Netherlands
Selection Criteria and Ranking for Sustainable Hydrogen Production Options
Aug 2022
Publication
This paper aims to holistically study hydrogen production options essential for a sustainable and carbon-free future. This study also outlines the benefits and challenges of hydrogen production methods to provide sustainable alternatives to fossil fuels by meeting the global energy demand and net-zero targets. In this study sixteen hydrogen production methods are selected for sustainability investigation based on seven different criteria. The criteria selected in the comparative evaluation cover various dimensions of hydrogen production in terms of economic technical environmental and thermodynamic aspects for better sustainability. The current study results show that steam methane reforming with carbon capture could provide sustainable hydrogen in the near future while the other technologies’ maturity levels increase and the costs decrease. In the medium- and long-terms photonic and thermal-based hydrogen production methods can be the key to sustainable hydrogen production.
Development of Risk Mitigation Guidance for Sensor Placement Inside Mechanically Ventilated Enclosures – Phase 1
Sep 2019
Publication
Guidance on Sensor Placement was identified as the top research priority for hydrogen sensors at the 2018 HySafe Research Priority Workshop on hydrogen safety in the category Mitigation Sensors Hazard Prevention and Risk Reduction. This paper discusses the initial steps (Phase 1) to develop such guidance for mechanically ventilated enclosures. This work was initiated as an international collaborative effort to respond to emerging market needs related to the design and deployment equipment for hydrogen infrastructure that is often installed in individual equipment cabinets or ventilated enclosures. The ultimate objective of this effort is to develop guidance for an optimal sensor placement such that when integrated into a facility design and operation will allow earlier detection at lower levels of incipient leaks leading to significant hazard reduction. Reliable and consistent early warning of hydrogen leaks will allow for the risk mitigation by reducing or even eliminating the probability of escalation of small leaks into large and uncontrolled events. To address this issue a study of a real-world mechanically ventilated enclosure containing GH2 equipment was conducted where CFD modelling of the hydrogen dispersion (performed by AVT and UQTR and independently by the JRC) was validated by the NREL Sensor laboratory using a Hydrogen Wide Area Monitor (HyWAM) consisting of a 10-point gas and temperature measurement analyzer. In the release test helium was used as a hydrogen surrogate. Expansion of indoor releases to other larger facilities (including parking structures vehicle maintenance facilities and potentially tunnels) and incorporation into QRA tools such as HyRAM is planned for Phase 2. It is anticipated that results of this work will be used to inform national and international standards such as NFPA 2 Hydrogen Technologies Code Canadian Hydrogen Installation Code (CHIC) and relevant ISO/TC 197 and CEN documents.
Experimental Investigation on CO2 Methanation Process for Solar Energy Storage Compared to CO2-Based Methanol Synthesis
Jun 2017
Publication
The utilization of the captured CO2 as a carbon source for the production of energy storage media offers a technological solution for overcoming crucial issues in current energy systems. Solar energy production generally does not match with energy demand because of its intermittent and non-programmable nature entailing the adoption of storage technologies. Hydrogen constitutes a chemical storage for renewable electricity if it is produced by water electrolysis and is also the key reactant for CO2 methanation (Sabatier reaction). The utilization of CO2 as a feedstock for producing methane contributes to alleviate global climate changes and sequestration related problems. The produced methane is a carbon neutral gas that fits into existing infrastructure and allows issues related to the aforementioned intermittency and non-programmability of solar energy to be overcome. In this paper an experimental apparatus composed of an electrolyzer and a tubular fixed bed reactor is built and used to produce methane via Sabatier reaction. The objective of the experimental campaign is the evaluation of the process performance and a comparison with other CO2 valorization paths such as methanol production. The investigated pressure range was 2–20 bar obtaining a methane volume fraction in outlet gaseous mixture of 64.75% at 8 bar and 97.24% at 20 bar with conversion efficiencies of respectively 84.64% and 99.06%. The methanol and methane processes were compared on the basis of an energy parameter defined as the spent energy/stored energy. It is higher for the methanol process (0.45) with respect to the methane production process (0.41–0.43) which has a higher energy storage capability.
Power-to-gas in Electricity Markets Dominated by Renewables
Oct 2018
Publication
This paper analyses the feasibility of power-to-gas in electricity markets dominated by renewables. The business case of a power-to-gas plant that is producing hydrogen is evaluated by determining the willingness to pay for electricity and by comparing this to the level and volatility of electricity prices in a number of European day-ahead markets. The short-term willingness to pay for electricity depends on the marginal costs and revenues of the plant while the long-term willingness to pay for electricity also takes into account investment and yearly fixed operational costs and therefore depends on the expected number of operating hours. The latter ultimately determines whether or not large-scale investments in the power-to-gas technology will take place.<br/>We find that power-to-gas plants are not profitable under current market conditions: even under the most optimistic assumptions for the cost and revenue parameters power-to-gas plants need to run for many hours during the year at very low prices (i.e. the long-term willingness to pay for electricity is very low) that do not currently exist in Europe. In an optimistic future scenario regarding investment costs efficiency and revenues of power-to-gas however the long-term willingness to pay for electricity is higher than the lowest recently observed day-ahead electricity prices. When prices remain at this low level investments in power-to-gas can thus become profitable.
Technical Potential of On-site Wind Powered Hydrogen Producing Refuelling Stations in the Netherlands
Aug 2020
Publication
This study assesses the technical potential of wind turbines to be installed next to existing fuelling stations in order to produce hydrogen. Hydrogen will be used for Fuel Cell Vehicle refuelling and feed-in existing local gas grids. The suitable fuelling stations are selected through a GIS assessment applying buffer zones and taking into account risks associated with wind turbine installation next to built-up areas critical infrastructures and ecological networks. It was found that 4.6% of existing fuelling stations are suitable. Further a hydrogen production potential assessment was made using weather station datasets land cover data and was expressed as potential future Fuel Cell Electric Vehicle demand coverage. It was found that for a 30% FCEV drivetrain scenario these stations can produce 2.3% of this demand. Finally a case study was made for the proximity of those stations in existing gas distribution grids.
