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Forecasting the Development of Clean Energy Vehicles in Large Cities: A System Dynamics Perspective
Jan 2024
Publication
Clean energy vehicles (CEVs) e.g. battery electric vehicles (BEVs) and fuel cell electric vehicles (FCEVs) are being adopted gradually to substitute for internal combustion engine vehicles (ICEVs) around the world. The fueling infrastructure is one of the key drivers for the development of the CEV market. When the government develops funding policies to support the fueling infrastructure development for FCEVs and BEVs it has to assess the effectiveness of different policy options and identify the optimal policy combination which is very challenging in transportation research. In this paper we develop a system dynamics model to study the feedback mechanism between the fueling infrastructure funding policies and the medium- to long-term diffusion of FCEVs and BEVs and the competition between FCEVs and BEVs based on relevant policy and market data in Guangzhou China. The results of the modeling analysis are as follows. (1) Funding hydrogen refueling stations and public charging piles has positive implications for achieving the substitution of CEVs for ICEVs. (2) Adjusting the funding ratio of hydrogen refueling stations and public charging piles or increasing the funding budget and extending the funding cycle does not have a significant impact on the overall substitution of CEVs for ICEVs but only impacts the relative competitive advantage between FCEVs and BEVs. (3) An equal share of funding for hydrogen refueling stations and public charging piles would have better strategic value for future net-zero-emissions urban transportation. (4) Making a moderate-level full investment in hydrogen refueling stations coupled with hydrogen refueling subsidies can provide the ideal conditions for FCEV diffusion.
Solar-driven (Photo)electrochemical Devices for Green Hydrogen Production and Storage: Working Principles and Design
Feb 2024
Publication
The large-scale deployment of technologies that enable energy from renewables is essential for a successful transition to a carbon-neutral future. While photovoltaic panels are one of the main technologies commonly used for harvesting energy from the Sun storage of renewable solar energy still presents some challenges and often requires integration with additional devices. It is believed that hydrogen – being a perfect energy carrier – can become one of the broadly utilised storage alternatives that would effectively mitigate the energy supply and demand issues associated with the intermittent nature of renewable energy sources. Current pathways in the development of green technologies indicate the need for more sustainable material utilisation and more efficient device operation. To address this requirement integration of various technologies for renewable energy harvesting conversion and storage in a single device appears as an advantageous option. From the hydrogen economy perspective systems driven by green solar electricity that allow for (photo)electrochemical water splitting would generate hydrogen with the minimal CO2 footprint. If at the same time one of the device electrodes could store the generated gas and release it on demand the utilisation of critical and often costly elements would be reduced with possible gain in more effective device operation. Although conceptually attractive this cross-disciplinary concept has not gained yet enough attention and only limited number of experimental setups have been designed tested and reported. This review presents the first exhaustive overview and critical examination of various laboratory-scale prototype setups that attempt to combine both the hydrogen production and storage processes in a single unit via integration of a metal hydride-based electrode into a photoelectrochemical cell. The architectures of presented configurations enables direct solar energy to hydrogen conversion and its subsequent storage in a single device which – in some cases – can also release the stored (hydrogen) energy on demand. In addition this work explores perspectives and challenges related with the potential upscaling of reviewed solar-to-hydrogen storage systems trying to map and indicate the main future directions of their technological development and optimization. Finally the review also combines information and expertise scattered among various research fields with the aim of stimulating much-needed exchange of knowledge to accelerate the progress in the development and deployment of optimum green hydrogen-based solutions.
Sustainable E-Fuels: Green Hydrogen, Methanol and Ammonia for Carbon-Neutral Transportation
Dec 2023
Publication
Increasingly stringent sustainability and decarbonization objectives drive investments in adopting environmentally friendly low and zero-carbon fuels. This study presents a comparative framework of green hydrogen green ammonia and green methanol production and application in a clear context. By harnessing publicly available data sources including from the literature this research delves into the evaluation of green fuels. Building on these insights this study outlines the production process application and strategic pathways to transition into a greener economy by 2050. This envisioned transformation unfolds in three progressive steps: the utilization of green hydrogen green ammonia and green methanol as a sustainable fuel source for transport applications; the integration of these green fuels in industries; and the establishment of mechanisms for achieving the net zero. However this research also reveals the formidable challenges of producing green hydrogen green ammonia and green methanol. These challenges encompass technological intricacies economic barriers societal considerations and far-reaching policy implications necessitating collaborative efforts and innovative solutions to successfully develop and deploy green hydrogen green ammonia and green methanol. The findings unequivocally demonstrate that renewable energy sources play a pivotal role in enabling the production of these green fuels positioning the global transition in the landscape of sustainable energy.
Look-ahead Scheduling of Energy-Water Nexus Integrated with Power2X Conversion Technologies under Multiple Uncertainties
Aug 2023
Publication
Co-optimizing energy and water resources in a microgrid can increase efficiency and improve economic performance. Energy-water storage (EWS) devices are crucial components of a high-efficient energy-water microgrid (EWMG). The state of charge (SoC) at the end of the first day of operation is one of the most significant variables in EWS devices since it is used as a parameter to indicate the starting SoC for the second day which influences the operating cost for the second day. Hence this paper examines the benefits and applicability of a lookahead optimization strategy for an EWMG integrated with multi-type energy conversion technologies and multienergy demand response to supply various energy-water demands related to electric/hydrogen vehicles and commercial/residential buildings with the lowest cost for two consecutive days. In addition a hybrid info-gap/robust optimization technique is applied to cover uncertainties in photovoltaic power and electricity prices as a tri-level optimization framework without generating scenarios and using the probability distribution functions. Duality theory is also used to convert the problem into a single-level MILP so that it can be solved by CPLEX. According to the findings the implemented energy-water storage systems and look-ahead strategy accounted for respectively 4.03% and 0.43% reduction in the total cost.
Phasing Out Steam Methane Reformers with Water Electrolysis in Producing Renewable Hydrogen and Ammonia: A Case Study Based on the Spanish Energy Markets
Jul 2023
Publication
Deploying renewable hydrogen presents a significant challenge in accessing off-takers who are willing to make long-term investments. To address this challenge current projects focus on large-scale deployment to replace the demand for non-renewable hydrogen particularly in ammonia synthesis for fertiliser production plants. The traditional process involving Steam Methane Reformers (SMR) connected to Haber-Bosch synthesis could potentially transition towards decarbonisation by gradually integrating water electrolysis. However the coexistence of these processes poses limitations in accommodating the integration of renewable hydrogen thereby creating operational challenges for industrial hubs. To tackle this issue this paper proposes an optimal dispatch model for producing green hydrogen and ammonia while considering the coexistence of different processes. Furthermore the objective is to analyse external factors that could determine the appropriate regulatory and pricing framework to facilitate the phase-out of SMR in favour of renewable hydrogen production. The paper presents a case study based in Spain utilising data from 2018 2022 and 2030 perspectives on the country's renewable resources gas and electricity wholesale markets pricing ranges and regulatory constraints to validate the model. The findings indicate that carbon emissions taxation and the availability and pricing of Power Purchase Agreements (PPAs) will play crucial roles in this transition - the carbon emission price required for total phasing out SMR with water electrolysis would be around 550 EUR/ton CO2.
