amount of wind energy surplus the use of hydrogen could produce more energy than the hydroelectric plant.

Power-to-X is one of the most attention-grabbing topics in the energy sector. Researchers are exploring the potential of harnessing power from renewable technologies and converting it into fuels used in various industries and the transportation sector. With the current market and research emphasis on Power-to-X and the accompanying substantial investments a review of Power-to-X is becoming essential. Optimization will be a crucial aspect of managing an energy portfolio that includes Power-to-X and electrolysis systems as the electrolyzer can participate in multiple markets. Based on the current literature and published reviews none of them adequately showcase the state-of-the-art optimization algorithms for energy portfolios focusing on Power-to-X. Therefore this paper provides an in-depth review of the optimization algorithms applied to energy portfolios with a specific emphasis on Power-to-X aiming to uncover the current state-of-the-art in the field.

The increasing penetration of renewable and distributed resources signals a global boom in energy transition but traditional grid utilities have yet to share in much of the triumph at the current stage. Higher grid management costs lower electricity prices fewer customers and other challenges have emerged along the path toward renewable energy but many more opportunities await to be seized. Most importantly there are insufficient studies on how grid utilities can thrive within the hydrogen economy. Through a case study on the State Grid Corporation of China we identify the strengths weaknesses opportunities and threats (SWOT) of grid utilities within the hydrogen economy. Based on these factors we recommend that grids integrate hydrogen into the energy-as-a-service model and deliver it to industrial customers who are under decarbonization pressure. We also recommend that grid utilities fund a joint venture with pipeline companies to optimize electricity and hydrogen transmissions simultaneously.

This article presents an analysis of the permeation tests established in the current regulations for the type-approval of on board tanks in hydrogen vehicles. The analysis is done from the point of view of a test maker regarding the preparation for the execution of a permeation test. The article contains a description of the required instrumentation and set-up to carry out a permeation test according to the applicable standards and regulations. Tank conditions at the beginning of the test configuration of permeation chamber duration of the test or permeation rate to be reported are aspects that are not well-defined in regulations. In this paper we examine the challenges when carrying out a permeation test and propose possible solutions to overcome them with the intention of supporting test makers and helping the development of permeation test guidelines.

Fossil fuels and materials on Earth are a finite resource and the disposal of waste into the air on land and into water has an impact on our environment on a global level. Using Switzerland as an example the energy demand and the technical challenges and the economic feasibility of a transition to an energy economy based entirely on renewable energy were analyzed. Three approaches for the complete substitution of fossil fuels with renewable energy from photovoltaics called energy systems (ES) were considered i.e. a purely electric system with battery storage (ELC) hydrogen (HYS) and synthetic hydrocarbons (HCR). ELC is the most energy efficient solution; however it requires seasonal electricity storage to meet year-round energy needs. Meeting this need through batteries has a significant capital cost and is not feasible at current rates of battery production and expanding pumped hydropower to the extent necessary will have a big impact on the environment. The HYS allows underground hydrogen storage to balance seasonal demand but requires building of a hydrogen infrastructure and applications working with hydrogen. Finally the HCR requires the largest photovoltaic (PV) field but the infrastructure and the applications already exist. The model for Switzerland can be applied to other countries adapting the solar irradiation the energy demand and the storage options.

Interest in reducing the greenhouse gas emissions from conventional power generation has increased the focus on the potential use of hydrogen to produce electricity. Numerous life-cycle assessment (LCA) studies of hydrogen-based power generation have been published. This study reviews the technological and methodological choices made in hydrogen-based power generation LCAs. A systematic review was chosen as the research method to achieve a comprehensive and minimally biased overview of hydrogen-based power generation LCAs. Relevant articles published between 2004 and 2021 were identified by searching the Scopus and Web of Science databases. Electrolysis from renewable energy resources was the most widely considered type of hydrogen production in the LCAs analyzed. Fuel cell technology was the most common conversion equipment used in hydrogen-based electricity LCAs. A significant number of scenarios examine the use of hydrogen for energy storage and co-generation purposes. Based on qualitative analysis the methodological choices of LCAs vary between studies in terms of the functional units allocations system boundaries and life-cycle impact assessment methods chosen. These discrepancies were likely to influence the value of the environmental impact results. The findings of the reviewed LCAs could provide an environmental profile of hydrogen-based electricity systems identify hotspots drive future research define performance goals and establish a baseline for their large-scale deployment.