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).
Evaluation of Selectivity and Resistance to Poisons of Commercial Hydrogen Sensors
Sep 2013
Publication
The development of reliable hydrogen sensors is crucial for the safe use of hydrogen. One of the main concerns of end-users is sensor reliability in the presence of species other than the target gas which can lead to false alarms or undetected harmful situations. In order to assess the selectivity of commercial of the shelf (COTS) hydrogen sensors a number of sensors of different technology types were exposed to various interferent gas species. Cross-sensitivity tests were performed in accordance to the recommendations of ISO 26142:2010 using the hydrogen sensor testing facilities of NREL and JRC-IET. The results and conclusions arising from this study are presented.
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.
A Comparison of Steam Reforming Concepts in Solid Oxide Fuel Cell Systems
Mar 2020
Publication
Various concepts have been proposed to use hydrocarbon fuels in solid oxide fuel cell (SOFC) systems. A combination of either allothermal or adiabatic pre-reforming and water recirculation (WR) or anode off-gas recirculation (AOGR) is commonly used to convert the fuel into a hydrogen rich mixture before it is electrochemically oxidised in the SOFC. However it is unclear how these reforming concepts affect the electrochemistry and temperature gradients in the SOFC stack. In this study four reforming concepts based on either allothermal or adiabatic pre-reforming and either WR or AOGR are modelled on both stack and system level. The electrochemistry and temperature gradients in the stack are simulated with a one-dimensional SOFC model and the results are used to calculate the corresponding system efficiencies. The highest system efficiencies are obtained with allothermal pre-reforming and WR. Adiabatic pre-reforming and AOGR result in a higher degree of internal reforming which reduces the cell voltage compared to allothermal pre-reforming and WR. Although this lowers the stack efficiency higher degrees of internal reforming reduce the power consumption by the cathode air blower as well leading to higher system efficiencies in some cases. This illustrates that both stack and system operation need to be considered to design an efficient SOFC system and predict potentially deteriorating temperature gradients in the stack.
Overview of First Outcomes of PNR Project HYTUNNEL-CS
Sep 2021
Publication
Dmitry Makarov,
Donatella Cirrone,
Volodymyr V. Shentsov,
Sergii Kashkarov,
Vladimir V. Molkov,
Z. Xu,
Mike Kuznetsov,
Alexandros G. Venetsanos,
Stella G. Giannissi,
Ilias C. Tolias,
Knut Vaagsaether,
André Vagner Gaathaug,
Mark R. Pursell,
W. M. Rattigan,
Frank Markert,
Luisa Giuliani,
L.S. Sørensen,
A. Bernad,
Mercedes Sanz Millán,
U. Kummer,
C. Brauner,
Paola Russo,
J. van den Berg,
F. de Jong,
Tom Van Esbroeck,
M. Van De Veire,
D. Bouix,
Gilles Bernard-Michel,
Sergey Kudriakov,
Etienne Studer,
Domenico Ferrero,
Joachim Grüne and
G. Stern
The paper presents the first outcomes of the experimental numerical and theoretical studies performed in the funded by Fuel Cell and Hydrogen Joint Undertaking (FCH2 JU) project HyTunnel-CS. The project aims to conduct pre-normative research (PNR) to close relevant knowledge gaps and technological bottlenecks in the provision of safety of hydrogen vehicles in underground transportation systems. Pre normative research performed in the project will ultimately result in three main outputs: harmonised recommendations on response to hydrogen accidents recommendations for inherently safer use of hydrogen vehicles in underground traffic systems and recommendations for RCS. The overall concept behind this project is to use inter-disciplinary and inter-sectoral prenormative research by bringing together theoretical modelling and experimental studies to maximise the impact. The originality of the overall project concept is the consideration of hydrogen vehicle and underground traffic structure as a single system with integrated safety approach. The project strives to develop and offer safety strategies reducing or completely excluding hydrogen-specific risks to drivers passengers public and first responders in case of hydrogen vehicle accidents within the currently available infrastructure.
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.
Vision for a European Metrology Network for Energy Gases
Mar 2022
Publication
As Europe moves towards decarbonising its energy infrastructure new measurement needs will arise that require collaborative efforts between European National Metrology Institutes and Designated Institutes to tackle. Such measurement needs include flow metering of hydrogen or hydrogen enriched natural gas in the gas grid for billing quality assurance of hydrogen at refuelling stations and equations of state for carbon dioxide in carbon capture and storage facilities. The European metrology network for energy gases for the first time provides a platform where metrology institutes can work together to develop a harmonised strategy prioritise new challenges and share expertise and capabilities to support the European energy gas industry to meet stringent EU targets for climate change and emissions reductions
The Role of Hydrogen in Heavy Transport to Operate within Planetary Boundaries
Jul 2021
Publication
Green hydrogen i.e. produced from renewable resources is attracting attention as an alternative fuel for the future of heavy road transport and long-distance driving. However the benefits linked to zero pollution at the usage stage can be overturned when considering the upstream processes linked to the raw materials and energy requirements. To better understand the global environmental implications of fuelling heavy transport with hydrogen we quantified the environmental impacts over the full life cycle of hydrogen use in the context of the Planetary Boundaries (PBs). The scenarios assessed cover hydrogen from biomass gasification (with and without carbon capture and storage [CCS]) and electrolysis powered by wind solar bioenergy with CCS nuclear and grid electricity. Our results show that the current diesel-based-heavy transport sector is unsustainable due to the transgression of the climate change-related PBs (exceeding standalone by two times the global climate-change budget). Hydrogen-fuelled heavy transport would reduce the global pressure on the climate change-related PBs helping the transport sector to stay within the safe operating space (i.e. below one-third of the global ecological budget in all the scenarios analysed). However the best scenarios in terms of climate change which are biomass-based would shift burdens to the biosphere integrity and nitrogen flow PBs. In contrast burden shifting in the electrolytic scenarios would be negligible with hydrogen from wind electricity emerging as an appealing technology despite attaining higher carbon emissions than the biomass routes
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.
