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Assessing the Social Acceptance of Key Technologies for the German Energy Transition
Jan 2022
Publication
Background: The widespread use of sustainable energy technologies is a key element in the transformation of the energy system from fossil-based to zero-carbon. In line with this technology acceptance is of great importance as resistance from the public can slow down or hinder the construction of energy technology projects. The current study assesses the social acceptance of three energy technologies relevant for the German energy transition: stationary battery storage biofuel production plants and hydrogen fuel station. Methods: An online survey was conducted to examine the public’s general and local acceptance of energy technologies. Explored factors included general and local acceptance public concerns trust in relevant stakeholders and attitudes towards financial support. Results: The results indicate that general acceptance for all technologies is slightly higher than local acceptance. In addition we discuss which public concerns exist with regard to the respective technologies and how they are more strongly associated with local than general acceptance. Further we show that trust in stakeholders and attitudes towards fnancial support is relatively high across the technologies discussed. Conclusions: Taken together the study provides evidence for the existence of a “general–local” gap despite measuring general and local acceptance at the same level of specifcity using a public sample. In addition the collected data can provide stakeholders with an overview of worries that might need to be addressed when planning to implement a certain energy project.
Advances in Methanol Production and Utilization, with Particular Emphasis toward Hydrogen Generation via Membrane Reactor Technology
Oct 2018
Publication
Methanol is currently considered one of the most useful chemical products and is a promising building block for obtaining more complex chemical compounds such as acetic acid methyl tertiary butyl ether dimethyl ether methylamine etc. Methanol is the simplest alcohol appearing as a colorless liquid and with a distinctive smell and can be produced by converting CO2 and H2 with the further benefit of significantly reducing CO2 emissions in the atmosphere. Indeed methanol synthesis currently represents the second largest source of hydrogen consumption after ammonia production. Furthermore a wide range of literature is focused on methanol utilization as a convenient energy carrier for hydrogen production via steam and autothermal reforming partial oxidation methanol decomposition or methanol–water electrolysis reactions. Last but not least methanol supply for direct methanol fuel cells is a well-established technology for power production. The aim of this work is to propose an overview on the commonly used feedstocks (natural gas CO2 or char/biomass) and methanol production processes (from BASF—Badische Anilin und Soda Fabrik to ICI—Imperial Chemical Industries process) as well as on membrane reactor technology utilization for generating high grade hydrogen from the catalytic conversion of methanol reviewing the most updated state of the art in this field.
Distributional Trends in the Generation and End-Use Sector of Low-Carbon Hydrogen Plants
Mar 2023
Publication
This paper uses established and recently introduced methods from the applied mathematics and statistics literature to study trends in the end-use sector and the capacity of low-carbon hydrogen projects in recent and upcoming decades. First we examine distributions in plants over time for various end-use sectors and classify them according to metric discrepancy observing clear similarity across all industry sectors. Next we compare the distribution of usage sectors between different continents and examine the changes in sector distribution over time. Finally we judiciously apply several regression models to analyse the association between various predictors and the capacity of global hydrogen projects. Across our experiments we see a welcome exponential growth in the capacity of zero-carbon hydrogen plants and significant growth of new and planned hydrogen plants in the 2020’s across every sector.
Fuel Cells in Road Vehicles
Nov 2022
Publication
Issues related to the reduction of the environmental impact of means of road transport by the use of electric motors powered by Proton Exchange Membrane (PEM) fuel cells are presented in this article. The overall functional characteristics of electric vehicles are presented as well as the essence of the operation of a fuel cell. On the basis of analyzing the energy conversion process significant advantages of electric drive are demonstrated especially in vehicles for urban and suburban applications. Moreover the analyzed literature indicated problems of controlling and maintaining fuel cell power caused by its highest dynamic and possible efficiency. This control was related to the variable load conditions of the fuel cell vehicle (FCV) engine. The relationship with the conventional dependencies in the field of vehicle dynamics is demonstrated. The final part of the study is related to the historical outline and examples of already operating fuel cell systems using hydrogen as an energy source for energy conversion to power propulsion vehicle’s engines. In conclusion the necessity to conduct research in the field of methods for controlling the power of fuel cells that enable their effective adaptation to the temporary load resulting from the conditions of vehicle motion is indicated.
Fission Battery Markets and Economic Requirements
Oct 2022
Publication
Fission Batteries (FBs) are nuclear reactors for customers with heat demands less than 250 MWt—replacing oil and natural gas in a low-carbon economy. Individual FBs would have outputs between 5 and 30 MWt. The small FB size has two major benefits: (1) the possibility of mass production and (2) ease of transport and leasing with return of used FBs to factory for refurbishing and reuse. Comparatively these two features are lacking in larger conventional reactors. Larger reactors are not transportable and thus can’t obtain the manufacturing economics possible with mass production or the operational advantages of returning the FB to the factory after use. Leasing places the regulatory maintenance and fuel-cycle burden on the leasing company that is minimized by large-fleet operations of identical units. The markets and economic requirements for FBs were examined. The primary existing markets are industrial biofuels off-grid electricity and container ships. Two major future markets were identified—advanced biofuels and hydrogen. In a low-carbon world the competitive price range for heat is $20–50/MWh ($6–15/million BTU) and $70–115/MWh for non-grid electricity. The primary competition in these sectors is likely to be biofuels and hydrogen produced using alternative energy sources—grid electricity is non-competitive. Larger users of energy have alternative low-carbon energy choices including modular nuclear reactors and fossil fuels with carbon capture and sequestration (CCS).
Source-to-sink Efficiency of Blue and Green District Heating and Hydrogen-based Heat Supply Systems
Apr 2022
Publication
Hydrogen is commonly mentioned as a future proof energy carrier. Hydrogen supporters 6 advocate for repurposing existing natural gas grids for a sustainable hydrogen supply. While the 7 long-term vision of the hydrogen community is green hydrogen the community acknowledges that 8 in the short term it will be to large extent manufactured from natural gas but in a decarbonized 9 way giving it the name blue hydrogen. While hydrogen has a role to play in hard to decarbonize 10 sectors its role for building heating demands is doubtful as mature and more energy efficient alter- 11 natives exist. As building heat supply infrastructures built today will operate for the decades to 12 come it is of highest importance to ensure that the most efficient and sustainable infrastructures are 13 chosen. This paper compares the source to sink efficiencies of hydrogen-based heat supply system 14 to a district heating system operating on the same primary energy source. The results show that a 15 natural gas-based district heating could be 267% more efficient and consequently have significantly 16 lower global warming potential than a blue hydrogen-based heat supply A renewable power-based 17 district heating could achieve above 440% higher efficiency than green hydrogen-based heat supply 18 system.
Optimal Configuration and Scheduling Model of a Multi-Park Integrated Energy System Based on Sustainable Development
Mar 2023
Publication
To maximize the utilization of renewable energy (RE) as much as possible in cold areas while reducing traditional energy use and carbon dioxide emissions a three-layer configuration optimization and scheduling model considering a multi-park integrated energy system (MPIES) a shared energy storage power station (SESPS) and a hydrogen refueling station (HRS) cooperation based on the Wasserstein generative adversarial networks the simultaneous backward reduction technique and the Quantity-Contour (WGAN-SBR_QC) method is proposed. Firstly the WGAN-SBR_QC method is used to generate typical scenarios of RE output. Secondly a three-layer configuration and schedule optimization model is constructed using MPIES SESPS and HRS. Finally the model’s validity is investigated by selecting a multi-park in Eastern Mongolia. The results show that: (1) the typical scenario of RE output improved the overall robustness of the system. (2) The profits of the MPIES and HRS increased by 1.84% and 52.68% respectively and the SESPS profit increased considerably. (3) The proposed approach increased RE utilization to 99.47% while reducing carbon emissions by 32.67%. Thus this model is a reference for complex energy system configuration and scheduling as well as a means of encouraging RE use.
Chile and its Potential Role Among the Most Affordable Green Hydrogen Producers in the World
Jul 2022
Publication
As result of the adverse effects caused by climate change the nations have decided to accelerate the transition of the energy matrix through the use of non-conventional sources free of polluting emissions. One of these alternatives is green hydrogen. In this context Chile stands out for the exceptional climate that makes it a country with a lot of renewable resources. Such availability of resources gives the nation clear advantages for hydrogen production strong gusts of wind throughout the country the most increased solar radiation in the world lower cost of production of electrical supplies among others. Due to this the nation would be between the lowest estimated cost for hydrogen production i.e. 1.5 USD/kg H2 approximately scenario that would place it as one of the cheapest green hydrogen producer in the world.
Thermodynamic Analysis of Solid Oxide Electrolyzer Integration with Engine Waste Heat Recovery for Hydrogen Production
Jul 2021
Publication
Water electrolysis based on solid oxide electrolysis cell (SOEC) exhibits high conversion efficiency due to part of energy demand can be derived from thermal energy. Therefore it can be integrated with other sources of thermal energy to reduce the consumption of electrical energy. In this paper a diesel engine is integrated with the SOEC stacks for heat recovery steam generator (HRSG). The thermal energy from the engine exhaust gas used to heat the inlet H2O of the SOEC is carried out as the integration case. A SOEC plant using electricity as the thermal heat input is selected as the base case. Thermodynamic analysis of the benchmark and integration scheme reveals that an electrical efficiency of 73.12% and 85.17% can be achieved respectively. The diesel to power efficiency can be increased to 70% when the exhaust gas is completely utilized by the SOEC system. The impacts of some key parameters including current density and operating temperature on system performance have also been conducted and found that the system has optimized parameters of current density and operating temperature to achieve better performance.
Review and Harmonization of the Life-Cycle Global Warming Impact of PV-Powered Hydrogen Production by Electrolysis
Sep 2021
Publication
This work presents a review of life-cycle assessment (LCA) studies of hydrogen electrolysis using power from photovoltaic (PV) systems. The paper discusses the assumptions strengths and weaknesses of 13 LCA studies and identifies the causes of the environmental impact. Differences in assumptions of system boundaries system sizes evaluation methods and functional units make it challenging to directly compare the Global Warming Potential (GWP) resulting from different studies. To simplify this process 13 selected LCA studies on PV-powered hydrogen production have been harmonized following a consistent framework described by this paper. The harmonized GWP values vary from 0.7 to 6.6 kg CO2-eq/kg H2 which can be considered a wide range. The maximum absolute difference between the original and harmonized GWP results of a study is 1.5 kg CO2-eq/kg H2. Yet even the highest GWP of this study is over four times lower than the GWP of grid-powered electrolysis in Germany. Due to the lack of transparency of most LCAs included in this review full identification of the sources of discrepancies (methods applied assumed production conditions) is not possible. Overall it can be concluded that the environmental impact of the electrolytic hydrogen production process is mainly caused by the GWP of the electricity supply. For future environmental impact studies on hydrogen production systems it is highly recommended to 1) divide the whole system into well-defined subsystems using compression as the final stage of the LCA and 2) to provide energy inputs/GWP results for the different subsystems.
P2H Modeling and Operation in the Microgrid Under Coupled Electricity–Hydrogen Markets
Dec 2021
Publication
The uncertainty and volatility of wind power have led to large-scale wind curtailment during grid connections. The adoption of power-to-hydrogen (P2H) system in a microgrid (MG) can mitigate the renewable curtailment by hydrogen conversion and storage. This paper conducts unified modeling for different types of P2H systems and considers the multi-energy trading in a hydrogen-coupled power market. The proposed bi-level equilibrium model is beneficial to minimize the energy cost of microgrids. Firstly a microgrid operation model applied to different P2H systems including an alkaline electrolysis cell (AEC) a proton exchange membrane electrolysis cell (PEMEC) or a solid oxide electrolysis cell (SOEC) is proposed at the upper level. Secondly an electricity market–clearing model and a hydrogen market model are constructed at the lower level. Then the diagonalization algorithm is adopted to solve the multi-market equilibrium problem. Finally case studies based on an IEEE 14-bus system are conducted to validate the proposed model and the results show that the microgrid with a P2H system could gain more profits and help increase the renewable penetration.
Assessment of the Co-combustion Process of Ammonia with Hydrogen in a Research VCR Piston Engine
Oct 2022
Publication
The presented work concerns experimental research of a spark-ignition engine with variable compression ratio (VCR) adapted to dual-fuel operation in which co-combustion of ammonia with hydrogen was conducted and the energy share of hydrogen varied from 0% to 70%. The research was aimed at assessing the impact of the energy share of hydrogen co-combusted with ammonia on the performance stability and emissions of an engine operating at a compression ratio of 8 (CR 8) and 10 (CR 10). The operation of the engine powered by ammonia alone for both CR 8 and CR 10 is associated with either a complete lack of ignition in a significant number of cycles or with significantly delayed ignition and the related low value of the maximum pressure pmax. Increasing the energy share of hydrogen in the fuel to 12% allows to completely eliminate the instability of the ignition process in the combustible mixture which is confirmed by a decrease in the IMEP uniqueness and a much lower pmax dispersion. For 12% of the energy share of hydrogen co-combusted with ammonia the most favorable course of the combustion process was obtained the highest engine efficiency and the highest IMEP value were recorded. The conducted research shows that increasing the H2 share causes an increase in NO emissions for both analyzed compression ratios
Comparative Life Cycle Assessment of Battery and Fuel Cell Electric Cars, Trucks, and Buses
Mar 2024
Publication
Addressing the pressing challenge of global warming reducing greenhouse gas emissions in the transportation sector is a critical imperative. Battery and fuel cell electric vehicles have emerged as promising solutions for curbing emissions in this sector. In this study we conducted a comprehensive life cycle assessment (LCA) for typical passenger vehicles heavy-duty trucks and city buses using either proton-exchange membrane fuel cells or Li-ion batteries with different cell chemistries. To ensure accuracy we supplemented existing studies with data from the literature particularly for the recycling phase as database limitations were encountered. Our results highlight that fuel cell and battery systems exhibit large emissions in the production phase. Recycling can significantly offset some of these emissions but a comparison of the technologies examined revealed considerable differences. Overall battery electric vehicles consistently outperform fuel cell electric vehicles regarding absolute greenhouse gas emissions. Hence we recommend prioritizing battery electric over fuel cell vehicles. However deploying fuel cell electric vehicles could become attractive in a hydrogen economy scenario where other factors e. g. the conversion and storage of surplus renewable electricity via electrolysis become important.