Blending Hydrogen in Existing Natural Gas Pipelines: Integrity Consequences from a Fitness for Service Perspective
Jun 2023
Publication
Blending hydrogen in existing natural gas pipelines compromises steel integrity because it increases fatigue crack growth promotes subcritical cracking and decreases fracture toughness. In this regard several laboratories reported that the fracture toughness measured in a hydrogen containing gaseous atmosphere KIH can be 50% or less than KIC the fracture toughness measured in air. From a pipeline integrity perspective fracture mechanics predicts that injecting hydrogen in a natural gas pipeline decreases the failure pressure and the size of the critical flaw at a given pressure level. For a pipeline with a given flaw size as shown in this work the effect of hydrogen embrittlement (HE) in the predicted failure pressure is largest when failure occurs by brittle fracture. The HE effect on failure pressure diminishes with a decreasing crack size or increasing fracture toughness. The safety margin after a successful hydrostatic test is reduced and therefore the time between hydrotests should be decreased. In this work all those effects were quantified using a crack assessment methodology (level 2 API 579-ASME FFS) considering literature values for KIH and KIC reported for an API 5L X52 pipeline steel. To characterize different scenarios various crack sizes were assumed including a small crack with a size close to the detection limit of current in-line inspection techniques and a larger crack that represents the largest crack size that could survive a hydrotest to 100% of the steel specified minimum yield stress. The implications of a smaller failure pressure and smaller critical crack size on pipeline integrity are discussed in this paper.
Green Hydrogen as a Clean Energy Resource and Its Applications as an Engine Fuel
Jan 2024
Publication
The world’s economy heavily depends on the energy resources used by various countries. India is one of the promising developing nations with very low crude reserves actively looking for new renewable energy resources to power its economy. Higher energy consumption and environmental pollution are two big global challenges for our sustainable development. The world is currently facing a dual problem of an energy crisis as well as environmental degradation. So there is a strong need to reduce our dependency on fossil fuels and greenhouse gas emissions. This can be achieved to a great extent by universally adopting clean fuels for all daily life uses like ethanol or liquified natural gas (LNG) as these burn very clean and do not emit many pollutants. Nowadays green hydrogen has emerged as a new clean energy source which is abundantly available and does not pollute much. This article explores the various benefits of green hydrogen with respect to fossil fuels various techniques of producing it and its possible use in different sectors such as industry transport and aviation as well as in day-to-day life. Finally it explores the use of green hydrogen as fuel in automobile engines its blending with CNG gas and its benefits in reducing emissions compared to fossil fuels. On combustion green hydrogen produces only water vapours and is thus a highly clean fuel. Thus it can potentially help humanity preserve the environment due to its ultra-low emissions and can be a consistent and reliable source of energy for generations to come thereby ending the clean energy security debate forever.
Evaluating Hydrogen-based Electricity Generation using the Concept of Total Efficiency
Aug 2023
Publication
The popularity of hydrogen has been increasing globally as a promising sustainable energy source. However hydrogen needs to be produced and processed before it can be used in the energy sector. This paper uses total efficiency to evaluate the lifecycle of hydrogen-driven power generation. Total efficiency introduces the energy requirement of fuel preparation in conventional efficiency and is a reliable method to fairly compare different energy sources. Two case studies in Spain and Germany with nine scenarios each are defined to study different hydrogen-preparation routes. The scenarios include the main colors of hydrogen production (grey turquoise yellow and green) and different combinations of processing and transportation choices. In most cases the highest energy penalty in the overall preparation process of the fuel is linked to the production step. A large difference is found between fossil fuel-based hydrogen and green hydrogen derived from excess renewable energy with fossil fuel-based hydrogen resulting in significantly lower total efficiencies compared to green hydrogen. The use of natural gas as the primary source to generate hydrogen is found to be a critical factor affecting total efficiency particularly in cases where the gas must be transported from far away. This shows the value of using excess renewable energy in the production of hydrogen instead of grid power. Even in the most efficient scenario of green hydrogen studied total efficiency was found to be 7 % lower than the respective conventional efficiency that does not account for hydrogen generation. These results emphasize the importance of considering the impact of fuel preparation stages in comparative thermodynamic analyses and evaluations.
Economic Evaluation and Technoeconomic Resilience Analysis of Two Routes for Hydrogen Production via Indirect Gasification in North Colombia
Nov 2023
Publication
Hydrogen has become a prospective energy carrier for a cleaner more sustainable economy offering carbon-free energy to reduce reliance on fossil fuels and address climate change challenges. However hydrogen production faces significant technological and economic hurdles that must be overcome to reveal its highest potential. This study focused on evaluating the economics and technoeconomic resilience of two large-scale hydrogen production routes from African palm empty fruit bunches (EFB) by indirect gasification. Computer-aided process engineering (CAPE) assessed multiple scenarios to identify bottlenecks and optimize economic performance indicators like gross profits including depreciation after-tax profitability payback period and net present value. Resilience for each route was also assessed considering raw material costs and the market price of hydrogen in relation to gross profits and after-tax profitability. Route 1 achieved a gross profit (DGP) of USD 47.12 million and a profit after taxes (PAT) of USD 28.74 million while Route 2 achieved a DGP of USD 46.53 million and a PAT of USD 28.38 million. The results indicated that Route 2 involving hydrogen production through an indirect gasification reactor with a Selexol solvent unit for carbon dioxide removal demonstrated greater resilience in terms of raw material costs and product selling price.
Risky Business? Evaluating Hydrogen Partnerships Established by Germany, The Netherlands, and Belgium
Dec 2023
Publication
Following the introduction of the EU’s Hydrogen Strategy in 2020 as part of the European Green Deal some EU member states have deployed a very active hydrogen diplomacy. Germany The Netherlands and Belgium have been the most active ones establishing no less than 40 bilateral hydrogen trade partnerships with 30 potential export countries in the last three years. However concerns have been voiced about whether such hydrogen trade relationships can be economically feasible geopolitically wise environmentally sustainable and socially just. This article therefore evaluates these partnerships considering three risk dimensions: economic political and sustainability (covering both environmental and justice) risks. The analysis reveals that the selection of partner countries entails significant trade-offs. Four groups of partner countries can be identified based on their respective risk profile: “Last Resorts” “Volatile Ventures” “Strategic Gambits” and “Trusted Friends”. Strikingly less than one-third of the agreements are concluded with countries that fall within the “Trusted Friends” category which have the lowest overall risk profile. These findings show the need for policy makers to think much more strategically about which partnerships to pursue and to confront tough choices about which risks and trade-offs they are willing to accept.
Large-Scale Hydrogen Production Systems Using Marine Renewable Energies: State-of-the-Art
Dec 2023
Publication
To achieve a more ecologically friendly energy transition by the year 2050 under the European “green” accord hydrogen has recently gained significant scientific interest due to its efficiency as an energy carrier. This paper focuses on large-scale hydrogen production systems based on marine renewable-energy-based wind turbines and tidal turbines. The paper reviews the different technologies of hydrogen production using water electrolyzers energy storage unit base hydrogen vectors and fuel cells (FC). The focus is on large-scale hydrogen production systems using marine renewable energies. This study compares electrolyzers energy storage units and FC technologies with the main factors considered being cost sustainability and efficiency. Furthermore a review of aging models of electrolyzers and FCs based on electrical circuit models is drawn from the literature and presented including characterization methods of the model components and the parameters extraction methods using a dynamic current profile. In addition industrial projects for producing hydrogen from renewable energies that have already been completed or are now in progress are examined. The paper is concluded through a summary of recent hydrogen production and energy storage advances as well as some applications. Perspectives on enhancing the sustainability and efficiency of hydrogen production systems are also proposed and discussed. This paper provides a review of behavioral aging models of electrolyzers and FCs when integrated into hydrogen production systems as this is crucial for their successful deployment in an ever-changing energy context. We also review the EU’s potential for renewable energy analysis. In summary this study provides valuable information for research and industry stakeholders aiming to promote a sustainable and environmentally friendly energy transition.