Supporting Hydrogen Technologies Deployment in EU Regions and Member States: The Smart Specialisation Platform on Energy (S3PEnergy)
May 2018
Publication
In order to maximise European national and regional research and innovation potential the European Union is investing in these fields through different funding mechanisms such as the ESIF or H2020 programme. This investment plan is part of the European 2020 strategy where the concept of Smart Specialisation is also included.<br/>Smart Specialisation is an innovation policy concept designed to promote the efficient and effective use of public investment in regional innovation in order to achieve economic growth. The Smart Specialisation Platform was created to support this concept by assisting regions and Member States in developing implementing and reviewing their research and innovation Smart Specialisation strategies.<br/>The Smart Specialisation Platform comprises several thematic platforms. The thematic Smart Specialisation Platform on energy (S3PEnergy) is a joint initiative of three European Commission services: DG REGIO DG ENER and the Joint Research Centre (JRC). The main objective of the S3PEnergy is to support the optimal and effective uptake of the Cohesion Policy funds for energy and to better align energy innovation activities at national local and regional level through the identification of the technologies and innovative solutions that support in the most cost-effective way the EU energy policy priorities.<br/>In the particular case of hydrogen technologies the activities of the platform are mainly focused on supporting the new Fuel Cells and Hydrogen Joint Undertaking (FCH JU) initiative involving regions and cities. To date more than 80 European cities and regions have committed to participate in this initiative through the signature of a Memorandum of Understanding and more participants are expected to join. S3PEnergy is helping in the identification of potential combination of H2020 funding (provided through FCH JU) and ESIF.<br/>To identify potential synergies among these two funding sources a mapping of the different ESIF opportunities has been performed. In order to map these opportunities Operational Programmes (OPs) and research and innovation strategies for Smart Specialisation (RIS3) of the different European regions and Member States were analysed. The results of this mapping and analysis are presented in this paper."
Combined Effects of Stress and Temperature on Hydrogen Diffusion in Non-hydride Forming Alloys Applied in Gas Turbines
Jul 2022
Publication
Hydrogen plays a vital role in the utilisation of renewable energy but ingress and diffusion of hydrogen in a gas turbine can induce hydrogen embrittlement on its metallic components. This paper aims to investigate the hydrogen transport in a non-hydride forming alloy such as Alloy 690 used in gas turbines inspired by service conditions of turbine blades i.e. under the combined effects of stress and temperature. An appropriate hydrogen transport equation is formulated accounting for both stress and temperature distributions of the domain in the non-hydride forming alloy. Finite element (FE) analyses are performed to predict steady-state hydrogen distribution in lattice sites and dislocation traps of a double notched specimen under constant tensile load and various temperature fields. Results demonstrate that the lattice hydrogen concentration is very sensitive to the temperature gradients whilst the stress concentration only slightly increases local lattice hydrogen concentration. The combined effects of stress and temperature result in the highest concentration of the dislocation trapped hydrogen in low-temperature regions although the plastic strain is only at a moderate level. Our results suggest that temperature gradients and stress concentrations in turbine blades due to cooling channels and holes make the relatively low-temperature regions susceptible to hydrogen embrittlement.
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.
A Green Hydrogen Energy System: Optimal Control Strategies for Integrated Hydrogen Storage and Power Generation with Wind Energy
Jul 2022
Publication
The intermittent nature of renewable energy resources such as wind and solar causes the energy supply to be less predictable leading to possible mismatches in the power network. To this end hydrogen production and storage can provide a solution by increasing flexibility within the system. Stored hydrogen as compressed gas can either be converted back to electricity or it can be used as feed-stock for industry heating for built environment and as fuel for vehicles. This research is the first to examine optimal strategies for operating integrated energy systems consisting of renewable energy production and hydrogen storage with direct gas-based use-cases for hydrogen. Using Markov decision process theory we construct optimal policies for day-to-day decisions on how much energy to store as hydrogen or buy from or sell to the electricity market and on how much hydrogen to sell for use as gas. We pay special emphasis to practical settings such as contractually binding power purchase agreements varying electricity prices different distribution channels green hydrogen offtake agreements and hydrogen market price uncertainties. Extensive experiments and analysis are performed in the context of Northern Netherlands where Europe’s first Hydrogen Valley is being formed. Results show that gains in operational revenues of up to 51% are possible by introducing hydrogen storage units and competitive hydrogen market-prices. This amounts to a e126000 increase in revenues per turbine per year for a 4.5 MW wind turbine. Moreover our results indicate that hydrogen offtake agreements will be crucial in keeping the energy transition on track.
Sector Coupling via Hydrogen to Lower the Cost of Energy System Decarbonization
Aug 2021
Publication
There is growing interest in using hydrogen (H2) as a long-duration energy storage resource in a future electric grid dominated by variable renewable energy (VRE) generation. Modeling H2 use exclusively for grid-scale energy storage often referred to as ‘‘power-to-gas-to-power (P2G2P)’’ overlooks the cost-sharing and CO2 emission benefits from using the deployed H2 assets to decarbonize other end-use sectors where direct electrification is challenging. Here we develop a generalized framework for co-optimizing infrastructure investments across the electricity and H2 supply chains accounting for the spatio-temporal variations in energy demand and supply. We apply this sector-coupling framework to the U.S. Northeast under a range of technology cost and carbon price scenarios and find greater value of power-to-H2 (P2G) vs. P2G2P routes. Specifically P2G provides grid flexibility to support VRE integration without the round-trip efficiency penalty and additional cost incurred by P2G2P routes. This form of sector coupling leads to: (a) VRE generation increase by 13–56% and (b) total system cost (and levelized costs of energy) reduction by 7–16% under deep decarbonization scenarios. Both effects increase as H2 demand for other end-uses increases more than doubling for a 97% decarbonization scenario as H2 demand quadruples. We also find that the grid flexibility enabled by sector coupling makes deployment of carbon capture and storage (CCS) for power generation less cost-effective than its use for low-carbon H2 production. These findings highlight the importance of using an integrated energy system framework with multiple energy vectors in planning cost-effective energy system decarbonization
JRC Reference Data from Experiments of Onboard Hydrogen Tanks Fast Filling
Sep 2013
Publication
At the JRC-IET on-board hydrogen tanks have been subjected to filling–emptying cycles to investigate their long-term mechanical and thermal behaviour and their safety performance. The local temperature history inside the tanks has been measured and compared with the temperatures outside and at the tank metallic bosses which is the measurement location identified by some standards. The outcome of these activities is a set of experimental data which will be made publicly available as reference for safety studies and validation of computational fluid dynamics.
