Netherlands
Influence of Hydrogen on Grid Investments for Smart Microgrids
Mar 2022
Publication
Electrification of the heat network in buildings together with a rise in popularity of Electric Vehicles (EVs) will result in a need to make investments in the electrical energy infrastructure in order to prevent congestion. This paper discusses the influence of hydrogen in future smart microgrids on these investments. Moreover smart control strategies i.e. EV management and demand response programs are used in this paper to lower the peak of electrical energy demand resulting in the reduction of these investments. Performances of microgrid with different levels of hydrogen penetration are discussed. It is shown that an increase in the level of hydrogen in the microgrid will reduce the electric grid investments costs but is not economically more beneficial than using ‘green’ gas due to the higher total economic costs.
Non-alloy Mg Anode for Ni-MH Batteries: Multiple Approaches Towards a Stable Cycling Performance
Apr 2021
Publication
Mg attracts much research interest as anode material for Ni-MH batteries thanks to its lightweight cost-effectiveness and high theoretical capacity (2200 mA h g−1). However its practical application is tremendously challenged by the poor hydrogen sorption kinetics passivation from aggressive aqueous electrolytes and insulating nature of MgH2. Mg-based alloys exhibit enhanced hydrogen sorption kinetics and electrical conductivity but significant amount of costly transition metal elements are required. In this work we have for the first time utilized non-alloyed but catalyzed Mg as anode for Ni-MH batteries. 5 mol.% TiF3 was added to nanosized Mg for accelerating the hydrogen sorption kinetics. Several strategies for preventing the problematic passivation of Mg have been studied including protective encapsulation of the electrode and utilizing room-temperature/high-temperature ionic liquids and an alkaline polymer membrane as working electrolyte. Promising electrochemical performance has been achieved in this Mg–TiF3 composite anode based Ni-MH batteries with room for further improvements.
Flexible Power & Biomass-to-Methanol Plants: Design Optimization and Economic Viability of the Electrolysis Integration
Nov 2021
Publication
This paper assesses the optimal design criteria of a flexible power and biomass to methanol (PBtM) plant 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 assessed plant includes a gasification section syngas cleaning and compression methanol synthesis and purification and heat recovery steam cycle to be flexibly operated. A sorption-enhanced gasification technology allows to produce a tailored syngas for the downstream synthesis in both the baseline and enhanced operating conditions by controlling the in-situ CO2 separation rate. Two designs are assessed for the methanol synthesis unit with two different reactor sizes: (i) a larger reactor designed on the enhanced operation mode (enhanced reactor design – ERD) and (ii) a smaller reactor designed on the baseline operation mode (baseline reactor design – BRD). The ERD design resulted to be preferable from the techno economic perspectives resulting in 20% lower cost of the e-MeOH (30.80 vs. 37.76 €/ GJLHV) with the baseline assumptions (i.e. 80% of electrolyzer capacity factor and 2019 Denmark day-ahead market electricity price). Other important outcomes are: (i) high electrolysis capacity factor is needed to obtain competitive cost of e-MeOH and (ii) advantages of flexibly operated PBtM plants with respect to inflexible PBtM plants are significant in scenarios with high penetration of intermittent renewables leading to low average prices of electricity but also longer periods of high peak prices.
1921–2021: A Century of Renewable Ammonia Synthesis
Apr 2022
Publication
Synthetic ammonia manufactured by the Haber–Bosch process and its variants is the key to securing global food security. Hydrogen is the most important feedstock for all synthetic ammonia processes. Renewable ammonia production relies on hydrogen generated by water electrolysis using electricity generated from hydropower. This was used commercially as early as 1921. In the present work we discuss how renewable ammonia production subsequently emerged in those countries endowed with abundant hydropower and in particular in regions with limited or no oil gas and coal deposits. Thus renewable ammonia played an important role in national food security for countries without fossil fuel resources until after the mid-20th century. For economic reasons renewable ammonia production declined from the 1960s onward in favor of fossil-based ammonia production. However renewable ammonia has recently gained traction again as an energy vector. It is an important component of the rapidly emerging hydrogen economy. Renewable ammonia will probably play a significant role in maintaining national and global energy and food security during the 21st century.
Moving Toward the Low-carbon Hydrogen Economy: Experiences and Key Learnings from National Case Studies
Sep 2022
Publication
The urgency to achieve net-zero carbon dioxide (CO2) emissions by 2050 as first presented by the IPCC special report on 1.5°C Global Warming has spurred renewed interest in hydrogen to complement electrification for widespread decarbonization of the economy. We present reflections on estimates of future hydrogen demand optimization of infrastructure for hydrogen production transport and storage development of viable business cases and environmental impact evaluations using life cycle assessments. We highlight challenges and opportunities that are common across studies of the business cases for hydrogen in Germany the UK the Netherlands Switzerland and Norway. The use of hydrogen in the industrial sector is an important driver and could incentivise large-scale hydrogen value chains. In the long-term hydrogen becomes important also for the transport sector. Hydrogen production from natural gas with capture and permanent storage of the produced CO2 (CCS) enables large-scale hydrogen production in the intermediate future and is complementary to hydrogen from renewable power. Furthermore timely establishment of hydrogen and CO2 infrastructures serves as an anchor to support the deployment of carbon dioxide removal technologies such as direct air carbon capture and storage (DACCS) and biohydrogen production with CCS. Significant public support is needed to ensure coordinated planning governance and the establishment of supportive regulatory frameworks which foster the growth of hydrogen markets.
High Technical and Temporal Resolution Integrated Energy System Modelling of Industrial Decarbonisation
Aug 2022
Publication
Owing to the complexity of the sector industrial activities are often represented with limited technological resolution in integrated energy system models. In this study we enriched the technological description of industrial activities in the integrated energy system analysis optimisation (IESA-Opt) model a peer-reviewed energy system optimisation model that can simultaneously provide optimal capacity planning for the hourly operation of all integrated sectors. We used this enriched model to analyse the industrial decarbonisation of the Netherlands for four key activities: high-value chemicals hydrocarbons ammonia and steel production. The analyses performed comprised 1) exploring optimality in a reference scenario; 2) exploring the feasibility and implications of four extreme industrial cases with different technological archetypes namely a bio-based industry a hydrogen-based industry a fully electrified industry and retrofitting of current assets into carbon capture utilisation and storage; and 3) performing sensitivity analyses on key topics such as imported biomass hydrogen and natural gas prices carbon storage potentials technological learning and the demand for olefins. The results of this study show that it is feasible for the energy system to have a fully bio-based hydrogen-based fully electrified and retrofitted industry to achieve full decarbonisation while allowing for an optimal technological mix to yield at least a 10% cheaper transition. We also show that owing to the high predominance of the fuel component in the levelled cost of industrial products substantial reductions in overnight investment costs of green technologies have a limited effect on their adoption. Finally we reveal that based on the current (2022) energy prices the energy transition is cost-effective and fossil fuels can be fully displaced from industry and the national mix by 2050
Critical Parameters Controlling Wettability in Hydrogen Underground Storage - An Analytical Study
Sep 2022
Publication
Hypothesis.<br/>The large-scale implementation of hydrogen economy requires immense storage spaces to facilitate the periodic storage/production cycles. Extensive modelling of hydrogen transport in porous media is required to comprehend the hydrogen-induced complexities prior to storage to avoid energy loss. Wettability of hydrogen-brine-rock systems influence flow properties (e.g. capillary pressure and relative permeability curves) and the residual saturations which are all essential for subsurface hydrogen systems.<br/>Model.<br/>This study aims to understand which parameters critically control the contact angle for hydrogen-brine-rock systems using the surface force analysis following the DLVO theory and sensitivity analysis. Furthermore the effect of roughness is studied using the Cassie-Baxter model.<br/>Findings.<br/>Our results reveal no considerable difference between H2 and other gases such as N2. Besides the inclusion of roughness highly affects the observed apparent contact angles and even lead to water-repelling features. It was observed that contact angle does not vary significantly with variations of surface charge and density at high salinity which is representative for reservoir conditions. Based on the analysis it is speculated that the influence of roughness on contact angle becomes significant at low water saturation (i.e. high capillary pressure).
