Spain
Potential for Hydrogen Production from Biomass Residues in the Valencian Community
Sep 2007
Publication
The production of hydrogen from renewable sources is essential to develop the future hydrogen economy. Biomass is an abundant clean and renewable energy source and it can be important in the production of hydrogen. The Valencian Community due to its great agricultural and forestry activities generates an important quantity of biomass residues that can be used for energy generation approximately 778 kt of wet biomass residues per year. This great quantity of biomass can be transformed into a hydrogen-rich gas by different thermochemical conversion processes. In this article the potential of production of hydrogen-rich gas is analyzed considering several factors affecting the conversion yield of these processes. As a result of this analysis it could be possible to produce 1271 MNm3 of H2 per year considering the total biomass residues of the community and selecting the gasification processes.
An Intercomparison Exercise on the Capabilities of CFD Models to Predict Deflagration of a Large-Scale H2-Air Mixture in Open Atmosphere
Sep 2005
Publication
This paper presents a compilation of the results supplied by HySafe partners participating in the Standard Benchmark Exercise Problem (SBEP) V2 which is based on an experiment on hydrogen combustion that is first described. A list of the results requested from participants is also included. The main characteristics of the models used for the calculations are compared in a very succinct way by using tables. The comparison between results together with the experimental data when available is made through a series of graphs. The results show quite good agreement with the experimental data. The calculations have demonstrated to be sensitive to computational domain size and far field boundary condition.
An Inter-Comparison Exercise on the Capabilities of CFD Models to Predict the Short and Long Term Distribution and Mixing of Hydrogen in a Garage
Sep 2007
Publication
Alexandros G. Venetsanos,
E. Papanikolaou,
J. García,
Olav Roald Hansen,
Matthias Heitsch,
Asmund Huser,
Wilfried Jahn,
Jean-Marc Lacome,
Thomas Jordan,
H. S. Ledin,
Dmitry Makarov,
Prankul Middha,
Etienne Studer,
Andrei V. Tchouvelev,
Franck Verbecke,
M. M. Voort,
Andrzej Teodorczyk and
M. A. Delichatsios
The paper presents the results of the CFD inter-comparison exercise SBEP-V3 performed within the activity InsHyde internal project of the HYSAFE network of excellence in the framework of evaluating the capability of various CFD tools and modelling approaches in predicting the physical phenomena associated to the short and long term mixing and distribution of hydrogen releases in confined spaces. The experiment simulated was INERIS-TEST-6C performed within the InsHyde project by INERIS consisting of a 1 g/s vertical hydrogen release for 240 s from an orifice of 20 mm diameter into a rectangular room (garage) of dimensions 3.78x7.2x2.88 m in width length and height respectively. Two small openings at the front and bottom side of the room assured constant pressure conditions. During the test hydrogen concentration time histories were measured at 12 positions in the room for a period up to 5160 s after the end of release covering both the release and the subsequent diffusion phases. The benchmark was organized in two phases. The first phase consisted of blind simulations performed prior to the execution of the tests. The second phase consisted of post calculations performed after the tests were concluded and the experimental results made available. The participation in the benchmark was high: 12 different organizations (2 non-HYSAFE partners) 10 different CFD codes and 8 different turbulence models. Large variation in predicted results was found in the first phase of the benchmark between the various modelling approaches. This was attributed mainly to differences in turbulence models and numerical accuracy options (time/space resolution and discretization schemes). During the second phase of the benchmark the variation between predicted results was reduced.
Ia-HySafe Standard Benchmark Exercise Sbep-V21- Hydrogen Release and Accumulation within a Non-Ventilated Ambient Pressure Garage at Low Release Rates
Sep 2011
Publication
The successful Computational Fluid Dynamics (CFD) benchmarking activity originally started within the EC-funded Network of Excellence HySafe (2004-2009) continues within the research topics of the recently established “International Association of Hydrogen Safety” (IA-HySafe). The present contribution reports the results of the standard benchmark problem SBEP-V21. Focus is given to hydrogen dispersion and accumulation within a non-ventilated ambient pressure garage both during the release and post-release periods but for very low release rates as compared to earlier work (SBEP-V3). The current experiments were performed by CEA at the GARAGE facility under highly controlled conditions. Helium was vertically released from the centre of the 5.76 m (length) x 2.96 m (width) x 2.42 m (height) facility 22 cm from the floor from a 29.7 mm diameter opening at a volumetric rate of 18 L/min (0.027 g/s equivalent hydrogen release rate compared to 1 g/s for SBEP-V3) and for a period of 3740 seconds. Helium concentrations were measured with 57 catharometric sensors at various locations for a period up to 1.1 days. The simulations were performed using a variety of CFD codes and turbulence models. The paper compares the results predicted by the participating partners and attempts to identify the reasons for any observed disagreements.
Non-stoichiometric Methanation as Strategy to Overcome the Limitations of Green Hydrogen Injection into the Natural Gas Grid
Jan 2022
Publication
The utilization of power to gas technologies to store renewable electricity surpluses in the form of hydrogen enables the integration of the gas and electricity sectors allowing the decarbonization of the natural gas network through green hydrogen injection. Nevertheless the injection of significant amounts of hydrogen may lead to high local concentrations that may degrade materials (e.g. hydrogen embrittlement of pipelines) and in general be not acceptable for the correct and safe operation of appliances. Most countries have specific regulations to limit hydrogen concentration in the gas network. The methanation of hydrogen represents a potential option to facilitate its injection into the grid. However stoichiometric methanation will lead to a significant presence of carbon dioxide limited in gas networks and requires an accurate design of several reactors in series to achieve relevant concentrations of methane. These requirements are smoothed when the methanation is undertaken under non-stoichiometric conditions (high H/C ratio). This study aims to assess to influence of nonstoichiometric methanation under different H/C ratios on the limitations presented by the pure hydrogen injection. The impact of this injection on the operation of the gas network at local level has been investigated and the fluid-dynamics and the quality of gas blends have been evaluated. Results show that non-stoichiometric methanation could be an alternative to increase the hydrogen injection in the gas network and facilitates the gas and electricity sector coupling.
Benchmark Exercise on Risk Assessment Methods Applied to a Virtual Hydrogen Refuelling Station
Sep 2009
Publication
A benchmarking exercise on quantitative risk assessment (QRA) methodologies has been conducted within the project HyQRA under the framework of the European Network of Excellence (NoE) HySafe. The aim of the exercise was basically twofold: (i) to identify the differences and similarities in approaches in a QRA and their results for a hydrogen installation between nine participating partners representing a broad spectrum of background in QRA culture and history and (ii) to identify knowledge gaps in the various steps and parameters underlying the risk quantification. In the first step a reference case was defined: a virtual hydrogen refuelling station (HRS) in virtual surroundings comprising housing school shops and other vulnerable objects. All partners were requested to conduct a QRA according to their usual approach and experience. Basically participants were free to define representative release cases to apply models and frequency assessments according their own methodology and to present risk according to their usual format. To enable inter-comparison a required set of results data was prescribed like distances to specific thermal radiation levels from fires and distances to specific overpressure levels. Moreover complete documentation of assumptions base data and references was to be reported. It was not surprising that a wide range of results was obtained both in the applied approaches as well as in the quantitative outcomes and conclusions. This made it difficult to identify exactly which assumptions and parameters were responsible for the differences in results as the paper will show. A second phase was defined in which the QRA was determined by a more limited number of release cases (scenarios). The partners in the project agreed to assess specific scenarios in order to identify the differences in consequence assessment approaches. The results of this phase provide a better understanding of the influence of modelling assumptions and limitations on the eventual conclusions with regard to risk to on-site people and to the off-site public. This paper presents the results and conclusions of both stages of the exercise.
New Insights into the Electrochemical Behaviour of Porous Carbon Electrodes for Supercapacitors
Aug 2018
Publication
Activated carbons with different surface chemistry and porous textures were used to study the mechanism of electrochemical hydrogen and oxygen evolution in supercapacitor devices. Cellulose precursor materials were activated with different potassium hydroxide (KOH) ratios and the electrochemical behaviour was studied in 6 M KOH electrolyte. In situ Raman spectra were collected to obtain the structural changes of the activated carbons under severe electrochemical oxidation and reduction conditions and the obtained data were correlated to the cyclic voltammograms obtained at high anodic and cathodic potentials. Carbon-hydrogen bonds were detected for the materials activated at high KOH ratios which form reversibly under cathodic conditions. The influence of the specific surface area narrow microporosity and functional groups in the carbon electrodes on their chemical stability and hydrogen capture mechanism in supercapacitor applications has been revealed.
