Netherlands
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.
A Positive Shift in the Public Acceptability of a Low-Carbon Energy Project After Implementation: The Case of a Hydrogen Fuel Station
Apr 2019
Publication
Public acceptability of low-carbon energy projects is often measured with one-off polls. This implies that opinion-shifts over time are not always taken into consideration by decision makers relying on these polls. Observations have given the impression that public acceptability of energy projects increases after implementation. However this positive shift over time has not yet been systematically studied and is not yet understood very well. This paper aims to fill this gap. Based on two psychological mechanisms loss aversion and cognitive dissonance reduction we hypothesize that specifically people who live in proximity of a risky low-carbon technology—a hydrogen fuel station (HFS) in this case—evaluate this technology as more positive after its implementation than before. We conducted a survey among Dutch citizen living nearby a HFS and indeed found a positive shift in the overall evaluation of HFS after implementation. We also found that the benefits weighed stronger and the risks weaker after the implementation. This shift did not occur for citizens living further away from the HFS. The perceived risks and benefits did not significantly change after implementation neither for citizens living in proximity nor for citizens living further away. The societal implications of the findings are discussed.
Expectations as a Key to Understanding Actor Strategies in the Field of Fuel Cell and Hydrogen Vehicles
Feb 2012
Publication
Due to its environmental impact the mobility system is increasingly under pressure. The challenges to cope with climate change air quality depleting fossil resources imply the need for a transition of the current mobility system towards a more sustainable one. Expectations and visions have been identified as crucial in the guidance of such transitions and more specifically of actor strategies. Still it remained unclear why the actors involved in transition activities appear to change their strategies frequently and suddenly. The empirical analysis of the expectations and strategies of three actors in the field of hydrogen and fuel cell technology indicates that changing actor strategies can be explained by rather volatile expectations related to different levels. Our case studies of the strategies of two large car manufacturers and the German government demonstrate that the car manufacturers refer strongly to expectations about the future regime while expectations related to the socio-technical landscape level appear to be crucial for the strategy of the German government.
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.
Microfluidics-based Analysis of Dynamic Contact Angles Relevant for Underground Hydrogen Storage
May 2022
Publication
Underground Hydrogen Storage (UHS) is an attractive technology for large-scale (TWh) renewable energy storage. To ensure the safety and efficiency of the UHS it is crucial to quantify the H2 interactions with the reservoir fluids and rocks across scales including the micro scale. This paper reports the experimental measurements of advancing and receding contact angles for different channel widths for a H2 /water system at P = 10 bar and T = 20 ◦C using a microfluidic chip. To analyse the characteristics of the H2 flow in straight pore throats the network is designed such that it holds several straight channels. More specifically the width of the microchannels range between 50 μm and 130 μm. For the drainage experiments H2 is injected into a fully water saturated system while for the imbibition tests water is injected into a fully H2 -saturated system. For both scenarios high-resolution images are captured starting the introduction of the new phase into the system allowing for fully-dynamic transport analyses. For better insights N2 /water and CO2 /water flows were also analysed and compared with H2 /water. Results indicate strong water-wet conditions with H2 /water advancing and receding contact angles of respectively 13◦–39◦ and 6◦–23◦ . It was found that the contact angles decrease with increasing channel widths. The receding contact angle measured in the 50 μm channel agrees well with the results presented in the literature by conducting a core-flood test for a sandstone rock. Furthermore the N2 /water and CO2 /water systems showed similar characteristics as the H2 /water system. In addition to the important characterization of the dynamic wettability the results are also crucially important for accurate construction of pore-scale simulators.
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.
Exploring Supply Chain Design and Expansion Planning of China's Green Ammonia Production with an Optimization-based Simulation Approach
Aug 2021
Publication
Green ammonia production as an important application for propelling the upcoming hydrogen economy has not been paid much attention by China the world's largest ammonia producer. As a result related studies are limited. This paper explores potential supply chain design and planning strategies of green ammonia production in the next decade of China with a case study in Inner Mongolia. A hybrid optimization-based simulation approach is applied considering traditional optimization approaches are insufficient to address uncertainties and dynamics in a long-term energy transition. Results show that the production cost of green ammonia will be at least twice that of the current level due to higher costs of hydrogen supply. Production accounts for the largest share of the total expense of green hydrogen (~80 %). The decline of electricity and electrolyser prices are key in driving down the overall costs. In addition by-product oxygen is also considered in the model to assess its economic benefits. We found that by-product oxygen sales could partly reduce the total expense of green hydrogen (~12 % at a price of USD 85/t) but it also should be noted that the volatile price of oxygen may pose uncertainties and risks to the effectiveness of the offset. Since the case study may represent the favourable conditions in China due to the abundant renewable energy resources and large-scale ammonia industry in this region we propose to take a moderate step towards green ammonia production and policies should be focused on reducing the electricity price and capital investments in green hydrogen production. We assume the findings and implications are informative to planning future green ammonia production in China.