Energy Transition in Aviation: The Role of Cryogenic Fuels
Dec 2020
Publication
Aviation is the backbone of our modern society. In 2019 around 4.5 billion passengers travelled through the air. However at the same time aviation was also responsible for around 5% of anthropogenic causes of global warming. The impact of the COVID-19 pandemic on the aviation sector in the short term is clearly very high but the long-term effects are still unknown. However with the increase in global GDP the number of travelers is expected to increase between three- to four-fold by the middle of this century. While other sectors of transportation are making steady progress in decarbonizing aviation is falling behind. This paper explores some of the various options for energy carriers in aviation and particularly highlights the possibilities and challenges of using cryogenic fuels/energy carriers such as liquid hydrogen (LH2) and liquefied natural gas (LNG).
Contact Angle Measurement for Hydrogen/Brine/Sandstone System Using Captive-Bubble Method Relevant for Underground Hydrogen Storage
May 2021
Publication
Subsurface porous formations provide large capacities for underground hydrogen storage (UHS). Successful utilization of these porous reservoirs for UHS depends on accurate quantification of the hydrogen transport characteristics at continuum (macro) scale specially in contact with other reservoir fluids. Relative-permeability and capillary-pressure curves are among the macro-scale transport characteristics which play crucial roles in quantification of the storage capacity and efficiency. For a given rock sample these functions can be determined if pore-scale (micro-scale) surface properties specially contact angles are known. For hydrogen/brine/rock system these properties are yet to a large extent unknown. In this study we characterize the contact angles of hydrogen in contact with brine and Bentheimer and Berea sandstones at various pressure temperature and brine salinity using captive-bubble method. The experiments are conducted close to the in-situ conditions which resulted in water-wet intrinsic contact angles about 25 to 45 degrees. Moreover no meaningful correlation was found with changing tested parameters. We monitor the bubbles over time and report the average contact angles with their minimum and maximum variations. Given rock pore structures using the contact angles reported in this study one can define relative-permeability and capillary-pressure functions for reservoir-scale simulations and storage optimization.
Optimization of Small-Scale Hydrogen Production with Membrane Reactors
Mar 2023
Publication
In the pathway towards decarbonization hydrogen can provide valid support in different sectors such as transportation iron and steel industries and domestic heating concurrently reducing air pollution. Thanks to its versatility hydrogen can be produced in different ways among which steam reforming of natural gas is still the most commonly used method. Today less than 0.7% of global hydrogen production can be considered low-carbon-emission. Among the various solutions under investigation for low-carbon hydrogen production membrane reactor technology has the potential especially at a small scale to efficiently convert biogas into green hydrogen leading to a substantial process intensification. Fluidized bed membrane reactors for autothermal reforming of biogas have reached industrial maturity. Reliable modelling support is thus necessary to develop their full potential. In this work a mathematical model of the reactor is used to provide guidelines for their design and operations in off-design conditions. The analysis shows the influence of temperature pressures catalyst and steam amounts and inlet temperature. Moreover the influence of different membrane lengths numbers and pitches is investigated. From the results guidelines are provided to properly design the geometry to obtain a set recovery factor value and hydrogen production. For a given reactor geometry and fluidization velocity operating the reactor at 12 bar and the permeate-side pressure of 0.1 bar while increasing reactor temperature from 450 to 500 °C leads to an increase of 33% in hydrogen production and about 40% in HRF. At a reactor temperature of 500 °C going from 8 to 20 bar inside the reactor doubled hydrogen production with a loss in recovery factor of about 16%. With the reactor at 12 bar a vacuum pressure of 0.5 bar reduces hydrogen production by 43% and HRF by 45%. With the given catalyst it is sufficient to have only 20% of solids filled into the reactor being catalytic particles. With the fixed operating conditions it is worth mentioning that by adding membranes and maintaining the same spacing it is possible to increase hydrogen production proportionally to the membrane area maintaining the same HRF.
Integration of Water Electrolysis Facilities in Power Grids: A Case Study in Northern Germany
Mar 2022
Publication
This work presents a study of the effects that integration of electrolysis facilities for Power-to-X processes have on the power grid. The novel simulation setup combines a high-resolution grid optimization model and a detailed scheduling model for alkaline water electrolysis. The utilization and congestion of power lines in northern Germany is investigated by setting different installed capacities and production strategies of the electrolysis facility. For electrolysis capacities up to 300 MW (~50 ktH2/a) local impacts on the grid are observed while higher capacities cause supra-regional impacts. Thereby impacts are defined as deviations from the average line utilization greater than 5%. In addition the minimum line congestion is determined to coincide with the dailyconstrained production strategy of the electrolysis facility. Our result show a good compromise for the integrated grid-facility operation with minimum production cost and reduced impact on the grid.
Perspective on the Hydrogen Economy as a Pathway to Reach Net-zero CO2 Emissions in Europe
Jan 2022
Publication
The envisioned role of hydrogen in the energy transition – or the concept of a hydrogen economy – has varied through the years. In the past hydrogen was mainly considered a clean fuel for cars and/or electricity production; but the current renewed interest stems from the versatility of hydrogen in aiding the transition to CO2 neutrality where the capability to tackle emissions from distributed applications and complex industrial processes is of paramount importance. However the hydrogen economy will not materialise without strong political support and robust infrastructure design. Hydrogen deployment needs to address multiple barriers at once including technology development for hydrogen production and conversion infrastructure co-creation policy market design and business model development. In light of these challenges we have brought together a group of hydrogen researchers who study the multiple interconnected disciplines to offer a perspective on what is needed to deploy the hydrogen economy as part of the drive towards net-zero-CO2 societies. We do this by analysing (i) hydrogen end-use technologies and applications (ii) hydrogen production methods (iii) hydrogen transport and storage networks (iv) legal and regulatory aspects and (v) business models. For each of these we provide key take home messages ranging from the current status to the outlook and needs for further research. Overall we provide the reader with a thorough understanding of the elements in the hydrogen economy state of play and gaps to be filled.
Reduction Kinetics of Hematite Powder in Hydrogen Atmosphere at Moderate Temperatures
Sep 2018
Publication
Hydrogen has received much attention in the development of direct reduction of iron ores because hydrogen metallurgy is one of the effective methods to reduce CO2 emission in the iron and steel industry. In this study the kinetic mechanism of reduction of hematite particles was studied in a hydrogen atmosphere. The phases and morphological transformation of hematite during the reduction were characterized using X-ray diffraction and scanning electron microscopy with energy dispersive spectroscopy. It was found that porous magnetite was formed and the particles were degraded during the reduction. Finally sintering of the reduced iron and wüstite retarded the reductive progress. The average activation energy was extracted to be 86.1 kJ/mol and 79.1 kJ/mol according to Flynn-Wall-Ozawa (FWO) and Starink methods respectively. The reaction fraction dependent values of activation energy were suggested to be the result of multi-stage reactions during the reduction process. Furthermore the variation of activation energy value was smoothed after heat treatment of hematite particles.