Application of Hydrides in Hydrogen Storage and Compression: Achievements, Outlook and Perspectives
Feb 2019
Publication
José Bellosta von Colbe,
Jose-Ramón Ares,
Jussara Barale,
Marcello Baricco,
Craig Buckley,
Giovanni Capurso,
Noris Gallandat,
David M. Grant,
Matylda N. Guzik,
Isaac Jacob,
Emil H. Jensen,
Julian Jepsen,
Thomas Klassen,
Mykhaylo V. Lototskyy,
Kandavel Manickam,
Amelia Montone,
Julian Puszkiel,
Martin Dornheim,
Sabrina Sartori,
Drew Sheppard,
Alastair D. Stuart,
Gavin Walker,
Colin Webb,
Heena Yang,
Volodymyr A. Yartys,
Andreas Züttel and
Torben R. Jensen
Metal hydrides are known as a potential efficient low-risk option for high-density hydrogen storage since the late 1970s. In this paper the present status and the future perspectives of the use of metal hydrides for hydrogen storage are discussed. Since the early 1990s interstitial metal hydrides are known as base materials for Ni – metal hydride rechargeable batteries. For hydrogen storage metal hydride systems have been developed in the 2010s [1] for use in emergency or backup power units i. e. for stationary applications.<br/>With the development and completion of the first submarines of the U212 A series by HDW (now Thyssen Krupp Marine Systems) in 2003 and its export class U214 in 2004 the use of metal hydrides for hydrogen storage in mobile applications has been established with new application fields coming into focus.<br/>In the last decades a huge number of new intermetallic and partially covalent hydrogen absorbing compounds has been identified and partly more partly less extensively characterized.<br/>In addition based on the thermodynamic properties of metal hydrides this class of materials gives the opportunity to develop a new hydrogen compression technology. They allow the direct conversion from thermal energy into the compression of hydrogen gas without the need of any moving parts. Such compressors have been developed and are nowadays commercially available for pressures up to 200 bar. Metal hydride based compressors for higher pressures are under development. Moreover storage systems consisting of the combination of metal hydrides and high-pressure vessels have been proposed as a realistic solution for on-board hydrogen storage on fuel cell vehicles.<br/>In the frame of the “Hydrogen Storage Systems for Mobile and Stationary Applications” Group in the International Energy Agency (IEA) Hydrogen Task 32 “Hydrogen-based energy storage” different compounds have been and will be scaled-up in the near future and tested in the range of 500 g to several hundred kg for use in hydrogen storage applications.
Enabling Large-scale Hydrogen Storage in Porous Media – The Scientific Challenges
Jan 2021
Publication
Niklas Heinemann,
Juan Alcalde,
Johannes M. Miocic,
Suzanne J. T. Hangx,
Jens Kallmeyer,
Christian Ostertag-Henning,
Aliakbar Hassanpouryouzband,
Eike M. Thaysen,
Gion J. Strobel,
Cornelia Schmidt-Hattenberger,
Katriona Edlmann,
Mark Wilkinson,
Michelle Bentham,
Stuart Haszeldine,
Ramon Carbonell and
Alexander Rudloff
Expectations for energy storage are high but large-scale underground hydrogen storage in porous media (UHSP) remains largely untested. This article identifies and discusses the scientific challenges of hydrogen storage in porous media for safe and efficient large-scale energy storage to enable a global hydrogen economy. To facilitate hydrogen supply on the scales required for a zero-carbon future it must be stored in porous geological formations such as saline aquifers and depleted hydrocarbon reservoirs. Large-scale UHSP offers the much-needed capacity to balance inter-seasonal discrepancies between demand and supply decouple energy generation from demand and decarbonise heating and transport supporting decarbonisation of the entire energy system. Despite the vast opportunity provided by UHSP the maturity is considered low and as such UHSP is associated with several uncertainties and challenges. Here the safety and economic impacts triggered by poorly understood key processes are identified such as the formation of corrosive hydrogen sulfide gas hydrogen loss due to the activity of microbes or permeability changes due to geochemical interactions impacting on the predictability of hydrogen flow through porous media. The wide range of scientific challenges facing UHSP are outlined to improve procedures and workflows for the hydrogen storage cycle from site selection to storage site operation. Multidisciplinary research including reservoir engineering chemistry geology and microbiology more complex than required for CH4 or CO2 storage is required in order to implement the safe efficient and much needed large-scale commercial deployment of UHSP.
Hydrogen Roadmap: A Commitment to Renewable Hydrogen - Executive Summary
Oct 2020
Publication
This Hydrogen Roadmap aims to identify the challenges and opportunities for the full development of renewable hydrogen in Spain providing a series of measures aimed at boosting investment action taking advantage of the European consensus on the role that this energy vector should play in the context of green recovery. This Roadmap is therefore aligned with the 2021 Annual Sustainable Growth Strategy published by the European Commission which identifies the future Recovery and Resilience Mechanism as an opportunity to create emblematic areas of action at European level making two of these areas of action (Power up and Recharge and Refuel) an explicit mention of the development of renewable hydrogen in the European Union.
The Membrane-assisted Chemical Looping Reforming Concept for Efficient H2 Production with Inherent CO2 Capture: Experimental Demonstration and Model Validation
Feb 2018
Publication
In this work a novel reactor concept referred to as Membrane-Assisted Chemical Looping Reforming (MA-CLR) has been demonstrated at lab scale under different operating conditions for a total working time of about 100 h. This reactor combines the advantages of Chemical Looping such as CO2 capture and good thermal integration with membrane technology for a better process integration and direct product separation in a single unit which in its turn leads to increased efficiencies and important benefits compared to conventional technologies for H2 production. The effect of different operating conditions (i.e. temperature steam-to-carbon ratio or oxygen feed in the reactor) has been evaluated in a continuous chemical looping reactor and methane conversions above 90% have been measured with (ultra-pure) hydrogen recovery from the membranes. For all the cases a maximum recovery factor of around 30% has been measured which could be increased by operating the concept at higher pressures and with more membranes. The optimum conditions have been found at temperatures around 600°C for a steam-to-carbon ratio of 3 and diluted air in the air reactor (5% O2). The complete demonstration has been carried out feeding up to 1 L/min of CH4 (corresponding to 0.6 kW of thermal input) while up to 1.15 L/min of H2 was recovered. Simultaneously a phenomenological model has been developed and validated with the experimental results. In general good agreement is observed with overall deviations below 10% in terms of methane conversion H2 recovery and separation factor. The model allows better understanding of the behavior of the MA-CLR concept and the optimization and design of scaled-up versions of the concept.
Low Temperature Autoignition of Diesel Fuel Under Dual Operation with Hydrogen and Hydrogen-carriers
Mar 2022
Publication
While electrification of light duty vehicles is becoming a real solution to abate local pollutant as well as greenhouse gases emission heavy duty applications (such as long distance freight and maritime transport) will keep requiring fuel-based propulsion systems. In these sectors dominated by compression ignition engines research on alternative biofuels and new combustion modes is still highly necessary. Dual-fuel combustion appears as a very promising concept to replace conventional diesel fuel by sustainable ones. Among the latter hydrogen-derived fuels (the so-called electrofuels or e-fuels) are maybe the most interesting. This work addresses the effect of partial substitution of diesel fuel by hydrogen and hydrogen-carriers (ammonia and methane) on the autoignition process under low temperature conditions. Tests were carried out in a constant volume combustion chamber at different temperatures (535 600 and 650 ◦C) and pressures (11 16 and 21 bar). While the cool flames timing and intensity was only slightly affected by the low reactivity fuel energy content the main ignition was delayed this effect being much more noticeable for ammonia followed by hydrogen and finally methane. Kinetic simulations showed a clear competition for active radicals between both fuels (diesel and low reactivity fuel). The combustion duration also increased with the hydrogen or hydrogen-carrier content which greatly points to the need of modifications in the injection strategy of compression ignition engines operating under dual mode. A correlation was proposed for estimating the autoignition delay time for dual-fuel lean combustion at low temperature.