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
Towards a Climate-neutral Energy System in the Netherlands
Jan 2022
Publication
This paper presents two different scenarios for the energy system of the Netherlands that achieve the Dutch government’s national target of near net-zero greenhouse gas emissions in 2050. Using the system optimisation model OPERA the authors have analysed the technology sector and cost implications of the assumptions underlying these scenarios. While the roles of a number of key energy technology and emission mitigation options are strongly dependent on the scenario and cost assumptions the analysis yields several common elements that appear in both scenarios and that consistently appear under differing cost assumptions. For example one of the main options for the decarbonisation of the Dutch energy system is electrification of energy use in end-use sectors and for the production of renewable hydrogen with electrolysers. As a result the level of electricity generation in 2050 will be three to four times higher than present generation levels. Ultimately renewable energy – particularly from wind turbines and solar panels – is projected to account for the vast majority of electricity generation around 99% in 2050. Imbalances between supply and demand resulting from this variable renewable electricity production can be managed via flexibility options including demand response and energy storage. Hydrogen also becomes an important energy carrier notably for transportation and in industry. If import prices are lower than costs of domestic production from natural gas with CCS or through electrolysis from renewable electricity (2.4–2.7 €/kgH2) the use of hydrogen increases especially in the built environment.
Modelling and Evaluation of PEM Hydrogen Technologies for Frequency Ancillary Services in Future Multi-energy Sustainable Power Systems
Mar 2019
Publication
This paper examines the prospect of PEM (Proton Exchange Membrane) electrolyzers and fuel cells to partake in European electrical ancillary services markets. First the current framework of ancillary services is reviewed and discussed emphasizing the ongoing European harmonization plans for future frequency balancing markets. Next the technical characteristics of PEM hydrogen technologies and their potential uses within the electrical power system are discussed to evaluate their adequacy to the requirements of ancillary services markets. Last a case study based on a realistic representation of the transmission grid in the north of the Netherlands for the year 2030 is presented. The main goal of this case study is to ascertain the effectiveness of PEM electrolyzers and fuel cells for the provision of primary frequency reserves. Dynamic generic models suitable for grid simulations are developed for both technologies including the required controllers to enable participation in ancillary services markets. The obtained results show that PEM hydrogen technologies can improve the frequency response when compared to the procurement with synchronous generators of the same reserve value. Moreover the fast dynamics of PEM electrolyzers and fuel cells can help mitigate the negative effects attributed to the reduction of inertia in the system.
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).
Flexible Power and Biomass-To-Methanol Plants With Different Gasification Technologies
Jan 2022
Publication
The competitiveness of biofuels may be increased by integrating biomass gasification plants with electrolysis units which generate hydrogen to be combined with carbon-rich syngas. This option allows increasing the yield of the final product by retaining a higher amount of biogenic carbon and improving the resilience of the energy sector by favoring electric grid services and sector coupling. This article illustrates a techno-economic comparative analysis of three flexible power and biomass to methanol plants based on different gasification technologies: direct gasification indirect gasification and sorptionenhanced gasification. The design and operational criteria of each plant are conceived to operate both without green hydrogen addition (baseline mode) and with hydrogen addition (enhanced mode) following an intermittent use of the electrolysis system which is turned on when the electricity price allows an economically viable hydrogen production. The methanol production plants include a gasification section syngas cleaning conditioning and compression section methanol synthesis and purification and heat recovery steam cycle to be flexibly operated. Due to the high oxygen demand in the gasifier the direct gasification-based plant obtains a great advantage to be operated between a minimum load to satisfy the oxygen demand at high electricity prices and a maximum load to maximize methanol production at low electricity prices. This allows avoiding large oxygen storages with significant benefits for Capex and safety issues. The analysis reports specific fixed-capital investments between 1823 and 2048 €/kW of methanol output in the enhanced operation and LCOFs between 29.7 and 31.7 €/GJLHV. Economic advantages may be derived from a decrease in the electrolysis capital investment especially for the direct gasification-based plants which employ the greatest sized electrolyzer. Methanol breakeven selling prices range between 545 and 582 €/t with the 2019 reference Denmark electricity price curve and between 484 and 535 €/t with an assumed modified electricity price curve of a future energy mix with increased penetration of intermittent renewables.
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 .