The Effects of Fuel Type and Cathode Off-gas Recirculation on Combined Heat and Power Generation of Marine SOFC Systems
Dec 2022
Publication
An increasing demand in the marine industry to reduce emissions led to investigations into more efficient power conversion using fuels with sustainable production pathways. Solid Oxide Fuel Cells (SOFCs) are under consideration for long-range shipping because of its high efficiency low pollutant emissions and fuel flexibility. SOFC systems also have great potential to cater for the heat demand in ships but the heat integration is not often considered when assessing its feasibility. This study evaluates the electrical and heat efficiency of a 100 kW SOFC system for marine applications fuelled with methane methanol diesel ammonia or hydrogen. In addition cathode off-gas recirculation (COGR) is investigated to tackle low oxygen utilisation and thus improve heat regeneration. The software Cycle Tempo is used to simulate the power plant which uses a 1D model for the SOFCs. At nominal conditions the highest net electrical efficiency (LHV) was found for methane (58.1%) followed by diesel (57.6%) and ammonia (55.1%). The highest heat efficiency was found for ammonia (27.4%) followed by hydrogen (25.6%). COGR resulted in similar electrical efficiencies but increased the heat efficiency by 11.9% to 105.0% for the different fuels. The model was verified with a sensitivity analysis and validated by comparison with similar studies. It is concluded that COGR is a promising method to increase the heat efficiency of marine SOFC systems.
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.
Hydrogen in the Electricity Value Chain
Mar 2019
Publication
Renewable energy sources like solar-PV and wind and the electrification of heating demand lead to more variability in the generation and demand of electricity. The need for flexibility in the electricity supply system e.g. by energy storage will therefore increase. Hydrogen has been a long-serving CO2-free energy carrier apt to store energy over a long period of time without significant losses.
Hydrogen Bubble Growth in Alkaline Water Electrolysis: An Immersed Boundary Simulation Study
Nov 2022
Publication
Enhancing the efficiency of industrial water electrolysis for hydrogen production is important for the energy transition. In electrolysis hydrogen is produced at the cathode which forms bubbles due to the diffusion of dissolved hydrogen in the surrounding supersaturated electrolyte. Hydrogen (and oxygen) bubbles play an important role in the achievable electrolysis efficiency. The growth of the bubbles is determined by diffusive and convective mass transfer. In turn the presence and the growth of the hydrogen bubbles affect the electrolysis process at the cathode.<br/>In the present study we simulate the growth of a single hydrogen bubble attached to a vertical cathode in a 30 wt KOH solution in a cathodic compartment represented by a narrow channel. We solve the Navier-Stokes equations mass transport equations and potential equation for a tertiary current distribution. A sharp interface immersed boundary method with an artificial compressibility method for the pressure is employed. To verify the numerical accuracy of the method we performed a grid refinement study and checked the global momentum and hydrogen mass balances. We investigate the effects of flow rate and operation pressure upon bubble growth behaviour species concentrations potential and current density. We compare different cases in two ways: for the same time and for the same bubble radius. We observe that increasing the flow velocity leads to a small increase in efficiency. Increasing the operation pressure causes higher hydrogen density which slows down the bubble growth. It is remarkable that for a given bubble radius increasing the pressure leads to a small decrease in efficiency.
Assessing Damaged Pipelines Transporting Hydrogen
Jun 2022
Publication
There is worldwide interest in transporting hydrogen using both new pipelines and pipelines converted from natural gas service. Laboratory tests investigating the effect of hydrogen on the mechanical properties of pipeline steels have shown that even low partial pressures of hydrogen can substantially reduce properties such as reduction in area and fracture toughness and increase fatigue crack growth rates. However qualitative arguments suggest that the effects on pipelines may not be as severe as predicted from the small scale tests. If the trends seen in laboratory tests do occur in service there are implications for the assessment of damage such as volumetric corrosion dents and mechanical interference. Most pipeline damage assessment methods are semi-empirical and have been calibrated with data from full scale tests that did not involve hydrogen. Hence the European Pipeline Research Group (EPRG) commissioned a study to investigate damage assessment methods in the presence of hydrogen. Two example pipeline designs were considered both were assessed assuming a modern high performance material and an older material. From these analyses the numerical results show that the high toughness material will tolerate damage even if the properties are degraded by hydrogen exposure. However low toughness materials may not be able to tolerate some types of severe damage. If the predictions are realistic operators may have to repair more damage or reduce operating pressures. Furthermore damage involving cracking may not Page 2 of 22 satisfy the ASME B31.12 requirements for preventing time dependent crack growth. Further work is required to determine if the effects predicted using small scale laboratory test data will occur in practice.
Modelling of Hydrogen-blended Dual-fuel Combustion using Flamelet-generated Manifold and Preferential Diffusion Effects
Oct 2022
Publication
In the present study Reynolds-Averaged Navier-Stokes simulations together with a novel flamelet generated manifold (FGM) hybrid combustion model incorporating preferential diffusion effects is utilised for the investigation of a hydrogen-blended diesel-hydrogen dual-fuel engine combustion process with high hydrogen energy share. The FGM hybrid combustion model was developed by coupling laminar flamelet databases obtained from diffusion flamelets and premixed flamelets. The model employed three control variables namely mixture fraction reaction progress variable and enthalpy. The preferential diffusion effects were included in the laminar flamelet calculations and in the diffusion terms in the transport equations of the control variables. The resulting model is then validated against an experimental diesel-hydrogen dual-fuel combustion engine. The results show that the FGM hybrid combustion model incorporating preferential diffusion effects in the flame chemistry and transport equations yields better predictions with good accuracy for the in-cylinder characteristics. The inclusion of preferential diffusion effects in the flame chemistry and transport equations was found to predict well several characteristics of the diesel-hydrogen dual-fuel combustion process: 1) ignition delay 2) start and end of combustion 3) faster flame propagation and quicker burning rate of hydrogen 4) high temperature combustion due to highly reactive nature of hydrogen radicals 5) peak values of the heat release rate due to high temperature combustion of the partially premixed pilot fuel spray with entrained hydrogen/air and then background hydrogen-air premixed mixture. The comparison between diesel-hydrogen dual-fuel combustion and diesel only combustion shows early start of combustion longer ignition delay time higher flame temperature and NOx emissions for dual-fuel combustion compared to diesel only combustion.
Islanded Ammonia Power Systems: Technology Review & Conceptual Process Design
Aug 2019
Publication
Recent advances in technologies for the decentralized islanded ammonia economy are reviewed with an emphasis on feasibility for long-term practical implementation. The emphasis in this review is on storage systems in the size range of 1–10 MW. Alternatives for hydrogen production nitrogen production ammonia synthesis ammonia separation ammonia storage and ammonia combustion are compared and evaluated. A conceptual process design based on the optimization of temperature and pressure levels of existing and recently proposed technologies is presented for an islanded ammonia energy system. This process design consists of wind turbines and solar panels for electricity generation a battery for short-term energy storage an electrolyzer for hydrogen production a pressure swing adsorption unit for nitrogen production a novel ruthenium-based catalyst for ammonia synthesis a supported metal halide for ammonia separation and storage and an ammonia fueled proton-conducting solid oxide fuel cell for electricity generation. In a generic location in northern Europe it is possible to operate the islanded energy system at a round-trip efficiency of 61% and at a cost of about 0.30–0.35 € kWh−1 .