Techno-economic Model and Feasibility Assessment of Green Hydrogen Projects Based on Electrolysis Supplied by Photovoltaic PPAs
Nov 2022
Publication
The use of hydrogen produced from renewable energy enables the reduction of greenhouse gas (GHG) emissions pursued in different international strategies. The use of power purchase agreements (PPAs) to supply renewable electricity to hydrogen production plants is an approach that can improve the feasibility of projects. This paper presents a model applicable to hydrogen projects regarding the technical and economic perspective and applies it to the Spanish case where pioneering projects are taking place via photovoltaic PPAs. The results show that PPAs are an enabling mechanism for sustaining green hydrogen projects.
Techno-economic Assessment of Blue and Green Ammonia as Energy Carriers in a Low-carbon Future
Feb 2022
Publication
Ammonia is an industrial chemical and the basic building block for the fertilizer industry. Lately attention has shifted towards using ammonia as a carbon-free energy vector due to the ease of transportation and storage in liquid state at − 33 ◦C and atmospheric pressure. This study evaluates the prospects of blue and green ammonia as future energy carriers; specifically the gas switching reforming (GSR) concept for H2 and N2 co-production from natural gas with inherent CO2 capture (blue) and H2 generation through an optimized value chain of wind and solar power electrolysers cryogenic N2 supply and various options for energy storage (green). These longer term concepts are benchmarked against conventional technologies integrating CO2 capture: the Kellogg Braun & Root (KBR) Purifier process and the Linde Ammonia Concept (LAC). All modelled plants utilize the same ammonia synthesis loop for a consistent comparison. A cash flow analysis showed that the GSR concept achieved an attractive levelized cost of ammonia (LCOA) of 332.1 €/ton relative to 385.1–385.9 €/ton for the conventional plants at European energy prices (6.5 €/GJ natural gas and 60 €/MWh electricity). Optimal technology integration for green ammonia using technology costs representative of 2050 was considerably more expensive: 484.7–772.1 €/ton when varying the location from Saudi Arabia to Germany. Furthermore the LCOA of the GSR technology drops to 192.7 €/ton when benefitting from low Saudi Arabian energy costs (2 €/GJ natural gas and 40 €/MWh electricity). This cost difference between green and blue ammonia remained robust in sensitivity analyses where input energy cost (natural gas or wind/solar power) was the most influential parameter. Given its low production costs and the techno-economic feasibility of international ammonia trade advanced blue ammonia production from GSR offers an attractive pathway for natural gas exporting regions to contribute to global decarbonization.
Optimal Design of Photovoltaic, Biomass, Fuel Cell, Hydrogen Tank Units and Electrolyzer Hybrid System for a Remote Area in Egypt
Jul 2022
Publication
In this paper a new isolated hybrid system is simulated and analyzed to obtain the optimal sizing and meet the electricity demand with cost improvement for servicing a small remote area with a peak load of 420 kW. The major configuration of this hybrid system is Photovoltaic (PV) modules Biomass gasifier (BG) Electrolyzer units Hydrogen Tank units (HT) and Fuel Cell (FC) system. A recent optimization algorithm namely Mayfly Optimization Algorithm (MOA) is utilized to ensure that all load demand is met at the lowest energy cost (EC) and minimize the greenhouse gas (GHG) emissions of the proposed system. The MOA is selected as it collects the main merits of swarm intelligence and evolutionary algorithms; hence it has good convergence characteristics. To ensure the superiority of the selected MOA the obtained results are compared with other well-known optimization algorithms namely Sooty Tern Optimization Algorithm (STOA) Whale Optimization Algorithm (WOA) and Sine Cosine Algorithm (SCA). The results reveal that the suggested MOA achieves the best system design achieving a stable convergence characteristic after 44 iterations. MOA yielded the best EC with 0.2106533 $/kWh the net present cost (NPC) with 6170134 $ the loss of power supply probability (LPSP) with 0.05993% and GHG with 792.534 t/y.
A Zero CO2 Emissions Large Ship Fuelled by an Ammonia-hydrogen Blend: Reaching the Decarbonisation Goals
Aug 2023
Publication
To reach the decarbonisation goals a zero CO2 emissions large ship propulsion system is proposed in this work. The ship selected is a large ferry propelled by an internal combustion engine fuelled by an ammonia-hydrogen blend. The only fuel loaded in the vessel will be ammonia. The hydrogen required for the combustion in the engine will be produced onboard employing ammonia decomposition. The heat required for this decomposition section will be supplied by using the hot flue gases of the combustion engine. To address the issues regarding NOx emissions a selective catalytic reduction (SCR) reactor was designed. The main operating variables for all the equipment were computed for engine load values of 25% 50% 75% and 100%. Considering the lowest SCR removal rate (91% at an engine load of 100%) the NOx emissions of the vessel were less than 0.5 g/kWh lower than the IMO requirements. An energy analysis of the system proposed to transform ammonia into energy for shipping was conducted. The global energy and exergy efficiencies were 42.4% and 48.1%. In addition an economic analysis of the system was performed. The total capital cost (CAPEX) for the system can be estimated at 8.66 M€ (784 €/kW) while the operating cost (OPEX) ranges between 210 €/MWh (engine load 100%) and 243 €/MWh (engine load of 25%). Finally a sensitivity analysis for the price of ammonia was performed resulting in the feasibility of reducing the operating cost to below 150 €/MWh in the near horizon.
Bioinspired Hybrid Model to Predict the Hydrogen Inlet Fuel Cell Flow Change of an Energy Storage System
Nov 2019
Publication
The present research work deals with prediction of hydrogen consumption of a fuel cell in an energy storage system. Due to the fact that these kind of systems have a very nonlinear behaviour the use of traditional techniques based on parametric models and other more sophisticated techniques such as soft computing methods seems not to be accurate enough to generate good models of the system under study. Due to that a hybrid intelligent system based on clustering and regression techniques has been developed and implemented to predict the necessary variation of the hydrogen flow consumption to satisfy the variation of demanded power to the fuel cell. In this research a hybrid intelligent model was created and validated over a dataset from a fuel cell energy storage system. Obtained results validate the proposal achieving better performance than other well-known classical regression methods allowing us to predict the hydrogen consumption with a Mean Absolute Error (MAE) of 3.73 with the validation dataset.
Hydrogen Production from Methanol–Water Solution and Pure Water Electrolysis Using Nanocomposite Perfluorinated Sulfocationic Membranes Modified by Polyaniline
Oct 2022
Publication
In this work we report the preparation of Nafion membranes containing two different nanocomposite MF-4SC membranes modified with polyaniline (PANI) by the casting method through two different polyaniline infiltration procedures. These membranes were evaluated as a polymer electrolyte membrane for water electrolysis. Operating conditions were optimized in terms of current density stability and methanol concentration. A study was made on the effects on the cell performance of various parameters such as methanol concentration water and cell voltage. The energy required for pure water electrolysis was analyzed at different temperatures for the different membranes. Our experiments showed that PEM electrolyzers provide hydrogen production of 30 mL/min working at 160 mA/cm2 . Our composite PANI membranes showed an improved behavior over pristine perfluorinated sulfocationic membranes (around 20% reduction in specific energy). Methanol–water electrolysis required considerably less (around 65%) electrical power than water electrolysis. The results provided the main characteristics of aqueous methanol electrolysis in which the power consumption is 2.34 kW h/kg of hydrogen at current densities higher than 0.5 A/cm2 . This value is ~20-fold times lower than the electrical energy required to produce 1 kg of hydrogen by water electrolysis.
Review and Comparison of Worldwide Hydrogen Activities in the Rail Sector with Special Focus on On-board Storage and Refueling Technologies
Aug 2022
Publication
"This paper investigates hydrogen storage and refueling technologies that were used in rail vehicles over the past 20 years as well as planned activities as part of demonstration projects or feasibility studies. Presented are details of the currently available technology and its vehicle integration market availability as well as standardization and research and development activities. A total of 80 international studies corporate announcements as well as vehicle and refueling demonstration projects were evaluated with regard to storage and refueling technology pressure level hydrogen amount and installation concepts inside rolling stock. Furthermore current hydrogen storage systems of worldwide manufacturers were analyzed in terms of technical data.<br/>We found that large fleets of hydrogen-fueled passenger railcars are currently being commissioned or are about to enter service along with many more vehicles on order worldwide. 35 MPa compressed gaseous storage system technology currently dominates in implementation projects. In terms of hydrogen storage requirements for railcars sufficient energy content and range are not a major barrier at present (assuming enough installation space is available). For this reason also hydrogen refueling stations required for 35 MPa vehicle operation are currently being set up worldwide.<br/>A wide variety of hydrogen demonstration and retrofit projects are currently underway for freight locomotive applications around the world in addition to completed and ongoing feasibility studies. Up to now no prevailing hydrogen storage technology emerged especially because line-haul locomotives are required to carry significantly more energy than passenger trains. The 35 MPa compressed storage systems commonly used in passenger trains offer too little energy density for mainline locomotive operation - alternative storage technologies are not yet established. Energy tender solutions could be an option to increase hydrogen storage capacity here."