A Review on Underground Gas Storage Systems: Natural Gas, Hydrogen and Carbon Sequestration
May 2023
Publication
The concept of underground gas storage is based on the natural capacity of geological formations such as aquifers depleted oil and gas reservoirs and salt caverns to store gases. Underground storage systems can be used to inject and store natural gas (NG) or hydrogen which can be withdrawn for transport to end-users or for use in industrial processes. Geological formations can additionally be used to securely contain harmful gases such as carbon dioxide deep underground by means of carbon capture and sequestration technologies. This paper defines and discusses underground gas storage highlighting commercial and pilot projects and the behavior of different gases (i.e. CH4 H2 and CO2) when stored underground as well as associated modeling investigations. For underground NG/H2 storage the maintenance of optimal subsurface conditions for efficient gas storage necessitates the use of a cushion gas. Cushion gas is injected before the injection of the working gas (NG/H2). The behavior of cushion gas varies based on the type of gas injected. Underground NG and H2 storage systems operate similarly. However compared to NG storage several challenges could be faced during H2 storage due to its low molecular mass. Underground NG storage is widely recognized and utilized as a reference for subsurface H2 storage systems. Furthermore this paper defines and briefly discusses carbon capture and sequestration underground. Most reported studies investigated the operating and cushion gas mixture. The mixture of operating and cushion gas was studied to explore how it could affect the recovered gas quality from the reservoir. The cushion gas was shown to influence the H2 capacity. By understanding and studying the different underground system technologies future directions for better management and successful operation of such systems are thereby highlighted.
Offshore Green Hydrogen Production from Wind Energy: Critical Review and Perspective
Feb 2024
Publication
Hydrogen is envisaged to play a major role in decarbonizing our future energy systems. Hydrogen is ideal for storing renewable energy over longer durations strengthening energy security. It can be used to provide electricity renewable heat power long-haul transport shipping and aviation and in decarbonizing several industrial processes. The cost of green hydrogen produced from renewable via electrolysis is dominated by the cost of electricity used. Operating electrolyzers only during periods of low electricity prices will limit production capacity and underutilize high investment costs in electrolyzer plants. Hydrogen production from deep offshore wind energy is a promising solution to unlock affordable electrolytic hydrogen at scale. Deep offshore locations can result in an increased capacity factor of generated wind power to 60–70% 4–5 times that of onshore locations. Dedicated wind farms for electrolysis can use the majority >80% of the produced energy to generate economical hydrogen. In some scenarios hydrogen can be the optimal carrier to transport the generated energy onshore. This review discusses the opportunities and challenges in offshore hydrogen production using electrolysis from wind energy and seawater. This includes the impact of site selection size of the electrolyzer and direct use of seawater without deionization. The review compares overall electrolysis system efficiency cost and lifetime when operating with direct seawater feed and deionized water feed using reverse osmosis and flash evaporation systems. In the short to medium term it is advised to install a reverse osmosis plant with an ion exchanger to feed the electrolysis instead of using seawater directly.
Dynamic Operation of Water Electrolyzers: A Review for Applications in Photovoltaic Systems Integration
May 2023
Publication
This review provides a comprehensive overview of the dynamics of low-temperature water electrolyzers and their influence on coupling the three major technologies alkaline Proton Exchange Membrane (PEM) and Anion Exchange Membrane (AEM) with photovoltaic (PV) systems. Hydrogen technology is experiencing considerable interest as a way to accelerate the energy transition. With no associated CO2 emissions and fast response water electrolyzers are an attractive option for producing green hydrogen on an industrial scale. This can be seen by the ambitious goals and large-scale projects being announced for hydrogen especially with solar energy dedicated entirely to drive the process. The electrical response of water electrolyzers is extremely fast making the slower variables such as temperature and pressure the limiting factors for variable operation typically associated with PV-powered electrolysis systems. The practical solar-to-hydrogen efficiency of these systems is in the range of 10% even with a very high coupling factor exceeding 99% for directly coupled systems. The solar-to-hydrogen efficiency can be boosted with a battery potentially sacrificing the cost. The intermittency of solar irradiance rather than its variability is the biggest challenge for PV-hydrogen systems regarding operation and degradation.
The Role of LNG in the Transition Toward Low- and Zero-carbon Shipping
Apr 2021
Publication
Due to its much lower air pollution and potential greenhouse gas (GHG) emissions benefits liquefied natural gas (LNG) is frequently discussed as a fuel pathway towards greener maritime transport. While LNG’s air quality improvements are undeniable there is debate within the sector as to what extent LNG may be able to contribute to decarbonizing shipping. This report “The Role of LNG in the Transition Toward Low- and Zero-Carbon Shipping” considers the potential of LNG to play either a transitional role in which existing LNG infrastructure and vessels could continue to be used with compatible zero-carbon bunker fuels after 2030 or a temporary one in which LNG would be rapidly supplanted by zero-carbon alternatives from 2030. Over concerns about methane leakage which could diminish or even offset any GHG benefits associated with LNG and additional capital expenditures the risk of stranded assets as well as a technology lock-in the report concludes that LNG is unlikely to play a significant role in decarbonizing maritime transport. Instead the research finds that LNG is likely to only be used in niche shipping applications or in its non-liquefied form as a feedstock to kickstart the production of zero-carbon bunker fuels when used in conjunction with carbon capture and storage technology. The research further suggests that new public policy in support of LNG as a bunker fuel should be avoided existing policy support should be reconsidered and methane emissions should be regulated.
Comparison of Alternative Marine Fuels
Sep 2019
Publication
The overall ambition of the study has been to assess the commercial and operational viability of alternative marine fuels based on review existing academic and industry literature. The approach assesses how well six alternative fuels perform compared to LNG fuel on a set of 11 key parameters. Conventional fuels are not covered in this study however 2020 compliant fuels (HFO+scrubber and low sulphur fuels are included in the conclusion for comparative purposes.
Identifying and Analysing Important Model Assumptions: Combining Techno-economic and Political Feasibility of Deep Decarbonisation Pathways in Norway
Mar 2024
Publication
Understanding the political feasibility of transition pathways is a key issue in energy transitions. Policy changes are a significant source of uncertainty in energy system optimisation modelling. Energy system models are nevertheless continuously being updated to reflect policy signals as realistically as possible. Using the concept of transition pathways as a starting point this cross-disciplinary study combines energy system optimization modelling with political feasibility of different transition pathways. This combination generates insights into key political decision points in the ongoing energy transition. Resting on actor support structure and political feasibility of four main pathway categories (electrification hydrogen biomass and energy efficiency) we identify critical model assumptions that are politically significant and impact model outcome. Then by replacing the critical assumptions with technical limitations we model a scenario that is unrestrained by assumptions about policy we identify areas where political choices are key to model outcomes. The combination of actor preferences and modelled energy system consequences enables the identification of future key decision points. We find that there is considerable support for electrification as the main pathway to net-zero. The implications of widespread electrification in terms of energy production and grid capacity lead us to identify challenging policy decisions with implications for the energy transition.