Seasonal Energy Storage for Zero-emissions Multi-energy Systems Via Underground Hydrogen Storage
Jan 2020
Publication
The deployment of diverse energy storage technologies with the combination of daily weekly and seasonal storage dynamics allows for the reduction of carbon dioxide (CO2) emissions per unit energy provided. In particular the production storage and re-utilization of hydrogen starting from renewable energy has proven to be one of the most promising solutions for offsetting seasonal mismatch between energy generation and consumption. A realistic possibility for large-scale hydrogen storage suitable for long-term storage dynamics is presented by salt caverns. In this contribution we provide a framework for modelling underground hydrogen storage with a focus on salt caverns and we evaluate its potential for reducing the CO2 emissions within an integrated energy systems context. To this end we develop a first-principle model which accounts for the transport phenomena within the rock and describes the dynamics of the stored energy when injecting and withdrawing hydrogen. Then we derive a linear reduced order model that can be used for mixed-integer linear program optimization while retaining an accurate description of the storage dynamics under a variety of operating conditions. Using this new framework we determine the minimum-emissions design and operation of a multi-energy system with H2 storage. Ultimately we assess the potential of hydrogen storage for reducing CO2 emissions when different capacities for renewable energy production and energy storage are available mapping emissions regions on a plane defined by storage capacity and renewable generation. We extend the analysis for solar- and wind-based energy generation and for different energy demands representing typical profiles of electrical and thermal demands and different CO2 emissions associated with the electric grid.
Soft-linking of a Behavioral Model for Transport with Energy System Cost optimization Applied to Hydrogen in EU
Sep 2019
Publication
Fuel cell electric vehicles (FCEV) currently have the challenge of high CAPEX mainly associated to the fuel cell. This study investigates strategies to promote FCEV deployment and overcome this initial high cost by combining a detailed simulation model of the passenger transport sector with an energy system model. The focus is on an energy system with 95% CO2 reduction by 2050. Soft-linking by taking the powertrain shares by country from the simulation model is preferred because it considers aspects such as car performance reliability and safety while keeping the cost optimization to evaluate the impact on the rest of the system. This caused a 14% increase in total cost of car ownership compared to the cost before soft-linking. Gas reforming combined with CO2 storage can provide a low-cost hydrogen source for FCEV in the first years of deployment. Once a lower CAPEX for FCEV is achieved a higher hydrogen cost from electrolysis can be afforded. The policy with the largest impact on FCEV was a purchase subsidy of 5 k€ per vehicle in the 2030–2034 period resulting in 24.3 million FCEV (on top of 67 million without policy) sold up to 2050 with total subsidies of 84 bln€. 5 bln€ of R&D incentives in the 2020–2024 period increased the cumulative sales up to 2050 by 10.5 million FCEV. Combining these two policies with infrastructure and fuel subsidies for 2030–2034 can result in 76 million FCEV on the road by 2050 representing more than 25% of the total car stock. Country specific incentives split of demand by distance or shift across modes of transport were not included in this study.
The Emotional Dimensions of Energy Projects: Anger, Fear, Joy and Pride About the First Hydrogen Fuel Station in the Netherlands
May 2018
Publication
Citizens’ emotional responses to energy technology projects influence the success of the technology’s implementation. Contrary to popular belief these emotions can have a systematic base. Bringing together insights from appraisal theory and from technology acceptance studies this study develops and tests hypotheses regarding antecedents of anger fear joy and pride about a local hydrogen fuel station (HFS). A questionnaire study was conducted among 271 citizens living near the first publicly accessible HFS in the Netherlands around the time of its implementation. The results show that anger is significantly explained by (from stronger to weaker effects) perceived procedural and distributive unfairness and fear by distributive unfairness perceived safety procedural unfairness gender and prior awareness. Joy is significantly explained by perceived environmental outcomes and perceived usefulness and pride by prior awareness perceived risks trust in industry and perceived usefulness. The study concludes that these predictors are understandable practical and moral considerations which can and should be taken into account when developing and executing a project.
Methane Pyrolysis in a Molten Gallium Bubble Column Reactor for Sustainable Hydrogen Production: Proof of Concept & Techno-economic Assessment
Dec 2020
Publication
Nowadays nearly 50% of the hydrogen produced worldwide comes from Steam Methane Reforming (SMR) at an environmental burden of 10.5 tCO2 eq/tH2 accelerating the consequences of global warming. One way to produce clean hydrogen is via methane pyrolysis using melts of metals and salts. Compared to SMR significant less CO2 is produced due to conversion of methane into hydrogen and carbon making this route more sustainable to generate hydrogen. Hydrogen is produced with high purity and solid carbon is segregated and deposited on the molten bath. Carbon may be sold as valuable co-product making industrial scale promising. In this work methane pyrolysis was performed in a quartz bubble column using molten gallium as heat transfer agent and catalyst. A maximum conversion of 91% was achieved at 1119 °C and ambient pressure with a residence time of the bubbles in the liquid of 0.5 s. Based on in-depth analysis of the carbon it can be characterized as carbon black. Techno-economic and sensitivity analyses of the industrial concept were done for different scenarios. The results showed that if co-product carbon is saleable and a CO2 tax of 50 euro per tonne is imposed to the processes the molten metal technology can be competitive with SMR.
Guidelines and Recommendations for Indoor Use of Fuel Cells and Hydrogen Systems
Oct 2015
Publication
Deborah Houssin-Agbomson,
Simon Jallais,
Elena Vyazmina,
Guy Dang-Nhu,
Gilles Bernard-Michel,
Mike Kuznetsov,
Vladimir V. Molkov,
Boris Chernyavsky,
Volodymyr V. Shentsov,
Dmitry Makarov,
Randy Dey,
Philip Hooker,
Daniele Baraldi,
Evelyn Weidner,
Daniele Melideo,
Valerio Palmisano,
Alexandros G. Venetsanos,
Jan Der Kinderen and
Béatrice L’Hostis
Hydrogen energy applications often require that systems are used indoors (e.g. industrial trucks for materials handling in a warehouse facility fuel cells located in a room or hydrogen stored and distributed from a gas cabinet). It may also be necessary or desirable to locate some hydrogen system components/equipment inside indoor or outdoor enclosures for security or safety reasons to isolate them from the end-user and the public or from weather conditions.<br/>Using of hydrogen in confined environments requires detailed assessments of hazards and associated risks including potential risk prevention and mitigation features. The release of hydrogen can potentially lead to the accumulation of hydrogen and the formation of a flammable hydrogen-air mixture or can result in jet-fires. Within Hyindoor European Project carried out for the EU Fuel Cells and Hydrogen Joint Undertaking safety design guidelines and engineering tools have been developed to prevent and mitigate hazardous consequences of hydrogen release in confined environments. Three main areas are considered: Hydrogen release conditions and accumulation vented deflagrations jet fires and including under-ventilated flame regimes (e.g. extinguishment or oscillating flames and steady burns). Potential RCS recommendations are also identified.
Hydrogen Permeation Studies of Composite Supported Alumina-carbon Molecular Sieves Membranes: Separation of Diluted Hydrogen from Mixtures with Methane
Jun 2020
Publication
One alternative for the storage and transport of hydrogen is blending a low amount of hydrogen (up to 15 or 20%) into existing natural gas grids. When demanded hydrogen can be then separated close to the end users using membranes. In this work composite alumina carbon molecular sieves membranes (Al-CMSM) supported on tubular porous alumina have been prepared and characterized. Single gas permeation studies showed that the H2/CH4 separation properties at 30 °C are well above the Robeson limit of polymeric membranes. H2 permeation studies of the H2–CH4 mixture gases containing 5–20% of H2 show that the H2 purity depends on the H2 content in the feed and the operating temperature. In the best scenario investigated in this work for samples containing 10% of H2 with an inlet pressure of 7.5 bar and permeated pressure of 0.01 bar at 30 °C the H2 purity obtained was 99.4%.