Technical Performance and Environmental Assessment of an Ionic Liquid-based CCS Process for Hydrogen Production
Apr 2023
Publication
Hydrogen (H2) production combined with carbon capture and storage (CCS) is anticipated to be an important technology contributing to reduce the carbon footprint of current fossil-based H2 production systems. This work addresses for the first time the techno-environmental assessment of a CCS process based on the ionic liquid [Bmim][Acetate] for H2 production by steam methane reforming (SMR) and the comparison to conventional amine-based systems. Two different SMR plants using MDEA or [Bmim][Acetate] for CO2 capture were rigorously modelled using Aspen Plus to compute material and energy needs and emissions. Literature and simulation results were then used to perform a life cycle impact assessment (LCIA) of these processes based on the ReCiPe model. Solvent synthesis CCS process and hydrogen production stages were considered for the cradle-to-gate analysis. Results showed that although [Bmim][Acetate] is a priori more harmful to the environment than amines (in a kg-to-kg comparison) LCIAs carried out for both CCS processes showed from 5 to 17 % lower environmental impacts values for all estimated categories when using [Bmim][Acetate] due to a 9.4 % more energy-efficient performance than MDEA which also reduced a 17.4 % the total utility cost. Indeed if a typical amine loss rate of 1.6 kg/tCO2 is assumed the values of the environmental impacts increase up to 14 % for the IL-based CCS plant but still maintaining its favorable results over MDEA. As consequence the SMR plant with the IL-based CCS system exhibited 3–20 % lower values for most of the studied impact categories. These results contribute to shed some light on evaluating the sustainability of ILs with respect to conventional solvents for CO2 capture and to guide the synthesis of new more sustainable ILs but also they would be used to compare the environmental burdens from the synthesis and process performance of other promising ILs for CO2 capture that are not environmentally assed yet.
Concept Design and Energy Balance Optimization of a Hydrogen Fuel Cell Helicoptor for Unmanned Aerial Vehicle and Aerotaxi Applications
May 2023
Publication
In the new scenario where the transportation sector must be decarbonized to limit global warming fuel cellpowered aerial vehicles have been selected as a strategic target application to compose part of the urban fleet to minimize road transport congestion and make goods and personal transportation fast and efficient. To address the necessity of clean and efficient urban air transport this work consists of the conceptual development of a lightweight rotary-winged transport vehicle using a hydrogen-based fuel cell propulsion system and the optimization of its energy balance. For that purpose the methods for integrating the coupled aerodynamic and propulsion system sizing and optimization was developed with the aim of designing concepts capable of carrying 0 (unmanned aerial vehicle — Design 1) and 1 (Aerotaxi — Design 2) passengers for a distance of 300 km at a cruise altitude of 500 m with a minimum climbing rate capability of 6 m s−1 at 1000 m. The results show how these designs with the desired performance specifications can be obtained with a vehicle mass ranging from 416 to 648 kg depending on the application and with specific range and endurance respectively within 46.2–47.8 km/kg and 20.4–21.3 min/kg for design 1 and 33.3–33.8 km/kg and 12.5–13.9 min/kg for design 2.
A Model-based Parametric and Optimal Sizing of a Battery/Hydrogen Storage of a Real Hybrid Microgrid Supplying a Residential Load: Towards Island Operation
Jun 2021
Publication
In this study the optimal sizing of a hybrid battery/hydrogen Energy Storage System “ESS” is assessed via a model-based parametric analysis in the context of a real hybrid renewable microgrid located in Huelva Spain supplying a real-time monitored residential load (3.5 kW; 5.6 MWh/year) in island mode. Four storage configurations (battery-only H2-only hybrid battery priority and hybrid H2 priority) are assessed under different Energy Management Strategies analysing system performance parameters such as Loss of Load “LL” (kWh;%) Over Production “OP” (kWh;%) round-trip storage efficiency ESS (%) and total storage cost (€) depending on the ESS sizing characteristics. A parallel approach to the storage optimal sizing via both multi-dimensional sensitivity analysis and PSO is carried out in order to address both sub-optimal and optimal regions respectively. Results show that a hybridised ESS capacity is beneficial from an energy security and efficiency point of view but can represent a substantial additional total cost (between 100 and 300 k€) to the hybrid energy system especially for the H2 ESS which presents higher costs. Reaching 100% supply from renewables is challenging and introducing a LL threshold induces a substantial relaxation of the sizing and cost requirements. Increase in battery capacity is more beneficial for the LL abatement while increasing H2 capacity is more useful to absorb large quantities of excess energy. The optimal design via PSO technique is complemented to the parametric study.
Photocatalytic Production of Hydrogen from Binary Mixtures of C-3 Alcohols on Pt/TiO2: Influence of Alcohol Structure
Oct 2018
Publication
The effect of alcohol structure on photocatalytic production of H2 from C-3 alcohols was studied on 0.5% Pt/TiO2. A C-2 alcohol (ethanol) was also included for comparative purposes. For individual reactions from 10% v/v aqueous solutions of alcohols hydrogen production followed the order ethanol ≈ propan-2-ol > propan-1- ol > propane-123-triol > propane-12-diol > propane-13-diol. The process was found to be quite sensitive to the presence of additional alcohols in the reaction medium as evidenced by competitive reactions. Therefore propan-2-ol conversion was retarded in the presence of traces of the other alcohols this effect being particularly significant for vicinal diols. Additional experiments showed that adsorption of alcohols on Pt/TiO2 followed the order propane-123-triol > propane-12-diol > propane-13-diol > propan-1-ol > ethanol > propan-2-ol. Adsorption studies (DRIFT) and monitoring of reaction products showed that the main photocatalyzed process for propan-2-ol and propan-1-ol transformation is dehydrogenation to the corresponding carbonyl compound (especially for propan-2-ol both in the liquid and the gas phase). In the case of liquid-phase transformation of propan-1-ol ethane was also detected which is indicative of the dissociative mechanism to lead to the corresponding C-1 alkane. All in all competitive reactions proved to be very useful for mechanistic studies.
Validation of GreenH2armony® as a Tool for the Computation of Harmonised Life-Cycle Indicators of Hydrogen
Apr 2020
Publication
The Life Cycle Assessment (LCA) methodology is often used to check the environmental suitability of hydrogen energy systems usually involving comparative studies. However these comparative studies are typically affected by inconsistent methodological choices between the case studies under comparison. In this regard protocols for the harmonisation of methodological choices in LCA of hydrogen are available. The step-by-step application of these protocols to a large number of case studies has already resulted in libraries of harmonised carbon energy and acidification footprints of hydrogen. In order to foster the applicability of these harmonisation protocols a web-based software for the calculation of harmonised life-cycle indicators of hydrogen has recently been developed. This work addresses—for the first time—the validation of such a tool by checking the deviation between the available libraries of harmonised carbon energy and acidification footprints of hydrogen and the corresponding tool-based harmonised results. A high correlation (R2 > 0.999) was found between the library- and tool-based harmonised life-cycle indicators of hydrogen thereby successfully validating the software. Hence this tool has the potential to effectively promote the use of harmonised life-cycle indicators for robust comparative LCA studies of hydrogen energy systems significantly mitigating misinterpretation.
Hydrogen Embrittlement Susceptibility of R4 and R5 High-Strength Mooring Steels in Cold and Warm Seawater
Sep 2018
Publication
Hydrogen embrittlement susceptibility ratios calculated from slow strain rate tensile tests have been employed to study the response of three high-strength mooring steels in cold and warm synthetic seawater. The selected nominal testing temperatures have been 3 °C and 23 °C in order to resemble sea sites of offshore platform installation interest such as the North Sea and the Gulf of Mexico respectively. Three scenarios have been studied for each temperature: free corrosion cathodic protection and overprotection. An improvement on the hydrogen embrittlement tendency of the steels has been observed when working in cold conditions. This provides a new insight on the relevance of the seawater temperature as a characteristic to be taken into account for mooring line design in terms of hydrogen embrittlement assessment.