Can an Energy Only Market Enable Resource Adequacy in a Decarbonized Power System? A Co-simulation with Two Agent-based-models
Feb 2024
Publication
Future power systems in which generation will come almost entirely from variable Renewable Energy Sources (vRES) will be characterized by weather-driven supply and flexible demand. In a simulation of the future Dutch power system we analyze whether there are sufficient incentives for market-driven investors to provide a sufficient level of security of supply considering the profit-seeking and myopic behavior of investors. We cosimulate two agent-based models (ABM) one for generation expansion and one for the operational time scale. The results suggest that in a system with a high share of vRES and flexibility prices will be set predominantly by the demand’s willingness to pay particularly by the opportunity cost of flexible hydrogen electrolyzers. The demand for electric heating could double the price of electricity in winter compared to summer and in years with low vRES could cause shortages. Simulations with stochastic weather profiles increase the year-to-year variability of cost recovery by more than threefold and the year-to-year price variability by more than tenfold compared to a scenario with no weather uncertainty. Dispatchable technologies have the most volatile annual returns due to high scarcity rents during years of low vRES production and diminished returns during years with high vRES production. We conclude that in a highly renewable EOM investors would not have sufficient incentives to ensure the reliability of the system. If they invested in such a way to ensure that demand could be met in a year with the lowest vRES yield they would not recover their fixed costs in the majority of years.
International Competitiveness of Low-carbon Hydrogen Supply to the Northwest European Market
Oct 2022
Publication
This paper analyses which sources of low-carbon hydrogen for the Northwest European market are most competitive taking into account costs of local production conversion and transport. Production costs of electrolysis are strongly affected by local renewable electricity costs and capacity factors. Transport costs are the lowest by pipelines for distances under 10000 km with costs linearly increasing with distance. For larger distances transport as ammonia is more efficient with less relation to distance despite higher conversion costs. The most competitive low-carbon hydrogen supply to the Northwest European market appears to be local Steam Methane Reforming with Carbon Capture and Storage when international gas prices return back to historical levels. When gas prices however remain high then import from Morocco with electrolysis directly connected to offshore wind generation is found to be the most competitive source of low-carbon hydrogen. These conclusions are robust for various assumptions on costs and capacity factors.
Interdisciplinary Perspectives on Offshore Energy System Integration in the North Sea: A Systematic Literature Review
Oct 2023
Publication
To facilitate the rapid and large-scale developments of offshore wind energy scholars policymakers and infrastructure developers must start considering its integration into the larger onshore energy system. Such offshore system integration is defined as the coordinated approach to planning and operation of energy generation transport and storage in the offshore energy system across multiple energy carriers and sectors. This article conducts a systematic literature review to identify infrastructure components of offshore energy system integration (including alternative cable connections offshore energy storage and power-to-hydrogen applications) and barriers to their development. An interdisciplinary perspective is provided where current offshore developments require not only mature and economically feasible technologies but equally strong legal and governance frameworks. The findings demonstrate that current literature lacks a holistic perspective on the offshore energy system. To date techno-economic assessments solving challenges of specific infrastructure components prevail over an integrated approach. Nevertheless permitting issues gaps in legal frameworks strict safety and environmental regulations and spatial competition also emerge as important barriers. Overall this literature review emphasizes the necessity of aligning various disciplines to provide a fundamental approach for the development of an integrated offshore energy system. More specifically timely policy and legal developments are key to incentivize technical development and enable economic feasibility of novel components of offshore system integration. Accordingly to maximize real-world application and policy learning future research will benefit from an interdisciplinary perspective.
Review on Ammonia as a Potential Fuel: From Synthesis to Economics
Feb 2021
Publication
Ammonia a molecule that is gaining more interest as a fueling vector has been considered as a candidate to power transport produce energy and support heating applications for decades. However the particular characteristics of the molecule always made it a chemical with low if any benefit once compared to conventional fossil fuels. Still the current need to decarbonize our economy makes the search of new methods crucial to use chemicals such as ammonia that can be produced and employed without incurring in the emission of carbon oxides. Therefore current efforts in this field are leading scientists industries and governments to seriously invest efforts in the development of holistic solutions capable of making ammonia a viable fuel for the transition toward a clean future. On that basis this review has approached the subject gathering inputs from scientists actively working on the topic. The review starts from the importance of ammonia as an energy vector moving through all of the steps in the production distribution utilization safety legal considerations and economic aspects of the use of such a molecule to support the future energy mix. Fundamentals of combustion and practical cases for the recovery of energy of ammonia are also addressed thus providing a complete view of what potentially could become a vector of crucial importance to the mitigation of carbon emissions. Different from other works this review seeks to provide a holistic perspective of ammonia as a chemical that presents benefits and constraints for storing energy from sustainable sources. State-of-the-art knowledge provided by academics actively engaged with the topic at various fronts also enables a clear vision of the progress in each of the branches of ammonia as an energy carrier. Further the fundamental boundaries of the use of the molecule are expanded to real technical issues for all potential technologies capable of using it for energy purposes legal barriers that will be faced to achieve its deployment safety and environmental considerations that impose a critical aspect for acceptance and wellbeing and economic implications for the use of ammonia across all aspects approached for the production and implementation of this chemical as a fueling source. Herein this work sets the principles research practicalities and future views of a transition toward a future where ammonia will be a major energy player.