Direct Route from Ethanol to Pure Hydrogen through Autothermal Reforming in a Membrane Reactor: Experimental Demonstration, Reactor Modelling and Design
Nov 2020
Publication
This work reports the integration of thin (~3e4 mm thick) Pd-based membranes for H2 separation in a fluidized bed catalytic reactor for ethanol auto-thermal reforming. The performance of a fluidized bed membrane reactor has been investigated from an experimental and numerical point of view. The demonstration of the technology has been carried out over 50 h under reactive conditions using 5 thin Pd-based alumina-supported membranes and a 3 wt%Pt-10 wt%Ni catalyst deposited on a mixed CeO2/SiO2 support. The results have confirmed the feasibility of the concept in particular the capacity to reach a hydrogen recovery factor up to 70% while the operation at different fluidization regimes oxygen-to-ethanol and steam-to-ethanol ratios feed pressures and reactor temperatures have been studied. The most critical part of the system is the sealing of the membranes where most of the gas leakage was detected. A fluidized bed membrane reactor model for ethanol reforming has been developed and validated with the obtained experimental results. The model has been subsequently used to design a small reactor unit for domestic use showing that 0.45 m2 membrane area is needed to produce the amount of H2 required for a 5 kWe PEM fuel-cell based micro-CHP system.
Life Cycle Assessments on Battery Electric Vehicles and Electrolytic Hydrogen: The Need for Calculation Rules and Better Databases on Electricity
May 2021
Publication
LCAs of electric cars and electrolytic hydrogen production are governed by the consumption of electricity. Therefore LCA benchmarking is prone to choices on electricity data. There are four issues: (1) leading Life Cycle Impact (LCI) databases suffer from inconvenient uncertainties and inaccuracies (2) electricity mix in countries is rapidly changing year after year (3) the electricity mix is strongly fluctuating on an hourly and daily basis which requires time-based allocation approaches and (4) how to deal with nuclear power in benchmarking. This analysis shows that: (a) the differences of the GHG emissions of the country production mix in leading databases are rather high (30%) (b) in LCA a distinction must be made between bundled and unbundled registered electricity certificates (RECs) and guarantees of origin (GOs); the residual mix should not be applied in LCA because of its huge inaccuracy (c) time-based allocation rules for renewables are required to cope with periods of overproduction (d) benchmarking of electricity is highly affected by the choice of midpoints and/or endpoint systems and (e) there is an urgent need for a new LCI database based on measured emission data continuously kept up-to-date transparent and open access.
Transient Reversible Solid Oxide Cell Reactor Operation – Experimentally Validated Modeling and Analysis
Oct 2018
Publication
A reversible solid oxide cell (rSOC) reactor can operate efficiently in both electrolysis mode and in fuel cell mode. The bidirectional operability enables rSOC reactors to play a central role as an efficient energy conversion system for energy storage and sector coupling for a renewable energy driven society. A combined system for electrolysis and fuel cell operation can result in complex system configurations that should be able to switch between the two modes as quickly as possible. This can lead to temperature profiles within the reactor that can potentially lead to the failure of the reactor and eventually the system. Hence the behavior of the reactor during the mode switch should be analyzed and optimal transition strategies should be taken into account during the process system design stage. In this paper a one dimensional transient reversible solid oxide cell model was built and experimentally validated using a commercially available reactor. A simple hydrogen based system model was built employing the validated reactor model to study reactor behavior during the mode switch. The simple design leads to a system efficiency of 49% in fuel cell operation and 87% in electrolysis operation where the electrolysis process is slightly endothermic. Three transient operation strategies were studied. It is shown that the voltage response to transient operation is very fast provided the reactant flows are changed equally fast. A possible solution to ensure a safe mode switch by controlling the reactant inlet temperatures is presented. By keeping the rate of change of reactant inlet temperatures five to ten times slower than the mode switch a safe transition can be ensured.
Thermodynamic Evaluation of Bi-directional Solid Oxide Cell Systems Including Year-round Cumulative Exergy Analysis
Jun 2018
Publication
Bi-directional solid oxide cell systems (Bi-SOC) are being increasingly considered as an electrical energy storage method and consequently as a means to boost the penetration of renewable energy (RE) and to improve the grid flexibility by power-to-gas electrochemical conversion. A major advantage of these systems is that the same SOC stack operates as both energy storage device (SOEC) and energy producing device (SOFC) based on the energy demand and production. SOEC and SOFC systems are now well-optimised as individual systems; this work studies the effect of using the bi-directionality of the SOC at a system level. Since the system performance is highly dependent on the cell-stack operating conditions this study improves the stack parameters for both operation modes. Moreover the year-round cumulative exergy method (CE) is introduced in the solid oxide cell (SOC) context for estimating the system exergy efficiencies. This method is an attempt to obtain more insightful exergy assessments since it takes into account the operational hours of the SOC system in both modes. The CE method therefore helps to predict more accurately the most efficient configuration and operating parameters based on the power production and consumption curves in a year. Variation of operating conditions configurations and SOC parameters show a variation of Bi-SOC system year-round cumulative exergy efficiency from 33% to 73%. The obtained thermodynamic performance shows that the Bi-SOC when feasible can prove to be a highly efficient flexible power plant as well as an energy storage system.
Potential Role of Natural Gas Infrastructure in China to Supply Low-carbon Gases During 2020–2050
Oct 2021
Publication
As natural gas (NG) demand increases in China the question arises how the NG infrastructure fit into a low greenhouse gas (GHG) emissions future towards 2050. Herein the potential role of the NG infrastructure in supplying low-carbon gases during 2020–2050 for China at a provincial resolution was analyzed for different scenarios. In total four low-carbon gases were considered in this study: biomethane bio-synthetic methane hydrogen and low-carbon synthetic methane. The results show that the total potential of low-carbon gas production can increase from 1.21 EJ to 5.25 EJ during 2020–2050 which can replace 20%–67% of the imported gas. In particular Yunnan and Inner Mongolia contribute 17% of China’s low-carbon gas production. As the deployment of NG infrastructure can be very different three scenarios replacing imported pipeline NG were found to reduce the expansion of gas infrastructure by 35%–42% while the three scenarios replacing LNG imports were found to increase infrastructure expansion by 31%–53% as compared to the base case. The cumulative avoided GHG emissions for the 6 analyzed scenarios were 6.0–8.3 Gt CO2. The GHG avoidance costs were highly influenced by the NG price. This study shows that the NG infrastructure has the potential to supply low-carbon gases in China thereby significantly reducing GHG emissions and increasing both China’s short- and long-term gas supply independence.
Wind Power to Methanol: Renewable Methanol Production Using Electricity, Electrolysis of Water and CO2 Air Capture
Feb 2020
Publication
A 100 MW stand-alone wind power to methanol process has been evaluated to determine the capital requirement and power to methanol efficiency. Power available for electrolysis determines the amount of hydrogen produced. The stoichiometric amount of CO2– required for the methanol synthesis – is produced using direct air capture. Integration of utilities for CO2 air capture hydrogen production from co-harvested water and methanol synthesis is incorporated and capital costs for all process steps are estimated. Power to methanol efficiency is determined to be around 50%. The cost of methanol is around 300€ ton−1 excluding and 800€ ton−1 including wind turbine capital cost. Excluding 300 M€ investment cost for 100 MW of wind turbines total plant capital cost is around 200 M€. About 45% of the capital cost is reserved for the electrolysers 50% for the CO2 air capture installation and 5% for the methanol synthesis system. The conceptual design and evaluation shows that renewable methanol produced from air captured CO2 water and renewable electricity is becoming a realistic option at reasonable costs of 750–800 € ton−1.