Potential Renewable Hydrogen from Curtailed Electricity to Decarbonize ASEAN’s Emissions: Policy Implications
Dec 2020
Publication
The power generation mix of the Association of Southeast Asian Nations (ASEAN) is dominated by fossil fuels which accounted for almost 80% in 2017 and are expected to account for 82% in 2050 if the region does not transition to cleaner energy systems. Solar and wind power are the most abundant energy resources but contribute negligibly to the power mix. Investors in solar or wind farms face high risks from electricity curtailment if surplus electricity is not used. Employing the policy scenario analysis of the energy outlook modelling results this paper examines the potential scalability of renewable hydrogen production from curtailed electricity in scenarios of high share of variable renewable energy in the power generation mix. The study found that ASEAN has high potential in developing renewable hydrogen production from curtailed electricity. The study further found that the falling cost of renewable hydrogen production could be a game changer to upscaling the large-scale hydrogen production in ASEAN through policy support. The results implied a future role of renewable hydrogen in energy transition to decarbonize ASEAN’s emissions.
Increasing Technical Efficiency of Renewable Energy Sources in Power Systems
Mar 2023
Publication
This paper presents a method for refining the forecast schedule of renewable energy sources (RES) generation by its intraday adjustment and investigates the measures for reserving RES with unstable generation in electric power systems (EPSs). Owing to the dependence of electricity generation by solar and wind power plants (PV and WPPs respectively) on natural conditions problems arise with their contribution to the process of balancing the power system. Therefore the EPS is obliged to keep a power reserve to compensate for deviations in RES from the planned generation amount. A system-wide reserve (mainly the shunting capacity of thermal and hydroelectric power plants) is used first followed by other means of power reserve: electrochemical hydrogen or biogas plants. To analyze the technical and economic efficiency of certain backup means mathematical models based on the theory of similarity and the criterion method were developed. This method is preferred because it provides the ability to compare different methods of backing up RES generation with each other assess their proportionality and determine the sensitivity of costs to the capacity of backup methods with minimal available initial information. Criterion models have been formed that allow us to build dependencies of the costs of backup means for unstable RES generation on the capacity of the backup means. It is shown that according to the results of the analysis of various methods and means of RES backup hydrogen technologies are relatively the most effective. The results of the analysis in relative units can be clarified if the current and near-term price indicators are known.
Green Hydrogen Blends with Natural Gas and Its Impact on the Gas Network
Oct 2022
Publication
With increasing shares of variable and uncertain renewable generation in many power systems there is an associated increase in the importance of energy storage to help balance supply and demand. Gas networks currently store and transport energy and they have the potential to play a vital role in longer-term renewable energy storage. Gas and electricity networks are becoming more integrated with quick-responding gas-fired power plants providing a significant backup source for renewable electricity in many systems. This study investigates Ireland’s gas network and operation when a variable green hydrogen input from excess wind power is blended with natural gas. How blended hydrogen impacts a gas network’s operational variables is also assessed by modelling a quasi-transient gas flow. The modelling approach incorporates gas density and a compressibility factor in addition to the gas network’s main pressure and flow rate characteristics. With an increasing concentration of green hydrogen up to 20% in the gas network the pipeline flow rate must be increased to compensate for reduced energy quality due to the lower energy density of the blended gas. Pressure drops across the gas pipeline have been investigated using different capacities of P2H from 18 MW to 124 MW. The results show significant potential for the gas network to store and transport renewable energy as hydrogen and improve renewable energy utilisation without upgrading the gas network infrastructure.
A Prompt Decarbonization Pathway for Shipping: Green Hydrogen, Ammonia, and Methanol Production and Utilization in Marine Engines
Mar 2023
Publication
The shipping industry has reached a higher level of maturity in terms of its knowledge and awareness of decarbonization challenges. Carbon-free or carbon-neutralized green fuel such as green hydrogen green ammonia and green methanol are being widely discussed. However little attention has paid to the green fuel pathway from renewable energy to shipping. This paper therefore provides a review of the production methods for green power (green hydrogen green ammonia and green methanol) and analyzes the potential of green fuel for application to shipping. The review shows that the potential production methods for green hydrogen green ammonia and green methanol for the shipping industry are (1) hydrogen production from seawater electrolysis using green power; (2) ammonia production from green hydrogen + Haber–Bosch process; and (3) methanol production from CO2 using green power. While the future of green fuel is bright in the short term the costs are expected to be higher than conventional fuel. Our recommendations are therefore as follows: improve green power production technology to reduce the production cost; develop electrochemical fuel production technology to increase the efficiency of green fuel production; and explore new technology. Strengthening the research and development of renewable energy and green fuel production technology and expanding fuel production capacity to ensure an adequate supply of low- and zero-emission marine fuel are important factors to achieve carbon reduction in shipping.
Flexible Power and Biomass-To-Methanol Plants With Different Gasification Technologies
Jan 2022
Publication
The competitiveness of biofuels may be increased by integrating biomass gasification plants with electrolysis units which generate hydrogen to be combined with carbon-rich syngas. This option allows increasing the yield of the final product by retaining a higher amount of biogenic carbon and improving the resilience of the energy sector by favoring electric grid services and sector coupling. This article illustrates a techno-economic comparative analysis of three flexible power and biomass to methanol plants based on different gasification technologies: direct gasification indirect gasification and sorptionenhanced gasification. The design and operational criteria of each plant are conceived to operate both without green hydrogen addition (baseline mode) and with hydrogen addition (enhanced mode) following an intermittent use of the electrolysis system which is turned on when the electricity price allows an economically viable hydrogen production. The methanol production plants include a gasification section syngas cleaning conditioning and compression section methanol synthesis and purification and heat recovery steam cycle to be flexibly operated. Due to the high oxygen demand in the gasifier the direct gasification-based plant obtains a great advantage to be operated between a minimum load to satisfy the oxygen demand at high electricity prices and a maximum load to maximize methanol production at low electricity prices. This allows avoiding large oxygen storages with significant benefits for Capex and safety issues. The analysis reports specific fixed-capital investments between 1823 and 2048 €/kW of methanol output in the enhanced operation and LCOFs between 29.7 and 31.7 €/GJLHV. Economic advantages may be derived from a decrease in the electrolysis capital investment especially for the direct gasification-based plants which employ the greatest sized electrolyzer. Methanol breakeven selling prices range between 545 and 582 €/t with the 2019 reference Denmark electricity price curve and between 484 and 535 €/t with an assumed modified electricity price curve of a future energy mix with increased penetration of intermittent renewables.
Methanol as a Renewable Energy Carrier: An Assessment of Production and Transportation Costs for Selected Global Locations
Jun 2021
Publication
The importing of renewable energy will be one part of the process of defossilizing the energy systems of countries and regions which are currently heavily dependent on the import of fossil-based energy carriers. This study investigates the possibility of importing renewable methanol comprised of hydrogen and carbon dioxide. Based on a methanol synthesis simulation model the net production costs of methanol are derived as a function of hydrogen and carbon dioxide expenses. These findings enable a comparison of the import costs of methanol and hydrogen. For this the hydrogen production and distribution costs for 2030 as reported in a recent study for four different origin/destination country combinations are considered. With the predicted hydrogen production costs of 1.35–2 €/kg and additional shipping costs methanol can be imported for 370–600 €/t if renewable or process-related carbon dioxide is available at costs of 100 €/t or below in the hydrogen-producing country. Compared to the current fossil market price of approximately 400 €/t renewable methanol could therefore become cost-competitive. Within the range of carbon dioxide prices of 30–100 €/t both hydrogen and methanol exhibit comparable energy-specific import costs of 18–30 €/GJ. Hence the additional costs for upgrading hydrogen to methanol are balanced out by the lower shipping costs of methanol compared to hydrogen. Lastly a comparison for producing methanol in the hydrogen’s origin or destination country indicates that carbon dioxide in the destination country must be 181–228 €/t less expensive than that in the origin country to balance out the more expensive shipping costs for hydrogen.
Jet Zero Strategy: One Year On
Jul 2023
Publication
This report sets out progress against our strategic framework for decarbonising aviation as well as the latest aviation emissions data and updated Jet Zero analysis.<br/>Among the significant milestones achieved since the Jet Zero strategy launch are the:<br/>- agreement at the International Civil Aviation Organization for a long-term aspirational goal for aviation of net zero 2050 carbon dioxide (CO2) emissions for international aviation<br/>- publication of the 2040 zero emissions airport target call for evidence<br/>significant progress on sustainable aviation fuels (SAF) including:<br/>- publishing the second SAF mandate consultation<br/>- launching a second round of the Advanced Fuels Fund<br/>- publishing the Philip New report and the government response on how to develop a UK SAF industry<br/>- publication of the government response to the UK ETS consultation setting out a range of commitments that will enhance the effectiveness of the UK Emissions Trading Scheme (ETS) for aviation<br/>- launch of the expressions of interest for 2 DfT- funded research projects into aviation’s non-CO2 impacts<br/>The report also acknowledges that big challenges remain and we need to continue to work across the aviation sector and with experts across the economy to ensure we continue to make progress on our path to decarbonise aviation.
Alternative-energy-vehicles Deployment Delivers Climate, Air Quality, and Health Co-benefits when Coupled with Decarbonizing Power Generation in China
Aug 2021
Publication
China is the world’s largest carbon emitter and suffers from severe air pollution which results in approximately one million premature deaths/year. Alternative energy vehicles (AEVs) (electric hydrogen fuel cell and natural gas vehicles) can reduce carbon emissions and improve air quality. However climate air quality and health benefits of AEVs powered with deeply decarbonized power generation are poorly quantified. Here we quantitatively estimate the air quality health carbon emission and economic benefits of replacing internal combustion engine vehicles with various AEVs. We find co-benefits increase dramatically as the electricity grid decarbonizes and hydrogen is produced from non-fossil fuels. Relative to 2015 a conversion to AEVs using largely non-fossil power can reduce air pollution and associated premature mortalities and years of life lost by 329000 persons/year and 1611000 life years/year. Thus maximizing climate air quality and health benefits of AEV deployment in China requires rapid decarbonization of the power system.
Numerical Study on Shockwave Attenuation by Water Mist in Confined Spaces
Sep 2021
Publication
Hydrogen safety has become the first consideration especially after fuel cell automobiles were pushed into commercial auto market. Tunnels are important parts of traffic infrastructure featured in confinement or semi-confinement. Hydrogen detonation is a potential accident scenario while hydrogen fuel cell vehicles are operated in a traffic tunnel with a confined space. Pressure shockwaves are mostly produced by hydrogen detonation and propagate along the tunnel. As a designed safety measure water mist injection is hopefully to mitigate the pressure loads of such shocks. To model the interaction between shockwaves and water droplets a droplet breakup model has been developed for the COM3D code which is a highly validated three-dimensional hydrogen explosion simulation code. By using the model the hydrogen detonation shockwave propagation in confined volumes is simulated in the study. The attenuation effects of water mist on the pressure shocks in the simulations are elaborated and discussed based on the simulation results.
EU Harmonised Testing Procedure: Determination of Water Electrolyser Energy Performance
Jan 2023
Publication
The objective of this pre-normative research (PNR) document is to present a testing procedure for establishing the energy performance of water (steam) electrolyser systems (WE systems) whether grid-connected or off-grid and individual water electrolysers (WEs)/high-temperature electrolysers (HTEs) for the generation of hydrogen by water/steam electrolysis. The WE systems use electricity mostly from variable renewable energy sources. HTE may additionally utilise (waste) heat from energy conversion and other industrial processes. By applying this procedure the determination of the specific energy consumption per unit of hydrogen output under standard ambient temperature and pressure (SATP) conditions allows for an adequate comparison of different WE systems. Also the energy performance potential of WEs or WE systems employing low-temperature water electrolysis (LTWE) technologies compared to HTE employing high-temperature steam electrolysis (HTSEL) technologies may be established under actual hydrogen output conditions by applying this procedure. The test method is to evaluate the specific energy consumption during steady-state operation at specified conditions including rated input power pressure and temperature of hydrogen recommended by the manufacturer of the WE or WE system. The energy efficiency and the electrical efficiency based on higher and lower heating value of hydrogen can be derived from respectively the specific energy consumption and the specific electric energy consumption as additional energy performance indicators (EPIs). In a plant setting the specific energy consumption of an individual water electrolyser including HTE under hydrogen output conditions may also be determined using this testing procedure. This procedure is intended to be used as a general characterisation method for evaluating the energy performance of WEs including HTEs and systems by the research community and industry alike.
Methane Cracking for Hydrogen Production: A Review of Catalytic and Molten Media Pyrolysis
May 2022
Publication
Currently hydrogen is mainly generated by steam methane reforming with significant CO2 emissions thus exacerbating the greenhouse effect. This environmental concern promotes methane cracking which represents one of the most promising alternatives for hydrogen production with theoretical zero CO/CO2 emissions. Methane cracking has been intensively investigated using metallic and carbonaceous catalysts. Recently research has focused on methane pyrolysis in molten metals/salts to prevent both reactor coking and rapid catalyst deactivation frequently encountered in conventional pyrolysis. Another expected advantage is the heat transfer improvement due to the high heat capacity of molten media. Apart from the reaction itself that produces hydrogen and solid carbon the energy source used in this endothermic process can also contribute to reducing environmental impacts. While most researchers used nonrenewable sources based on fossil fuel combustion or electrical heating concentrated solar energy has not been thoroughly investigated to date for pyrolysis in molten media. However it could be a promising innovative pathway to further improve hydrogen production sustainability from methane cracking. After recalling the basics of conventional catalytic methane cracking and the developed solar cracking reactors this review delves into the most significant results of the state-of-the-art methane pyrolysis in melts (molten metals and salts) to show the advantages and the perspectives of this new path as well as the carbon products’ characteristics and the main factors governing methane conversion.