Exploring the Possibility of Using Molten Carbonate Fuel Cell for the Flexible Coproduction of Hydrogen and Power
Sep 2021
Publication
Fuel cells are electrochemical devices that are conventionally used to convert the chemical energy of fuels into electricity while producing heat as a byproduct. High temperature fuel cells such as molten carbonate fuel cells and solid oxide fuel cells produce significant amounts of heat that can be used for internal reforming of fuels such as natural gas to produce gas mixtures which are rich in hydrogen while also producing electricity. This opens up the possibility of using high temperature fuel cells in systems designed for flexible coproduction of hydrogen and power at very high system efficiency. In a previous study the flowsheet software Cycle-Tempo has been used to determine the technical feasibility of a solid oxide fuel cell system for flexible coproduction of hydrogen and power by running the system at different fuel utilization factors (between 60 and 95%). Lower utilization factors correspond to higher hydrogen production while at a higher fuel utilization standard fuel cell operation is achieved. This study uses the same basis to investigate how a system with molten carbonate fuel cells performs in identical conditions also using Cycle-Tempo. A comparison is made with the results from the solid oxide fuel cell study.
Benchmark of J55 and X56 Steels on Cracking and Corrosion Effects Under Hydrogen Salt Cavern Boundary Conditions
Feb 2024
Publication
Salt caverns have great potential to store relevant amounts of hydrogen as part of the energy transition. However the durability and suitability of commonly used steels for piping in hydrogen salt caverns is still under research. In this work aging effects focusing on corrosion and cracking patterns of casing steel API 5CT J55 and “H2ready” pipeline steel API 5L X56 were investigated with scanning electron microscopy and energy dispersive X-ray spectroscopy after accelerated stress tests with pressure/temperature cycling under hydrogen salt cavern-like conditions. Compared to dry conditions significant more corrosion by presence of salt ions was detected. However compared to X56 only for J55 an intensification of corrosion and cracking at the surface due to hydrogen atmosphere was revealed. Pronounced surface cracks were observed for J55 over the entire samples. Overall the results strongly suggest that X56 is more resistant than J55 under the conditions of a hydrogen salt cavern.
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.
Review and Survey of Methods for Analysis of Impurities in Hydrogen for Fuel Cell Vehicles According to ISO 14687:2019
Feb 2021
Publication
Gaseous hydrogen for fuel cell electric vehicles must meet quality standards such as ISO 14687:2019 which contains maximal control thresholds for several impurities which could damage the fuel cells or the infrastructure. A review of analytical techniques for impurities analysis has already been carried out by Murugan et al. in 2014. Similarly this document intends to review the sampling of hydrogen and the available analytical methods together with a survey of laboratories performing the analysis of hydrogen about the techniques being used. Most impurities are addressed however some of them are challenging especially the halogenated compounds since only some halogenated compounds are covered not all of them. The analysis of impurities following ISO 14687:2019 remains expensive and complex enhancing the need for further research in this area. Novel and promising analyzers have been developed which need to be validated according to ISO 21087:2019 requirements.
Economic Complexity of Green Hydrogen Production Technologies - A Trade Data-based Analysis of Country-sepcific Industrial Preconditions
May 2023
Publication
Countries with high energy demand but limited renewable energy potential are planning to meet part of their future energy needs by importing green hydrogen. For potential exporting countries in addition to sufficient renewable resources industrial preconditions are also relevant for the successful implementation of green hydrogen production value chains. A list of 36 “Green H2 Products” needed for stand-alone hydrogen production plants was defined and their economic complexity was analyzed using international trade data from 1995 to 2019. These products were found to be comparatively complex to produce and represent an opportunity for countries to enter new areas of the product space through green diversification. Large differences were revealed between countries in terms of industrial preconditions and their evolution over time. A detailed analysis of nine MENA countries showed that Turkey and Tunisia already possess industrial know-how in various green hydrogen technology components and perform only slightly worse than potential European competitors while Algeria Libya and Saudi Arabia score the lowest in terms of calculated hydrogen-related green complexity. These findings are supported by statistical tests showing that countries with a higher share of natural resources rents in their gross domestic product score significantly lower on economic and green complexity. The results thus provide new perspectives for assessing the capabilities of potential hydrogen-producing countries which may prove useful for policymakers and investors. Simultaneously this paper contributes to the theory of economic complexity by applying its methods to a new subset of products and using a dataset with long-term coverage.