Ammonia as a Carrier for Hydrogen Production by using Lanthanum Based Perovskites
Sep 2021
Publication
LaNiO3 and LaCoO3 perovskites synthesized by self-combustion were characterised and studied in the ammonia decomposition reaction for obtaining hydrogen. Both the fuel to metal nitrates molar ratio and calcination temperature were found to be crucial to synthesize perovskites by self-combustion. Moreover generating non-precursor species during synthesis and small metal size were two factors which significantly influenced catalytic activity. Hence with a citric acid to metal nitrates molar ratio equal to one a LaNiO3 perovskite was obtained with suitable physicochemical properties (specific surface area lower impurities and basicity). In addition a lower calcination temperature (650 ◦C) resulted in small and well-dispersed Ni0 crystallite size after reduction which in turn promoted the catalytic transformation of ammonia into hydrogen. For cobalt perovskites calcination temperature below 900 ◦C did not have a significant influence on the size of the metallic cobalt crystallite size. The nickel and cobalt perovskite-derived catalysts calcined at 650 ◦C and 750 ◦C respectively yielded excellent H2 production from ammonia decomposition. In particular at 450 ◦C almost 100% of the ammonia was converted over the LaNiO3 under study. Furthermore these materials displayed admirable performance and stability after one day of reaction.
Prediction of Hydrogen-Heavy Fuel Combustion Process with Water Addition in an Adapted Low Speed Two Stroke Diesel Engine: Performance Improvement
Jun 2021
Publication
Despite their high thermal efficiency (>50%) large two-stroke (2 T) diesel engines burning very cheap heavy fuel oil (HFO) produce a high level of carbon dioxide (CO2). To achieve the low emission levels of greenhouse gases (GHG) that will be imposed by future legislation the use of hydrogen (H2) as fuel in 2 T diesel engines is a viable option for reducing or almost eliminate CO2 emissions. In this work from experimental data and system modelling an analysis of dual combustion is carried out considering different strategies to supply H2 to the engine and for different H2 fractions in energy basis. Previously a complete thermodynamic model of a 2 T diesel engine with an innovative scavenging model is developed and validated. The most important drawbacks of this type of engines are controlled in this work using dual combustion and water injection reducing nitrogen oxides emissions (NOx) self-ignition and combustion knocking. The results show that the developed model matches engine performance data in diesel mode achieving a higher efficiency and mean effective pressure (MEP) in hydrogen mode of 53% and 14.62 bar respectively.
Flammability Reduction in a Pressurised Water Electrolyser Based on a Thin Polymer Electrolyte Membrane through a Pt-alloy Catalytic Approach
Jan 2019
Publication
Various Pt-based materials (unsupported Pt PtRu PtCo) were investigated as catalysts for recombining hydrogen and oxygen back into water. The recombination performance correlated well with the surface Pt metallic state. Alloying cobalt to platinum was observed to produce an electron transfer favouring the occurrence of a large fraction of the Pt metallic state on the catalyst surface. Unsupported PtCo showed both excellent recombination performance and dynamic behaviour. In a packed bed catalytic reactor when hydrogen was fed at 4% vol. in the oxygen stream (flammability limit) 99.5% of the total H2 content was immediately converted to water in the presence of PtCo thus avoiding safety issues. The PtCo catalyst was thus integrated in the anode of the membrane-electrode assembly of a polymer electrolyte membrane electrolysis cell. This catalyst showed good capability to reduce the concentration of hydrogen in the oxygen stream under differential pressure operation (1–20 bar) in the presence of a thin (90 μm) Aquivion® membrane. The modified system showed lower hydrogen concentration in the oxygen flow than electrolysis cells based on state-of-the-art thick polymer electrolyte membranes and allowed to expand the minimum current density load down to 0.15 A cm−2 . This was mainly due to the electrochemical oxidation of permeated H2 to protons that were transported back to the cathode. The electrolysis cell equipped with a dual layer PtCo/IrRuOx oxidation catalyst achieved a high operating current density (3 A cm−2 ) as requested to decrease the system capital costs under high efficiency conditions (about 77% efficiency at 55 °C and 20 bar). Moreover the electrolysis system showed reduced probability to reach the flammability limit under both high differential pressure (20 bar) and partial load operation (5%) as needed to properly address grid-balancing service
Solid State Hydrogen Storage in Alanates and Alanate-Based Compounds: A Review
Jul 2018
Publication
The safest way to store hydrogen is in solid form physically entrapped in molecular form in highly porous materials or chemically bound in atomic form in hydrides. Among the different families of these compounds alkaline and alkaline earth metals alumino-hydrides (alanates) have been regarded as promising storing media and have been extensively studied since 1997 when Bogdanovic and Schwickardi reported that Ti-doped sodium alanate could be reversibly dehydrogenated under moderate conditions. In this review the preparative methods; the crystal structure; the physico-chemical and hydrogen absorption-desorption properties of the alanates of Li Na K Ca Mg Y Eu and Sr; and of some of the most interesting multi-cation alanates will be summarized and discussed. The most promising alanate-based reactive hydride composite (RHC) systems developed in the last few years will also be described and commented on concerning their hydrogen absorption and desorption performance.
Hydrogen vs. Battery in the Long-term Operation. A Comparative Between Energy Management Strategies for Hybrid Renewable Microgrids
Apr 2020
Publication
The growth of the world’s energy demand over recent decades in relation to energy intensity and demography is clear. At the same time the use of renewable energy sources is pursued to address decarbonization targets but the stochasticity of renewable energy systems produces an increasing need for management systems to supply such energy volume while guaranteeing at the same time the security and reliability of the microgrids. Locally distributed energy storage systems (ESS) may provide the capacity to temporarily decouple production and demand. In this sense the most implemented ESS in local energy districts are small–medium-scale electrochemical batteries. However hydrogen systems are viable for storing larger energy quantities thanks to its intrinsic high mass-energy density. To match generation demand and storage energy management systems (EMSs) become crucial. This paper compares two strategies for an energy management system based on hydrogen-priority vs. battery-priority for the operation of a hybrid renewable microgrid. The overall performance of the two mentioned strategies is compared in the long-term operation via a set of evaluation parameters defined by the unmet load storage efficiency operating hours and cumulative energy. The results show that the hydrogen-priority strategy allows the microgrid to be led towards island operation because it saves a higher amount of energy while the battery-priority strategy reduces the energy efficiency in the storage round trip. The main contribution of this work lies in the demonstration that conventional EMS for microgrids’ operation based on battery-priority strategy should turn into hydrogen-priority to keep the reliability and independence of the microgrid in the long-term operation.
Exploring Key Operational Factors for Improving Hydrogen Production in a Pilot-scale Microbial Electrolysis Cell Treating Urban Wastewater
Jun 2023
Publication
Bioelectrochemical systems (BES) are becoming popular technologies with a plethora of applications in the environmental field. However research on the scale-up of these systems is scarce. To understand the limiting factors of hydrogen production in microbial electrolysis cell (MEC) at pilot scale a 135 L MEC was operated for six months under a wide range of operational conditions: applied potential [0.8-1.1 V] hydraulic residence time [1.1-3.9 d] and temperature [18-30 ºC] using three types of wastewater; synthetic (900 mg CODs L-1) raw urban wastewater (200 mg CODs L-1) and urban wastewater amended with acetate (1000 mg CODs L-1). The synthetic wastewater yielded the maximum current density (1.23 A m-2) and hydrogen production (0.1 m3 m-3 d-1) ever reported in a pilot scale MEC with a cathodic recovery of 70% and a coulombic efficiency of 27%. In contrast the use of low COD urban wastewater limited the plant performance. Interestingly it was possible to improve hydrogen production by reducing the hydraulic residence time finding the optimal applied potential or increasing the temperature. Further the pilot plant demonstrated a robust capacity to remove the organic matter present in the wastewater under different conditions with removal efficiencies above 70%. This study shows improved results compared to similar MEC pilot plants treating domestic wastewater in terms of hydrogen production and treatment efficiency and also compares its performance against conventional activated sludge processes.