Enhancing Waste-to-Energy and Hydrogen Production through Urban–Industrial Symbiosis: A Multi-Objective Optimisation Model Incorporating a Bayesian Best-Worst Method
Feb 2024
Publication
A surging demand for sustainable energy and the urgency to lower greenhouse gas emissions is driving industrial systems towards more eco-friendly and cost-effective models. Biogas from agricultural and municipal organic waste is gaining momentum as a renewable energy source. Concurrently the European Hydrogen Strategy focuses on green hydrogen for decarbonising the industrial and transportation sectors. This paper presents a multi-objective network design model for urban–industrial symbiosis incorporating anaerobic digestion cogeneration photovoltaic and hydrogen production technologies. Additionally a Bayesian best-worst method is used to evaluate the weights of the sustainability aspects by decision-makers integrating these into the mathematical model. The model optimises industrial plant locations considering economic environmental and social parameters including the net present value energy consumption and carbon footprint. The model’s functionalities are demonstrated through a real-world case study based in Emilia Romagna Italy. It is subject to sensitivity analysis to evaluate how changes in the inputs affect the outcomes and highlights feasible trade-offs through the exploration of the ϵ-constraint. The findings demonstrate that the model substantially boosts energy and hydrogen production. It is not only economically viable but also reduces the carbon footprint associated with fossil fuels and landfilling. Additionally it contributes to job creation. This research has significant implications with potential future studies intended to focus on system resilience plant location optimisation and sustainability assessment.
A Multi-Criteria Decision-Making Framework for Zero Emission Vehicle Fleet Renewal Considering Lifecycle and Scenario Uncertainty
Mar 2024
Publication
: In the last decade with the increased concerns about the global environment attempts have been made to promote the replacement of fossil fuels with sustainable sources. For transport which accounts for around a quarter of total greenhouse gas emissions meeting climate neutrality goals will require replacing existing fleets with electric or hydrogen-propelled vehicles. However the lack of adequate decision support approach makes the introduction of new propulsion technologies in the transportation sector a complex strategic decision problem where distorted non-optimal decisions may easily result in long-term negative effects on the performance of logistic operators. This research addresses the problem of transport fleet renewal by proposing a multi-criteria decision-making approach and takes into account the multiple propulsion technologies currently available and the objectives of the EU Green Deal as well as the inherent scenario uncertainty. The proposed approach based on the TOPSIS model involves a novel decision framework referred to as a generalized life cycle evaluation of the environmental and cost objectives which is necessary when comparing green and traditional propulsion systems in a long-term perspective to avoid distorted decisions. Since the objective of the study is to provide a practical methodology to support strategic decisions the framework proposed has been validated against a practical case referred to the strategic fleet renewal decision process. The results obtained demonstrate how the decision maker’s perception of the technological evolution of the propulsion technologies influences the decision process thus leading to different optimal choices.
Assessing Fluctuating Wind to Hydrogen Production via Long-term Testing of Solid Oxide Electrolysis Stacks
Mar 2024
Publication
The Danish government plans two energy islands to collect offshore wind power for power distribution and green fuel production. Wind power is often criticized for lacking stability which challenges downstream fuel synthesis processes. Solid oxide electrolysis cells (SOEC) are promising for green hydrogen production on a commercial scale but the impact of fluctuating power on SOEC remains uncertain. This paper explores the feasibility of a Wind-SOEC coupled system by conducting a 2104-h durability test with the state-of-the-art Topsoe TSP-1 stack. Three periods of steady operation and two periods of dynamic operation were conducted. Wind power fluctuation was simulated during the dynamic period and two control strategies were used to handle it. The constant flow (CF) and constant conversion (CC) strategies maintain the feedstock flow rate and conversion ratio of steamto‑hydrogen respectively. Compared to steady operation the stack shows no signs of additional degradation in dynamic operation. Thus the TSP-1 stack has been proven robust and flexible enough to handle fluctuating wind power supplies under both operation strategies. Further stack performance during dynamic periods was compared and analyzed by removing degradation effects. Accordingly SOEC stacks with CC control will consume less external heat than CF to maintain a heat balance. Nevertheless SOEC systems with CF and CC control strategies may have different efficiency or hydrogen production costs. Tech-economic analyses will be needed to investigate control strategies at the system level.
Low-Carbon Economic Dispatch of Integrated Energy Systems in Industrial Parks Considering Comprehensive Demand Response and Multi-Hydrogen Supply
Mar 2024
Publication
To address the increasing hydrogen demand and carbon emissions of industrial parks this paper proposes an integrated energy system dispatch strategy considering multi-hydrogen supply and comprehensive demand response. This model adopts power-to-gas technology to produce green hydrogen replacing a portion of gray hydrogen and incorporates a carbon capture system to effectively reduce the overall carbon emissions of the industrial park. Meanwhile incentive-based and price-based demand response strategies are implemented to optimize the load curve. A scheduling model is established targeting the minimization of procurement operation carbon emission and wind curtailment costs. The case study of a northern industrial park in China demonstrates that the joint supply of green and gray hydrogen reduces carbon emissions by 40.98% and costs by 17.93% compared to solely using gray hydrogen. The proposed approach successfully coordinates the economic and environmental performance of the integrated energy system. This study provides an effective scheduling strategy for industrial parks to accommodate high shares of renewables while meeting hydrogen needs and carbon reduction targets.
Life Cycle Cost Analysis of an Autonomous Underwater Vehicle that Employs Hydrogen Fuel Cell
Feb 2024
Publication
The use of autonomous vehicles for marine and submarine work has risen considerably in the last decade. Developing new monitoring systems navigation and communications technologies allows a wide range of operational possibilities. Autonomous Underwater Vehicles (AUVs) are being used in offshore missions and applications with some innovative purposes by using sustainable and green energy sources. This paper considers an AUV that uses a hydrogen fuel cell achieving zero emissions. This paper analyses the life cycle cost of the UAV and compares it with a UAV powered by conventional energy. The EN 60300-3-3 guidelines have been employed to develop the cost models. The output results show estimations for the net present value under different scenarios and financial strategies. The study has been completed with the discount rate sensibility analysis in terms of financial viability.
Ammonia as Hydrogen Carrier for Transportation; Investigation of the Ammonia Exhaust Gas Fuel Reforming
Jun 2013
Publication
In this paper we show for the first time the feasibility of ammonia exhaust gas reforming as a strategy for hydrogen production used in transportation. The application of the reforming process and the impact of the product on diesel combustion and emissions were evaluated. The research was started with an initial study of ammonia autothermal reforming (NH3 e ATR) that combined selective oxidation of ammonia (into nitrogen and water) and ammonia thermal decomposition over a ruthenium catalyst using air as the oxygen source. The air was later replaced by real diesel engine exhaust gas to provide the oxygen needed for the exothermic reactions to raise the temperature and promote the NH3 decomposition. The main parameters varied in the reforming experiments are O2/NH3 ratios NH3 concentration in feed gas and gas e hourly e space e velocity (GHSV). The O2/NH3 ratio and NH3 concentration were the key factors that dominated both the hydrogen production and the reforming process efficiencies: by applying an O2/NH3 ratio ranged from 0.04 to 0.175 2.5e3.2 l/min of gaseous H2 production was achieved using a fixed NH3 feed flow of 3 l/min. The reforming reactor products at different concentrations (H2 and unconverted NH3) were then added into a diesel engine intake. The addition of considerably small amount of carbon e free reformate i.e. represented by 5% of primary diesel replacement reduced quite effectively the engine carbon emissions including CO2 CO and total hydrocarbons.
OIES Podcast - Renewable Hydrogen Import Routes into the EU
Jun 2023
Publication
In this podcast David Ledesma talks to Martin Lambert and Abdurahman Alsulaiman about the potential hydrogen import market particularly focusing on the EU which currently holds the largest and earliest hydrogen target. The podcast explores the emerging hydrogen trade market and considers numerous possibilities for its open up providing better clarity on policy statements and balance them against project announcements.