Opportunities for Production and Utilization of Green Hydrogen in the Philippines
Jun 2021
Publication
The Philippines is exploring different alternative sources of energy to become energy-independent while significantly reducing the country’s greenhouse gas emissions. Green hydrogen from renewable energy is one of the most sustainable alternatives with its application as an energy carrier and as a source of clean and sustainable energy as well as raw material for various industrial processes. As a preliminary study in the country this paper aims to explore different production and utilization routes for a green hydrogen economy in the Philippines. Production from electrolysis includes various available renewable sources consisting of geothermal hydropower wind solar and biomass as well as ocean technology and nuclear energy when they become available in the future. Different utilization routes include the application of green hydrogen in the transportation power generation industry and utility sectors. The results of this study can be incorporated in the development of the pathways for hydrogen economy in the Philippines and can be applied in other emerging economies.
Impact of Experimentally Measured Relative Permeability Hysteresis on Reservoir-scale Performance of Undergound Hydrogen Storage (UHS)
Jan 2024
Publication
Underground Hydrogen Storage (UHS) is an emerging large-scale energy storage technology. Researchers are investigating its feasibility and performance including its injectivity productivity and storage capacity through numerical simulations. However several ad-hoc relative permeability and capillary pressure functions have been used in the literature with no direct link to the underlying physics of the hydrogen storage and production process. Recent relative permeability measurements for the hydrogen-brine system show very low hydrogen relative permeability and strong liquid phase hysteresis very different to what has been observed for other fluid systems for the same rock type. This raises the concern as to what extend the existing studies in the literature are able to reliably quantify the feasibility of the potential storage projects. In this study we investigate how experimentally measured hydrogen-brine relative permeability hysteresis affects the performance of UHS projects through numerical reservoir simulations. Relative permeability data measured during a hydrogen-water core-flooding experiment within ADMIRE project is used to design a relative permeability hysteresis model. Next numerical simulation for a UHS project in a generic braided-fluvial water-gas reservoir is performed using this hysteresis model. A performance assessment is carried out for several UHS scenarios with different drainage relative permeability curves hysteresis model coefficients and injection/production rates. Our results show that both gas and liquid relative permeability hysteresis play an important role in UHS irrespective of injection/production rate. Ignoring gas hysteresis may cause up to 338% of uncertainty on cumulative hydrogen production as it has negative effects on injectivity and productivity due to the resulting limited variation range of gas saturation and pressure during cyclic operations. In contrast hysteresis in the liquid phase relative permeability resolves this issue to some extent by improving the displacement of the liquid phase. Finally implementing relative permeability curves from other fluid systems during UHS performance assessment will cause uncertainty in terms of gas saturation and up to 141% underestimation on cumulative hydrogen production. These observations illustrate the importance of using relative permeability curves characteristic of hydrogen-brine system for assessing the UHS performances.
Green Hydrogen for Ammonia Production - A Case for the Netherlands
Jul 2023
Publication
An integrated system is studied to supply green hydrogen feedstock for ammonia production in the Netherlands. The system is modeled to compare wind and solar resources when coupled to Alkaline Electrolysis (AEL) and Proton Exchange Membrane Electrolysis (PEMEL) technologies with a compressed hydrogen storage system. The nominal installed capacity of the electrolysis plant is around 2.3 GW with the most suitable energy source offshore wind and the preferred storage technology pressurized tubes. For Alkaline Electrolysis and Proton Exchange Membrane Electrolysis technologies the levelized cost of hydrogen is 5.30 V/kg H2 and 6.03 V/kg H2 respectively.
Maximisation of PV Energy Use and Performance Analysis of a Stand-alone PV-hydrogen System
Sep 2023
Publication
The development of clean hydrogen and photovoltaic (PV) systems is lagging behind the goals set in the Net Zero Emissions scenario of the International Energy Agency. For this reason efficient hydrogen production systems powered from renewable energy need to be deployed faster. This work presents an optimization procedure for a stand-alone fully PVpowered alkaline electrolysis system. The approach is based on the Particle Swarm Optimization algorithm to obtain the best configuration of the PV plant that powers the electrolyzer and its compressor. The best configuration is determined with one of three indicators: cost efficiency or wasted energy. The PV plant needs to be oversized 2.63 times with respect to the electrolyzer to obtain minimum cost while for high efficiency this number increases by 2%. Additionally the configuration that minimizes cost wasted energy or maximizes efficiency does not correspond to the configuration that maximizes the annual PV yield. Optimizing for cost results also leads to the best operation of the electrolyzer at partial loads than optimizing for efficiency or wasted energy.