Optimal Design of Multi-energy Systems with Seasonal Storage
Oct 2017
Publication
Optimal design and operation of multi-energy systems involving seasonal energy storage are often hindered by the complexity of the optimization problem. Indeed the description of seasonal cycles requires a year-long time horizon while the system operation calls for hourly resolution; this turns into a large number of decision variables including binary variables when large systems are analyzed. This work presents novel mixed integer linear program methodologies that allow considering a year time horizon with hour resolution while significantly reducing the complexity of the optimization problem. First the validity of the proposed techniques is tested by considering a simple system that can be solved in a reasonable computational time without resorting to design days. Findings show that the results of the proposed approaches are in good agreement with the full-scale optimization thus allowing to correctly size the energy storage and to operate the system with a long-term policy while significantly simplifying the optimization problem. Furthermore the developed methodology is adopted to design a multi-energy system based on a neighborhood in Zurich Switzerland which is optimized in terms of total annual costs and carbon dioxide emissions. Finally the system behavior is revealed by performing a sensitivity analysis on different features of the energy system and by looking at the topology of the energy hub along the Pareto sets.
Clean or Renewable – Hydrogen and Power-to-gas in EU Energy Law
Aug 2020
Publication
Interest in hydrogen as a carbon-neutral energy carrier is on the rise around the globe including in Europe. In particular power-to-gas as a technology to transform electricity to hydrogen is receiving ample attention. This article scrutinises current updates in the energy law framework of the EU to explain the legal pre-conditions for the various possible applications of power-to-gas technology. It highlights the influence of both electricity and gas legislation on conversion storage and transmission of hydrogen and demonstrates why ‘green’ hydrogen might come with certain legal privileges under the Renewable Energy Directive attached to it as opposed to the European Commission’s so-called ‘clean’ hydrogen. The article concludes by advocating for legal system integration in EU energy law namely merging the currently distinct EU electricity and gas law frameworks into one unified EU Energy Act.
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.
Onboard Compressed Hydrogen Storage: Fast Filling Experiments and Simulations
Nov 2021
Publication
Technology safety represents a key enabling factor for the commercial use of hydrogen within the automotive industry. In the last years considerable pre-normative and normative research effort has produced regulations at national European and global level as well as international standards. Their validation is at the moment on going internationally. Additional research is required to improve this regulatory and standardization frame which is also expected to have a beneficial effect on cost and product optimization. The present paper addresses results related to the experimental assessment and modeling of safety performance of high pressure onboard storage. To simulate the lifetime of onboard hydrogen tanks commercial tanks have been subjected to filling-emptying cycles encompassing a fast-filling phase as prescribed by the European regulation on type-approval of hydrogen vehicles. The local temperature history inside the tanks has been measured and compared with the temperature outside at the tank metallic bosses which is the measurement location identified by the regulation. Experimental activities are complemented by computational fluid-dynamics (CFD) modeling of the fast-filling process by means of a numerical model previously validated. The outcome of these activities is a set of scientifically based data which will serve as input to future regulations and standards improvement.
A Review at the Role of Storage in Energy Systems with a Focus on Power to Gas and Long-term Storage
Aug 2017
Publication
A review of more than 60 studies (plus m4ore than 65 studies on P2G) on power and energy models based on simulation and optimization was done. Based on these for power systems with up to 95% renewables the electricity storage size is found to be below 1.5% of the annual demand (in energy terms). While for 100% renewables energy systems (power heat mobility) it can remain below 6% of the annual energy demand. Combination of sectors and diverting the electricity to another sector can play a large role in reducing the storage size. From the potential alternatives to satisfy this demand pumped hydro storage (PHS) global potential is not enough and new technologies with a higher energy density are needed. Hydrogen with more than 250 times the energy density of PHS is a potential option to satisfy the storage need. However changes needed in infrastructure to deal with high hydrogen content and the suitability of salt caverns for its storage can pose limitations for this technology. Power to Gas (P2G) arises as possible alternative overcoming both the facilities and the energy density issues. The global storage requirement would represent only 2% of the global annual natural gas production or 10% of the gas storage facilities (in energy equivalent). The more options considered to deal with intermittent sources the lower the storage requirement will be. Therefore future studies aiming to quantify storage needs should focus on the entire energy system including technology vectors (e.g. Power to Heat Liquid Gas Chemicals) to avoid overestimating the amount of storage needed.
On the Climate Impacts of Blue Hydrogen Production
Nov 2021
Publication
Natural gas based hydrogen production with carbon capture and storage is referred to as blue hydrogen. If substantial amounts of CO2 from natural gas reforming are captured and permanently stored such hydrogen could be a low-carbon energy carrier. However recent research raises questions about the effective climate impacts of blue hydrogen from a life cycle perspective. Our analysis sheds light on the relevant issues and provides a balanced perspective on the impacts on climate change associated with blue hydrogen. We show that such impacts may indeed vary over large ranges and depend on only a few key parameters: the methane emission rate of the natural gas supply chain the CO2 removal rate at the hydrogen production plant and the global warming metric applied. State-of-the-art reforming with high CO2 capture rates combined with natural gas supply featuring low methane emissions does indeed allow for substantial reduction of greenhouse gas emissions compared to both conventional natural gas reforming and direct combustion of natural gas. Under such conditions blue hydrogen is compatible with low-carbon economies and exhibits climate change impacts at the upper end of the range of those caused by hydrogen production from renewable-based electricity. However neither current blue nor green hydrogen production pathways render fully “net-zero” hydrogen without additional CO2 removal.