Cost Minimisation of Renewable Hydrogen in a Dutch Neighbourhood While Meeting European Union Sustainability Targets
Jun 2022
Publication
Decentralised renewable energy production in the form of fuels or electricity can have large scale deployment in future energy systems but the feasibility needs to be assessed. The novelty of this paper is in the design and implementation of a mixed integer linear programming optimisation model to minimise the net present cost of decentralised hydrogen production for different energy demands on neighbourhood urban scale while simultaneously adhering to European Union targets on greenhouse gas emission reductions. The energy system configurations optimised were assumed to possibly consist of a variable number or size of wind turbines solar photovoltaics grey grid electricity usage battery storage electrolyser and hydrogen storage. The demands served are hydrogen for heating and mobility and electricity for the households. A hydrogen residential heating project currently being developed in Hoogeveen The Netherlands served as a case study. Six scenarios were compared each taking one or multiple energy demand services into question. For each scenario the levelised cost of hydrogen was calculated. The lowest levelised cost of hydrogen was found for the combined heating and mobility scenario: 8.36 € kg− 1 for heating and 9.83 € kg− 1 for mobility. The results support potential cost reductions of combined demand patterns of different energy services. A sensitivity analysis showed a strong influence of electrolyser efficiency wind turbine parameters and emission reduction factor on levelised cost. Wind energy was strongly preferred because of the lower cost and the low greenhouse gas emissions compared to solar photovoltaics and grid electricity. Increasing electrolyser efficiency and greenhouse gas emission reduction of the used technologies deserve further research.
Fatigue Behavior of AA2198 in Liquid Hydrogen
Aug 2019
Publication
Tensile and fatigue tests were performed on an AA2198 aluminum alloy in the T851 condition in ambient air and liquid hydrogen (LH2). All fatigue tests were performed under load control at a frequency of 20 Hz and a stress ratio of R=0.1. The Gecks-Och-Function [1] was fitted on the measured cyclic lifetimes.<br/><br/>The tensile strength in LH2 was measured to be 46 % higher compared to the value determined at ambient conditions and the fatigue limit was increased by approximately 60 %. Both S-N curves show a distinct S-shape but also significant differences. Under LH2 environment the transition from LCF- to HCF-region as well as the transition to the fatigue limit is shifted to higher cyclic lifetimes compared to ambient test results. The investigation of the crack surfaces showed distinct differences between ambient and LH2 conditions. These observed differences are important factors in the fatigue behavior change.
Internal and Surface Damage after Electrochemical Hydrogen Charging for Ultra Low Carbon Steel with Various Degrees of Recrystallization
Jul 2016
Publication
An ultra low carbon (ULC) steel was subjected to electrochemical hydrogen charging to provoke hydrogen induced damage in the material. The damage characteristics were analyzed for recrystallized partially recrystallized and cold deformed material. The goal of the study is to understand the effect of cold deformation on the hydrogen induced cracking behavior of a material which is subjected to cathodic hydrogen charging. Additionally charging conditions i.e. charging time and current density were varied in order to identify correlations between on the one hand crack initiation and propagation and on the other hand the charging conditions. The obtained hydrogen induced cracks were studied by optical microscopy scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). Hydrogen induced cracks were observed to propagate transgranularly independently of the state of the material. Deformed samples were considerably more sensitive to hydrogen induced cracking which implies the important role of dislocations in hydrogen induced damage mechanisms.
Towards a CO2-neutral Steel Industry: Justice Aspects of CO2 Capture and Storage, Biomass- and Green Hydrogen-based Emission Reductions
Apr 2022
Publication
A rapid transition towards a CO2-neutral steel industry is required to limit climate change. Such a transition raises questions of justice as it entails positive and negative impacts unevenly distributed across societal stakeholders. To enable stakeholders to address such concerns this paper assesses the justice implications of three options that reduce emissions: CO2 capture and storage (CCS) on steel (up to 70%) bio-based steelmaking (up to 50%) and green hydrogen-based steel production (up to 100%). We select justice indicators from the energy climate labour and environmental justice literature and assess these indicators qualitatively for each of the technological routes based on literature and desk research. We find context-dependent differences in justness between the different technological routes. The impact on stakeholders varies across regions. There are justice concerns for local communities because of economic dependence on and environmental impact of the industry. Communities elsewhere are impacted through the siting of infrastructure and feedstock production. CCS and bio-based steelmaking routes can help retain industry and associated economic benefits on location while hydrogen-based steelmaking may deal better with environmental concerns. We conclude that besides techno-economic and environmental information transparency on sector-specific justice implications of transforming steel industries is essential for decision-making on technological routes
Influence of the Gas Injector Configuration on the Temperature Evolution During Refueling of On-board Hydrogen Tanks
Jul 2016
Publication
In this article we show a refuelling strategy analysis using different injector configurations to refuel a 70 MPa composite reinforced type 4 tank. The gas has been injected through single openings of different diameters (3 mm 6 mm and 10 mm) and alternatively through multiple small holes (4 × 3 mm). For each injector configuration slow (12 min) and faster (3 min) fillings have been performed. The gas temperature has been measured at different positions inside the tank as well as the temperatures of the wall materials at various locations: on the external surface and at the interface between the liner and the fiber reinforced composite. In general the larger the injector diameter and the slower the filling the higher the chance that the gas develops vertical temperature gradients (a so-called gas temperature stratification) resulting in higher than average temperatures near the top of the tank and lower than average at its bottom. While the single 3 mm opening injector causes homogeneous gas temperatures for both filling speeds both the 6 mm and 10 mm opening injectors induce gas temperature stratification during the 12 min fillings. The injector with multiple holes has an area comparable to the 6 mm single opening injector: in general this more complex geometry tends to limit the inhomogeneity of gas temperatures during slow fillings. When gas temperature stratification develops the wall materials temperature is also locally affected. This results in a higher than average temperature at the top of the tank and higher the slower the filling.
Trace Level Analysis of Reactive ISO 14687 Impurities in Hydrogen Fuel Using Laser-based Spectroscopic Detection Methods
Oct 2020
Publication
Hydrogen fuelled vehicles can play a key role in the decarbonisation of transport and reducing emissions. To ensure the durability of fuel cells a specification has been developed (ISO 14687) setting upper limits to the amount fraction of a series of impurities. Demonstrating conformity with this standard requires demonstrating by measurement that the actual levels of the impurities are below the thresholds. Currently the industry is unable to do so for measurement standards and sensitive dedicated analytical methods are lacking. In this work we report on the development of such measurement standards and methods for four reactive components: formaldehyde formic acid hydrogen chloride and hydrogen fluoride. The primary measurement standard is based on permeation and the analytical methods on highly sensitive and selective laser-based spectroscopic techniques. Relative expanded uncertainties at the ISO 14687 threshold level in hydrogen of 4% (formaldehyde) 8% (formic acid) 5% (hydrogen chloride) and 8% (hydrogen fluoride) have been achieved.
Optimal Hydrogen Production in a Wind-dominated Zero-emission Energy System
May 2021
Publication
The role of hydrogen in future energy systems is widely acknowledged: from fuel for difficult-to-decarbonize applications to feedstock for chemicals synthesis to energy storage for high penetration of undispatchable renewable electricity. While several literature studies investigate such energy systems the details of how electrolysers and renewable technologies optimally behave and interact remain an open question. With this work we study the interplay between (i) renewable electricity generation through wind and solar (ii) electricity storage in batteries (iii) electricity storage via Power-to-H2 and (iv) hydrogen commodity demand. We do so by designing a cost-optimal zero-emission energy system and use the Netherlands as a case study in a mixed integer linear model with hourly resolution for a time horizon of one year. To account for the significant role of wind we also provide an elaborate approach to model broad portfolios of wind turbines. The results show that if electrolyzers can operate flexibly batteries and power-to-H2-to-power are complementary with the latter using renewable power peaks and the former using lower renewable power outputs. If the operating modes of the power-to-H2-to-power system are limited - artificially or technically - the competitive advantage over batteries decreases. The preference of electrolyzers for power peaks also leads to an increase in renewable energy utilization for increased levels of operation flexibility highlighting the importance of capturing this feature both from a technical and a modeling perspective. When adding a commodity hydrogen demand the amount of hydrogen converted to electricity decreases hence decreasing its role as electricity storage medium.