Hubs and Clusters Approach to Unlock the Development of Carbon Capture and Storage - Case Study in Spain
Jul 2021
Publication
Xiaolong Sun,
Juan Alcalde,
Mahdi Bakhtbidar,
Javier Elío,
Víctor Vilarrasa,
Jacobo Canal,
Julio Ballesteros,
Niklas Heinemann,
Stuart Haszeldine,
Andrew Cavanagh,
David Vega-Maza,
Fernando Rubiera,
Roberto Martínez-Orio,
Gareth Johnson,
Ramon Carbonell,
Ignacio Marzan,
Anna Travé and
Enrique Gomez-Rivas
Many countries have assigned an indispensable role for carbon capture and storage (CCS) in their national climate change mitigation pathways. However CCS deployment has stalled in most countries with only limited commercial projects realised mainly in hydrocarbon-rich countries for enhanced oil recovery. If the Paris Agreement is to be met then this progress must be replicated widely including hydrocarbon-limited countries. In this study we present a novel source-to-sink assessment methodology based on a hubs and clusters approach to identify favourable regions for CCS deployment and attract renewed public and political interest in viable deployment pathways. Here we apply this methodology to Spain where fifteen emission hubs from both the power and the hard-to-abate industrial sectors are identified as potential CO2 sources. A priority storage structure and two reserves for each hub are selected based on screening and ranking processes using a multi-criteria decision-making method. The priority source-to-sink clusters are identified indicating four potential development regions with the North-Western and North-Eastern Spain recognised as priority regions due to resilience provided by different types of CO2 sources and geological structures. Up to 68.7 Mt CO2 per year comprising around 21% of Spanish emissions can be connected to clusters linked to feasible storage. CCS especially in the hard-to-abate sector and in combination with other low-carbon energies (e.g. blue hydrogen and bioenergy) remains a significant and unavoidable contributor to the Paris Agreement’s mid-century net-zero target. This study shows that the hubs and clusters approach can facilitate CCS deployment in Spain and other hydrocarbon-limited countries.
Investment in Wind-based Hydrogen Production under Economic and Physical Uncertainties
Feb 2023
Publication
This paper evaluates the economic viability of a combined wind-based green-hydrogen facility from an investor’s viewpoint. The paper introduces a theoretical model and demonstrates it by example. The valuation model assumes that both the spot price of electricity and wind capacity factor evolve stochastically over time; these state variables can in principle be correlated. Besides it explicitly considers the possibility to use curtailed wind energy for producing hydrogen. The model derives the investment project’s net present value (NPV) as a function of hydrogen price and conversion capacity. Thus the NPV is computed for a given price and a range of capacities. The one that leads to the maximum NPV is the ‘optimal’ capacity (for the given price). Next the authors estimate the parameters underlying the two stochastic processes from Spanish hourly data. These numerical estimates allow simulate hourly paths of both variables over the facility’s expected useful lifetime (30 years). According to the results green hydrogen production starts becoming economically viable above 3 €/kg. Besides it takes a hydrogen price of 4.7 €/kg to reach an optimal conversion capacity half the capacity of the wind park. The authors develop sensitivity analyses with respect to wind capacity factor curtailment rate and discount rate.
Perspectives for a Sustainable Implementation of Super-green Hydrogen Production by Photoelectrochemical Technology in Hard-to-abate Sectors
May 2023
Publication
The energy transition's success hinges on the effectiveness to curbing carbon emissions from hard-to-abate sectors. Hydrogen (H2) has been proposed as the candidate vector that could be used to replace fossils in such energy-intensive industries. Despite green H2 via solar-powered water electrolysis being a reality today the overall defossilization of the hard-to-abate sectors by electrolytic H2 would be unfeasible as it relies on the availability of renewable electricity. In this sense the unbiassed photoelectrochemical water splitting (PEC) as inspired by natural photosynthesis may be a promising alternative expected in the long term. PEC could be partly or even completely decoupled from renewable electricity and then could produce H2 autonomously. However some remaining challenges still limit PEC water splitting to operate sustainably. These limitations need to be evaluated before the scaling up and implementation. A prospective life cycle assessment (LCA) has been used to elucidate a positive performance scenario in which the so-called super-green H2 or photo-H2 could be a sustainable alternative to electro-H2. The study has defined future scenarios by conducting a set of sensitivity assessments determining the figures of operating parameters such as i) the energy to produce the cell; ii) solar-to-hydrogen efficiency (STH); and iii) lifetime. These parameters have been evaluated based on two impact categories: i) Global Warming Potential (GWP); and ii) fossil Abiotic Depletion Potentials (fADP). The mature water electrolysis was used for benchmarking in order to elucidate the target performance in which PEC technology could be positively implemented at large-scale. Efficiencies over 10% (STH) and 7 years of lifetime are compulsory in the coming developments to achieve a positive scaling-up.
Batteries and Hydrogen Storage: Technical Analysis and Commercial Revision to Select the Best Option
Aug 2022
Publication
This paper aims to analyse two energy storage methods—batteries and hydrogen storage technologies—that in some cases are treated as complementary technologies but in other ones they are considered opposed technologies. A detailed technical description of each technology will allow to understand the evolution of batteries and hydrogen storage technologies: batteries looking for higher energy capacity and lower maintenance while hydrogen storage technologies pursuing better volumetric and gravimetric densities. Additionally as energy storage systems a mathematical model is required to know the state of charge of the system. For this purpose a mathematical model is proposed for conventional batteries for compressed hydrogen tanks for liquid hydrogen storage and for metal hydride tanks which makes it possible to integrate energy storage systems into management strategies that aim to solve the energy balance in plants based on hybrid energy storage systems. From the technical point of view most batteries are easier to operate and do not require special operating conditions while hydrogen storage methods are currently functioning at the two extremes (high temperatures for metal and complex hydrides and low temperatures for liquid hydrogen or physisorption). Additionally the technical comparison made in this paper also includes research trends and future possibilities in an attempt to help plan future policies.
Recent Insights into Low-Surface-Area Catalysts for Hydrogen Production from Ammonia
Nov 2022
Publication
A potential method of storing and transporting hydrogen safely in a cost-effective and practical way involves the utilization of molecules that contain hydrogen in their structure such as ammonia. Because of its high hydrogen content and carbon-free molecular structure as well as the maturity of related technology (easy liquefaction) ammonia has gained attention as a “hydrogen carrier” for the generation of energy. Unfortunately hydrogen production from ammonia requires an efficient catalyst to achieve high conversion at low reaction temperatures. Recently very attractive results have been obtained with low-surface-area materials. This review paper is focused on summarizing and comparing recent advances in novel economic and active catalysts for this reaction paying particular attention to materials with low surface area such as silicon carbide (SiC) and perovskites (ABO3 structure). The effects of the supports the active phase and the addition of promoters in such low-porosity materials have been analyzed in detail. Advances in adequate catalytic systems (including support and active metal) benefit the perspective of ammonia as a hydrogen carrier for the decarbonization of the energy sector and accelerate the “hydrogen economy”.
Transition to a Low-carbon Building Stock. Techno-economic and Spatial Optimization of Renewables‑hydrogen Strategies in Spain
Oct 2022
Publication
Europe has set ambitious targets to reduce the final energy consumption of buildings in concerning the degree of electrification energy efficiency and penetration of renewable energy sources (RES). So far hydrogen is becoming an increasingly important energy vector offering huge opportunities to promote the share of intermittent RES. Thus this manuscript proposes an energy model for the complete decarbonization of the estimated electricity consumed by the Spanish building stock in 2030 and 2050 scenarios; the model is based on the combination of photovoltaic and wind primary sources and hydrogen technologies considering both distributed and centralized configurations applying also geospatial criteria for their optimal allocation. Large-scale RES generation centralized hydrogen production and re-electrification along with underground hydrogen storage result in the lowest levelized cost of energy (LCOE) hydrogen production costs (HPC) and the highest overall efficiency (μSYS). Wind energy is mainly harvested in the north of Spain while large PV farms are deployed in the mid-south. Furthermore reinforcement of underground hydrogen storage enhances the overall system performance reducing surplus energy and the required RES generation capacity. Finally all the considered scenarios achieve LCOE below the Spanish utility grid benchmark apart from accomplishing the decarbonization goals established for the year 2030.