Photocatalytic Hydrogen Production by Photo-Reforming of Methanol with One-pot Synthesized Pt-containing TiO2 Photocatalysts
Jul 2019
Publication
Functionalization of semiconductors by metallic nanoparticle is considered to be one of the most effective procedure to improve photocatalytic hydrogen production. Photodeposition is frequently used for functionalization but particle sizes and dispersions are still difficult to control. Here Pt functionalization is achieved in a one-pot synthesis. The as-prepared samples are compared to reference materials prepared by conventional photodeposition and our results confirm that small and well-dispersed nanoparticles with superior stability are obtained by one-pot synthesis. The enhanced stability is attributed to a limited leaching of Pt nanoparticles during illumination likely caused by the preferable interaction of small well dispersed Pt nanoparticles with the TiO2 support material. In addition our results demonstrate that Na-residues are detrimental for the photocatalytic performance and washing in acidic solution is mandatory to effectively reduce the sodium contamination.
Detecting Hydrogen Concentrations During Admixing Hydrogen in Natural Gas Grids
Aug 2021
Publication
The first applications of hydrogen in a natural gas grid will be the admixing of low concentrations in an existing distribution grid. For easy quality and process control it is essential to monitor the hydrogen concentration in real time preferably using cost effective monitoring solutions. In this paper we introduce the use of a platinum based hydrogen sensor that can accurately (at 0.1 vol%) and reversibly monitor the concentration of hydrogen in a carrier gas. This carrier gas that can be nitrogen methane or natural gas has no influence on the accuracy of the hydrogen detection. The hydrogen sensor consists of an interdigitated electrode on a chip coated with a platinum nanocomposite layer that interacts with the gas. This chip can be easily added to a gas sensor for natural gas and biogas that was already developed in previous research. Just by the addition of an extra chip we extended the applicability of the natural gas sensor to hydrogen admixing. The feasibility of the sensor was demonstrated in our own (TNO) laboratory and at a field test location of the HyDeploy program at Keele University in the U.K
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.
Simulation of the Inelastic Deformation of Porous Reservoirs Under Cyclic Loading Relevant for Underground Hydrogen Storage
Dec 2022
Publication
Subsurface geological formations can be utilized to safely store large-scale (TWh) renewable energy in the form of green gases such as hydrogen. Successful implementation of this technology involves estimating feasible storage sites including rigorous mechanical safety analyses. Geological formations are often highly heterogeneous and entail complex nonlinear inelastic rock deformation physics when utilized for cyclic energy storage. In this work we present a novel scalable computational framework to analyse the impact of nonlinear deformation of porous reservoirs under cyclic loading. The proposed methodology includes three diferent time-dependent nonlinear constitutive models to appropriately describe the behavior of sandstone shale rock and salt rock. These constitutive models are studied and benchmarked against both numerical and experimental results in the literature. An implicit time-integration scheme is developed to preserve the stability of the simulation. In order to ensure its scalability the numerical strategy adopts a multiscale fnite element formulation in which coarse scale systems with locally-computed basis functions are constructed and solved. Further the efect of heterogeneity on the results and estimation of deformation is analyzed. Lastly the Bergermeer test case—an active Dutch natural gas storage feld—is studied to investigate the infuence of inelastic deformation on the uplift caused by cyclic injection and production of gas. The present study shows acceptable subsidence predictions in this feld-scale test once the properties of the fnite element representative elementary volumes are tuned with the experimental data.
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.
A Review of Fuel Cell Systems for Maritime Applications
Jul 2016
Publication
Progressing limits on pollutant emissions oblige ship owners to reduce the environmental impact of their operations. Fuel cells may provide a suitable solution since they are fuel efficient while they emit few hazardous compounds. Various choices can be made with regard to the type of fuel cell system and logistic fuel and it is unclear which have the best prospects for maritime application. An overview of fuel cell types and fuel processing equipment is presented and maritime fuel cell application is reviewed with regard to efficiency gravimetric and volumetric density dynamic behaviour environmental impact safety and economics. It is shown that low temperature fuel cells using liquefied hydrogen provide a compact solution for ships with a refuelling interval up to a tens of hours but may result in total system sizes up to five times larger than high temperature fuel cells and more energy dense fuels for vessels with longer mission requirements. The expanding infrastructure of liquefied natural gas and development state of natural gas-fuelled fuel cell systems can facilitate the introduction of gaseous fuels and fuel cells on ships. Fuel cell combined cycles hybridisation with auxiliary electricity storage systems and redundancy improvements are identified as topics for further study
Production Costs for Synthetic Methane in 2030 and 2050 of an Optimized Power-to-Gas Plant with Intermediate Hydrogen Storage
Aug 2019
Publication
The publication gives an overview of the production costs of synthetic methane in a Power-to-Gas process. The production costs depend in particularly on the electricity price and the full load hours of the plant sub-systems electrolysis and methanation. The full-load hours of electrolysis are given by the electricity supply concept. In order to increase the full-load hours of methanation the size of the intermediate hydrogen storage tank and the size of the methanation are optimised on the basis of the availability of hydrogen. The calculation of the production costs for synthetic methane are done with economics for 2030 and 2050 and the expenditures are calculated for one year of operation. The sources of volume of purchased electricity are the short-term market long-term contracts direct-coupled renewable energy sources or seasonal use of surpluses. Gas sales are either traded on the short-term market or guaranteed by long-term contracts. The calculations show that an intermediate storage tank for hydrogen adjustment of the methanation size and operating electrolysis and methanation separately increase the workload of the sub-system methanation. The gas production costs can be significantly reduced. With the future expected development of capital expenditures operational expenditure electricity prices gas costs and efficiencies an economic production of synthetic natural gas for the years 2030 especially for 2050 is feasible. The results show that Power-to-Gas is an option for long-term large-scale seasonal storage of renewable energy. Especially the cases with high operating hours for the sub-system methanation and low electricity prices show gas production costs below the expected market prices for synthetic gas and biogas.