Quantifying the Impacts of Heat Decarbonisation Pathways on the Future Electricity and Gas Demand
May 2022
Publication
The decarbonisation of heat supply will play a critical role in meeting the emissions reduction target. There is however great uncertainty associated with the achievable levels of heat decarbonisation and the optimal heat technology mix which can have serious implications for the future electricity and gas demand. This work employs an integrated gas electricity and heat supply model to quantify the impacts of heat decarbonisation pathways on the future electricity and gas demand. A case study in the Great Britain is performed considering two heat decarbonisation scenarios in 2050: one is the predominantly electrified heat supply and the other is the predominantly hydrogen-based heat supply. The electricity demand becomes more volatile in the electrified heat scenario as the peak surges to 107.3 GW compared to 51.1 GW in the 2018 reference scenario while the peak in hydrogen-based heat scenario is 78.4 GW. The peak gas demand declines from 247.6 GW for 2018 to 81.7 GW for electrified heat scenario and to 85.1 GW for hydrogen-based heat scenario confirming that the seasonality associated with heat demand is shifting away from the gas network and towards electricity network. Moreover a sensitivity analysis shows that the future electricity demand is highly sensitive to parameters such as relative heat demand coefficient of performance of air source heat pumps and share of electricity in hydrogen production. Finally the application of a load shifting strategy demonstrates that demand-side flexibility has the potential to maintain the electricity system balance and minimise the generation and network infrastructure requirements arising from heat electrification. While the case study presented in this paper is based on the Great Britain the findings regarding the future electricity and gas demand are relevant for the global energy transition.
Thermocatalytic Hydrogen Production Through Decomposition of Methane-A Review
Oct 2021
Publication
Consumption of fossil fuels especially in transport and energy-dependent sectors has led to large greenhouse gas production. Hydrogen is an exciting energy source that can serve our energy purposes and decrease toxic waste production. Decomposition of methane yields hydrogen devoid of COx components thereby aiding as an eco-friendly approach towards large-scale hydrogen production. This review article is focused on hydrogen production through thermocatalytic methane decomposition (TMD) for hydrogen production. The thermodynamics of this approach has been highlighted. Various methods of hydrogen production from fossil fuels and renewable resources were discussed. Methods including steam methane reforming partial oxidation of methane auto thermal reforming direct biomass gasification thermal water splitting methane pyrolysis aqueous reforming and coal gasification have been reported in this article. A detailed overview of the different types of catalysts available the reasons behind their deactivation and their possible regeneration methods were discussed. Finally we presented the challenges and future perspectives for hydrogen production via TMD. This review concluded that among all catalysts nickel ruthenium and platinum-based catalysts show the highest activity and catalytic efficiency and gave carbon-free hydrogen products during the TMD process. However their rapid deactivation at high temperatures still needs the attention of the scientific community.
Jet Zero Strategy: Delivering Net Zero Aviation by 2050
Jul 2022
Publication
The Jet Zero strategy sets out how we will achieve net zero aviation by 2050.<br/>It focuses on the rapid development of technologies in a way that maintains the benefits of air travel whilst maximising the opportunities that decarbonisation can bring to the UK.<br/>The Jet Zero strategy includes a 5-year delivery plan setting out the actions that will need to be taken in the coming years to support the delivery of net zero aviation by 2050. We will be monitoring progress and reviewing and updating our strategy every 5 years.<br/>The strategy is informed by over 1500 responses to the Jet Zero consultation and the Jet Zero further technical consultation to which we have issued a summary of responses and government response.<br/>The Jet Zero investment flightpath is part of a series of roadmaps to be published over the course of 2022 for each sector of the Prime Minister’s Ten point plan for a green industrial revolution.<br/>It showcases the UK’s leading role in the development and commercialisation of new low and zero emission aviation technologies. It also highlights investment opportunities across systems efficiencies sustainable aviation fuels and zero emission aircraft.
The EU Green Deal (2022 ed.)
Jan 2023
Publication
In this report we focus on the fundamentals of energy and climate policy as reformulated in the EU Green Deal. The 2022 edition includes updates following the publication of the Fit for 55 Package and the EU Hydrogen and Decarbonised Gas Markets Package. The reader is guided through the landscape of EU climate and energy policy. Starting with the big picture of the foundations of energy and climate policy we then move to discussing in more detail European climate policy security of supply and energy networks. We continue with energy wholesale and retail markets and finish with a closer look at energy innovation. Each chapter is divided into several sections aiming to give the reader a broad overview of the areas of climate and energy policy that are impacted by the EU Green Deal. The references at the end of each section serve as suggestions for further reading on each topic.
Recent Advances of Metal Borohydrides for Hydrogen Storage
Aug 2022
Publication
Hydrogen energy is an excellent carrier for connecting various renewable energy sources and has many advantages. However hydrogen is flammable and explosive and its density is low and easy to escape which brings inconvenience to the storage and transportation of hydrogen. Therefore hydrogen storage technology has become one of the key steps in the application of hydrogen energy. Solid-state hydrogen storage method has a very high volumetric hydrogen density compared to the traditional compressed hydrogen method. The main issue of solid-state hydrogen storage method is the development of advanced hydrogen storage materials. Metal borohydrides have very high hydrogen density and have received much attention over the past two decades. However high hydrogen sorption temperature slow kinetics and poor reversibility still severely restrict its practical applications. This paper mainly discusses the research progress and problems to be solved of metal borohydride hydrogen storage materials for solid-state hydrogen storage.
Prospects and Challenges of Green Hydrogen Economy via Multi-Sector Global Symbiosis in Qatar
Jan 2021
Publication
Low carbon hydrogen can be an excellent source of clean energy which can combat global climate change and poor air quality. Hydrogen based economy can be a great opportunity for a country like Qatar to decarbonize its multiple sectors including transportation shipping global energy markets and industrial sectors. However there are still some barriers to the realization of a hydrogen-based economy which includes large scale hydrogen production cost infrastructure investments bulk storage transport & distribution safety consideration and matching supply-demand uncertainties. This paper highlights how the aforementioned challenges can be handled strategically through a multi-sector industrial-urban symbiosis for the hydrogen supply chain implementation. Such symbiosis can enhance the mutual relationship between diverse industries and urban planning by exploring varied scopes of multi-purpose hydrogen usage (i.e. clean energy source as a safer carrier industrial feedstock and intermittent products vehicle and shipping fuel and international energy trading etc.) both in local and international markets. It enables individual entities and businesses to participate in the physical exchange of materials by-products energy and water with strategic advantages for all participants. Besides waste/by-product exchanges several different kinds of synergies are also possible such as the sharing of resources and shared facilities. The diversified economic base regional proximity and the facilitation of rules strategies and policies may be the key drivers that support the creation of a multi-sector hydrogen supply chain in Qatar.
What is Stored, Why, and How? Mental Models, Knowledge, and Public Acceptance of Hydrogen Storage
Nov 2016
Publication
Although electricity storage plays a decisive role for the German “Energiewende” and it has become evident that the successful diffusion of technologies is not only a question of technical feasibility but also of social acceptance research on electricity storage technologies from a social science point of view is still scarce. This study therefore empirically explores laypersons’ mindsets and knowledge related to storage technologies focusing on hydrogen. While the results indicate overall supportive attitudes and trust in hydrogen storage some misconceptions a lack of information as well as concerns were identified which should be addressed in future communication concepts.
Electric Aircraft Fueled by Liquid Hydrogen and Liquefied Natural Gas
Jul 2021
Publication
The paper is a review of the opportunities and challenges of cryogenic power devices of electric aircraft and the ongoing research and development efforts of the government agencies and the industry. Liquid Hydrogen (LH2) and Liquefied Natural Gas (LNG) are compared to support high temperature superconducting (HTS) and normal metal devices respectively. The power devices were assumed to operate at the normal boiling point of the fuel used. The efficiencies of the electrical devices are estimated based on state-of-the-art technology. The mass flow rates and total fuel requirements for both the cryogenic fuels required to maintain the operating temperatures of the devices were simulated using thermal network models. A twin-aisle 300 passenger aircraft with a 5.5 h flight duration was used for the models. The results show that the required masses of LH2 and LNG are 744 kg and 13638 kg respectively for the cooling requirement. The corresponding volumes of LH2 and LNG required are 9760 and 30300 L respectively. In both cases the estimated mass of the fuel needed for the aircraft is more than what is needed to maintain the cryogenic environment of the power devices. It was concluded that an electric aircraft with LNG cooled normal metal devices is feasible. However an aircraft with HTS devices and cooled with LH2 is more attractive if the ongoing R&D efforts on HTS devices and LH2 infrastructure are successful. The emission reductions would be substantially higher with LH2 particularly when H2 is produced using renewable energy sources.
Cold Start Cycling Durability of Fuel Cell Stacks for Commercial Automotive Applications
Sep 2022
Publication
System durability is crucial for the successful commercialization of polymer electrolyte fuel cells (PEFCs) in fuel cell electric vehicles (FCEVs). Besides conventional electrochemical cycling durability during long-term operation the effect of operation in cold climates must also be considered. Ice formation during start up in sub-zero conditions may result in damage to the electrocatalyst layer and the polymer electrolyte membrane (PEM). Here we conduct accelerated cold start cycling tests on prototype fuel cell stacks intended for incorporation into commercial FCEVs. The effect of this on the stack performance is evaluated the resulting mechanical damage is investigated and degradation mechanisms are proposed. Overall only a small voltage drop is observed after the durability tests only minor damage occurs in the electrocatalyst layer and no increase in gas crossover is observed. This indicates that these prototype fuel cell stacks successfully meet the cold start durability targets for automotive applications in FCEVs.
Sustainable Ammonia Production Processes
Mar 2021
Publication
Due to the important role of ammonia as a fertilizer in the agricultural industry and its promising prospects as an energy carrier many studies have recently attempted to find the most environmentally benign energy efficient and economically viable production process for ammonia synthesis. The most commonly utilized ammonia production method is the Haber-Bosch process. The downside to this technology is the high greenhouse gas emissions surpassing 2.16 kgCO2-eq/kg NH3 and high amounts of energy usage of over 30 GJ/tonne NH3 mainly due to the strict operational conditions at high temperature and pressure. The most widely adopted technology for sustainable hydrogen production used for ammonia synthesis is water electrolysis coupled with renewable technologies such as wind and solar. In general a water electrolyzer requires a continuous supply of pretreated water with high purity levels for its operation. Moreover for production of 1 tonne of hydrogen 9 tonnes of water is required. Based on this data for the production of the same amount of ammonia through water electrolysis 233.6 million tonnes/yr of water is required. In this paper a critical review of different sustainable hydrogen production processes and emerging technologies for sustainable ammonia synthesis along with a comparative life cycle assessment of various ammonia production methods has been carried out. We find that through the review of each of the studied technologies either large amounts of GHG emissions are produced or high volumes of pretreated water is required or a combination of both these factors occur.
On the Road to Sustainable Transport: Acceptance and Preferences for Renewable Fuel Production Infrastructure
Sep 2022
Publication
To abate climate change and ameliorate the air quality in urban areas innovative solutions are required to reduce CO2 and pollutant emissions from traffic. Alternative fuels made from biomass or CO2 and hydrogen can contribute to these goals by substituting fossil gasoline or diesel in combustion engines. Using a conjoint analysis approach the current study investigates preferences of laypeople (n = 303) for fuel production facilities in terms of siting location plant size raw material used in the production and raw material transport. The location was most decision-relevant followed by raw material transport whereas plant size and type of raw material played a less prominent role for the preference choice. The best-case scenario from the point of view of acceptance would be the installation of a rather small bio-hybrid fuel production plant in an industrial area (instead of an agricultural or pristine environment). No transport or transport via underground pipeline were preferred over truck/tank car or overground pipeline. The findings can be used as a basis for planning and decision-making for designing production networks for new fuel types.
Low-carbon Economic Dispatch of Power Systems Based on Mobile Hydrogen Storage
Mar 2022
Publication
To alleviate the global warming crisis carbon reduction is an inevitable trend of sustainable development. The energy carrier with Hydrogen (H2) is considered to be one of the promising choices for realizing a low-carbon economy. With the increasing penetration level of wind power generation and for well-balancing wind generation fluctuations this paper proposes a low-carbon economic dispatch method for power systems based on mobile hydrogen storage(MHS). The wind power surplus during off-peak load periods is first utilized to generate green H2. Afterward the green H2 is optimally transported to multiple hydrogen storage(HS) stations for generating power electricity by flexibly controlling the electrolysis(EL) methanation(ME) carbon capture(CCS) and H2 power generation processes in such a way the wind power is coordinated with the hydrogen production transport and utilization to reduce the total carbon emission and minimize the operation cost of power systems. Finally the proposed power system low-carbon economic dispatch model is verified by case studies.
Technical Evaluation of the Flexibility of Water Electrolysis Systems to Increase Energy Flexibility: A Review
Jan 2023
Publication
The goal of achieving water electrolysis on a gigawatt scale faces numerous challenges regarding technological feasibility and market application. Here the flexibility of operation scenarios such as load changes and capacity of electrolysis plays a key role. This raises the question of how flexible electrolysis systems currently are and what possibilities there are to increase flexibility. In order to be able to answer this question in the following a systematic literature research was carried out with the aim to show the current technical possibilities to adapt load and capacity of electrolysis technologies and to determine limits. The result of the systematic literature research is an overview matrix of the electrolysis types AEL PEMEL HTEL and AEMEL already applied in the market. Technical data on the operation of the respective electrolysis stacks as well as details and materials for the respective stack structure (cathode anode electrolyte) were summarized. The flexibility of the individual technologies is addressed by expressing it in values such as load flexibility and startup-times. The overview matrix contains values from various sour1ces in order to make electrolysis comparable at the stack level and to be able to make statements about flexibility. The result of the overview article shows the still open need for research and development to make electrolysis more flexible.
Prospect of Green Hydrogen Generation from Hybrid Renewable Energy Sources: A Review
Feb 2023
Publication
Hydrogen is one of the prospective clean energies that could potentially address two pressing areas of global concern namely energy crises and environmental issues. Nowadays fossil‐ based technologies are widely used to produce hydrogen and release higher greenhouse gas emis‐ sions during the process. Decarbonizing the planet has been one of the major goals in the recent decades. To achieve this goal it is necessary to find clean sustainable and reliable hydrogen pro‐ duction technologies with low costs and zero emissions. Therefore this study aims to analyse the hydrogen generation from solar and wind energy sources and observe broad prospects with hybrid renewable energy sources in producing green hydrogen. The study mainly focuses on the critical assessment of solar wind and hybrid‐powered electrolysis technologies in producing hydrogen. Furthermore the key challenges and opportunities associated with commercial‐scale deployment are addressed. Finally the potential applications and their scopes are discussed to analyse the important barriers to the overall commercial development of solar‐wind‐based hydrogen production systems. The study found that the production of hydrogen appears to be the best candidate to be employed for multiple purposes blending the roles of fuel energy carrier and energy storage modality. Further studies are recommended to find technical and sustainable solutions to overcome the current issues that are identified in this study.