Throughout the podcast Martin and Abdulrahman delve into various key points – they shed light on the primary areas of focus for projects set to be completed by or before 2030 as well as the distinction between announcements and tangible progress such as projects currently at the Final Investment Decision stage or under construction.
Additionally they explore the EU’s role as one of the few countries to have publicly announced its requirements for hydrogen imports and its ambitious hydrogen import target. The EU is currently establishing a benchmark for the future hydrogen market. However in order for the EU to succeed in establishing future hydrogen supply lines with future trade partners it will be crucial to engage in open dialogues covering a wide range of topics.
Join us in this podcast as we uncover the potential of the hydrogen import market with a specific focus on the EU and discuss the necessary steps for its success.
The podcast can be found on their website.
Throughout the podcast Martin and Abdulrahman delve into various key points – they shed light on the primary areas of focus for projects set to be completed by or before 2030 as well as the distinction between announcements and tangible progress such as projects currently at the Final Investment Decision stage or under construction.
Additionally they explore the EU’s role as one of the few countries to have publicly announced its requirements for hydrogen imports and its ambitious hydrogen import target. The EU is currently establishing a benchmark for the future hydrogen market. However in order for the EU to succeed in establishing future hydrogen supply lines with future trade partners it will be crucial to engage in open dialogues covering a wide range of topics.
Join us in this podcast as we uncover the potential of the hydrogen import market with a specific focus on the EU and discuss the necessary steps for its success.
The podcast can be found on their website.
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.
Potential for Natural Hydrogen in Quebec (Canada): A First Review
Mar 2024
Publication
The energy transition calls for natural hydrogen exploration with most occurrences discovered either inadvertently or more recently at the location of potentially diffusive circles observed from a change of vegetation cover at the surface. However some notable hydrogen occurrences are not directly associated with the presence of diffusive circles like the Bourakebougou field in Mali. Thus the objective of this work was to highlight geological areas that have some potential to find natural hydrogen in Quebec a Canadian province where no diffusive circles have yet been documented but which is rich in potential source rocks and where no exploration for natural hydrogen has been undertaken so far. A review of the different geological regions of Quebec was undertaken to highlight the relevant characteristics and geographical distribution of geological assemblages that may produce or have produced natural hydrogen in particular iron-rich rocks but also uranium-rich rocks supramature shales and zones where significant structural discontinuities are documented or suspected which may act as conduits for the migration of fluids of mantle origin. In addition to regional and local geological data an inventory of available geochemical data is also carried out to identify potential tracers or proxies to facilitate subsequent exploration efforts. A rating was then proposed based on the quality of the potential source rocks which also considers the presence of reservoir rocks and the proximity to end-users. This analysis allowed rating areas of interest for which fieldwork can be considered thus minimizing the exploratory risks and investments required to develop this resource. The size of the study area (over 1.5 million km2 ) the diversity of its geological environments (from metamorphic cratons to sedimentary basins) and their wide age range (from Archean to Paleozoic) make Quebec a promising territory for natural hydrogen exploration and to test the systematic rating method proposed here.
Green Hydrogen Value Chain: Modelling of a PV Power Plant Integrated with H2 Production for Industry Application
Mar 2024
Publication
Based on the Sustainable Development Goals outlined in the 2030 agenda of the United Nations affordable and clean energy is one of the most relevant goals to achieve the decarbonization targets and break down the global climate change effects. The use of renewable energy sources namely solar energy is gaining attention and market share due to reductions in investment costs. Nevertheless it is important to overcome the energy storage problems mostly in industrial applications. The integration of photovoltaic power plants with hydrogen production and its storage for further conversion to usable electricity are an interesting option from both the technical and economic points of view. The main objective of this study is to analyse the potential for green hydrogen production and storage through PV production based on technical data and operational considerations. We also present a conceptual model and the configuration of a PV power plant integrated with hydrogen production for industry supply. The proposed power plant configuration identifies different pathways to improve energy use: supply an industrial facility supply the hydrogen production and storage unit sell the energy surplus to the electrical grid and provide energy to a backup battery. One of the greatest challenges for the proposed model is the component sizing and water electrolysis process for hydrogen production due to the operational requirements and the technology costs.
The Interaction between Short- and Long-Term Energy Storage in an nZEB Office Building
Mar 2024
Publication
The establishment of near-autonomous micro-grids in commercial or public building complexes is gaining increasing popularity. Short-term storage capacity is provided by means of large battery installations or more often by the employees’ increasing use of electric vehicle batteries which are allowed to operate in bi-directional charging mode. In addition to the above short-term storage means a long-term storage medium is considered essential to the optimal operation of the building’s micro-grid. The most promising long-term energy storage carrier is hydrogen which is produced by standard electrolyzer units by exploiting the surplus electricity produced by photovoltaic installation due to the seasonal or weekly variation in a building’s electricity consumption. To this end a novel concept is studied in this paper. The details of the proposed concept are described in the context of a nearly Zero Energy Building (nZEB) and the associated micro-grid. The hydrogen produced is stored in a high-pressure tank to be used occasionally as fuel in an advanced technology hydrogen spark ignition engine which moves a synchronous generator. A size optimization study is carried out to determine the genset’s rating the electrolyzer units’ capacity and the tilt angle of the rooftop’s photovoltaic panels which minimize the building’s interaction with the external grid. The hydrogen-fueled genset engine is optimally sized to 40 kW (0.18 kW/kWp PV). The optimal tilt angle of the rooftop PV panels is 39◦ . The maximum capacity of the electrolyzer units is optimized to 72 kW (0.33 kWmax/kWp PV). The resulting system is tacitly assumed to integrate to an external hydrogen network to make up for the expected mismatches between hydrogen production and consumption. The significance of technology in addressing the current challenges in the field of energy storage and micro-grid optimization is discussed with an emphasis on its potential benefits. Moreover areas for further research are highlighted aiming to further advance sustainable energy solutions.
Evaluating Fuel Cell vs. Battery Electric Trucks: Economic Perspectives in Alignment with China’s Carbon Neutrality Target
Mar 2024
Publication
The electrification of heavy-duty trucks stands as a critical and challenging cornerstone in the low-carbon transition of the transportation sector. This paper employs the total cost of ownership (TCO) as the economic evaluation metric framed within the context of China’s ambitious goals for heavy truck electrification by 2035. A detailed TCO model is developed encompassing not only the vehicles but also their related energy replenishing infrastructures. This comprehensive approach enables a sophisticated examination of the economic feasibility for different deployment contexts of both fuel cell and battery electric heavy-duty trucks emphasizing renewable energy utilization. This study demonstrates that in the context where both fuel cell components and hydrogen energy are costly fuel cell trucks (FCTs) exhibit a significantly higher TCO compared to battery electric trucks (BETs). Specifically for a 16 ton truck with a 500 km range the TCO for the FCT is 0.034 USD/tkm representing a 122% increase over its BET counterpart. In the case of a 49 ton truck designed for a 1000 km range the TCO for the FCT is 0.024 USD/tkm marking a 36% premium compared to the BET model. The technological roadmap suggests a narrowing cost disparity between FCTs and BETs by 2035. For the aforementioned 16 ton truck model the projected TCO for the FCT is expected to be 0.016 USD/tkm which is 58% above the BET and for the 49 ton variant it is anticipated at 0.012 USD per ton-kilometer narrowing the difference to just 4.5% relative to BET. Further analysis within this study on the influences of renewable energy pricing and operational range on FCT and BET costs highlights a pivotal finding: for the 49 ton truck achieving TCO parity between FCTs and BETs is feasible when renewable energy electricity prices fall to 0.022 USD/kWh or when the operational range extends to 1890 km. This underscores the critical role of energy costs and efficiency in bridging the cost gap between FCTs and BETs.