In Spain the institutional framework for photovoltaic energy production has experienced distinct stages. From 2007 to 2012 the feed-in-tariff system led to high annual growth rates of this renewable energy but after the suppression of the policy of public subsidies the sector stagnated. In recent years green hydrogen an innocuous gas in the atmosphere has become a driving force that stimulates photovoltaic energy production. Since 2020 encouraged by the European energy strategies and corresponding funds Spain has established a regulation to promote green hydrogen as a form of energy resource. Adopting the new institutional economics (NIE) approach this article investigates the process of changing incentives for the energy business sector and its impact on photovoltaic energy production. The results show an increase in the number of both projects approved or on approval and companies involved in green hydrogen that are planning to use photovoltaic energy in Spain thus engendering the creation of a new photovoltaic business environment based on innovation and sustainability.

This study presents a methodology of a quantitative risk assessment for the scenario of an onboard hydrogen storage tank rupture and tunnel fire incident. The application of the methodology is demonstrated on a road tunnel. The consequence analysis is carried out for the rupture of a 70 MPa 62.4-litre hydrogen storage tank in a fire that has a thermally activated pressure relief device (TPRD) failed or blocked during an incident. Scenarios with two states of charge (SoC) of the tank i.e. SoC = 99% and SoC = 59% are investigated. The risks in terms of fatalities per vehicle per year and the cost per incident are assessed. It is found that for the reduction in the risk with the hydrogen-powered vehicle in a road tunnel fire incident to the acceptable level of 10−5 fatality/vehicle/year the fireresistance rating (FRR) of the hydrogen storage tank should exceed 84 min. The FRR increase to this level reduces the societal risk to an acceptable level. The increase in the FRR to 91 min reduces the risk in terms of the cost of the incident to GBP 300 following the threshold cost of minor injury published by the UK Health and Safety Executive. The Frequency–Number (F–N) of the fatalities curve is developed to demonstrate the effect of mitigation measures on the risk reduction to socially acceptable levels. The performed sensitivity study confirms that with the broad range of input parameters including the fire brigade response time the risk of rupture of standard hydrogen tank-TPRD systems inside the road tunnel is unacceptable. One of the solutions enabling an inherently safer use of hydrogen-powered vehicles in tunnels is the implementation of breakthrough safety technology—the explosion free in a fire self-venting (TPRD-less) tanks.

Integrating the exergy and economic analyses of water electrolyzers is the pivotal way to comprehend the interplay of system costs and improve system performance. For this a 3D numerical model based on COMSOL Multiphysics Software (version 5.6 COMSOL Stockholm Sweden) is integrated with the exergy and exergoeconomic analysis to evaluate the exergoeconomic performance of the proton exchange membrane water electrolysis (PEMWE) under different operating conditions (operating temperature cathode pressure current density) and design parameter (membrane thickness). Further the gas crossover phenomenon is investigated to estimate the impact of gas leakage on analysis reliability under various conditions and criteria. The results reveal that increasing the operating temperature or decreasing the membrane thickness improves both the efficiency and cost of hydrogen exergy while increasing the gas leakage through the membrane. Likewise raising the current density and the cathode pressure lowers the hydrogen exergy cost and improves the economic performance. The increase in exergy destroyed and hydrogen exergy cost as well as the decline in second law efficiency due to the gas crossover are more noticeable at higher pressures. As the cathode pressure rises from 1 to 30 bar at a current density of 10000 A/m2 the increase in exergy destroyed and hydrogen exergy cost as well as the decline in second law efficiency are increased by 37.6 kJ/mol 4.49 USD/GJ and 7.1% respectively. The cheapest green electricity source which is achieved using onshore wind energy and hydropower reduces hydrogen production costs and enhances economic efficiency. The growth in the hydrogen exergy cost is by about 4.23 USD/GJ for a 0.01 USD/kWh increase in electricity price at the current density of 20000 A/m2. All findings would be expected to be quite useful for researchers engaged in the design development and optimization of PEMWE.