Renewable Hydrogen Implementations for Combined Energy Storage, Transportation and Stationary Applications
Dec 2019
Publication
The purpose of this paper is to discuss the potential of hydrogen obtained from renewable sources for energy generation and storage systems. The first part of analysis will address such issues as various methods of green hydrogen production storage and transportation. The review of hydrogen generation methods will be followed by the critical analysis and the selection of production method. This selection is justified by the results of the comparative research on alternative green hydrogen generation technologies with focus on their environmental impacts and costs. The comparative analysis includes the biomass-based methods as well as water splitting and photo-catalysis methods while water electrolysis is taken as a benchmark. Hydrogen storage and transportation issues will be further discussed in purpose to form the list of recommended solutions. In the second part of the paper the technology readiness and technical feasibility for joint hydrogen applications will be analysed. This will include the energy storage and production systems based on renewable hydrogen in combination with hydrogen usage in mobility systems as well as the stationary applications in buildings such as combined heat and power (CHP) plants or fuel cell electric generators. Based on the analysis of the selected case studies the author will discuss the role of hydrogen for the carbon emission reduction with the stress on the real value of carbon footprint of hydrogen depending on the gas source storage transportation and applications.
A Comprehensive Review on Recent Advancements in Thermochemical Processes for Clean Hydrogen Production to Decarbonize the Energy Sector
Sep 2022
Publication
Hydrogen is a source of clean energy as it can produce electricity and heat with water as a by-product and no carbon content is emitted when hydrogen is used as burning fuel in a fuel cell. Hydrogen is a potential energy carrier and powerful fuel as it has high flammability fast flame speed no carbon content and no emission of pollutants. Hydrogen production is possible through different technologies by utilizing several feedstock materials but the main concern in recent years is to reduce the emission of carbon dioxide and other greenhouse gases from energy sectors. Hydrogen production by thermochemical conversion of biomass and greenhouse gases has achieved much attention as researchers have developed several novel thermochemical methods which can be operated with low cost and high efficiency in an environmentally friendly way. This review explained the novel technologies which are being developed for thermochemical hydrogen production with minimum or zero carbon emission. The main concern of this paper was to review the advancements in hydrogen production technologies and to discuss different novel catalysts and novel CO2 -absorbent materials which can enhance the hydrogen production rate with zero carbon emission. Recent developments in thermochemical hydrogen production technologies were discussed in this paper. Biomass gasification and pyrolysis steam methane reforming and thermal plasma are promising thermochemical processes which can be further enhanced by using catalysts and sorbents. This paper also reviewed the developments and influences of different catalysts and sorbents to understand their suitability for continuous clean industrial hydrogen production.
The Hydrogen Economy and Jobs of the Future
Nov 2018
Publication
Growth in the hydrogen and fuel cell industries will lead to vast new employment opportunities and these will be created in a wide variety of industries skills tasks and earnings. Many of these jobs do not currently exist and do not have occupational titles defined in official classifications. In addition many of these jobs require different skills and education than current jobs and training requirements must be assessed so that this rapidly growing part of the economy has a sufficient supply of trained and qualified workers. We discuss the current hydrogen economy and technologies. We then identify by occupational titles the new jobs that will be created in the expanding hydrogen/fuel cell economy estimate the average US salary for each job identify the minimum educational attainment required to gain entry into that occupation and specify the recommended university degree for the advanced educational requirements. We provide recommendations for further research.
Water Electrolysis: From Textbook Knowledge to the Latest Scientific Strategies and Industrial Developments
May 2022
Publication
Replacing fossil fuels with energy sources and carriers that are sustainable environmentally benign and affordable is amongst the most pressing challenges for future socio-economic development. To that goal hydrogen is presumed to be the most promising energy carrier. Electrocatalytic water splitting if driven by green electricity would provide hydrogen with minimal CO2 footprint. The viability of water electrolysis still hinges on the availability of durable earth-abundant electrocatalyst materials and the overall process efficiency. This review spans from the fundamentals of electrocatalytically initiated water splitting to the very latest scientific findings from university and institutional research also covering specifications and special features of the current industrial processes and those processes currently being tested in large-scale applications. Recently developed strategies are described for the optimisation and discovery of active and durable materials for electrodes that ever-increasingly harness first principles calculations and machine learning. In addition a technoeconomic analysis of water electrolysis is included that allows an assessment of the extent to which a large-scale implementation of water splitting can help to combat climate change. This review article is intended to cross-pollinate and strengthen efforts from fundamental understanding to technical implementation and to improve the ‘junctions’ between the field’s physical chemists materials scientists and engineers as well as stimulate much-needed exchange among these groups on challenges encountered in the different domains.
Sizing of a Fuel Cell–battery Backup System for a University Building Based on the Probability of the Power Outages Length
Jul 2022
Publication
Hydrogen is a bright energy vector that could be crucial to decarbonise and combat climate change. This energy evolution involves several sectors including power backup systems to supply priority facility loads during power outages. As buildings now integrate complex automation domotics and security systems energy backup systems cause interest. A hydrogen-based backup system could supply loads in a multi-day blackout; however the backup system should be sized appropriately to ensure the survival of essential loads and low cost. In this sense this work proposes a sizing of fuel cell (FC) backup systems for low voltage (LV) buildings using the history of power outages. Historical data allows fitting a probability function to determine the appropriate survival of loads. The proposed sizing is applied to a university building with a photovoltaic generation system as a case study. Results show that the sizing of an FC–battery backup system for the installation is 7.6% cheaper than a battery-only system under a usual 330-minutes outage scenario. And 59.3% cheaper in the case of an unusual 48-hours outage scenario. It ensures a 99% probability of supplying essential load during power outages. It evidences the pertinence of an FC backup system to attend to outages of long-duration and the integration of batteries to support the abrupt load variations. This research is highlighted by using historical data from actual outages to define the survival of essential loads with total service probability. It also makes it possible to determine adequate survival for non-priority loads. The proposed sizing is generalisable and scalable for other buildings and allows quantifying the reliability of the backup system tending to the resilience of electrical systems.
The Role of Hydrogen in the Visegrad Group Approach to Energy Transition
Oct 2022
Publication
Hydrogen is an energy carrier in which hopes are placed for an easier achievement of climate neutrality. Together with electrification energy efficiency development and RES hydrogen is expected to enable the ambitious energy goals of the European Green Deal. Hence the aim of the article is to query the development of the hydrogen economy in the Visegrad Group countries (V4). The study considers six diagnostic features: sources of hydrogen production hydrogen legislation financial mechanisms objectives included in the hydrogen strategy environmental impact of H2 and costs of green hydrogen investments. The analysis also allowed to indicate the role that hydrogen will play in the energy transition process of the V4 countries. The analysis shows that the V4 countries have similar approaches to the development of the hydrogen market but the hydrogen strategies published by each of the Visegrad countries are not the same. Each document sets goals based on the hydrogen production to date and the specifics of the domestic energy and transport sectors as there are no solutions that are equally effective for all. Poland’s hydrogen strategy definitely stands out the strongest.
Underground Bio-methanation: Concept and Potential
Feb 2020
Publication
As a major part of the energy turn around the European Union and other countries are supporting the development of renewable energy technologies to decrease nuclear and fossil energy production. Therefore efficient use of renewable energy resources is one challenge as they are influenced by environmental conditions and hence the intensity of resources such as wind or solar power fluctuates. To secure constant energy supply suitable energy storage and conversion techniques are required. An upcoming solution is the utilization and storage of hydrogen or hydrogen-rich natural gas in porous formations in the underground. In the past microbial methanation was observed as a side effect during these gas storage operations. The concept of underground bio-methanation arised which uses the microbial metabolism to convert hydrogen and carbon dioxide into methane. The concept consists of injecting gaseous hydrogen and carbon dioxide into an underground structure during energy production peaks which are subsequently partly converted into methane. The resulting methane-rich gas mixture is withdrawn during high energy demand. The concept is comparable to engineered bio-reactors which are already locally integrated into the gas infrastructure. In both technologies the conversion process of hydrogen into methane is driven by hydrogenotrophic methanogenic archaea present in the aqueous phase of the natural underground or above-ground engineered reactor. Nevertheless the porous medium in the underground provides compared to the engineered bio-reactors a larger interface between the gas and aqueous phase caused by the enormous volume in the underground porous media. The following article summarizes the potential and concept of underground methanation and the current state of the art in terms of laboratory investigations and pilot tests. A short system potential analysis shows that an underground bio-reactor with a storage capacity of 850 Mio. Sm3 could deliver methane to more than 600000 households based on a hydrogen production from renewable energies.
Life Cycle Assessment of Waste-to-hydrogen Systems for Fuel Cell Electric Buses in Glasgow, Scotland
Jun 2022
Publication
Waste-to-hydrogen (WtH) technologies are proposed as a dual-purpose method for simultaneous non-fossil-fuel based hydrogen production and sustainable waste management. This work applied the life cycle assessment approach to evaluate the carbon saving potential of two main WtH technologies (gasification and fermentation) in comparison to the conventional hydrogen production method of steam methane reforming (SMR) powering fuel cell electric buses in Glasgow. It was shown that WtH technologies could reduce CO2-eq emissions per kg H2 by 50–69% as compared to SMR. Gasification treating municipal solid waste and waste wood had global warming potentials of 4.99 and 4.11 kg CO2-eq/kg H2 respectively which were lower than dark fermentation treating wet waste at 6.6 kg CO2-eq/kg H2 and combined dark and photo fermentation at 6.4 kg CO2-eq/kg H2. The distance emissions of WtH-based fuel cell electric bus scenarios were 0.33–0.44 kg CO2-eq/km as compared to 0.89 kg CO2-eq/km for the SMR-based scenario.
Smart Power-to-gas Deployment Strategies Informed by Spatially Explicit Cost and Value Models
Oct 2022
Publication
Green hydrogen allows coupling renewable electricity to hard-to-decarbonize sectors such as long-distance transport and carbon-intensive industries in order to achieve net zero emissions. Evaluating the cost and value of power-to-gas is a major challenge owing to the spatial distribution and temporal variability of renewable electricity CO2 and energy demand. Here we propose a method based on geographic information system (GIS) and techno-economic modeling to: (i) compare the levelized cost and levelized value of power-to-gas across locations; (ii) identify potential hotspots for their future implementation in Switzerland; and (iii) set cost improvement targets as well as smart deployment strategies. Our method accounts for the spatial and temporal (both hourly and seasonal) availability of renewable electricity and CO2 sources as well as the presence of gas infrastructure heating networks oxygen and gas demand centers. We find that only green hydrogen plants connected directly to run-of-river hydropower plants are currently profitable in Switzerland (with NPV per CAPEX ranging between 2.3-5.6). However considering technological progress by 2050 a few green hydrogen plants deployed in the demand centers and powered by rooftop PV electricity will also become economically attractive. Moreover a few synthetic methane plants connected to run-of-river hydropower plants currently show slight profitability (NPV per CAPEX reaching values up to 1.3) and in 2050 (NPV per CAPEX up to 3.1) whereas those connected to rooftop PV will remain uneconomical even in 2050. Based on our findings we devise a long-term roadmap for policy makers and project developers to plan future green hydrogen projects. The proposed methodology which is applied to Switzerland can be extended to other countries.
Hydrogen or Hydrogen-derived Methanol for Dual-fuel Compression-ignition Combustion: An Engine Perspective
Oct 2022
Publication
Synthetic fuels or e-fuels produced from captured CO2 and renewable hydrogen are envisaged as a feasible path towards a climate-neutral transportation in medium/heavy-duty and maritime sectors. EU is presently debating energy targets by 2030 for these fuels. As their production involves chemical processing of hydrogen it must be evaluated if the extra cost is worthy at least in applications where hydrogen use is possible. This manuscript focuses on the performance and environmental impact when hydrogen and methanol are fed to a heavy-duty compression-ignition engine working under dual-fuel combustion. The trade-off thermal efficiency-NOx emissions is primary considered in the assessment by combining both variables in an own defined function. During the work engine operating settings were adjusted to exploit the potential of methanol and hydrogen. Compared to conventional combustion methanol required centering the combustion towards TDC and doubling the EGR rate resulting in a low temperature highly premixed combustion almost soot-free and with extremely low NOx emissions. The best settings for hydrogen were in the middle of those for methanol and conventional combustion. Results showed great dependance with the engine load but methanol proved superior to hydrogen for all conditions. At high load 20–60 % methanol even improved the efficiency and reduced the NOx emissions obtained by conventional combustion. However at low load hydrogen could substitute 90 % of the diesel fuel while methanol failed at substitutions higher than 55 %.
Synergistic Value in Vertically Integrated Power-to-Gas Energy Systems
Oct 2019
Publication
In vertically integrated energy systems integration frequently entails operational gains that must be traded off against the requisite cost of capacity investments. In the context of the model analyzed in this study the operational gains are subject to inherent volatility in both the price and the output of the intermediate product transferred within the vertically integrated structure. Our model framework provides necessary and sufficient conditions for the value (NPV) of an integrated system to exceed the sum of two optimized subsystems on their own. We then calibrate the model in Germany and Texas for systems that combine wind energy with Power-to-Gas (PtG) facilities that produce hydrogen. Depending on the prices for hydrogen in different market segments we find that a synergistic investment value emerges in some settings. In the context of Texas for instance neither electricity generation from wind power nor hydrogen production from PtG is profitable on its own in the current market environment. Yet provided both subsystems are sized optimally in relative terms the attendant operational gains from vertical integration more than compensate for the stand-alone losses of the two subsystems.