Electrocatalysts for the Generation of Hydrogen, Oxygen and Synthesis Gas
Sep 2016
Publication
Water electrolysis is the most promising method for efficient production of high purity hydrogen (and oxygen) while the required power input for the electrolysis process can be provided by renewable sources (e.g. solar or wind). The thus produced hydrogen can be used either directly as a fuel or as a reducing agent in chemical processes such as in Fischer–Tropsch synthesis. Water splitting can be realized both at low temperatures (typically below 100 °C) and at high temperatures (steam water electrolysis at 500– 1000 °C) while different ionic agents can be electrochemically transferred during the electrolysis process (OH− H+ O2− ). Singular requirements apply in each of the electrolysis technologies (alkaline polymer electrolyte membrane and solid oxide electrolysis) for ensuring high electrocatalytic activity and long-term stability. The aim of the present article is to provide a brief overview on the effect of the nature and structure of the catalyst–electrode materials on the electrolyzer’s performance. Past findings and recent progress in the development of efficient anode and cathode materials appropriate for large-scale water electrolysis are presented. The current trends limitations and perspectives for future developments are summarized for the diverse electrolysis technologies of water splitting while the case of CO2/H2O co-electrolysis (for synthesis gas production) is also discussed.
Renewable Hydrogen Production: A Techno-economic Comparison of Photoelectrochemical Cells and Photovoltaic-electrolysis
Aug 2020
Publication
The present paper reports a techno-economic analysis of two solar assisted hydrogen production technologies: a photoelectrochemical (PEC) system and its major competitor a photovoltaic system connected to a conventional water electrolyzer (PV-E system). A comparison between these two types was performed to identify the more promising technology based on the levelized cost of hydrogen (LCOH). The technical evaluation was carried out by considering proven designs and materials for the PV-E system and a conceptually design for the PEC system extrapolated to future commercial scale. The LCOH for the off-grid PV-E system was found to be 6.22 $/kgH2 with a solar to hydrogen efficiency of 10.9%. For the PEC system with a similar efficiency of 10% the LCOH was calculated to be much higher namely 8.43 $/kgH2. A sensitivity analysis reveals a great uncertainty in the LCOH of the prospective PEC system. This implies that much effort would be needed for this technology to become competitive on the market. Therefore we conclude that the potential techno-economic benefits that PEC systems offer over PV-E are uncertain and even in the best case limited. While research into photoelectrochemical cells remains of interest it presents a poor case for dedicated investment in the technology’s development and scale-up.
Stakeholder Perspectives on the Scale-up of Green Hydrogen and Electrolyzers
Nov 2023
Publication
Green hydrogen is a promising alternative to fossil fuels. However current production capacities for electrolyzers and green hydrogen are not in line with national political goals and projected demand. Considering these issues we conducted semi-structured interviews to determine the narratives of different stakeholders during this transformation as well as challenges and opportunities for the green hydrogen value chain. We interviewed eight experts with different roles along the green hydrogen value chain ranging from producers and consumers of green hydrogen to electrolyzer manufacturers and consultants as well as experts from the political sphere. Most experts see the government as necessary for scale-up by setting national capacity targets policy support and providing subsidies. However the experts also accuse the governments of delaying development through overregulation and long implementation times for regulations. The main challenges that were identified are the current lack of renewable electricity and demand for green hydrogen. Demand for green hydrogen is influenced by supply costs which partly depend on prices for electrolyzers. However one key takeaway of the interviews is the skeptical assessments by the experts on the currently discussed estimates for price reduction potential of electrolyzers. While demand supply and prices are all factors that influence each other they result in feedback loops in investment decisions for the energy and manufacturing industries. A second key takeaway is that according to the experts current investment decisions in new production capacities are not solely dependent on short-term financial gains but also based on expected first mover advantages. These include experience and market share which are seen as factors for opportunities for future financial gains. Summarized the results present several challenges and opportunities for green hydrogen and electrolyzers and how to address them effectively. These insights contribute to a deeper understanding of the dynamics of the emerging green hydrogen value chain.
Carbon Footprint of Hydrogen-powered Inland Shipping: Impacts and Hotspots
Aug 2023
Publication
The shipping sector is facing increasing pressure to implement clean fuels and drivetrains. Especially hydrogen fuel cell drivetrains seem attractive. Although several studies have been conducted to assess the carbon footprint of hydrogen and its application in ships their results remain hard to interpret and compare. Namely it is necessary to include a variety of drivetrain solutions and different studies are based on various assumptions and are expressed in other units. This paper addresses this problem by offering a three-step meta-review of life cycle assessment studies. First a literature review was conducted. Second results from the literature were harmonized to make the different analyses comparable serving cross-examination. The entire life cycle of both the fuels and drivetrains were included. The results showed that the dominant impact was fuel use and related fuel production. And finally life-cycle hot spots have been identified by looking at the effect of specific configurations in more detail. Hydrogen production by electrolysis powered by wind has the most negligible impact. For this ultra-low carbon pathway the modes of hydrogen transport and the use of specific materials and components become relevant.