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.
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.
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.
Potential for Hydrogen and Power-to-Liquid in a Low-carbon EU Energy System Using Cost Optimization
Oct 2018
Publication
Hydrogen represents a versatile energy carrier with net zero end use emissions. Power-to-Liquid (PtL) includes the combination of hydrogen with CO2 to produce liquid fuels and satisfy mostly transport demand. This study assesses the role of these pathways across scenarios that achieve 80–95% CO2 reduction by 2050 (vs. 1990) using the JRC-EU-TIMES model. The gaps in the literature covered in this study include a broader spatial coverage (EU28+) and hydrogen use in all sectors (beyond transport). The large uncertainty in the possible evolution of the energy system has been tackled with an extensive sensitivity analysis. 15 parameters were varied to produce more than 50 scenarios. Results indicate that parameters with the largest influence are the CO2 target the availability of CO2 underground storage and the biomass potential.
Hydrogen demand increases from 7 mtpa today to 20–120 mtpa (2.4–14.4 EJ/yr) mainly used for PtL (up to 70 mtpa) transport (up to 40 mtpa) and industry (25 mtpa). Only when CO2 storage was not possible due to a political ban or social acceptance issues was electrolysis the main hydrogen production route (90% share) and CO2 use for PtL became attractive. Otherwise hydrogen was produced through gas reforming with CO2 capture and the preferred CO2 sink was underground. Hydrogen and PtL contribute to energy security and independence allowing to reduce energy related import cost from 420 bln€/yr today to 350 or 50 bln€/yr for 95% CO2 reduction with and without CO2 storage. Development of electrolyzers fuel cells and fuel synthesis should continue to ensure these technologies are ready when needed. Results from this study should be complemented with studies with higher spatial and temporal resolution. Scenarios with global trading of hydrogen and potential import to the EU were not included.
Hydrogen demand increases from 7 mtpa today to 20–120 mtpa (2.4–14.4 EJ/yr) mainly used for PtL (up to 70 mtpa) transport (up to 40 mtpa) and industry (25 mtpa). Only when CO2 storage was not possible due to a political ban or social acceptance issues was electrolysis the main hydrogen production route (90% share) and CO2 use for PtL became attractive. Otherwise hydrogen was produced through gas reforming with CO2 capture and the preferred CO2 sink was underground. Hydrogen and PtL contribute to energy security and independence allowing to reduce energy related import cost from 420 bln€/yr today to 350 or 50 bln€/yr for 95% CO2 reduction with and without CO2 storage. Development of electrolyzers fuel cells and fuel synthesis should continue to ensure these technologies are ready when needed. Results from this study should be complemented with studies with higher spatial and temporal resolution. Scenarios with global trading of hydrogen and potential import to the EU were not included.
Value of Power-to-gas as a Flexibility Option in Integrated Electricity and Hydrogen Markets
Oct 2021
Publication
This paper analyzes the economic potential of Power-to-Gas (PtG) as a source of flexibility in electricity markets with both high shares of renewables and high external demand for hydrogen. The contribution of this paper is that it develops and applies a short-term (hourly) partial equilibrium model of integrated electricity and hydrogen markets including markets for green certificates while using a welfare-economic framework to assess the market outcomes. We find that strongly increasing the share of renewable electricity makes electricity prices much more volatile while the presence of PtG reduces this price volatility. However a large demand for hydrogen from outside the electricity sector reduces the impact of PtG on the volatility of electricity prices. In a scenario with a high external hydrogen demand PtG can deliver positive benefits for some groups as it can provide hydrogen at lower costs than Steam Methane Reforming (SMR) during hours when electricity prices are low but these positive welfare effects are outweighed by the fixed costs of PtG assets plus the costs of replacing a less expensive energy carrier (natural gas) with a more expensive one (hydrogen). Investments in PtG are profitable from a social-welfare perspective when the induced reduction in carbon emissions is valued at 150–750 euro/ton. Hence at lower carbon prices PtG can only become a valuable provider of flexibility when installation costs are significantly reduced and conversion efficiencies of electrolysers increased.
Methanol Synthesis Using Captured CO2 as Raw Material: Techno-economic and Environmental Assessment
Aug 2015
Publication
The purpose of this paper is to assess via techno-economic and environmental metrics the production of methanol (MeOH) using H2 and captured CO2 as raw materials. It evaluates the potential of this type of carbon capture and utilisation (CCU) plant on (i) the net reduction of CO2 emissions and (ii) the cost of production in comparison with the conventional synthesis process of MeOH Europe. Process flow modelling is used to estimate the operational performance and the total purchased equipment cost; the flowsheet is implemented in CHEMCAD and the obtained mass and energy flows are utilised as input to calculate the selected key performance indicators (KPIs). CO2 -based metrics are used to assess the environmental impact. The evaluated MeOH plant produces 440 ktMeOH/yr and its configuration is the result of a heat integration process. Its specific capital cost is lower than for conventional plants. However raw materials prices i.e. H2 and captured CO2 do not allow such a project to be financially viable. In order to make the CCU plant financially attractive the price of MeOH should increase in a factor of almost 2 or H2 costs should decrease almost 2.5 times or CO2 should have a value of around 222 €/t under the assumptions of this work. The MeOH CCU-plant studied can utilise about 21.5% of the CO2 emissions of a pulverised coal (PC) power plant that produces 550MWnet of electricity. The net CO2 emissions savings represent 8% of the emissions of the PC plant (mainly due to the avoidance of consuming fossil fuels as in the conventional MeOH synthesis process). The results demonstrate that there is a net but small potential for CO2 emissions reduction; assuming that such CCU plants are constructed in Europe to meet the MeOH demand growth and the quantities that are currently imported the net CO2 emissions reduction could be of 2.71 MtCO2/yr.