Techno-Economic Model for Scaling up of Hydrogen Refueling Stations
Oct 2022
Publication
In a recent publication the Hydrogen Council states that scaling up to greater production volumes leads to significant cost savings as a consequence of the industrialization of equipment manufacturing increased utilization standardization and improvements in system efficiency and flexibility. In this study a component-oriented techno-economic model is applied to five different European hydrogen refueling stations within the 3Emotion project which is planned to ensure capacities sufficient for increasing a fleet to 100 fuel cell buses. The investigation of the various cases shows that the levelized cost of hydrogen (LCOH) for large-scale applications will be in the range of about 4 €/kg to 7 €/kg within the boundaries analyzed. On-site production facilities were found to be the lower-cost design benefiting from the high volumes at stake and the economy of scale with respect to decentralized production due to the significant costs associated with retail hydrogen and transport. This study also illustrates the effects on the LCOH of varying the hydrogen delivery and production prices using a sensitivity analysis. The results show that by utilizing high-capacity trailers the costs associated with delivery could be reduced by 30%. Furthermore green hydrogen production could be a competitive solution if coupled with low electricity prices resulting in an LCOH between 4.21 €/kg and 6.80 €/kg.
Analysis of Hydrogen Production Costs in Steam-Methane Reforming Considering Integration with Electrolysis and CO2 Capture
Aug 2022
Publication
Global hydrogen production is dominated by the Steam-Methane Reforming (SMR) route which is associated with significant CO2 emissions and excess process heat. Two paths to lower specific CO2 emissions in SMR hydrogen production are investigated: (1) the integration of CO2 capture and compression for subsequent sequestration or utilization and (2) the integration of electrolysis for increased hydrogen production. In both cases the excess process heat is utilized to drive the emissions reduction options. Four different design regimes for integration of carbon capture and compression with the SMR process are identified. Techno-economic analyses are performed to study the effect of CO2 mitigation on hydrogen production costs compared to grey hydrogen production without emissions mitigation options. Integration with electrolysis is shown to be less attractive compared to the proposed heat and power integration schemes for the SMR process with CO2 capture and compression for subsequent sequestration or utilization which can reduce emissions by 90% with hydrogen production costs increasing only moderately by 13%. This blue hydrogen production is compared in terms of costs and emissions against the emerging alternative production by electrolysis in the context of renewable and fossil electricity generation and electricity mixes while considering life-cycle emissions.
Potential Transitions in the Iron and Steel Industry in Sweden: Towards a Hydrogen-based Future?
May 2018
Publication
The iron and steel industry accounts for one third of global industrial CO2 emissions putting pressure on the industry to shift towards more sustainable modes of production. However for an industry characterised by path dependency and technological lock-ins sustainability transitions are not straightforward. In this study we aim to explore the potential pathways for sustainability transitions in the iron and steel industry. To do so we have conducted a case study in Sweden where there are policy and industry commitments towards fossil-free steel production. Our theoretical points of departure are the technological innovation system (TIS) approach and the multi-level perspective (MLP) and our paper presents the dynamics behind an emerging case of transition towards a hydrogen-based future. The paper has two major contributions to the literature on sustainability transitions. First it attempts to borrow some concepts from the MLP and integrate them with the TIS approach. Second it empirically presents an in-depth case study of the iron and steel industry e an understudied context in the field of sustainability transitions. By doing so it sheds some light on the dynamics between an emerging TIS and potential transition pathways of a regime.
Analysis of Control-System Strategy and Design of a Small Modular Reactor with Different Working Fluids for Electricity and Hydrogen Production as Part of a Decentralised Mini Grid
Mar 2022
Publication
Hydrogen is increasingly being viewed as a significant fuel for future industrial processes as it offers pathways to zero emission. The UK sees hydrogen as one of a handful of low-carbon solutions for transition to net zero. Currently most hydrogen production is from steam reforming of natural gas or coal gasification both of which involve the release of carbon dioxide. Hydrogen production from mini decentralised grids via a thermochemical process coupled with electricity production could offer favourable economics for small modular reactors (SMRs) whereby demand or grid management as a solution would include redirecting the power for hydrogen production when electricity demand is low. It also offers a clean-energy alternative to the aforementioned means. SMRs could offer favourable economics due to their flexible power system as part of the dual-output function. This study objective is to investigate the critical performance parameters associated with the nuclear power plant (NPP) the cycle working fluids and control-system design for switching between electricity and hydrogen demand to support delivery as part of a mini grid system for a reactor power delivering up to approximately 600 MWth power. The novelty of the work is in the holistic parametric analysis undertaken using a novel in-house tool which analyses the NPP using different working fluids with a control function bolt-on at the offtake for hydrogen production. The results indicate that the flow conditions at the offtake can be maintained. The choice of working fluids affects the pressure component. However the recuperator and heat-exchanger effectiveness are considered as efficiency-limiting factors for hydrogen production and electricity generation. As such the benefit of high-technology heat exchangers cannot be underestimated. This is also true when deciding on the thermochemical process to bolt onto the plant. The temperature of the gas at the end of the pipeline should also be considered to ensure that the minimum temperature-requirement status for hydrogen production is me
The Role of New Energy in Carbon Neutral
Mar 2021
Publication
Carbon dioxide is an important medium of the global carbon cycle and has the dual properties of realizing the conversion of organic matter in the ecosystem and causing the greenhouse effect. The fixed or available carbon dioxide in the atmosphere is defined as “gray carbon” while the carbon dioxide that cannot be fixed or used and remains in the atmosphere is called “black carbon”. Carbon neutral is the consensus of human development but its implementation still faces many challenges in politics resources technology market and energy structure etc. It is proposed that carbon replacement carbon emission reduction carbon sequestration and carbon cycle are the four main approaches to achieve carbon neutral among which carbon replacement is the backbone. New energy has become the leading role of the third energy conversion and will dominate carbon neutral in the future. Nowadays solar energy wind energy hydropower nuclear energy and hydrogen energy are the main forces of new energy helping the power sector to achieve low carbon emissions. “Green hydrogen” is the reserve force of new energy helping further reduce carbon emissions in industrial and transportation fields. Artificial carbon conversion technology is a bridge connecting new energy and fossil energy effectively reducing the carbon emissions of fossil energy. It is predicted that the peak value of China’s carbon dioxide emissions will reach 110108 t in 2030. The study predicts that China's carbon emissions will drop to 22108 t 33108 t and 44108 t respectively in 2060 according to three scenarios of high medium and low levels. To realize carbon neutral in China seven implementation suggestions have been put forward to build a new “three small and one large” energy structure in China and promote the realization of China's energy independence strategy.
Operating Hydrogen-Based Energy Storage Systems in Wind Farms for Smooth Power Injection: A Penalty Fees Aware Model Predictive Control
Aug 2022
Publication
Smooth power injection is one of the possible services that modern wind farms could provide in the not-so-far future for which energy storage is required. Indeed this is one among the three possible operations identified by the International Energy Agency (IEA)-Hydrogen Implementing Agreement (HIA) within the Task 24 final report that may promote their integration into the main grid in particular when paired to hydrogen-based energy storages. In general energy storage can mitigate the inherent unpredictability of wind generation providing that they are deployed with appropriate control algorithms. On the contrary in the case of no storage wind farm operations would be strongly affected as well as their economic performances since the penalty fees wind farm owners/operators incur in case of mismatches between the contracted power and that actually delivered. This paper proposes a Model Predictive Control (MPC) algorithm that operates a Hydrogen-based Energy Storage System (HESS) consisting of one electrolyzer one fuel cell and one tank paired to a wind farm committed to smooth power injection into the grid. The MPC relies on Mixed-Logic Dynamic (MLD) models of the electrolyzer and the fuel cell in order to leverage their advanced features and handles appropriate cost functions in order to account for the operating costs the potential value of hydrogen as a fuel and the penalty fee mechanism that may negatively affect the expected profits generated by the injection of smooth power. Numerical simulations are conducted by considering wind generation profiles from a real wind farm in the center-south of Italy and spot prices according to the corresponding market zone. The results show the impact of each cost term on the performances of the controller and how they can be effectively combined in order to achieve some reasonable trade-off. In particular it is highlighted that a static choice of the corresponding weights can lead to not very effective handling of the effects given by the combination of the system conditions with the various exogenous’ while a dynamic choice may suit the purpose instead. Moreover the simulations show that the developed models and the set-up mathematical program can be fruitfully leveraged for inferring indications on the devices’ sizing.
Progress of Performance, Emission, and Technical Measures of Hydrogen Fuel Internal-Combustion Engines
Oct 2022
Publication
To achieve the goals of low carbon emission and carbon neutrality some urgent challenges include the development and utilization of low-carbon or zero-carbon internal combustion engine fuels. Hydrogen as a clean efficient and sustainable fuel has the potential to meet the abovementioned challenges. Thereby hydrogen internal combustion engines have been attracting attention because of their zero carbon emissions high thermal efficiency high reliability and low cost. In this paper the opportunities and challenges faced by hydrogen internal-combustion engines were analyzed. The progress of hydrogen internal-combustion engines on the mixture formation combustion mode emission reduction knock formation mechanism and knock suppression measures were summarized. Moreover possible technical measures for hydrogen internal-combustion engines to achieve higher efficiency and lower emissions were suggested.
The Role of Synthetic Fuels for a Carbon Neutral Economy
Apr 2017
Publication
Fossil fuels depletion and increasing environmental impacts arising from their use call for seeking growing supplies from renewable and nuclear primary energy sources. However it is necessary to simultaneously attend to both the electrical power needs and the specificities of the transport and industrial sector requirements. A major question posed by the shift away from traditional fossil fuels towards renewable energy sources lies in matching the power demand with the daily and seasonal oscillation and the intermittency of these natural energy fluxes. Huge energy storage requirements become necessary or otherwise the decline of the power factor of both the renewable and conventional generation would mean loss of resources. On the other hand liquid and gaseous fuels for which there is vast storage and distribution capacity available appear essential to supply the transport sector for a very long time ahead besides their domestic and industrial roles. Within this context the present assessment suggests that proven technologies and sound tested principles are available to develop an integrated energy system relying on synthetic fuels. These would incorporate carbon capture and utilization in a closed carbon cycle progressively relying mostly on solar and/or nuclear primary sources providing both electric power and gaseous/liquid hydrocarbon fuels having ample storage capacity and able to timely satisfy all forms of energy demand. The principles and means are already available to develop a carbon-neutral synthetic fuel economy.
Global Trade of Hydrogen: What is the Best Way to Transfer Hydrogen Over Long Distances?
Aug 2022
Publication
As a manufactured fuel hydrogen can be produced in a decentralized way in most countries around the world. This means even in a net zero economy the global trade of hydrogen could look quite different to the current international trade in fossil fuels including natural gas. With further declines in the costs of renewable electricity and electrolyzers regions which have lower cost renewable electricity may develop an economic advantage in the production of low-cost hydrogen but for hydrogen to become a globally traded commodity the cost of imports needs to be lower than the cost of domestic production. Unlike oil or natural gas transporting hydrogen over long distances is not an easy task. Hydrogen liquefaction is an extremely energy-intensive process while maintaining the low temperature required for long-distance transportation and storage purposes results in additional energy losses and accompanying costs. The upside is that hydrogen can be converted into multiple carriers that have a higher energy density and higher transport capacity and can potentially be cheaper to transport over long distances. Among the substances currently identified as potential hydrogen carriers suitable for marine shipping liquid ammonia the so-called ‘liquid organic hydrogen carriers’ in general (toluene-methylcyclohexane (MCH) in particular) and methanol have received the most attention in recent years. This paper compares the key techno-economic characteristics of these potential carriers with that of liquified hydrogen in order to develop a better understanding of the ways in which hydrogen could be transported overseas in an efficient manner. The paper also discusses other factors beyond techno-economic features that may affect the choice of optimum hydrogen carrier for long distance transport as well as the global trade of hydrogen.
Improved Hydrogen-Production-Based Power Management Control of a Wind Turbine Conversion System Coupled with Multistack Proton Exchange Membrane Electrolyzers
Mar 2020
Publication
This paper deals with two main issues regarding the specific energy consumption in an electrolyzer (i.e. the Faraday efficiency and the converter topology). The first aspect is addressed using a multistack configuration of proton exchange membrane (PEM) electrolyzers supplied by a wind turbine conversion system (WTCS). This approach is based on the modeling of the wind turbine and the electrolyzers. The WTCS and the electrolyzers are interfaced through a stacked interleaved DC–DC buck converter (SIBC) due to its benefits for this application in terms of the output current ripple and reliability. This converter is controlled so that it can offer dynamic behavior that is faster than the wind turbine avoiding overvoltage during transients which could damage the PEM electrolyzers. The SIBC is designed to be connected in array configuration (i.e. parallel architecture) so that each converter operates at its maximum efficiency. To assess the performance of the power management strategy experimental tests were carried out. The reported results demonstrate the correct behavior of the system during transient operation.
Goal and Scope in Life Cycle Sustainability Analysis: The Case of Hydrogen Production from Biomass
Aug 2014
Publication
The framework for life cycle sustainability analysis (LCSA) developed within the project CALCAS (Co-ordination Action for innovation in Life-Cycle Analysis for Sustainability) is introducing a truly integrated approach for sustainability studies. However it needs to be further conceptually refined and to be made operational. In particular one of the gaps still hindering the adoption of integrated analytic tools for sustainability studies is the lack of a clear link between the goal and scope definition and the modeling phase. This paper presents an approach to structure the goal and scope phase of LCSA so as to identify the relevant mechanisms to be further detailed and analyzed in the modeling phase. The approach is illustrated with an on-going study on a new technology for the production of high purity hydrogen from biomass to be used in automotive fuel cells.
Top Level Design and Evaluation of Advanced Low/zero Carbon Fuel Ships Power Technology
Oct 2022
Publication
The greenhouse effect has always been a problem troubling various country many fields have made corresponding technological improvements and regulations and the shipping industry is no exception. In the shipping field governments are actively looking for viable low-carbon/zero-carbon alternative fuels to reduce their dependence on traditional fossil fuels. This paper discusses the challenges and opportunities of replacing fuel oil with clean energies. Firstly the alternative fuels that have been proposed frequently and widely in recent years are summarized and their sources adaptive power systems and relationships among fuels are systematically summarized. Secondly when evaluating the advantages and future development trends of each energy the environmental economic and safety factors are digitally quantified. Results show that the analysis focuses on the efficiency and economics of carbon reduction. Hydrogen ammonia and nuclear energy show advantages in environmental quantification factors while LNG biofuels and alcohols show benefits in economic quantification factors considering calorific value and fuel price and LNG and alcohols received high scores in safety assessment. Finally the study predicts the evolution and development trend of ship fuels in the future and evaluates the most suitable energy for ship development in different periods.