Impact of Large-scale Hydrogen Electrification and Retrofitting of Natural Gas Infrastructure on the European Power System
Nov 2023
Publication
In this paper we aim to analyse the impact of hydrogen production decarbonisation and electrification scenarios on the infrastructure development generation mix CO2 emissions and system costs of the European power system considering the retrofit of the natural gas infrastructure. We define a reference scenario for the European power system in 2050 and use scenario variants to obtain additional insights by breaking down the effects of different assumptions. The scenarios were analysed using the European electricity market model COMPETES including a proposed formulation to consider retrofitting existing natural gas networks to transport hydrogen instead of methane. According to the results 60% of the EU’s hydrogen demand is electrified and approximately 30% of the total electricity demand will be to cover that hydrogen demand. The primary source of this electricity would be non-polluting technologies. Moreover hydrogen flexibility significantly increases variable renewable energy investment and production and reduces CO2 emissions. In contrast relying on only electricity transmission increases costs and CO2 emissions emphasising the importance of investing in an H2 network through retrofitting or new pipelines. In conclusion this paper shows that electrifying hydrogen is necessary and cost-effective to achieve the EU’s objective of reducing long-term emissions.
Techno-economic Analysis of Underground Hydrogen Storage in Europe
Dec 2023
Publication
Hydrogen storage is crucial to developing secure renewable energy systems to meet the European Union’s 2050 carbon neutrality objectives. However a knowledge gap exists concerning the site-specific performance and economic viability of utilizing underground gas storage (UGS) sites for hydrogen storage in Europe. We compile information on European UGS sites to assess potential hydrogen storage capacity and evaluate the associated current and future costs. The total hydrogen storage potential in Europe is 349 TWh of working gas energy (WGE) with site-specific capital costs ranging from $10 million to $1 billion. Porous media and salt caverns boasting a minimum storage capacity of 0.5 TWh WGE exhibit levelized costs of $1.5 and $0.8 per kilogram of hydrogen respectively. It is estimated that future levelized costs associated with hydrogen storage can potentially decrease to as low as $0.4 per kilogram after three experience cycles. Leveraging these techno-economic considerations we identify suitable storage sites.
Towards Renewable Hydrogen-based Electrolysis: Alkaline vs Proton Exchange Membrane
Jul 2023
Publication
This paper focuses on the battle for a dominant design for renewable hydrogen electrolysis in which the designs alkaline and proton exchange membrane compete for dominance. First a literature review is performed to determine the most relevant factors that influence technology dominance. Following that a Best Worst Method analysis is conducted by interviewing multiple industry experts. The most important factors appear to be: Price Safety Energy consumption Flexibility Lifetime Stack size and Materials used. The opinion of experts on Proton Exchange Membrane and alkaline electrolyser technologies is slightly skewed in favour of alkaline technologies. However the margin is too small to identify a winner in this technology battle. The following paper contributes to the ongoing research on modelling the process of technology selection in the energy sector.
Hydrogen Fuel Quality from Two Main Production Processes: Steam Methane Reforming and Proton Exchange Membrane Water Electrolysis
Oct 2019
Publication
Thomas Bacquart,
Karine Arrhenius,
Stefan Persijn,
Andrés Rojo,
Fabien Auprêtre,
Bruno Gozlan,
Abigail Morris,
Andreas Fischer,
Arul Murugan,
Sam Bartlett,
Niamh Moore,
Guillaume Doucet,
François Laridant,
Eric Gernot,
Teresa E. Fernandez,
Concepcion Gomez,
Martine Carré,
Guy De Reals and
Frédérique Haloua
The absence of contaminants in the hydrogen delivered at the hydrogen refuelling station is critical to ensure the length life of FCEV. Hydrogen quality has to be ensured according to the two international standards ISO 14687–2:2012 and ISO/DIS 19880-8. Amount fraction of contaminants from the two hydrogen production processes steam methane reforming and PEM water electrolyser is not clearly documented. Twenty five different hydrogen samples were taken and analysed for all contaminants listed in ISO 14687-2. The first results of hydrogen quality from production processes: PEM water electrolysis with TSA and SMR with PSA are presented. The results on more than 16 different plants or occasions demonstrated that in all cases the 13 compounds listed in ISO 14687 were below the threshold of the international standards. Several contaminated hydrogen samples demonstrated the needs for validated and standardised sampling system and procedure. The results validated the probability of contaminants presence proposed in ISO/DIS 19880-8. It will support the implementation of ISO/ DIS 19880-8 and the development of hydrogen quality control monitoring plan. It is recommended to extend the study to other production method (i.e. alkaline electrolysis) the HRS supply chain (i.e. compressor) to support the technology growth.