Electrochemical Conversion Technologies for Optimal Design of Decentralized Multi-energy Systems: Modeling Framework and Technology Assessment
Apr 2018
Publication
The design and operation of integrated multi-energy systems require models that adequately describe the behavior of conversion and storage technologies. Typically linear conversion performance or fixed data from technology manufacturers are employed especially for new or advanced technologies. This contribution provides a new modeling framework for electrochemical devices that bridges first-principles models to their simplified implementation in the optimization routine. First thermodynamic models are implemented to determine the on/off-design performance and dynamic behavior of different types of fuel cells and of electrolyzers. Then as such nonlinear models are intractable for use in the optimization of integrated systems different linear approximations are developed. The proposed strategies for the synthesis of reduced order models are compared to assess the impact of modeling approximations on the optimal design of multi-energy systems including fuel cells and electrolyzers. This allows to determine the most suitable level of detail for modeling the underlying electrochemical technologies from an integrated system perspective. It is found that the approximation methodology affects both the design and operation of the system with a significant effect on system costs and violation of the thermal energy demand. Finally the optimization and technology modeling framework is exploited to determine guidelines for the installation of the most suitable fuel cell technology in decentralized multi-energy systems. We show how the installation costs of PEMFC SOFC and MCFC their electrical and thermal efficiencies their conversion dynamics and the electricity price affect the system design and technology selection.
Timmermans’ Dream: An Electricity and Hydrogen Partnership Between Europe and North Africa
Oct 2021
Publication
Because of differences in irradiation levels it could be more efficient to produce solar electricity and hydrogen in North Africa and import these energy carriers to Europe rather than generating them at higher costs domestically in Europe. From a global climate change mitigation point of view exploiting such efficiencies can be profitable since they reduce overall renewable electricity capacity requirements. Yet the construction of this capacity in North Africa would imply costs associated with the infrastructure needed to transport electricity and hydrogen. The ensuing geopolitical dependencies may also raise energy security concerns. With the integrated assessment model TIAM-ECN we quantify the trade-off between costs and benefits emanating from establishing import-export links between Europe and North Africa for electricity and hydrogen. We show that for Europe a net price may have to be paid for exploiting such interlinkages even while they reduce the domestic investments for renewable electricity capacity needed to implement the EU’s Green Deal. For North African countries the potential net benefits thanks to trade revenues may build up to 50 billion €/yr in 2050. Despite fears over costs and security Europe should seriously consider an energy partnership with North Africa because trade revenues are likely to lead to positive employment income and stability effects in North Africa. Europe can indirectly benefit from such impacts.
Integrating a Hydrogen Fuel Cell Electric Vehicle with Vehicle-to-grid Technology, Photovoltaic Power and a Residential Building
Feb 2018
Publication
This paper presents the results of a demonstration project including building-integrated photovoltaic (BIPV) solar panels a residential building and a hydrogen fuel cell electric vehicle (FCEV) for combined mobility and power generation aiming to achieve a net zero-energy residential building target. The experiment was conducted as part of the Car as Power Plant project at The Green Village in the Netherlands. The main objective was to assess the end-user’s potential of implementing FCEVs in vehicle-to-grid operation (FCEV2G) to act as a local energy source. FCEV2G field test performance with a Hyundai ix35 FCEV are presented. The car was adapted using a power output socket capable of delivering up to 10 kW direct current (DC) to the alternating current (AC) national grid when parked via an off-board (grid-tie) inverter. A Tank-To-AC-Grid efficiency (analogous to Tank- To-Wheel efficiency when driving) of 44% (measured on a Higher Heating Value basis) was obtained when the car was operating in vehicle-to-grid (V2G) mode at the maximum power output. By collecting and analysing real data on the FCEV power production in V2G mode and on BIPV production and household consumption two different operating modes for the FCEV offering balanced services to a residential microgrid were identified namely fixed power output and load following. Based on the data collected one-year simulations of a microgrid consisting of 10 all-electric dwellings and 5 cars with the different FCEV2G modes of operation were performed. Simulation results were evaluated on the factors of autonomy self-consumption of locally produced energy and net-energy consumption by implementing different energy indicators. The results show that utilizing an FCEV working in V2G mode can reduce the annual imported electricity from the grid by approximately 71% over one year and aiding the buildings in the microgrid to achieve a net zero-energy building target. Furthermore the simulation results show that utilizing the FCEV2G setup in both modes analysed could be economically beneficial for the end-user if hydrogen prices at the pump fall below 8.24 €/kg.
Fuel Cell Electric Vehicle as a Power Plant and SOFC as a Natural Gas Reformer: An Exergy Analysis of Different System Designs
Apr 2016
Publication
Delft University of Technology under its ‘‘Green Village” programme has an initiative to build a power plant (car parking lot) based on the fuel cells used in vehicles for motive power. It is a trigeneration system capable of producing electricity heat and hydrogen. It comprises three main zones: a hydrogen production zone a parking zone and a pump station zone. This study focuses mainly on the hydrogen production zone which assesses four different system designs in two different operation modes of the facility: Car as Power Plant (CaPP) mode corresponding to the open period of the facility which uses fuel cell electric vehicles (FCEVs) as energy and water producers while parked; and Pump mode corresponding to the closed period which compresses the hydrogen and pumps to the vehicle’s fuel tank. These system designs differ by the reforming technology: the existing catalytic reformer (CR) and a solid oxide fuel cell operating as reformer (SOFCR); and the option of integrating a carbon capture and storage (CCS). Results reveal that the SOFCR unit significantly reduces the exergy destruction resulting in an improvement of efficiency over 20% in SOFCR-based system designs compared to CR-based system designs in both operation modes. It also mitigates the reduction in system efficiency by integration of a CCS unit achieving a value of 2% whereas in CR-based systems is 7–8%. The SOFCR-based system running in Pump mode achieves a trigeneration efficiency of 60%.
Modeling Photovoltaic-electrochemical Water Splitting Devices for the Production of Hydrogen Under Real Working Conditions
Jan 2022
Publication
Photoelectrochemical splitting of water is potentially a sustainable and affordable solution to produce hydrogen from sun light. Given the infancy stage of technology development it is important to compare the different experimental concepts and identify the most promising routes. The performance of photoelectrochemical devices is typically measured and reported under ideal irradiation conditions i.e. 1 sun. However real-life operating conditions are very different and are varying in time according to daily and seasonal cycles. In this work we present an equivalent circuit model for computing the steady state performance of photoelectrochemical cells. The model allows for a computationally efficient yet precise prediction of the system performance and a comparison of different devices working in real operating conditions. To this end five different photo-electrochemical devices are modeled using experimental results from literature. The calculated performance shows good agreement with experimental data of the different devices. Furthermore the model is extended to include the effect of illumination and tilt angle on the hydrogen production efficiency. The resulting model is used to compare the devices for different locations with high and low average illumination and different tilt angles. The results show that including real illumination data has a considerable impact on the efficiency of the PV-EC device. The yearly average solar-to-hydrogen efficiency is significantly lower than the ideal one. Moreover it is dependent on the tilt angle whose optimal value for European-like latitude is around 40. Notably we also show that the most performing device through the whole year might not necessarily be the one with highest sun-to-hydrogen efficiency for one-sun illumination.