On Green Hydrogen Generation Technologies: A Bibliometric Review
Mar 2024
Publication
Green hydrogen produced by water electrolysis with renewable energy plays a crucial role in the revolution towards energy sustainability and it is considered a key source of clean energy and efficient storage. Its ability to address the intermittency of renewable sources and its potential to decarbonize sectors that are difficult to electrify make it a strategic component in climate change mitigation. By using a method based on a bibliometric review of scientific publications this paper represents a significant contribution to the emerging field of research on green hydrogen and provides a detailed review of electrolyzer technologies identifying key areas for future research and technology development. The results reflect the immaturity of a technology which advances with different technical advancements waiting to find the optimal technical solution that allows for its massive implementation as a source of green hydrogen generation. According to the results found in this article alkaline (ALK) and proton exchange membrane (PEM) electrolyzers seem to be the ones that interest the scientific community the most. Similarly in terms of regional analysis Europe is clearly committed to green hydrogen in view of the analysis of its scientific results on materials and electrolyzer capacity forecasts for 2030.
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.
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.
Low Carbon Economic Dispatch of Integrated Energy Systems Considering Utilization of Hydrogen and Oxygen Energy
Mar 2024
Publication
Power-to-gas (P2G) facilities use surplus electricity to convert to natural gas in integrated energy systems (IES) increasing the capacity of wind power to be consumed. However the capacity limitation of P2G and the antipeaking characteristic of wind power make the wind abandonment problem still exist. Meanwhile the oxygen generated by P2G electrolysis is not fully utilized. Therefore this study proposes a low-carbon economic dispatch model considering the utilization of hydrogen and oxygen energy. First the two-stage reaction model of P2G is established and the energy utilization paths of hydrogen blending and oxygen-rich deep peaking are proposed. Specifically hydrogen energy is blended into the gas grid to supply gas-fired units and oxygen assists oxygenrich units into deep peaking. Subsequently the stochastic optimization is used to deal with the uncertainty of the system and the objective function and constraints of the IES are given to establish a low-carbon dispatch model under the energy utilization model. Finally the effectiveness of the proposed method is verified based on the modified IEEE 39-node electric network 20-node gas network and 6-node heat network models.
Revolutionising Energy Storage: The Latest Breakthrough in Liquid Organic Hydrogen Carriers
Mar 2024
Publication
Liquid organic hydrogen carriers (LOHC) can be used as a lossless form of hydrogen storage at ambient conditions. The storage cycle consists of the exothermic hydrogenation of a hydrogen-lean molecule at the start of the transport usually the hydrogen production site becoming a hydrogen-rich molecule. This loaded molecule can be transported long distances or be used as long-term storage due to its ability to not lose hydrogen over long periods of time. At the site or time of required hydrogen production the hydrogen can be released through an endothermic dehydrogenation reaction. LOHCs show similar properties to crude oils such as petroleum and diesel allowing easy handling and possibilities of integration with current infrastructure. Using this background this paper reviews a variety of aspects of the LOHC life cycle with a focus on currently studied materials. Important factors such as the hydrogenation and dehydrogenation requirements for each material are analysed to determine their ability to be used in current scenarios. Toluene and dibenzyltoluene are attractive options with promising storage attributes however their dehydrogenation enthalpies remain a problem. The economic feasibility of LOHCs being used as a delivery device were briefly analysed. LOHCs have been shown to be the cheapest option for long distance transport (>200 km) and are cheaper than most at shorter distances in terms of specifically transport costs. The major capital cost of an LOHC delivery chain remains the initial investment for the raw materials and the cost of equipment for performing hydrogenation and dehydrogenation. Finally some studies in developing the LOHC field were discussed such as microwave enhancing parts of the process and mixing LOHCs to acquire more advantageous properties.
Renewable Energy Potentials and Roadmap in Brazil, Austria, and Germany
Mar 2024
Publication
The emerging energy transition is particularly described as a move towards a cleaner lower-carbon system. In the context of the global shift towards sustainable energy sources this paper reviews the potential and roadmap for hydrogen energy as a crucial component of the clean energy landscape. The primary objective is to present a comprehensive literature overview illuminating key themes trends and research gaps in the scientific discourse concerning hydrogen production and energy policy. This review focuses particularly on specified geographic contexts with an emphasis on understanding the unique energy policies related to renewable energy in Brazil Austria and Germany. Given their distinct social systems and developmental stages this paper aims to delineate the nuanced approaches these countries adopt in their pursuit of renewable energy and the integration of hydrogen within their energy frameworks. Brazil exhibits vast renewable energy potential particularly in wind and solar energy sectors positioning itself for substantial growth in the coming years. Germany showcases a regulatory framework that promotes innovation and technological expansion reflecting its highly developed social system and commitment to transitioning away from fossil fuels. Austria demonstrates dedication to decarbonization particularly through the exploration of biomethane for residential heating and cooling.
Performance and Emission Optimisation of an Ammonia/ Hydrogen Fuelled Linear Joule Engine Generator
Mar 2024
Publication
This paper presents a Linear Joule Engine Generator (LJEG) powered by ammonia and hydrogen co-combustion to tackle decarbonisation in the electrification of transport propulsion systems. A dynamic model of the LJEG which integrates mechanics thermodynamics and electromagnetics sub-models as well as detailed combustion chemistry analysis for emissions is presented. The dynamic model is integrated and validated and the LJEG performance is optimised for improved performance and reduced emissions. At optimal conditions the engine could generate 1.96 kWe at a thermal efficiency of 34.3% and an electrical efficiency of 91%. It is found that the electromagnetic force of the linear alternator and heat addition from the external combustor and engine valve timing have the most significant influences on performance whereas the piston stroke has a lesser impact. The impacts of hydrogen ratio oxygen concentration inlet pressure and equivalence ratio of ammonia-air on nitric oxide (NO) formation and reduction are revealed using a detailed chemical kinetic analysis. Results indicated that rich combustion and elevated pressure are beneficial for NO reduction. The rate of production analysis indicates that the equivalence ratio significantly changes the relative contribution among the critical NO formation and reduction reaction pathways.
Circular Economy for the Energy System as a Leverage for Low-carbon Transition: Long-Ter, Analysis of the Case of the South-East Region of France
Mar 2024
Publication
The circular economy is a decisive strategy for reconciling economic development and the environment. In France the CE was introduced into the law in 2015 with the objective of closing the loop. The legislation also delegates energy policy towards the French regions by granting them the jurisdiction to directly plan the energy–climate issues on their territory and to develop local energy resources. Thereby the SUD PACA region has redefined its objectives and targeted carbon neutrality and the transition to a CE by 2050. To study this transition we developed a TIMESPACA optimization model. The results show that following a CE perspective to develop a local energy system could contribute to reducing CO2 emissions by 50% in final energy consumption and reaching almost free electricity production. To obtain greater reductions the development of the regional energy systems should follow a careful policy design favoring the transition to low energy-consuming behavior and the strategical allocation of resources across the different sectors. Biomethane should be allocated to the buildings and industrial sector while hydrogen should be deployed for buses and freight transport vehicles.