Comprehensive Review of Geomechanics of Underground Hydrogen Storage in Depleted Reservoirs and Salt Caverns
Sep 2023
Publication
Hydrogen is a promising energy carrier for a low-carbon future energy system as it can be stored on a megaton scale (equivalent to TWh of energy) in subsurface reservoirs. However safe and efficient underground hydrogen storage requires a thorough understanding of the geomechanics of the host rock under fluid pressure fluctuations. In this context we summarize the current state of knowledge regarding geomechanics relevant to carbon dioxide and natural gas storage in salt caverns and depleted reservoirs. We further elaborate on how this knowledge can be applied to underground hydrogen storage. The primary focus lies on the mechanical response of rocks under cyclic hydrogen injection and production fault reactivation the impact of hydrogen on rock properties and other associated risks and challenges. In addition we discuss wellbore integrity from the perspective of underground hydrogen storage. The paper provides insights into the history of energy storage laboratory scale experiments and analytical and simulation studies at the field scale. We also emphasize the current knowledge gaps and the necessity to enhance our understanding of the geomechanical aspects of hydrogen storage. This involves developing predictive models coupled with laboratory scale and field-scale testing along with benchmarking methodologies.
Energy Use and Greenhouse Gas Emissions of Traction Alternatives for Regional Railways
Feb 2024
Publication
This paper presents a method for estimating Well-to-Wheel (WTW) energy use and greenhouse gas (GHG) emissions attributed to the advanced railway propulsion systems implemented in conjunction with different energy carriers and their production pathways. The analysis encompasses diesel-electric multiple unit vehicles converted to their hybrid-electric plug-in hybrid-electric fuel cell hybrid-electric or battery-electric counterparts combined with biodiesel or hydrotreated vegetable oil (HVO) as the first and second generation biofuels liquefied natural gas (LNG) hydrogen and/or electricity. The method is demonstrated using non-electrified regional railway network with heterogeneous vehicle fleet in the Netherlands as a case. Battery-electric system utilizing green electricity is identified as the only configuration leading to emission-free transport while offering the highest energy use reduction by 65–71% compared to the current diesel-powered hybrid-electric system. When using grey electricity based on the EU2030 production mix these savings are reduced to about 27–39% in WTW energy use and around 68–73% in WTW GHG emissions. Significant reductions in overall energy use and emissions are obtained for the plug-in hybrid-electric concept when combining diesel LNG or waste cooking oil-based HVO with electricity. The remaining configurations that reduce energy use and GHG emissions are hybrid-electric systems running on LNG or HVO from waste cooking oil. The latter led to approximately 88% lower WTW emissions than the baseline for each vehicle type. When produced from natural gas or EU2030-mix-based electrolysis hydrogen negatively affected both aspects irrespective of the prime mover technology. However when produced via green electricity it offers a GHG reduction of approximately 90% for hybrid-electric and fuel cell hybrid-electric configurations with a further reduction of up to 92–93% if combined with green electricity in plug-in hybrid-electric systems. The results indicate that HVO from waste cooking oil could be an effective and instantly implementable transition solution towards carbon–neutral regional trains allowing for a smooth transition and development of supporting infrastructure required for more energy-efficient and environment-friendly technologies.
Multiperiod Modeling and Optimization of Hydrogen-Based Dense Energy Carrier Supply Chains
Feb 2024
Publication
The production of hydrogen-based dense energy carriers (DECs) has been proposed as a combined solution for the storage and dispatch of power generated through intermittent renewables. Frameworks that model and optimize the production storage and dispatch of generated energy are important for data-driven decision making in the energy systems space. The proposed multiperiod framework considers the evolution of technology costs under different levels of promotion through research and targeted policies using the year 2021 as a baseline. Furthermore carbon credits are included as proposed by the 45Q tax amendment for the capture sequestration and utilization of carbon. The implementation of the mixed-integer linear programming (MILP) framework is illustrated through computational case studies to meet set hydrogen demands. The trade-offs between different technology pathways and contributions to system expenditure are elucidated and promising configurations and technology niches are identified. It is found that while carbon credits can subsidize carbon capture utilization and sequestration (CCUS) pathways substantial reductions in the cost of novel processes are needed to compete with extant technology pathways. Further research and policy push can reduce the levelized cost of hydrogen (LCOH) by upwards of 2 USD/kg.
Hazard Identification of Hydrogen-Based Alternative Fuels Onboard Ships
Dec 2023
Publication
It is essential to use alternative fuels if we are to reach the emission reduction targets set by the IMO. Hydrogen carriers are classified as zero-emission while having a higher energy density (including packing factor) than pure hydrogen. They are often considered as safe alternative fuels. The exact definition of what safety entails is often lacking both for hydrogen carriers as well as for ship safety. The aim of this study is to review the safety of hydrogen carriers from two perspectives investigating potential connections between the chemical and maritime approaches to safety. This enables a reasoned consideration between safety aspects and other design drivers in ship design and operation. The hydrogen carriers AB NaBH4 KBH4 and two LOHCs (NEC and DBT) are taken into consideration together with a couple reference fuels (ammonia methanol and MDO). After the evaluation of chemical properties related to safety and the scope of the current IMO safety framework it can be concluded that safety remains a vague and non-explicit concept from both perspectives. Therefore further research is required to prove the safe application of hydrogen carriers onboard ships.
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.
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