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.
Is a 100% Renewable European Power System Feasible by 2050?
Nov 2018
Publication
In this study we model seven scenarios for the European power system in 2050 based on 100% renewable energy sources assuming different levels of future demand and technology availability and compare them with a scenario which includes low-carbon non-renewable technologies. We find that a 100% renewable European power system could operate with the same level of system adequacy as today when relying on European resources alone even in the most challenging weather year observed in the period from 1979 to 2015. However based on our scenario results realising such a system by 2050 would require: (i) a 90% increase in generation capacity to at least 1.9 TW (compared with 1 TW installed today) (ii) reliable cross-border transmission capacity at least 140GW higher than current levels (60 GW) (iii) the well-managed integration of heat pumps and electric vehicles into the power system to reduce demand peaks and biogas requirements (iv) the implementation of energy efficiency measures to avoid even larger increases in required biomass demand generation and transmission capacity (v) wind deployment levels of 7.5GWy−1 (currently 10.6GWy−1) to be maintained while solar photovoltaic deployment to increase to at least 15GWy−1 (currently 10.5GWy−1) (vi) large-scale mobilisation of Europe’s biomass resources with power sector biomass consumption reaching at least 8.5 EJ in the most challenging year (compared with 1.9 EJ today) and (vii) increasing solid biomass and biogas capacity deployment to at least 4GWy−1 and 6 GWy−1 respectively. We find that even when wind and solar photovoltaic capacity is installed in optimum locations the total cost of a 100% renewable power system (∼530 €bn y−1) would be approximately 30% higher than a power system which includes other low-carbon technologies such as nuclear or carbon capture and storage (∼410 €bn y−1). Furthermore a 100% renewable system may not deliver the level of emission reductions necessary to achieve Europe’s climate goals by 2050 as negative emissions from biomass with carbon capture and storage may still be required to offset an increase in indirect emissions or to realise more ambitious decarbonisation pathways.
Modelling a Highly Decarbonised North Sea Energy System in 2050: a Multinational Approach
Dec 2021
Publication
The North Sea region located in the Northwest of Europe is expected to be a frontrunner in the European energy transition. This paper aims to analyse different optimal system configurations in order to meet net-zero emission targets in 2050. Overall the paper presents two main contributions: first we develop and introduce the IESA-NS model. The IESA-NS model is an optimization integrated energy system model written as a linear problem. The IESA-NS model optimizes the long-term investment planning and short-term operation of seven North Sea region countries (Belgium Denmark Germany the Netherlands Norway Sweden and the United Kingdom). The model can optimize multiple years simultaneously accounts for all the national GHG emissions and includes a thorough representation of all the sectors of the energy system. Second we run several decarbonisation scenarios with net-zero emission targets in 2050. Relevant parameters varied to produce the scenarios include biomass availability VRE potentials low social acceptance of onshore VRE ban of CCUS or mitigation targets in international transport and industry feedstock. Results show a large use of hydrogen when international transport emissions are considered in the targets (5.6 EJ to 7.3 EJ). Electrolysis is the preferred pathway for hydrogen production (up to 6.4 EJ) far ahead of natural gas reforming (up to 2.2 EJ). Allowing offshore interconnectors (e.g. meshed offshore grid between the Netherlands Germany and the United Kingdom) permits to integrate larger amounts of offshore wind (122 GW to 191 GW of additional capacity compared to reference scenarios) while substantially increasing the cross-border interconnection capacities (up to 120 GW). All the biomass available is used in the scenarios across multiple end uses including biofuel production (up to 3.5 EJ) high temperature heat (up to 2.5 EJ) feedstock for industry (up to 2 EJ) residential heat (up to 600 PJ) and power generation (up to 900 PJ). In general most of the results justify the development of multinational energy system models in which the spatial coverage lays between national and continental models.
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.
Ammonia Production from Clean Hydrogen and the Implications for Global Natural Gas Demand
Jan 2023
Publication
Non-energy use of natural gas is gaining importance. Gas used for 183 million tons annual ammonia production represents 4% of total global gas supply. 1.5-degree pathways estimate an ammonia demand growth of 3–4-fold until 2050 as new markets in hydrogen transport shipping and power generation emerge. Ammonia production from hydrogen produced via water electrolysis with renewable power (green ammonia) and from natural gas with CO2 storage (blue ammonia) is gaining attention due to the potential role of ammonia in decarbonizing energy value chains and aiding nations in achieving their net-zero targets. This study assesses the technical and economic viability of different routes of ammonia production with an emphasis on a systems level perspective and related process integration. Additional cost reductions may be driven by optimum sizing of renewable power capacity reducing losses in the value chain technology learning and scale-up reducing risk and a lower cost of capital. Developing certification and standards will be necessary to ascertain the extent of greenhouse gas emissions throughout the supply chain as well as improving the enabling conditions including innovative finance and de-risking for facilitating international trade market creation and large-scale project development.
Hydrogen Infrastructure Project Risks in The Netherlands
Sep 2021
Publication
This study aims to assess the potential risks of setting up a hydrogen infrastructure in the Netherlands. An integrated risk assessment framework capable of analyzing projects identifying risks and comparing projects is used to identify and analyze the main risks in the upcoming Dutch hydrogen infrastructure project. A time multiplier is added to the framework to develop parameters. The impact of the different risk categories provided by the integrated framework is calculated using the discounted cash flow (DCF) model. Despite resource risks having the highest impact scope risks are shown to be the most prominent in the hydrogen infrastructure project. To present the DCF model results a risk assessment matrix is constructed. Compared to the conventional Risk Assessment Matrix (RAM) used to present project risks this matrix presents additional information in terms of the internal rate of return and risk specifics.