Climate Impact Reduction Potentials of Synthetic Kerosene and Green Hydrogen Powered Mid-Range Aircraft Concepts
Jun 2022
Publication
One of aviation’s major challenges for the upcoming decades is the reduction in its climate impact. As synthetic kerosene and green hydrogen are two promising candidates their potentials in decreasing the climate impact is investigated for the mid-range segment. Evolutionary advancements for 2040 are applied first with an conventional and second with an advanced low-NOx and low-soot combustion chamber. Experts and methods from all relevant disciplines are involved starting from combustion turbofan engine overall aircraft design fleet level and climate impact assessment allowing a sophisticated and holistic evaluation. The main takeaway is that both energy carriers have the potential to strongly reduce the fleet level climate impact by more than 75% compared with the reference. Applying a flight-level constraint of 290 and a cruise Mach number of 0.75 causing 5% higher average Direct Operating Costs (DOC) the reduction is even more than 85%. The main levers to achieve this are the advanced combustion chamber an efficient contrail avoidance strategy in this case a pure flight-level constraint and the use of CO2 neutral energy carrier in a descending priority order. Although vehicle efficiency gains only lead to rather low impact reduction they are very important to compensate the increased costs of synthetic fuels or green hydrogen.
Hydrogen–Natural Gas Blending in Distribution Systems—An Energy, Economic, and Environmental Assessment
Aug 2022
Publication
Taking into account the international policies in the field of environmental protection in the world in general and in the European Union in particular the reduction of greenhouse gas (GHG) emissions and primarily of carbon dioxide has become one of the most important objectives. This can be obtained through various renewable energy sources and non-polluting technologies such as the mixing of hydrogen and natural gas. Combining hydrogen with natural gas is an emerging trend in the energy industry and represents one of the most important changes in the efforts to achieve extensive decarbonisation. The importance of this article consists of carrying out a techno-economic study based on the simulation of annual consumptions regarding the construction and use of production capacities for hydrogen to be used in mixtures with natural gas in various percentages in the distribution network of an important operator in Romania. In order to obtain relevant results natural gas was treated as a mixture of real gases with a known composition as defined in the chromatographic bulletin. The survey presents a case study for the injection of 5% 10% and 20% hydrogen in the natural gas distribution system of Bucharest the largest city in Romania. In addition to conducting this techno-economic study the implications for final consumers of this technical solution in reducing greenhouse gas emissions—mainly those of carbon dioxide from combustion—are also presented.
Hydrogen Production Possibility using Mongolian Renewable Energy
Jan 2019
Publication
There is widespread popular support for using renewable energy particularly solar and wind energy which provide electricity without giving rise to any carbon dioxide emissions. Harnessing these for electricity depends on the cost and efficiency of the technology which is constantly improving thus reducing costs per peak kilowatt and per kWh. Utilizing solar and wind-generated electricity in a stand-alone system requires corresponding battery or other storage capacity. The possibility of large-scale use of hydrogen in the future as a transport fuel increases the potential for both renewables and base-load electricity supply.
Dynamic Electric Simulation Model of a Proton Exchange Membrane Electrolyzer System for Hydrogen Production
Sep 2022
Publication
An energy storage system based on a Proton Exchange Membrane (PEM) electrolyzer system which could be managed by a nanoGrid for Home Applications (nGfHA) is able to convert the surplus of electric energy produced by renewable sources into hydrogen which can be stored in pressurized tanks. The PEM electrolyzer system must be able to operate at variable feeding power for converting all the surplus of renewable electric energy into hydrogen in reasonable time. In this article the dynamic electric simulation model of a PEM electrolyzer system with its pressurized hydrogen tanks is developed in a proper calculation environment. Through the calculation code the stack voltage and current peaks to a supply power variation from the minimum value (about 56 W) to the maximum value (about 440 W) are controlled and zeroed to preserve the stack the best range of the operating stack current is evaluated and hydrogen production is monitored.
The Impact of Fuel Cell Electric Freight Vehicles on Fuel Consumption and CO2 Emissions: The Case of Italy
Oct 2022
Publication
The Italian Recovery and Resilience Plan promotes among its many actions the use of hydrogen by the deployment of refuelling stations for heavy-duty vehicles predicting a 5–7% penetration rate of fuel cell electric vehicles (FCEVs) for long-distance freight transport. In this work the impact of this action on the reduction of greenhouse gas emissions and consumption was estimated assuming the plan’s objectives are met. To achieve this aim a national simulation model of the road freight transport system was implemented consisting of a graph of the national road network and an inter-provincial origin-destination matrix; the graph was based on data available from OpenStreetMap while the interprovincial matrix was estimated from the interregional matrix with the use of two linear regression models one for emitted goods and one for attracted goods. The simulation of the system made it possible to estimate the impact of this action on CO2 emissions and fuel consumption under three different scenarios. From 2025 to 2040 a reduction in CO2 emissions ranging from around 9 to around 16.5 million tonnes was estimated and a reduction in consumption ranging from around 3 billion to around 5.6 billion litres of diesel. These results show how this action can be seen as one of the bricks contributing to the fight against global warming.
Heat in Buildings Strategy: Achieving Net Zero Emissions in Scotland's Buildings
Oct 2021
Publication
Sets out our vision for the future of heat in buildings and the actions we are taking in the buildings sector to deliver our climate change commitments maximise economic opportunities and ensure a just transition including helping address fuel poverty.
A New Model for Constant Fuel Utilization and Constant Fuel Flow in Fuel Cells
Mar 2019
Publication
This paper presents a new model of fuel cells for two different modes of operation: constant fuel utilization control (constant stoichiometry condition) and constant fuel flow control (constant flow rate condition). The model solves the long-standing problem of mixing reversible and irreversible potentials (equilibrium and non-equilibrium states) in the Nernst voltage expression. Specifically a Nernstian gain term is introduced for the constant fuel utilization condition and it is shown that the Nernstian gain is an irreversibility in the computation of the output voltage of the fuel cell. A Nernstian loss term accounts for an irreversibility for the constant fuel flow operation. Simulation results are presented. The model has been validated against experimental data from the literature.
Techno-Economic Evaluation of Hydrogen Production via Gasification of Vacuum Residue Integrated with Dry Methane Reforming
Dec 2021
Publication
The continuous rise of global carbon emissions demands the utilization of fossil fuels in a sustainable way. Owing to various forms of emissions our environment conditions might be affected necessitating more focus of scientists and researchers to upgrade oil processing to more efficient manner. Gasification is a potential technology that can convert fossil fuels to produce clean and environmentally friendly hydrogen fuel in an economical manner. Therefore this study analyzed and examined it critically. In this study two different routes for the production of high-purity hydrogen from vacuum residue while minimizing the carbon emissions were proposed. The first route (Case I) studied the gasification of heavy vacuum residue (VR) in series with dry methane reforming (DMR). The second route studied the gasification of VR in parallel integration with DMR (Case II). After investigating both processes a brief comparison was made between the two routes of hydrogen production in terms of their CO2 emissions energy efficiency energy consumption and environmental and economic impacts. In this study the two vacuum-residue-to-hydrogen (VRTH) processes were simulated using Aspen Plus for a hydrogen production capacity of 50 t/h with 99.9 wt.% purity. The results showed that Case II offered a process energy efficiency of 57.8% which was slightly higher than that of Case I. The unit cost of the hydrogen product for Case II was USD 15.95 per metric ton of hydrogen which was almost 9% lower than that of Case I. In terms of the environmental analysis both cases had comparably low carbon emissions of around 8.3 kg of CO2/kg of hydrogen produced; with such high purity the hydrogen could be used for production of other products further downstream or for industrial applications.
Development of a Flashback Correlation for Burner-stabilized Hydrogen-air Premixed Flames
Feb 2022
Publication
With a growing need for replacing fossil fuels with cleaner alternatives hydrogen has emerged as a viable candidate for providing heat and power. However stable and safe combustion of hydrogen is not simple and as such a number of key issues have been identified that need to be understood for a safe design of combustion chambers. One such issue is the higher propensity of hydrogen flames to flashback compared to that for methane flames. The flashback problem is coupled with higher burner temperatures that could cause strong thermal stresses in burners and could hinder their performance. In order to systematically investigate flashback in premixed hydrogen-air flames for finding a global flashback criteria in this study we use numerical simulations as a basic tool to study flashback limits of slit burners. Flashback limits are found for varying geometrical parameters and equivalence ratios and the sensitivity of each parameter on the flashback limit and burner temperatures are identified and analyzed. It is shown that the conventional flashback correlation with critical velocity gradient does not collapse the flashback data as it does not take into account stretch induced preferential diffusion effects. A new Karlovitz number definition is introduced with physical insights that collapses the flashback data at all tested conditions in an excellent manner.
Hydrogen Research: Technology First, Society Second?
Jul 2021
Publication
Hydrogen futures are in the making right in front of our eyes and will determine socio-ecological path dependencies for decades to come. However expertise on the societal effects of the hydrogen transition is in its infancy. Future energy research needs to include the social sciences humanities and interdisciplinary studies: energy cultures have to be examined as well as power relations and anticipation processes since the need for (green) hydrogen is likely to require a massive expansion of renewable energy plants.
Towards Net-zero Compatible Hydrogen from Steam Reformation - Techno-economic Analysis of Process Design Options
Dec 2022
Publication
Increased consumption of low-carbon hydrogen is prominent in the decarbonisation strategies of many jurisdictions. Yet prior studies assessing the current most prevalent production method steam reformation of natural gas (SRNG) have not sufficiently evaluated how process design decisions affect life cycle greenhouse gas (GHG) emissions. This techno-economic case study assesses cradle-to-gate emissions of hydrogen produced from SRNG with CO2 capture and storage (CCS) in British Columbia Canada. Four process configurations with amine-based CCS using existing technology and novel process designs are evaluated. We find that cradle-to-gate GHG emission intensity ranges from 0.7 to 2.7 kgCO2e/kgH2 – significantly lower than previous studies of SRNG with CCS and similar to the range of published estimates for hydrogen produced from renewable-powered electrolysis. The levelized cost of hydrogen (LCOH) in this study (US$1.1–1.3/kgH2) is significantly lower than published estimates for renewable-powered electrolysis.
Low Carbon Scenario Analysis of a Hydrogen-Based Energy Transition for On-Road Transportation in California
Nov 2021
Publication
Fuel cell electric vehicles (FCEV) are emerging as one of the prominent zero emission vehicle technologies. This study follows a deterministic modeling approach to project two scenarios of FCEV adoption and the resulting hydrogen demand (low and high) up to 2050 in California using a transportation transition model. The study then estimates the number of hydrogen production and refueling facilities required to meet demand. The impact of system scale-up and learning rates on hydrogen price is evaluated using standalone supply chain models: H2A HDSAM HRSAM and HDRSAM. A sensitivity analysis explores key factors that affect hydrogen prices. In the high scenario light and heavy-duty fuel cell vehicle stocks reach 12.5 million and 1 million by 2050 respectively. The resulting annual hydrogen demand is 3.9 billion kg making hydrogen the dominant transportation fuel. Satisfying such high future demands will require rapid increases in infrastructure investments starting now but especially after 2030 when there is an exponential increase in the number of production plants and refueling stations. In the long term electrolytic hydrogen delivered using dedicated hydrogen pipelines to larger stations offers substantial cost savings. Feedstock prices size of the hydrogen market and station utilization are the prominent parameters that affect hydrogen price.
Going Offshore or Not: Where to Generate Hydrogen in Future Integrated Energy Systems?
Jan 2023
Publication
Hydrogen can be key in the energy system transition. We investigate the role of offshore hydrogen generation in a future integrated energy system. By performing energy system optimisation in a model application of the Northern-central European energy system and the North Sea offshore grid towards 2050 we find that offshore hydrogen generation may likely only play a limited role and that offshore wind energy has higher value when sent to shore in the form of electricity. Forcing all hydrogen generation offshore would lead to increased energy system costs. Under the assumed scenario conditions which result in deep decarbonisation of the energy system towards 2050 hydrogen generation – both onshore and offshore – follows solar PV generation patterns. Combined with hydrogen storage this is the most cost-effective solution to satisfy future hydrogen demand. Overall we find that the role of future offshore hydrogen generation should not simply be derived from minimising costs for the offshore sub-system but by also considering the economic value that such generation would create for the whole integrated energy system. We find as a no-regret option to enable and promote the integration of offshore wind in onshore energy markets via electrical connections.
Development and Comparison of the Test Methods Proposed in the Chinese Test Specifications for Fuel Cell Electric Vehicles
Feb 2022
Publication
Fuel cell electric vehicles are generally considered to have broad development prospects due to their high efficiency and zero emissions. The governments of the United States Japan the European Union and China are taking action to promote the development of the industry. In 2020 China launched a fuel cell electric vehicle demonstration project and there will be 30∼50 thousand FCEVs included in this project by the end of 2025. How to standardize the consistency of data and develop a unified and accurate evaluation method is an important topic. The difficulty is how to keep balance among scientificity neutrality and feasibility in the evaluation method. In order to evaluate the performance of vehicles in demonstration operation projects China has issued the "Fuel Cell Electric Vehicle Test Specifications" which is an important guide for the future development of fuel cell electric vehicles in China. This paper compares the test methods for critical parameters in this specifications with those used in the United States and Japan. It explains China’s technical considerations in detail including fuel cell system rated power the volume power density of the fuel cell stack fuel cell system specific power fuel cell system sub-zero cold start and fuel cell electric vehicle range contributed by hydrogen. For the volume power density of the fuel cell stack as an example both the US Department of Energy and Japan’s New Energy and Industrial Technology Development Organization have proposed technical goals. However the lack of specific and detailed test methods has confused the industry. We propose a new test method using bipolar plate measurement based on scientificity feasibility and neutrality This is the first time to define the measuring method of the volume and specific power density of the fuel cell stack. For sub-zero cold start we put forward a feasible scheme for sub-zero cold start at the system level. For range contributed by hydrogen we propose a new test method that can distinguish the contributing of electric and hydrogen energy. Furthermore a hydrogen-to-electric conversion formula is proposed to calculate the equivalent hydrogen consumption which makes it possible to compare the energy consumption between plug-in and non-plug-in vehicles. At the same time this approach is significant in helping fuel cell-related enterprises to understand the formulation of China’s “Fuel Cell Electric Vehicle Test Specifications”. It should also be helpful for guiding product design and predicting fuel cell electric vehicle policy direction in China.