Fuel-Cell Electric Vehicles: Plotting a Scientific and Technological Knowledge Map
Mar 2020
Publication
The fuel-cell electric vehicle (FCEV) has been defined as a promising way to avoid road transport greenhouse emissions but nowadays they are not commercially available. However few studies have attempted to monitor the global scientific research and technological profile of FCEVs. For this reason scientific research and technological development in the field of FCEV from 1999 to 2019 have been researched using bibliometric and patent data analysis including network analysis. Based on reports the current status indicates that FCEV research topics have reached maturity. In addition the analysis reveals other important findings: (1) The USA is the most productive in science and patent jurisdiction; (2) both Chinese universities and their authors are the most productive in science; however technological development is led by Japanese car manufacturers; (3) in scientific research collaboration is located within the tri-polar world (North America–Europe–Asia-Pacific); nonetheless technological development is isolated to collaborations between companies of the same automotive group; (4) science is currently directing its efforts towards hydrogen production and storage energy management systems related to battery and hydrogen energy Life Cycle Assessment and greenhouse gas (GHG) emissions. The technological development focuses on technologies related to electrically propelled vehicles; (5) the International Journal of Hydrogen Energy and SAE Technical Papers are the two most important sources of knowledge diffusion. This study concludes by outlining the knowledge map and directions for further research.
Optimal Allocation of Energy Sources in Hydrogen Production for Sustainable Deployment of Electric Vehicles
Jan 2023
Publication
We analyze the use of hydrogen as a fuel for the automotive industry with the aim of decarbonizing the economy. Hydrogen is a suitable option for avoiding pollutant gas emissions developing environmentally friendly technologies replacing fossil fuels with clean renewable energies and complying with the Paris Agreement and Glasgow resolutions. In this sense renewable energies such as wind solar photovoltaic geothermal biomass etc. can be used to produce the necessary hydrogen to power vehicles. In this way the entire process from hydrogen production to its consumption as fuel will be 100% clean. If we are to meet future energy demands it is necessary to forecast the amount of hydrogen needed taking into account the facilities currently available and new ones that will be required for its generation storage and distribution. This paper presents a process for optimizing hydrogen production for the automotive industry that considers the amount of hydrogen needed the type of facilities from which it will be produced how the different sources of production are to be combined to achieve a competitive product and the potential environmental impacts of each energy source. It can serve as a frame of reference for the various actors in the hydropower and automotive industries so that more efficient designs can be planned for the gradual introduction of hydrogen fuel cell vehicles (HFCVs). The methodology implemented in this paper sets an optimization problem for minimizing energy production costs and reducing environmental impacts according to the source of energy production. The EU framework with respect to the decarbonization of the economy the percentages of the different types of energy sources used and the non-polluting vehicle fleet in the automotive sector will be considered.
Analysis of the European Strategy for Hydrogen: A Comprehensive Review
May 2023
Publication
This review focuses on analysing the strategy and aspirations of the European Union within the hydrogen sector. This aim is achieved through the examination of the European Parliament’s hydrogen strategy allowing for a study of actions and projects in hydrogen technologies. The Parliament’s hydrogen strategy is the document that provides the guideline of how the EU intends to function in the hydrogen sector and manages to cover a wide range of topics all of them significant to represent the entirety of the hydrogen sector. It touches on subjects such as hydrogen demand infrastructure research and standards among others. The review discusses also the aspect that the EU intends to be a leader in the hydrogen sector including the large-scale industrialization of key elements such as electrolysers and this purpose is corroborated by the large number of associations strategies plans and projects that are being established and developed by the European Union. The most important conclusions to learn from this analysis are that hydrogen has many of the right characteristics to make it the key to decarbonisation especially in hard-to-abate sectors and that it is bound to be one of the main actors in the imminent green transition. Moreover hydrogen seems to be having its breakthrough and this field’s development can have benefits not only from an environmental perspective but also from an economical one enabling the way into the green transition and the fight against climate change.
Analysis of Power to Gas Technologies for Energy Intensive Industries in European Union
Jan 2023
Publication
Energy Intensive Industries (EII) are high users of energy and some of these facilities are extremely dependent on Natural Gas for processing heat production. In European countries where Natural Gas is mostly imported from external producers the increase in international Natural Gas prices is making it difficult for some industries to deliver the required financial results. Therefore they are facing complex challenges that could cause their delocalization in regions with lower energy costs. European countries lack on-site Natural Gas resources and the plans to reduce greenhouse gas emissions in the industrial sector make it necessary to find an alternative. Many different processes cannot be electrified and in these cases synthetic methane is one of the solutions and also represents an opportunity to reduce external energy supply dependency. This study analyzes the current development of power-to-gas technological solutions that could be implemented in large industrial consumers to produce Synthetic Methane using Green Hydrogen as a raw source and using Renewable Energy electricity mainly produced with photovoltaic or wind energy. The study also reviews the triple bottom line impact and the current development status and associated costs for each key component of a power-to-gas plant and the requirements to be fulfilled in the coming years to develop a cost-competitive solution available for commercial use.
Optimal Sizing of Storage Elements for a Vehicle Based on Fuel Cells, Supercapacitors, and Batteries
Mar 2019
Publication
To achieve a vehicle-efficient energy management system an architecture composed of a PEM fuel cell as the main energy source and a hybrid storage system based on battery banks and supercapacitors is proposed. This paper introduces a methodology for the optimal component sizing aiming at minimizing the total cost achieving a cheaper system that can achieve the requirements of the speed profiles. The chosen vehicle is an urban transport bus which must meet the Buenos Aires Driving Cycle and the Manhattan Driving Cycle. The combination of batteries and supercapacitors allows a better response to the vehicle’s power demand since it combines the high energy density of the batteries with the high power density of the supercapacitors allowing the best absorption of energy coming from braking. In this way we address the rapid changes in power without reducing the global efficiency of the system. Optimum use of storage systems and fuel cell is analyzed through dynamic programming.
Comprehensive Analysis of the Combustion of Low Carbon Fuels (Hydrogen, Methane and Coke Oven Gas) in a Spark Ignition Engine through CFD Modeling
Nov 2021
Publication
The use of low carbon fuels (LCFs) in internal combustion engines is a promising alternative to reduce pollution while achieving high performance through the conversion of the high energy content of the fuels into mechanical energy. However optimizing the engine design requires deep knowledge of the complex phenomena involved in combustion that depend on the operating conditions and the fuel employed. In this work computational fluid dynamics (CFD) simulation tools have been used to get insight into the performance of a Volkswagen Polo 1.4L port-fuel injection spark ignition engine that has been fueled with three different LCFs coke oven gas (COG) a gaseous by-product of coke manufacture H2 and CH4. The comparison is made in terms of power pressure temperature heat release flame growth speed emissions and volumetric efficiency. Simulations in Ansys® Forte® were validated with experiments at the same operating conditions with optimal spark advance wide open throttle a wide range of engine speed (2000–5000 rpm) and air-fuel ratio (λ) between 1 and 2. A sensitivity analysis of spark timing has been added to assess its impact on combustion variables. COG with intermediate flame growth speed produced the greatest power values but with lower pressure and temperature values at λ = 1.5 reducing the emissions of NO and the wall heat transfer. The useful energy released with COG was up to 16.5% and 5.1% higher than CH4 and H2 respectively. At richer and leaner mixtures (λ = 1 and λ = 2) similar performances were obtained compared to CH4 and H2 combining advantages of both pure fuels and widening the λ operation range without abnormal combustion. Therefore suitable management of the operating conditions maximizes the conversion of the waste stream fuel energy into useful energy while limiting emissions.
A Review on CO2 Mitigation in the Iron and Steel Industry through Power to X Processes
Feb 2021
Publication
In this paper we present the first systematic review of Power to X processes applied to the iron and steel industry. These processes convert renewable electricity into valuable chemicals through an electrolysis stage that produces the final product or a necessary intermediate. We have classified them in five categories (Power to Iron Power to Hydrogen Power to Syngas Power to Methane and Power to Methanol) to compare the results of the different studies published so far gathering specific energy consumption electrolysis power capacity CO2 emissions and technology readiness level. We also present for the first time novel concepts that integrate oxy-fuel ironmaking and Power to Gas. Lastly we round the review off with a summary of the most important research projects on the topic including relevant data on the largest pilot facilities (2–6 MW).