Techno-economic Evaluation on a Hybrid Technology for Low Hydrogen Concentration Separation and Purification from Natural Gas Grid
Jul 2020
Publication
Hydrogen can be stored and distributed by injecting into existing natural grids then at the user site separated and used in different applications. The conventional technology for hydrogen separation is pressure swing adsorption (PSA). The recent NREL study showed the extraction cost for separating hydrogen from a 10% H2 stream with a recovery of 80% is around 3.3e8.3 US$/kg. In this document new system configurations for low hydrogen concentration separation from the natural gas grid by combining novel membrane-based hybrid technologies will be described in detail. The focus of the manuscript will be on the description of different configurations for the direct hydrogen separation which comprises a membrane module a vacuum pump and an electrochemical hydrogen compressor. These technological combinations bring substantial synergy effect of one another while improving the total hydrogen recovery purity and total cost of hydrogen. Simulation has been carried out for 17 different configurations; according to the results a configuration of two-stage membrane modules (in series) with a vacuum pump and an electrochemical hydrogen compressor (EHC) shows highest hydrogen purity (99.9997%) for 25 kg/day of hydrogen production for low-pressure grid. However this configuration shows a higher electric consumption (configuration B) due to the additional mechanical compressor between the two-stage membrane modules and the EHC. Whereas when the compressor is excluded and a double skin Pd membrane (PdDS) module is used in a single stage while connected to a vacuum pump (configuration A5) the hydrogen purity (99.92%) slightly decreases yet the power consumption considerably improves (1.53 times lower). Besides to these two complementary configurations the combination of a single membrane module a vacuum pump and the electrochemical compressor has been also carried out (configuration A) and results show that relatively higher purity can be achieved. Based on four master configurations this document presents a different novel hybrid system by integrating two to three technologies for hydrogen purification combined in a way that enhances the strengths of each of them.
Introducing Power-to-H3: Combining Renewable Electricity with Heat, Water and Hydrogen Production and Storage in a Neighbourhood
Oct 2019
Publication
In the transition from fossil to renewable energy the energy system should become clean while remaining reliable and affordable. Because of the intermittent nature of both renewable energy production and energy demand an integrated system approach is required that includes energy conversion and storage. We propose a concept for a neighbourhood where locally produced renewable energy is partly converted and stored in the form of heat and hydrogen accompanied by rainwater collection storage purification and use (Power-to-H3). A model is developed to create an energy balance and perform a techno-economic analysis including an analysis of the avoided costs within the concept. The results show that a solar park of 8.7 MWp combined with rainwater collection and solar panels on roofs can supply 900 houses over the year with heat (20 TJ) via an underground heat storage system as well as with almost half of their water demand (36000m3) and 540 hydrogen electric vehicles can be supplied with hydrogen (90 tonnes). The production costs for both hydrogen (8.7 €/kg) and heat (26 €/GJ) are below the current end user selling price in the Netherlands (10 €/kg and 34 €/GJ) making the system affordable. When taking avoided costs into account the prices could decrease with 20–26% while at the same time avoiding 3600 tonnes of CO2 a year. These results make clear that it is possible to provide a neighbourhood with all these different utilities completely based on solar power and rainwater in a reliable affordable and clean way.
Greenhouse Gas Implications of Extending the Service Life of PEM Fuel Cells for Automotive Applications: A Life Cycle Assessment
Feb 2022
Publication
A larger adoption of hydrogen fuel-cell electric vehicles (FCEVs) is typically included in the strategies to decarbonize the transportation sector. This inclusion is supported by life-cycle assessments (LCAs) which show the potential greenhouse gas (GHG) emission benefit of replacing internal combustion engine vehicles with their fuel cell counterpart. However the literature review performed in this study shows that the effects of durability and performance losses of fuel cells on the life-cycle environmental impact of the vehicle have rarely been assessed. Most of the LCAs assume a constant fuel consumption (ranging from 0.58 to 1.15 kgH2/100 km) for the vehicles throughout their service life which ranges in the assessments from 120000 to 225000 km. In this study the effect of performance losses on the life-cycle GHG emissions of the vehicles was assessed based on laboratory experiments. Losses have the effect of increasing the life-cycle GHG emissions of the vehicle up to 13%. Moreover this study attempted for the first time to investigate via laboratory analyses the GHG implications of replacing the hydrophobic polymer for the gas diffusion medium (GDM) of fuel cells to increase their durability. LCA showed that when the service life of the vehicle was fixed at 150000 km the GHG emission savings of using an FC with lower performance losses (i.e. FC coated with fluorinated ethylene propylene (FEP) instead of polytetrafluoroethylene (PTFE)) are negligible compared to the overall life-cycle impact of the vehicle. Both the GDM coating and the amount of hydrogen saved account for less than 2% of the GHG emissions arising during vehicle operation. On the other hand when the service life of the vehicle depends on the operability of the fuel cell the global warming potential per driven km of the FEP-based FCEV reduces by 7 to 32%. The range of results depends on several variables such as the GHG emissions from hydrogen production and the initial fuel consumption of the vehicle. Higher GHG savings are expected from an FC vehicle with high consumption of hydrogen produced with fossil fuels. Based on the results we recommend the inclusion of fuel-cell durability in future LCAs of FCEVs. We also advocate for more research on the real-life performance of fuel cells employing alternative materials.
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.
CFD Analysis of Fast Filling Strategies for Hydrogen Tanks and their Effects on Key-parameters
Nov 2014
Publication
A major requirement for the filling of hydrogen tanks is the maximum gas temperature within the vessels during the process. Different filling strategies in terms of pressure and temperature of the gas injected into the cylinder and their effects on key parameters like maximum temperature state of charge and energy cooling demand are investigated. It is shown that pre-cooling of the gas is required but is not necessary for the whole duration of the filling. Relevant energy savings can be achieved with pre-cooling over a fraction of the time. The most convenient filling strategy from the cooling energy point of view is identified: with an almost linear pressure rise and pre-cooling in the second half of the process a 60% reduction of the cooling energy demand is achieved compared to the case of pre-cooling for the whole filling.
No more items...