Carbon-neutral Cement: The Role of Green Hydrogen
Mar 2024
Publication
Business-as-usual (BAU) cement production is associated with a linear model that contributes significantly to global warming and is dependent on volatile energy markets. A novel circular model is proposed by adding three power-to-gas system components to current production systems: a calcium-looping (CaL) CO2 capture unit; water electrolysis for hydrogen and oxygen generation; and a methanation unit for synthetic natural gas (SNG) production. The paper presents the first analysis of the combined industrial-scale operation of these components in a closed loop where the SNG fuels the cement kiln and the CaL unit while the O2 produced feeds it. The circular hybrid and BAU models are compared in three feasibility scenarios. It is concluded that the circular model outperforms the other alternatives environmentally opening a potential pathway for the cement industry to achieve near net-zero CO2 emissions reduce energy dependence and improve economic efficiency.
Optimal Design of a Hydrogen-powered Fuel Cell System for Aircraft Applications
Mar 2024
Publication
Recently hydrogen and fuel cells have gained interest as an emerging technology to mitigate the effects of climate change caused by the aviation sector. The aim of this work is to evaluate the applicability of this technology to an existing regional aircraft in order to assess its electrification with the aim of reducing greenhouse gas emissions and achieving sustainability goals. The design of a proton-exchange membrane fuel cell system (PEMFC) with the inclusion of liquid hydrogen storage is carried out. Specifically a general mathematical model is developed which involves multiple scales ranging from individual cells to aircraft scale. First the fuel cell electrochemical model is developed and validated against published polarization curves. Then different sizing approaches are used to compute the overall weight of the hydrogen-based propulsion system in order to optimize the system and minimize its weight. Crucially this work underscores that the feasibility of hydrogenbased fuel cell systems relies not only on hydrogen storage but especially on the electrochemical cell performance which influences the size of the balance of plant and especially its thermal management section. In particular the strategic significance of working with fuel cells at partial loads is demonstrated. This entails achieving an optimal balance between the stacks oversizing and the weights of both hydrogen storage and balance of plant thereby minimizing the overall weight of the system. It is thus shown that an integrated approach is imperative to guide progress towards efficient and implementable hydrogen technology in regional aviation. Furthermore a high-performance PEMFC is analyzed resulting in an overall weight reduction up to nearly 10% compared to the baseline case study. In this way it is demonstrated as technological advancements in PEMFCs can offer further prospects for improving system efficiency.
A Hydrogen-fuelled Compressed Air Energy Storage System for Flexibility Reinforcement and Variable Renewable Energy Integration in Grids with High Generation Curtailment
Mar 2024
Publication
Globally the increasing share of renewables prominently driven by intermittent sources such as solar and wind power poses significant challenges to the reliability of current electrical infrastructures leading to the adoption of extreme measures such as generation curtailment to preserve grid security. Within this framework it is essential to develop energy storage systems that contribute to reinforce the flexibility and security of power grids while simultaneously reducing the share of generation curtailment. Therefore this study investigates the performance of an integrated photovoltaic-hydrogen fuelled-compressed air energy storage system whose configuration is specifically conceived to enable the connection of additional intermittent sources in already saturated grids. The yearly and seasonal performance of the integrated energy storage system specifically designed to supply flexibility services are evaluated for a scenario represented by a real grid with high-variable renewables penetration and frequent dispatchability issues. Results show that the integrated system with performanceoptimized components and a new energy management strategy minimizes photovoltaic energy curtailment otherwise around 50% to as low as 4% per year achieving system efficiencies of up to 62% and reinforces the grid by supplying inertial power for up to 20% of nighttime hours. In conclusion the integrated plant operating with zero emissions on-site hydrogen production and optimized for non-dispatchable photovoltaic energy utilization proves to be effective in integrating new variable renewable sources and reinforcing saturated grids particularly during spring and summer.
Effects of Fuel Cell Size and Dynamic Limitations on the Durability and Efficiency of Fuel Cell Hybrid Electric Vehicles under Driving Conditions
Mar 2024
Publication
In order to enhance the durability of fuel cell systems in fuel cell hybrid electric vehicles (FCHEVs) researchers have been dedicated to studying the degradation monitoring models of fuel cells under driving conditions. To predict the actual degradation factors and lifespan of fuel cell systems a semi-empirical and semi-physical degradation model suitable for automotive was proposed and developed. This degradation model is based on reference degradation rates obtained from experiments under known conditions which are then adjusted using coefficients based on the electrochemical model. By integrating the degradation model into the vehicle simulation model of FCHEVs the impact of different fuel cell sizes and dynamic limitations on the efficiency and durability of FCHEVs was analyzed. The results indicate that increasing the fuel cell stack power improves durability while reducing hydrogen consumption but this effect plateaus after a certain point. Increasing the dynamic limitations of the fuel cell leads to higher hydrogen consumption but also improves durability. When considering only the rated power of the fuel cell a comparison between 160 kW and 100 kW resulted in a 6% reduction in hydrogen consumption and a 10% increase in durability. However when considering dynamic limitation factors comparing the maximum and minimum limitations of a 160 kW fuel cell hydrogen consumption increased by 10% while durability increased by 83%.
A Power Dispatch Allocation Strategy to Produce Green Hydrogen in a Grid-integrated Offshore Hybrid Energy System
Mar 2024
Publication
A dedicated grid-tied offshore hybrid energy system for hydrogen production is a promising solution to unlock the full benefit of offshore wind and solar energy and realize decarbonization and sustainable energy security targets in electricity and other sectors. Current knowledge of these offshore hybrid systems is limited particularly in the integration component control and allocation aspects. Therefore a grid-integrated analytical model with a power dispatch allocation strategy between the grid and electrolyzer for the co-production of hydrogen from the offshore hybrid energy system is developed in this paper. While producing hydrogen the proposed offshore hybrid energy system supplies a percentage of its capacity to the onshore grid facility and the amount of the electricity is quantified based on the electricity market price and available total offshore generation. The detailed controls of each component are discussed. A case study considers a hypothetical hybrid offshore energy system of 10 MW situated in a potential offshore off the NSW of Australia based on realistic metrological data. A grid-scale proton-exchange membrane electrolyzer stack is used and a model predictive power controller is implemented on the distributed hydrogen generation scheme. The model is helpful for the assessment or optimization of both the economics and feasibility of the dedicated offshore hybrid energy farm for hydrogen production systems.
Investigation of Pre-cooling Strategies for Heavy-duty Hydrogen Refuelling
Mar 2024
Publication
Green hydrogen presents a promising solution for transitioning from fossil fuels to a clean energy future particularly with the application of fuel cell electric vehicles (FCEVs). However the hydrogen refuelling process for FCEVs requires extensive pre-cooling to achieve fast filling times. This study presents experiments and simulations of a hydrogen refuelling station equipped with an adaptable cold-fill unit aiming to maximize fuelling efficiencies. For this purpose we developed and experimentally validated simulation models for a hydrogen tank and an aluminium block heat exchanger. Different pre-cooling parameters affect the final tank temperatures during the parallel filling of three 350 L type IV tanks. The results indicate significant potential for optimizing the required cooling energy with achievable savings of over 50 % depending on the pre-cooling strategy. The optimized pre-cooling strategies and energy savings aid in advancing the refuelling process for FCEVs effectively contributing to the transition to clean energy.