Life Cycle Environmental and Cost Comparison of Current and Future Passenger Cars under Different Energy Scenarios
Apr 2020
Publication
In this analysis life cycle environmental burdens and total costs of ownership (TCO) of current (2017) and future (2040) passenger cars with different powertrain configurations are compared. For all vehicle configurations probability distributions are defined for all performance parameters. Using these a Monte Carlo based global sensitivity analysis is performed to determine the input parameters that contribute most to overall variability of results. To capture the systematic effects of the energy transition future electricity scenarios are deeply integrated into the ecoinvent life cycle assessment background database. With this integration not only the way how future electric vehicles are charged is captured but also how future vehicles and batteries are produced. If electricity has a life cycle carbon content similar to or better than a modern natural gas combined cycle powerplant full powertrain electrification makes sense from a climate point of view and in many cases also provides reductions in TCO. In general vehicles with smaller batteries and longer lifetime distances have the best cost and climate performance. If a very large driving range is required or clean electricity is not available hybrid powertrain and compressed natural gas vehicles are good options in terms of both costs and climate change impacts. Alternative powertrains containing large batteries or fuel cells are the most sensitive to changes in the future electricity system as their life cycles are more electricity intensive. The benefits of these alternative drivetrains are strongly linked to the success of the energy transition: the more the electricity sector is decarbonized the greater the benefit of electrifying passenger vehicles.
Advanced Polymeric/inorganic Nanohybrids: An Integrated Platform for Gas Sensing Applications
Jan 2022
Publication
Rapid industrial development vehicles domestic activities and mishandling of garbage are the main sources of pollutants which are destroying the atmosphere. There is a need to continuously monitor these pollutants for the safety of the environment and human beings. Conventional instruments for monitoring of toxic gases are expensive bigger in size and time-consuming. Hybrid materials containing organic and inorganic components are considered potential candidates for diverse applications including gas sensing. Gas sensors convert the information regarding the analyte into signals. Various polymeric/inorganic nanohybrids have been used for the sensing of toxic gases. Composites of different polymeric materials like polyaniline (PANI) poly (4-styrene sulfonate) (PSS) poly (34-ethylene dioxythiophene) (PEDOT) etc. with various metal/metal oxide nanoparticles have been reported as sensing materials for gas sensors because of their unique redox features conductivity and facile operation at room temperature. Polymeric nanohybrids showed better performance because of the larger surface area of nanohybrids and the synergistic effect between polymeric and inorganic materials. This review article focuses on the recent developments of emerging polymeric/inorganic nanohybrids for sensing various toxic gases including ammonia hydrogen nitrogen dioxide carbon oxides and liquefied petroleum gas. Advantages disadvantages operating conditions and prospects of hybrid composites have also been discussed.
Assessing the Environmental Impacts of Wind-based Hydrogen Production in the Netherlands Using Ex-ante LCA and Scenarios Analysis
Mar 2021
Publication
Two electrolysis technologies fed with renewable energy sources are promising for the production of CO2-free hydrogen and enabling the transition to a hydrogen society: Alkaline Electrolyte (AE) and Polymer Electrolyte Membrane (PEM). However limited information exists on the potential environmental impacts of these promising sustainable innovations when operating on a large-scale. To fill this gap the performance of AE and PEM systems is compared using ex-ante Life Cycle Assessment (LCA) technology analysis and exploratory scenarios for which a refined methodology has been developed to study the effects of implementing large-scale sustainable hydrogen production systems. Ex-ante LCA allows modelling the environmental impacts of hydrogen production exploratory scenario analysis allows modelling possible upscaling effects at potential future states of hydrogen production and use in vehicles in the Netherlands in 2050. A bridging tool for mapping the technological field has been created enabling the combination of quantitative LCAs with qualitative scenarios. This tool also enables diversity for exploring multiple sets of visions. The main results from the paper show with an exception for the “ozone depletion” impact category (1) that large-scale AE and PEM systems have similar environmental impacts with variations lower than 7% in all impact categories (2) that the contribution of the electrolyser is limited to 10% of all impact categories results and (3) that the origin of the electricity is the largest contributor to the environmental impact contributing to more than 90% in all impact categories even when renewable energy sources are used. It is concluded that the methodology was applied successfully and provides a solid basis for an ex-ante assessment framework that can be applied to emerging technological systems.
A Review of Fuel Cell Powertrains for Long-Haul Heavy-Duty Vehicles: Technology, Hydrogen, Energy and Thermal Management Solutions
Dec 2022
Publication
Long-haul heavy-duty vehicles including trucks and coaches contribute to a substantial portion of the modern-day European carbon footprint and pose a major challenge in emissions reduction due to their energy-intensive usage. Depending on the hydrogen fuel source the use of fuel cell electric vehicles (FCEV) for long-haul applications has shown significant potential in reducing road freight CO2 emissions until the possible maturity of future long-distance battery-electric mobility. Fuel cell heavy-duty (HD) propulsion presents some specific characteristics advantages and operating constraints along with the notable possibility of gains in powertrain efficiency and usability through improved system design and intelligent onboard energy and thermal management. This paper provides an overview of the FCEV powertrain topology suited for long-haul HD applications their operating limitations cooling requirements waste heat recovery techniques state-of-the-art in powertrain control energy and thermal management strategies and over-the-air route data based predictive powertrain management including V2X connectivity. A case study simulation analysis of an HD 40-tonne FCEV truck is also presented focusing on the comparison of powertrain losses and energy expenditures in different subsystems while running on VECTO Regional delivery and Long-haul cycles. The importance of hydrogen fuel production pathways onboard storage approaches refuelling and safety standards and fleet management is also discussed. Through a comprehensive review of the H2 fuel cell powertrain technology intelligent energy management thermal management requirements and strategies and challenges in hydrogen production storage and refuelling this article aims at helping stakeholders in the promotion and integration of H2 FCEV technology towards road freight decarbonisation.
Particle Size and Crystal Phase Effects in Fischer-Tropsch Catalysts
Aug 2017
Publication
Fischer-Tropsch synthesis (FTS) is an increasingly important approach for producing liquid fuels and chemicals via syngas—that is synthesis gas a mixture of carbon monoxide and hydrogen—generated from coal natural gas or biomass. In FTS dispersed transition metal nanoparticles are used to catalyze the reactions underlying the formation of carbon-carbon bonds. Catalytic activity and selectivity are strongly correlated with the electronic and geometric structure of the nanoparticles which depend on the particle size morphology and crystallographic phase of the nanoparticles. In this article we review recent works dealing with the aspects of bulk and surface sensitivity of the FTS reaction. Understanding the different catalytic behavior in more detail as a function of these parameters may guide the design of more active selective and stable FTS catalysts.
Potential and Challenges of Low-carbon Energy Options: Comparative Assessment of Alternative Fuels for the Transport Sector
Dec 2018
Publication
The deployment of low-emission alternative fuels is crucial to decarbonise the transport sector. A number of alternatives like hydrogen or dimethyl ether/methanol synthesised using CO2 as feedstock for fuel production (hereafter refer to “CO2-based fuels”) have been proposed to combat climate change. However the decarbonisation potential of CO2-based fuels is under debate because CO2 is re-emitted to the atmosphere when the fuel is combusted; and the majority of hydrogen still relies on fossil resources which makes its prospects of being a low-carbon fuel dependent on its manufacturing process. First this paper investigates the relative economic and environmental performance of hydrogen (produced from conventional steam methane reforming and produced via electrolysis using renewable energy) and CO2- based fuels (dimethyl ether and methanol) considering the full carbon cycle. The results reveal that hydrogen produced from steam methane reforming is the most economical option and that hydrogen produced via electrolysis using renewables has the best environmental profile. Whereas the idea of CO2-based fuels has recently gained much interest it has for the foreseeable future rather limited practical relevance since there is no favourable combination of cost and environmental performance. This will only change in the long run and requires that CO2 is of non-fossil origin i.e. from biomass combustion or captured from air. Second this paper address unresolved methodological issues in the assessment of CO2-based fuels such as the possible allocation of emissions to the different sectors involved. The outcomes indicate that implementing different allocation approaches substantially influences the carbon footprint of CO2-based fuels. To avoid allocation issues expanding the boundaries including the entire system and is therefore recommended.
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