Integration of Hydrogen and Synthetic Natural Gas within Legacy Power Generation Facilities
Jun 2022
Publication
Whilst various new technologies for power generation are continuously being evaluated the owners of almost-new facilities such as combined-cycle gas turbine (CCGT) plants remain motivated to adapt these to new circumstances and avoid the balance-sheet financial impairments of underutilization. Not only are the owners reluctant to decommission the legacy CCGT assets but system operators value the inertia and flexibilities they contribute to a system becoming predominated with renewable generation. This analysis therefore focuses on the reinvestment cases for adapting CCGT to hydrogen (H2 ) synthetic natural gas (SNG) and/or retrofitted carbon capture and utilization systems (CCUS). Although H2 either by itself or as part of SNG has been evaluated attractively for longer-term electricity storage the business case for how it can be part of a hybrid legacy CCGT system has not been analyzed in a market context. This work compares the power to synthetic natural gas to power (PSNGP) adaptation with the simpler and less expensive power to hydrogen to power (P2HP) adaptation. Both the P2HP and PSNGP configurations are effective in terms of decarbonizations. The best results of the feasibility analysis for a UK application with low CCGT load factors (around 31%) were obtained for 100% H2 (P2HP) in the lower range of wholesale electricity prices (less than 178 GBP/MWh) but in the higher range of prices it would be preferable to use the PSNGP configuration with a low proportion of SNG (25%). If the CCGT load factor increased to 55% (the medium scenario) the breakeven profitability point between P2HP and PSNGP decreased to a market price of 145 GBP/MWh. Alternatively with the higher load factors (above 77%) satisfactory results were obtained for PSNGP using 50% SNG if with market prices above 185 GBP/MWh.
Sustainability Indicators for the Manufacturing and Use of a Fuel Cell Prototype and Hydrogen Storage for Portable Uses
Oct 2021
Publication
A sustainability assessment regarding the manufacturing process and the use of a new proton exchange membrane fuel cell (PEMFC) specially designed for portable hydrogen applications is presented. The initial fuel cell prototype has been configured by taking into account exclusively technical issues. However a life cycle analysis considering environmental and socioeconomic impacts is crucial to improve the model to develop a more sustainable product. From the environ‐ mental perspective the durability of the system and its efficiency are key elements required to de‐ crease the potential overall impacts. High electricity consumption for manufacturing requires a commitment to the use of renewable energies due to the high current value of the projected impact of climate change (42.5 tonnes of CO2 eq). From the socioeconomic point of view the dependence of imported components required for the synthesis of some materials displaces the effects of value added and employment in Spain potentially concentrating the largest impact on countries such as Singapore Japan and the UK whereas the cell assembly would have a greater benefit for the country of fabrication. These results provide a basis for new research strategies since they can be considered standard values for improving future upgrades of the fuel cell in terms of sustainability.
Assessing the Life-Cycle Performance of Hydrogen Production via Biofuel Reforming in Europe
Jun 2015
Publication
Currently hydrogen is mainly produced through steam reforming of natural gas. However this conventional process involves environmental and energy security concerns. This has led to the development of alternative technologies for (potentially) green hydrogen production. In this work the environmental and energy performance of biohydrogen produced in Europe via steam reforming of glycerol and bio-oil is evaluated from a life-cycle perspective and contrasted with that of conventional hydrogen from steam methane reforming. Glycerol as a by-product from the production of rapeseed biodiesel and bio-oil from the fast pyrolysis of poplar biomass are considered. The processing plants are simulated in Aspen Plus® to provide inventory data for the life cycle assessment. The environmental impact potentials evaluated include abiotic depletion global warming ozone layer depletion photochemical oxidant formation land competition acidification and eutrophication. Furthermore the cumulative (total and non-renewable) energy demand is calculated as well as the corresponding renewability scores and life-cycle energy balances and efficiencies of the biohydrogen products. In addition to quantitative evidence of the (expected) relevance of the feedstock and impact categories considered results show that poplar-derived bio-oil could be a suitable feedstock for steam reforming in contrast to first-generation bioglycerol.
Solar Hydrogen Fuel Generation from Wastewater—Beyond Photoelectrochemical Water Splitting: A Perspective
Oct 2022
Publication
Green hydrogen—a carbon-free renewable fuel—has the capability to decarbonise a variety of sectors. The generation of green hydrogen is currently restricted to water electrolysers. The use of freshwater resources and critical raw materials however limits their use. Alternative water splitting methods for green hydrogen generation via photocatalysis and photoelectrocatalysis (PEC) have been explored in the past few decades; however their commercial potential still remains unexploited due to the high hydrogen generation costs. Novel PEC-based simultaneous generation of green hydrogen and wastewater treatment/high-value product production is therefore seen as an alternative to conventional water splitting. Interestingly the organic/inorganic pollutants in wastewater and biomass favourably act as electron donors and facilitate the dual-functional process of recovering green hydrogen while oxidising the organic matter. The generation of green hydrogen through the dual-functional PEC process opens up opportunities for a “circular economy”. It further enables the end-of-life commodities to be reused recycled and resourced for a better life-cycle design while being economically viable for commercialisation. This review brings together and critically analyses the recent trends towards simultaneous wastewater treatment/biomass reforming while generating hydrogen gas by employing the PEC technology. We have briefly discussed the technical challenges associated with the tandem PEC process new avenues techno-economic feasibility and future directions towards achieving net neutrality.
Overview of First Outcomes of PNR Project HYTUNNEL-CS
Sep 2021
Publication
Dmitry Makarov,
Donatella Cirrone,
Volodymyr V. Shentsov,
Sergii Kashkarov,
Vladimir V. Molkov,
Z. Xu,
Mike Kuznetsov,
Alexandros G. Venetsanos,
Stella G. Giannissi,
Ilias C. Tolias,
Knut Vaagsaether,
André Vagner Gaathaug,
Mark R. Pursell,
W. M. Rattigan,
Frank Markert,
Luisa Giuliani,
L.S. Sørensen,
A. Bernad,
Mercedes Sanz Millán,
U. Kummer,
C. Brauner,
Paola Russo,
J. van den Berg,
F. de Jong,
Tom Van Esbroeck,
M. Van De Veire,
D. Bouix,
Gilles Bernard-Michel,
Sergey Kudriakov,
Etienne Studer,
Domenico Ferrero,
Joachim Grüne and
G. Stern
The paper presents the first outcomes of the experimental numerical and theoretical studies performed in the funded by Fuel Cell and Hydrogen Joint Undertaking (FCH2 JU) project HyTunnel-CS. The project aims to conduct pre-normative research (PNR) to close relevant knowledge gaps and technological bottlenecks in the provision of safety of hydrogen vehicles in underground transportation systems. Pre normative research performed in the project will ultimately result in three main outputs: harmonised recommendations on response to hydrogen accidents recommendations for inherently safer use of hydrogen vehicles in underground traffic systems and recommendations for RCS. The overall concept behind this project is to use inter-disciplinary and inter-sectoral prenormative research by bringing together theoretical modelling and experimental studies to maximise the impact. The originality of the overall project concept is the consideration of hydrogen vehicle and underground traffic structure as a single system with integrated safety approach. The project strives to develop and offer safety strategies reducing or completely excluding hydrogen-specific risks to drivers passengers public and first responders in case of hydrogen vehicle accidents within the currently available infrastructure.
Analysis of the Use of Recycled Aluminum to Generate Green Hydrogen in an Electric Bicycle
Feb 2023
Publication
This article proposes using recycled aluminum generating hydrogen in situ at low pressure to power a 250 W electric bicycle with a fuel cell (FC) to increase the average speed and autonomy compared to a conventional electric bicycle with a battery. To generate hydrogen the aluminum–water reaction with a 6 M NaOH solution is used as a catalyst. This article details the parts of the generation system the electronic configuration used the aluminum- and reagent-loading procedure and the by-products obtained as well as the results of the operation without pedaling with a resistance equivalent to a flat terrain and at maximum power of the accelerator for one and two loads of about 100 g of aluminum each. This allows us to observe different hybrid strategies with a low-capacity battery in each case. The goal is to demonstrate that it is possible to store energy in a long-lasting transportable low-pressure and sustainable manner using recycled-aluminum test tubes and to apply this to mobility
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