Techno-Economic Analysis of Solar Thermal Hydrogen Production in the United Arab Emirates
Oct 2022
Publication
Solar thermal technology can provide the United Arab Emirates and the Middle East region with abundant clean electricity to mitigate the rising levels of carbon dioxide and satisfy future demand. Hydrogen can play a key role in the large-scale application of solar thermal technologies such as concentrated solar plants in the region by storing the surplus electricity and exporting it to needed countries for profit placing the Middle East and the United Arab Emirates as major future green hydrogen suppliers. However a hydrogen supply chain comparison between hydrogen from CSP and other renewable under the UAE’s technical and economic conditions for hydrogen export is yet to be fully considered. Therefore in this study we provide a techno-economic analysis for well-to-ship solar hydrogen supply chain that compares CSP and PV technologies with a solid oxide water electrolyzer for hydrogen production assuming four different hydrogen delivery pathways based on the location of electrolyzer and source of electricity assuming the SOEC can be coupled to the CSP plant when placed at the same site or provided with electric heaters when placed at PV plant site or port sites. The results show that the PV plant achieves a lower levelized cost of electricity than that of the CSP plant with 5.08 ¢/kWh and 8.6 ¢/kWh respectively. Hydrogen production results show that the scenario where SOEC is coupled to the CSP plant is the most competitive scenario as it achieves the payback period in the shortest period compared to the other scenarios and also provides higher revenues and a cheaper LCOH of 7.85 $/kgH2.
A Quantitative Study of Policy-driven Changes and Forecasts in the Development of the Hydrogen Transportation Industry
Feb 2022
Publication
Through data mining and analysis of the word frequency and occurrence position of industrial policy keywords the main policy parameters affecting industrial development are determined and the functional relationship between industrial policy and industrial development is obtained through multi-parameter non-linear regression: Yit−1 (y1 y2 y3 y4 y5) = β1it X1 + β2it ln X2 + β3it ln X3 + β4it X1it ∗ ln X3 + εit . The time series function of the industrial development index: Y (t) = 0.174 ∗ e (0.256∗t) is established and the industrial development under the influence of next year’s policy is predicted. It is concluded from the mathematical expression of the statistical model that there is a certain coupling effect between different policies and that industrial development is influenced by the joint effect on the parent and sub-industries. This ultimately proves that there is a clear correlation between policy and industry development.
Strategies for Hydrogen-Enriched Methane Flameless Combustion in a Quasi-Industrial Furnace
Jan 2020
Publication
In this present work simulations of 20 kW furnace were carried out with hydrogenenriched methane mixtures to identify optimal geometrical configurations and operating conditions to operate in flameless combustion regime. The objective of this work is to show the advantages of flameless combustion for hydrogen-enriched fuels and the limits of current typical industrial designs for these mixtures. The performances of a semi-industrial combustion chamber equipped with a self-recuperative flameless burner are evaluated with increasing H2 concentrations. For highly H2-enriched mixtures typical burners employed for methane appear to be inadequate to reach flameless conditions. In particular for a typical coaxial injector configuration an equimolar mixture of hydrogen and methane represents the limit for hydrogen enrichment. To achieve flameless conditions different injector geometries and configuration were tested. Fuel dilution with CO2 and H2O was also investigated. Dilution slows the mixing process consequently helping the transition to flameless conditions. CO2 and H2O are typical products of hydrogen generation processes therefore their use in fuel dilution is convenient for industrial applications. Dilution thus allows the use of greater hydrogen percentages in the mixture.
Energy and Environmental Assessment of Hydrogen from Biomass Sources: Challenges and Perspectives
Aug 2022
Publication
Hydrogen is considered as one of the pillars of the European decarbonisation strategy boosting a novel concept of the energy system in line with the EU’s commitment to achieve clean energy transition and reach the European Green Deal carbon neutrality goals by 2050. Hydrogen from biomass sources can significantly contribute to integrate the renewable hydrogen supply through electrolysis at large-scale production. Specifically it can cover the non-continuous production of green hydrogen coming from solar and wind energy to offer an alternative solution to such industrial sectors necessitating of stable supply. Biomass-derived hydrogen can be produced either from thermochemical pathways (i.e. pyrolysis liquefaction and gasification) or from biological routes (i.e. direct or indirect-biophotolysis biological water–gas shift reaction photo- and dark-fermentation). The paper reviews several production pathways to produce hydrogen from biomass or biomass-derived sources (biogas liquid bio-intermediates sugars) and provides an exhaustive review of the most promising technologies towards commercialisation. While some pathways are still at low technology readiness level others such as the steam bio-methane reforming and biomass gasification are ready for an immediate market uptake. The various production pathways are evaluated in terms of energy and environmental performances highlighting the limits and barriers of the available LCA studies. The paper shows that hydrogen production technologies from biomass appears today to be an interesting option almost ready to constitute a complementing option to electrolysis.
Dynamic Modeling of a PEM Fuel Cell Power Plant for Flexibility Optimization and Grid Support
Jun 2022
Publication
The transition toward high shares of non-programmable renewable energy sources in the power grid requires an increase in the grid flexibility to guarantee grid reliability and stability. This work developed within the EU project Grasshopper identifies hydrogen Fuel Cell (FC) power plants based on low temperature PEM cells as a source of flexibility for the power grid. A dynamic numerical model of the flexible FC system is developed and tested against experimental data from a 100-kW pilot plant built within the Grasshopper project. The model is then applied to assess the flexible performance of a 1 MW system in order to optimize the scale-up of the pilot plant to the MW-size. Simulations of load-following operation show the flexibility of the plant which can ramp up and down with a ramp rate depending only on an externally imposed limit. Warm-up simulations allow proposing solutions to limit the warm-up time. Of main importance are the minimization of the water inventory in the system and the construction of a compact system which minimizes the distance between the components.
Quantitive Risk Assessment of the Model Representing Latest Japanese Hydrogen Refuelling Stations
Sep 2021
Publication
Current safety codes and technical standards related to Japanese hydrogen refueling stations (HRSs) have been established based on qualitative risk assessment and quantitative effectiveness validation of safety measures for more than ten years. In the last decade there has been significant development in the technologies and significant increment in operational experience related to HRSs. We performed a quantitative risk assessment (QRA) of the HRS model representing Japanese HRSs with the latest information in the previous study. The QRA results were obtained by summing risk contours derived from each process unit. They showed that the risk contours of 10-3 and 10-4 per year were confined within the HRS boundaries whereas those of 10-5 and 10-6 per year are still present outside the HRS boundaries. Therefore we analyzed the summation of risk contours derived from each unit and identified the largest risk scenarios outside the station. The HRS model in the previous study did not consider fire and blast protection walls which could reduce the risks outside the station. Therefore we conducted a detailed risk analysis of the identified scenarios using 3D structure modeling. The heat radiation and temperature rise of jet fire scenarios that pose the greatest risk to the physical surroundings in the HRS model were estimated in detail based on computational fluid dynamics with 3D structures including fire protection walls. Results show that the risks spreading outside the north- west- and east-side station boundaries are expected to be acceptable by incorporating the fire protection wall into the Japanese HRS model.
Strategies for the Sampling of Hydrogen at Refuelling Stations for Purity Assessment
Aug 2021
Publication
Hydrogen delivered at hydrogen refuelling station must be compliant with requirements stated in different standards which require specialized sampling device and personnel to operate it. Currently different strategies are implemented in different parts of the world and these strategies have already been used to perform 100s of hydrogen fuel sampling in USA EU and Japan. However these strategies have never been compared on a large systematic study. The purpose of this paper is to describe and compare the different strategies for sampling hydrogen at the nozzle and summarize the key aspects of all the existing hydrogen fuel sampling including discussion on material compatibility with the impurities that must be assessed. This review highlights the fact it is currently difficult to evaluate the impact or the difference these strategies would have on the hydrogen fuel quality assessment. Therefore comparative sampling studies are required to evaluate the equivalence between the different sampling strategies. This is the first step to support the standardization of hydrogen fuel sampling and to identify future research and development area for hydrogen fuel sampling.
The Potential Role of Flying Vehicles in Progressing the Energy Transition
Oct 2022
Publication
An energy transition is in progress around the globe notably led by an increase in the deployment of renewable energy and a shift toward less emissions-intense options notably in the transportation sector. This research investigates the potential role that new transportation options namely flying vehicles may play toward progressing the energy transition. As flying vehicles are a relatively new technology yet to penetrate the market it is also prudent to consider the ethical legal and social issues (ELSI) associated with their implementation alongside the potential energy and environmental impacts. Through a review of ELSI and energy and environmental literature we identify research gaps and identify how flying vehicles may impact upon the energy transition over time. Our research identifies several critical aspects of both ELSI and energy and environmental academia relevant to the future deployment of flying vehicles and describes a deployment timeline and the resultant societal outcomes. We find that flying vehicles could drive the energy transition and the hydrogen economy and that their widespread adoption could engender shared socio-environmental benefits. Our findings are relevant to transportation and environmental policymakers and identify critical considerations for the planned introduction of new shared transportation options to the market conducive to a sustainable energy transition.
Combined Hydrogen Production and Electricity Storage using a Vanadium Manganese Redox Dual-flow Battery
Aug 2021
Publication
A redox dual-flow battery is distinct from a traditional redox flow battery (RFB) in that the former includes a secondary energy platform in which the pre-charged electrolytes can be discharged in external catalytic reactors through decoupled redox-mediated hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The concept offers several advantages over conventional electrolysis in terms of safety durability modularity and purity. In this work we demonstrate a vanadium-manganese redox-flow battery in which Mn3+/Mn2+ and V3+/V2+ respectively mediate the OER and the HER in Mo2C-based and RuO2-based catalysts. The flow battery demonstrates an average energy efficiency of 68% at a current density of 50 mA ⋅ cm−2 (cell voltage = 1.92 V) and a relative energy density 45% higher than the conventional all-vanadium RFB. Both electrolytes are spontaneously discharged through redox-mediated HER and OER with a faradic efficiency close to 100%.
Everything About Hydrogen Podcast: Why the Fuel Cell World is Different This Time
Aug 2019
Publication
The fuel cell game is not new and for many it is has been a long time coming. Few know this better than Ballard Power Systems the third ever founded Fuel Cell company that has operated since the 1970s. On the show we ask Nicolas Pocard about Ballards history and why this time the market is different for fuel cell companies.
The podcast can be found on their website
The podcast can be found on their website
Thermodynamic Assessment of a Hybrid Methane Cracking System for Liquified Hydrogen Production and Enhanced Oil Recovery Using CO2
Oct 2022
Publication
Hydrogen fuel production from methane cracking is a cleaner process compared to steam methane reforming due to zero greenhouse gas emissions. Carbon black that is co-produced is valuable and can be marketed to other industries. As this is a high-temperature process using solar energy can further improve its sustainability. In this study an integrated solar methane cracking system is proposed and the efficient utilization of the hydrogen and carbon products is explored. The carbon by-product is used in a direct carbon fuel cell and oxy- combustion. These processes eliminate the need for carbon capture technologies as they produce pure CO2 exhaust streams. The CO2 produced from the systems is used for enhanced oil recovery to produce crude oil. The produced turquoise hydrogen is liquified to make it suitable for exportation. The process is simulated on Aspen Plus® and its energy and exergy efficiencies are evaluated by carrying out a detailed thermodynamic analysis. A reservoir simulation is used to study the amount of oil that can be produced using the captured CO2. The overall system is studied for oil production over 20 years and energy and exergy of efficiencies 42.18% and 40.18% respectively were found. Enhanced oil recovery improves the recovery rate from 24.8% to 64.3%.
A Statistical Assessment of Blending Hydrogen into Gas Networks
Aug 2021
Publication
The deployment of low-carbon hydrogen in gas grids comes with strategic benefits in terms of energy system integration and decarbonization. However hydrogen thermophysical properties substantially differ from natural gas and pose concerns of technical and regulatory nature. The present study investigates the blending of hydrogen into distribution gas networks focusing on the steady-state fluid dynamic response of the grids and gas quality compliance issues at increasing hydrogen admixture levels. Two blending strategies are analyzed the first of which involves the supply of NG–H2 blends at the city gate while the latter addresses the injection of pure hydrogen in internal grid locations. In contrast with traditional case-specific analyses results are derived from simulations executed over a large number (i.e. one thousand) of synthetic models of gas networks. The responses of the grids are therefore analyzed in a statistical fashion. The results highlight that lower probabilities of violating fluid dynamic and quality restrictions are obtained when hydrogen injection occurs close to or in correspondence with the system city gate. When pure hydrogen is injected in internal grid locations even very low volumes (1% vol of the total) may determine gas quality violations while fluid dynamic issues arise only in rare cases of significant hydrogen injection volumes (30% vol of the total).
Hydrogen Production Methods Based on Solar and Wind Energy: A Review
Jan 2023
Publication
Several research works have investigated the direct supply of renewable electricity to electrolysis particularly from photovoltaic (PV) and wind generator (WG) systems. Hydrogen (H2 ) production based on solar energy is considered to be the newest solution for sustainable energy. Different technologies based on solar energy which allow hydrogen production are presented to study their benefits and inconveniences. The technology of water decomposition based on renewable energy sources to produce hydrogen can be achieved by different processes (photochemical systems; photocatalysis systems photo-electrolysis systems bio-photolysis systems thermolysis systems thermochemical cycles steam electrolysis hybrid processes and concentrated solar energy systems). A comparison of the different methods for hydrogen production based on PV and WG systems was given in this study. A comparative study of different types of electrolyzers was also presented and discussed. Finally an economic assessment of green hydrogen production is given. The hydrogen production cost depends on several factors such as renewable energy sources electrolysis type weather conditions installation cost and the productivity of hydrogen per day. PV/H2 and wind/H2 systems are both suitable in remote and arid areas. Minimum maintenance is required and a power cycle is not needed to produce electricity. The concentrated CSP/H2 system needs a power cycle. The hydrogen production cost is higher if using wind/H2 rather than PV/H2 . The green energy sources are useful for multiple applications such as hydrogen production cooling systems heating and water desalination.