Multi-port Coordination: Unlocking Flexibility and Hydrogen Opportunities in Green Energy Networks
Mar 2024
Publication
Seaports are responsible for consuming a large amount of energy and producing a sizeable amount of environmental emissions. However optimal coordination and cooperation present an opportunity to transform this challenge into an opportunity by enabling flexibility in their generation and load units. This paper introduces a coordination framework for exploiting flexibility across multiple ports. The proposed method fosters cooperation between ports in achieving lower environmental emissions while leveraging flexibility to increase their revenue. This platform allows ports to participate in providing flexibility for the energy grid through the introduction of a green port-to-grid concept while optimising their cooperation. Furthermore the proximity to offshore wind farms is considered an opportunity for the ports to investigate their role in harnessing green hydrogen. The proposed method explores the hydrogen storage capability of ports as an opportunity for increasing the techno-economic benefits particularly through coupling them with offshore wind farms. Compared to existing literature the proposed method enjoys a comprehensive logistics-electric model for the ports a novel coordination framework for multi-port flexibility and the potentials of hydrogen storage for the ports. These unique features position this paper a valuable reference for research and industry by demonstrating realistic cooperation among ports in the energy network. The simulation results confirm the effectiveness of the proposed port flexibility coordination from both environmental and economic perspectives.
Cost and Thermodynamic Analysis of Wind-Hydrogen Production via Multi-energy Systems
Mar 2024
Publication
With rising temperatures extreme weather events and environmental challenges there is a strong push towards decarbonization and an emphasis on renewable energy with wind energy emerging as a key player. The concept of multi-energy systems offers an innovative approach to decarbonization with the potential to produce hydrogen as one of the output streams creating another avenue for clean energy production. Hydrogen has significant potential for decarbonizing multiple sectors across buildings transport and industries. This paper explores the integration of wind energy and hydrogen production particularly in areas where clean energy solutions are crucial such as impoverished villages in Africa. It models three systems: distinct configurations of micro-multi-energy systems that generate electricity space cooling hot water and hydrogen using the thermodynamics and cost approach. System 1 combines a wind turbine a hydrogen-producing electrolyzer and a heat pump for cooling and hot water. System 2 integrates this with a biomass-fired reheat-regenerative power cycle to balance out the intermittency of wind power. System 3 incorporates hydrogen production a solid oxide fuel cell for continuous electricity production an absorption cooling system for refrigeration and a heat exchanger for hot water production. These systems are modeled with Engineering Equation Solver and analyzed based on energy and exergy efficiencies and on economic metrics like levelized cost of electricity (LCOE) cooling (LCOC) refrigeration (LCOR) and hydrogen (LCOH) under steady-state conditions. A sensitivity analysis of various parameters is presented to assess the change in performance. Systems were optimized using a multiobjective method with maximizing exergy efficiency and minimizing total product unit cost used as objective functions. The results show that System 1 achieves 79.78 % energy efficiency and 53.94 % exergy efficiency. System 2 achieves efficiencies of 55.26 % and 27.05 % respectively while System 3 attains 78.73 % and 58.51 % respectively. The levelized costs for micro-multi-energy System 1 are LCOE = 0.04993 $/kWh LCOC = 0.004722 $/kWh and LCOH = 0.03328 $/kWh. For System 2 these values are 0.03653 $/kWh 0.003743 $/kWh and 0.03328 $/kWh. In the case of System 3 they are 0.03736 $/kWh 0.004726 $/kWh and 0.03335 $/kWh and LCOR = 0.03309 $/kWh. The results show that the systems modeled here have competitive performance with existing multi-energy systems powered by other renewables. Integrating these systems will further the sustainable and net zero energy system transition especially in rural communities.
Strategies for Life Cycle Impact Reduction of Green Hydrogen Production - Influence of Electrolyser Value Chain Design
Mar 2024
Publication
Green Hydrogen (H2 via renewable-driven electrolysis) is emerging as a vector to meet net-zero emission targets provided it is produced with a low life cycle impact. While certification schemes for green H2 have been introduced they mainly focus on the embodied emissions from energy supply during electrolyser operation. This narrow focus on just operation is an oversight considering that a complete green H2 value chain also includes the electrolyser’s manufacturing transport/installation and end-of-life. Each step of this chain involves materials and energy flows that impart impacts that undermine the clean and sustainable status of H2. Therefore holistic and harmonised assessments of the green H2 production chain are required to ensure both economic and environmental deployment of H2. Herein we conduct an overarching environmental assessment encompassing the production chain described above using Australia as a case study. Our results indicate that while the energy source has the most impact material and manufacturing inputs associated with electrolyser production are increasingly significant as the scale of H2 output expands. Moreover wind power electrolysis has a greater chance of achieving green H2 certification compared to solar powered while increasing the amount of localised manufactured content and investment in end-of-life recycling of electrolyser components can reduce the overall life cycle impact of green H2 production by 20%.
Levelised Cost of Transmission Comparison for Green Hydrogen and Ammonia in New-build Offshore Energy Infrastructure: Pipelines, Tankers, and HVDC
Mar 2024
Publication
As the global market develops for green hydrogen and ammonia derived from renewable electricity the bulk transmission of hydrogen and ammonia from production areas to demand-intensive consumption areas will increase. Repurposing existing infrastructure may be economically and technically feasible but increases in supply and demand will necessitate new developments. Bulk transmission of hydrogen and ammonia may be effected by dedicated pipelines or liquefied fuel tankers. Transmission of electricity using HVDC lines to directly power electrolysers producing hydrogen near the demand markets is another option. This paper presents and validates detailed cost models for newly-built dedicated offshore transmission methods for green hydrogen and ammonia and carries out a techno-economic comparison over a range of transmission distances and production volumes. New pipelines are economical for short distances while new HVDC interconnectors are suited to medium-large transmission capacities over a wide range of distances and liquefied gas tankers are best for long distances.
On the Way to Utilizing Green Hydrogen as an Energy Carrier—A Case of Northern Sweden
Mar 2024
Publication
Low or even zero carbon dioxide emissions will be an essential requirement for energy supplies in the near future. Besides transport and electricity generation industry is another large carbon emitter. Hydrogen produced by renewable energy provides a flexible way of utilizing that energy. Hydrogen as an energy carrier could be stored in a large capacity compared to electricity. In Sweden hydrogen will be used to replace coal for steel production. This paper discusses how the need for electricity to produce hydrogen will affect the electricity supply and power flow in the Swedish power grid and whether it will result in increased emissions in other regions. Data of the Swedish system will be used to study the feasibility of implementing the hydrogen system from the power system viewpoint and discuss the electricity price and emission issues caused by the hydrogen production in different scenarios. This paper concludes that the Swedish power grid is feasible for accommodating the additional electricity capacity requirement of producing green hydrogen for the steel industry. The obtained results could be references for decision makers investors and power system operators.
Assessing the Performance of Fuel Cell Electric Vehicles Using Synthetic Hydrogen Fuel
Mar 2024
Publication
The deployment of hydrogen fuel cell electric vehicles (FCEVs) is critical to achieve zero emissions. A key parameter influencing FCEV performance and durability is hydrogen fuel quality. The real impact of contaminants on FCEV performance is not well understood and requires reliable measurements from real-life events (e.g. hydrogen fuel in poor-performing FCEVs) and controlled studies on the impact of synthetic hydrogen fuel on FCEV performance. This paper presents a novel methodology to flow traceable hydrogen synthetic fuel directly into the FCEV tank. Four different synthetic fuels containing N2 (90–200 µmol/mol) CO (0.14–5 µmol/mol) and H2S (4–11 nmol/mol) were supplied to an FCEV and subsequently sampled and analyzed. The synthetic fuels containing known contaminants powered the FCEV and provided real-life performance testing of the fuel cell system. The results showed for the first time that synthetic hydrogen fuel can be used in FCEVs without the requirement of a large infrastructure. In addition this study carried out a traceable H2 contamination impact study with an FCEV. The impact of CO and H2S at ISO 14687:2019 threshold levels on FCEV performance showed that small exceedances of the threshold levels had a significant impact even for short exposures. The methodology proposed can be deployed to evaluate the composition of any hydrogen fuel.
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