Hydrogen Production, Distribution, Storage and Power Conversion in a Hydrogen Economy - A Technology Review
Aug 2021
Publication
To meet ambitious targets for greenhouse gas emissions reduction in the 2035-2050 timeframe hydrogen has been identified as a clean “green” fuel of interest. In comparison to fossil fuel use the burning of hydrogen results in zero CO2 emissions and it can be obtained from renewable energy sources. In addition to zero CO2 emissions hydrogen has several other attractive properties such as higher gravimetric energy content and wider flammability limits than most fossil fuels. However there are practical limitations to its widespread use at present which include low volumetric energy density in the gaseous state and high well-to-wheel costs when compared to fossil fuel production and distribution. In this paper a review is undertaken to identify the current state of development of key areas of the hydrogen network such as production distribution storage and power conversion technology. At present high technology costs still are a barrier to widespread hydrogen adoption but it is envisioned that as scale of production increases then costs are likely to fall. Technical barriers to a hydrogen economy adoption are not as significant as one might think as key technologies in the hydrogen network are already mature with working prototypes already developed for technologies such as liquid hydrogen composite cryotanks and proton exchange membrane fuel cells. It is envisioned that with continuous investment to achieve requisite scale that a hydrogen economy could be realised sooner rather than later with novel concepts such as turboelectric distributed propulsion enabled by a shift to hydrogen-powered network.
Operation of Power-to-X-Related Processes Based on Advanced Data-Driven Methods: A Comprehensive Review
Oct 2022
Publication
This study is a systematic analysis of selected research articles about power-to-X (P2X)- related processes. The relevance of this resides in the fact that most of the world’s energy is produced using fossil fuels which has led to a huge amount of greenhouse gas emissions that are the source of global warming. One of the most supported actions against such a phenomenon is to employ renewable energy resources some of which are intermittent such as solar and wind. This brings the need for large-scale longer-period energy storage solutions. In this sense the P2X process chain could play this role: renewable energy can be converted into storable hydrogen chemicals and fuels via electrolysis and subsequent synthesis with CO2. The main contribution of this study is to provide a systematic articulation of advanced data-driven methods and latest technologies such as the Internet of Things (IoT) big data analytics and machine learning for the efficient operation of P2X-related processes. We summarize our findings into different working architectures and illustrate them with a numerical result that employs a machine learning model using historic data to define operational parameters for a given P2X process.
On-Board Cold Thermal Energy Storage System for Hydrogen Fueling Process
Feb 2019
Publication
The hydrogen storage pressure in fuel cell vehicles has been increased from 35 MPa to 70 MPa in order to accommodate longer driving range. On the downside such pressure increase results in significant temperature rise inside the hydrogen tank during fast filling at a fueling station which may pose safety issues. Installation of a chiller often mitigates this concern because it cools the hydrogen gas before its deposition into the tank. To address both the energy efficiency improvement and safety concerns this paper proposed an on-board cold thermal energy storage (CTES) system cooled by expanded hydrogen. During the driving cycle the proposed system uses an expander instead of a pressure regulator to generate additional power and cold hydrogen gas. Moreover CTES is equipped with phase change materials (PCM) to recover the cold energy of the expanded hydrogen gas which is later used in the next filling to cool the high-pressure hydrogen gas from the fueling station.
Solar Power and Energy Storage for Decarbonization of Land Transport in India
Dec 2021
Publication
By considering the weight penalty of batteries on payload and total vehicle weight this paper shows that almost all forms of land-based transport may be served by battery electric vehicles (BEV) with acceptable cost and driving range. Only long-distance road freight is unsuitable for battery electrification. The paper models the future Indian electricity grid supplied entirely by low-carbon forms of generation to quantify the additional solar PV power required to supply energy for transport. Hydrogen produced by water electrolysis for use as a fuel for road freight provides an inter-seasonal energy store that accommodates variations in renewable energy supply. The advantages and disadvantages are considered of midday electric vehicle charging vs. overnight charging considering the temporal variations in supply of renewable energy and demand for transport services. There appears to be little to choose between these two options in terms of total system costs. The result is an energy scenario for decarbonized surface transport in India based on renewable energy that is possible realistically achievable and affordable in a time frame of year 2050.
Investigation on the Effects of Blending Hydrogen-rich Gas in the Spark-ignition Engine
May 2022
Publication
In order to improve the energy efficiency of the internal combustion engine and replace fossil fuel with alternative fuels a concept of the methanol-syngas engine was proposed and the prototype was developed. Gasoline and dissociated methanol gas (GDM) were used as dual fuels and the engine performance was investigated by simulation and experiments. Dissociated methanol gas is produced by recycling the exhaust heat. The performance and combustion process was studied and compared with the gasoline engine counterpart. There is 1.9% energy efficiency improvement and 5.5% fuel consumption reduction under 2000r/min 100 N · m working condition with methanol substitution ratio of 10%. In addition the engine efficiency further improves with an increase of dissociated methanol gas substitution ratio because of the increased heating value of the fuel and effects of hydrogen. The peak pressure in the cylinder and the peak heat release rate of the GDM engine are higher than that of the original gasoline engine with a phase closer to the top dead center (TDC). Therefore blending hydrogen-rich gas in the spark-ignition engine can recycle the exhaust heat and improve the thermal efficiency of the engine.
Optimal Energy Management for Hydrogen Economy in a Hybrid Electric Vehicle
Feb 2023
Publication
Fuel cell hybrid electric vehicles (FCEVs) are mainly electrified by the fuel cell (FC) system. As a supplementary power source a battery or supercapacitor (SC) is employed (besides the FC) to enhance the power response due to the slow dynamics of the FC. Indeed the performance of the hybrid power system mainly depends on the required power distribution manner among the sources which is managed by the energy management strategy (EMS). This paper considers an FCEV based on the proton exchange membrane FC (PEMFC)/battery/SC. The energy management strategy is designed to ensure optimum power distribution between the sources considering hydrogen consumption. Its main objective is to meet the electric motor’s required power with economic hydrogen consumption and better electrical efficiency. The proposed EMS combines the external energy maximization strategy (EEMS) and the bald eagle search algorithm (BES). Simulation tests for the Extra-Urban Driving Cycle (EUDC) and New European Driving Cycle (NEDC) profiles were performed. The test is supposed to be performed in typical conditions t = 25 ◦C on a flat road without no wind effect. In addition this strategy was compared with the state machine control strategy classic PI and equivalent consumption minimization strategy. In terms of optimization the proposed approach was compared with the original EEMS particle swarm optimization (PSO)-based EEMS and equilibrium optimizer (EO)-based EEMS. The results confirm the ability of the proposed strategy to reduce fuel consumption and enhance system efficiency. This strategy provides 26.36% for NEDC and 11.35% for EUDC fuel-saving and efficiency enhancement by 6.74% for NEDC and 36.19% for EUDC.
Boron Hydrogen Compounds: Hydrogen Storage and Battery Applications
Dec 2021
Publication
About 25 years ago Bogdanovic and Schwickardi (B. Bogdanovic M. Schwickardi: J. Alloys Compd. 1–9 253 (1997) discovered the catalyzed release of hydrogen from NaAlH4 . This discovery stimulated a vast research effort on light hydrides as hydrogen storage materials in particular boron hydrogen compounds. Mg(BH4 )2 with a hydrogen content of 14.9 wt % has been extensively studied and recent results shed new light on intermediate species formed during dehydrogenation. The chemistry of B3H8 − which is an important intermediate between BH4 − and B12H12 2− is presented in detail. The discovery of high ionic conductivity in the high-temperature phases of LiBH4 and Na2B12H12 opened a new research direction. The high chemical and electrochemical stability of closo-hydroborates has stimulated new research for their applications in batteries. Very recently an all-solid-state 4 V Na battery prototype using a Na4 (CB11H12)2 (B12H12) solid electrolyte has been demonstrated. In this review we present the current knowledge of possible reaction pathways involved in the successive hydrogen release reactions from BH4 − to B12H12 2− and a discussion of relevant necessary properties for high-ionic-conduction materials.
Water Electrolysis and Hydrogen in the European Union
Nov 2022
Publication
Renewable and low carbon hydrogen is both an energy carrier able to produce other fuels and downstream products such as the e-fuels or e-ammonia and a decarbonised gas produced through renewable electricity. It has the potential to decarbonise hard to abate sectors which are difficult to directly electrify and play a crucial role in achieving net zero emissions target in 2050. The European Commission has recently outlined the policy context and necessary actions for the development and deployment of renewable and low carbon hydrogen within the 2030 time horizon with the Hydrogen Strategy for a Climate Neutral Europe Communication (the Hydrogen Strategy). The REPowerEU Communication4 has further addressed the joint EU and Member State actions needed in the context of the crisis triggered by the invasion of Ukraine in February 2022 and the necessity to phase out dependence on Russian supplies. The EC has strengthened the policy narrative around hydrogen and increased objectives for a pan European framework accelerating and upscaling the production of RES and low-carbon hydrogen. The main objectives and actions of the REPowerEU Plan which build on the Hydrogen Strategy are the deployment of several tens of GW of electrolyser capacity and the production and imports of 10 Mt and 10 Mt respectively of renewable hydrogen by 2030. Currently the most mature and promising green hydrogen production technology is water electrolysis. The main technologies5 considered in this report are: Alkaline electrolysis Polymer Exchange Membrane (PEM) electrolysis Solid Oxide electrolysis and Anion Exchange Membrane electrolysers (AEM).
An Evaluation of Turbocharging and Supercharging Options for High-Efficiency Fuel Cell Electric Vehicles
Dec 2018
Publication
Mass-produced off-the-shelf automotive air compressors cannot be directly used for boosting a fuel cell vehicle (FCV) application in the same way that they are used in internal combustion engines since the requirements are different. These include a high pressure ratio a low mass flow rate a high efficiency requirement and a compact size. From the established fuel cell types the most promising for application in passenger cars or light commercial vehicle applications is the proton exchange membrane fuel cell (PEMFC) operating at around 80 ◦C. In this case an electric-assisted turbocharger (E-turbocharger) and electric supercharger (single or two-stage) are more suitable than screw and scroll compressors. In order to determine which type of these boosting options is the most suitable for FCV application and assess their individual merits a co-simulation of FCV powertrains between GT-SUITE and MATLAB/SIMULINK is realised to compare vehicle performance on the Worldwide Harmonised Light Vehicle Test Procedure (WLTP) driving cycle. The results showed that the vehicle equipped with an E-turbocharger had higher performance than the vehicle equipped with a two-stage compressor in the aspects of electric system efficiency (+1.6%) and driving range (+3.7%); however for the same maximal output power the vehicle’s stack was 12.5% heavier and larger. Then due to the existence of the turbine the E-turbocharger led to higher performance than the single-stage compressor for the same stack size. The solid oxide fuel cell is also promising for transportation application especially for a use as range extender. The results show that a 24-kWh electric vehicle can increase its driving range by 252% due to a 5 kW solid oxide fuel cell (SOFC) stack and a gas turbine recovery system. The WLTP driving range depends on the charge cycle but with a pure hydrogen tank of 6.2 kg the vehicle can reach more than 600 km.
Scientific Assessment in Support of the Materials Roadmap enabling Low Carbon Energy Technologies Hydrogen and Fuel Cells
Apr 2014
Publication
A group experts from European research organisations and industry have assessed the state of the art and future needs for materials' R&D for hydrogen and fuel cell technologies. The work was performed as input to the European Commission's roadmapping exercise on materials for the European Strategic Energy Technology Plan. The report summarises the results including key targets identified for medium term (2020/2030) and long term (2050) timescales.
Roadmap Towards Zero Emissions, BEVs and FCEVs
Oct 2021
Publication
A “combined world” of fuel cell electric vehicles (FCEVs) and battery electric vehicles (BEVs) will create a greener transportation sector faster and cheaper than one of the solutions alone. Hydrogen Council with analytical support from McKinsey and Company published a report that highlights the complementary roles of FCEVs and BEVs in a decarbonised transportation sector.
The analysis found that each solution has comparable systemic efficiencies and similar CO2 life cycle intensity. From the vehicle user perspective FCEVs and BEVs will provide the flexibility and convenience to meet their specific context of use and geographic location. Additionally the costs of two supporting infrastructure for FCEVs and BEVs is cheaper than one infrastructure network primarily due to the reduced peak loads and avoidance of costly upgrades on the electricity grid. The report’s messages were developed in dialogue with the Observatory Group which consisted of representatives of government agencies and academia as well as associations and companies active in sectors like regenerative electricity generation electricity grid equipment manufacturing electric vehicle charging fleet management.
The paper can be found on their website.
The analysis found that each solution has comparable systemic efficiencies and similar CO2 life cycle intensity. From the vehicle user perspective FCEVs and BEVs will provide the flexibility and convenience to meet their specific context of use and geographic location. Additionally the costs of two supporting infrastructure for FCEVs and BEVs is cheaper than one infrastructure network primarily due to the reduced peak loads and avoidance of costly upgrades on the electricity grid. The report’s messages were developed in dialogue with the Observatory Group which consisted of representatives of government agencies and academia as well as associations and companies active in sectors like regenerative electricity generation electricity grid equipment manufacturing electric vehicle charging fleet management.
The paper can be found on their website.
Hydrogen Storage Assessment in Depleted Oil Reservoir and Saline Aquifer
Oct 2022
Publication
Hydrogen (H2 ) is an attractive energy carrier to move store and deliver energy in a form that can be easily used. Field proven technology for underground hydrogen storage (UHS) is essential for a successful hydrogen economy. Options for this are manmade caverns salt domes/caverns saline aquifers and depleted oil/gas fields where large quantities of gaseous hydrogen have been stored in caverns for many years. The key requirements intrinsic of a porous rock formation for seasonal storage of hydrogen are: adequate capacity ability to contain H2 capability to inject/extract high volumes of H2 and a reliable caprock to prevent leakage. We have carefully evaluated a commercial non-isothermal compositional gas reservoir simulator and its suitability for hydrogen storage and withdrawal from saline aquifers and depleted oil/gas reservoirs. We have successfully calibrated the gas equation of state model against published laboratory H2 density and viscosity data as a function of pressure and temperature. Comparisons between the H2 natural gas and CO2 storage in real field models were also performed. Our numerical models demonstrated more lateral spread of the H2 when compared to CO2 and natural gas with a need for special containment in H2 projects. It was also observed that the experience with CO2 and natural gas storage cannot be simply replicated with H2 .
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