Netherlands
Cost-optimal Reliable Power Generation in a Deep Decarbonisation Future
Jul 2019
Publication
Considering the targets of the Paris agreement rapid decarbonisation of the power system is needed. In order to study cost-optimal and reliable zero and negative carbon power systems a power system model of Western Europe for 2050 is developed. Realistic future technology costs demand levels and generator flexibility constraints are considered. The optimised portfolios are tested for both favourable and unfavourable future weather conditions using results from a global climate model accounting for the potential impacts of climate change on Europe’s weather. The cost optimal mix for zero or negative carbon power systems consists of firm low-carbon capacity intermittent renewable energy sources and flexibility capacity. In most scenarios the amount of low-carbon firm capacity is around 75% of peak load providing roughly 65% of the electricity demand. Furthermore it is found that with a high penetration of intermittent renewable energy sources a high dependence on cross border transmission batteries and a shift to new types of ancillary services is required to maintain a reliable power system. Despite relatively small changes in the total generation from intermittent renewable energy sources between favourable and unfavourable weather years of 6% emissions differ up to 70 MtCO2 yr−1 and variable systems costs up to 25%. In a highly interconnected power system with significant flexible capacity in the portfolio and minimal curtailment of intermittent renewables the potential role of green hydrogen as a means of electricity storage appears to be limited.
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
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.
The Membrane-assisted Chemical Looping Reforming Concept for Efficient H2 Production with Inherent CO2 Capture: Experimental Demonstration and Model Validation
Feb 2018
Publication
In this work a novel reactor concept referred to as Membrane-Assisted Chemical Looping Reforming (MA-CLR) has been demonstrated at lab scale under different operating conditions for a total working time of about 100 h. This reactor combines the advantages of Chemical Looping such as CO2 capture and good thermal integration with membrane technology for a better process integration and direct product separation in a single unit which in its turn leads to increased efficiencies and important benefits compared to conventional technologies for H2 production. The effect of different operating conditions (i.e. temperature steam-to-carbon ratio or oxygen feed in the reactor) has been evaluated in a continuous chemical looping reactor and methane conversions above 90% have been measured with (ultra-pure) hydrogen recovery from the membranes. For all the cases a maximum recovery factor of around 30% has been measured which could be increased by operating the concept at higher pressures and with more membranes. The optimum conditions have been found at temperatures around 600°C for a steam-to-carbon ratio of 3 and diluted air in the air reactor (5% O2). The complete demonstration has been carried out feeding up to 1 L/min of CH4 (corresponding to 0.6 kW of thermal input) while up to 1.15 L/min of H2 was recovered. Simultaneously a phenomenological model has been developed and validated with the experimental results. In general good agreement is observed with overall deviations below 10% in terms of methane conversion H2 recovery and separation factor. The model allows better understanding of the behavior of the MA-CLR concept and the optimization and design of scaled-up versions of the concept.
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.
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.
Control of Electrons’ Spin Eliminates Hydrogen Peroxide Formation During Water Splitting
Jul 2017
Publication
The production of hydrogen through water splitting in a photoelectrochemical cell suffers from an overpotential that limits the efficiencies. In addition hydrogen-peroxide formation is identified as a competing process affecting the oxidative stability of photoelectrodes. We impose spin-selectivity by coating the anode with chiral organic semiconductors from helically aggregated dyes as sensitizers; Zn-porphyrins and triarylamines. Hydrogen peroxide formation is dramatically suppressed while the overall current through the cell correlating with the water splitting process is enhanced. Evidence for a strong spin-selection in the chiral semiconductors is presented by magnetic conducting (mc-)AFM measurements in which chiral and achiral Zn-porphyrins are compared. These findings contribute to our understanding of the underlying mechanism of spin selectivity in multiple electron-transfer reactions and pave the way toward better chiral dye-sensitized photoelectrochemical cells.
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.
Decarbonization of Australia’s Energy System: Integrated Modelling of the Transformation of Electricity, Transportation, and Industrial Sectors
Jul 2020
Publication
To achieve the Paris Agreement’s long-term temperature goal current energy systems must be transformed. Australia represents an interesting case for energy system transformation modelling: with a power system dominated by fossil fuels and specifically with a heavy coal component there is at the same time a vast potential for expansion and use of renewables. We used the multi-sectoral Australian Energy Modelling System (AUSeMOSYS) to perform an integrated analysis of implications for the electricity transport and selected industry sectors to the mid-century. The state-level resolution allows representation of regional discrepancies in renewable supply and the quantification of inter-regional grid extensions necessary for the physical integration of variable renewables. We investigated the impacts of different CO2 budgets and selected key factors on energy system transformation. Results indicate that coal-fired generation has to be phased out completely by 2030 and a fully renewable electricity supply achieved in the 2030s according to the cost-optimal pathway implied by the 1.5 °C Paris Agreement-compatible carbon budget. Wind and solar PV can play a dominant role in decarbonizing Australia’s energy system with continuous growth of demand due to the strong electrification of linked energy sectors.
Potential of Power-to-Methane in the EU Energy Transition to a Low Carbon System Using Cost Optimization
Oct 2018
Publication
Power-to-Methane (PtM) can provide flexibility to the electricity grid while aiding decarbonization of other sectors. This study focuses specifically on the methanation component of PtM in 2050. Scenarios with 80–95% CO2 reduction by 2050 (vs. 1990) are analyzed and barriers and drivers for methanation are identified. PtM arises for scenarios with 95% CO2 reduction no CO2 underground storage and low CAPEX (75 €/kW only for methanation). Capacity deployed across EU is 40 GW (8% of gas demand) for these conditions which increases to 122 GW when liquefied methane gas (LMG) is used for marine transport. The simultaneous occurrence of all positive drivers for PtM which include limited biomass potential low Power-to-Liquid performance use of PtM waste heat among others can increase this capacity to 546 GW (75% of gas demand). Gas demand is reduced to between 3.8 and 14 EJ (compared to ∼20 EJ for 2015) with lower values corresponding to scenarios that are more restricted. Annual costs for PtM are between 2.5 and 10 bln€/year with EU28’s GDP being 15.3 trillion €/year (2017). Results indicate that direct subsidy of the technology is more effective and specific than taxing the fossil alternative (natural gas) if the objective is to promote the technology. Studies with higher spatial resolution should be done to identify specific local conditions that could make PtM more attractive compared to an EU scale.
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.
Fuel Cell Cars in a Microgrid for Synergies Between Hydrogen and Electricity Networks
Nov 2016
Publication
Fuel cell electric vehicles convert chemical energy of hydrogen into electricity to power their motor. Since cars are used for transport only during a small part of the time energy stored in the on-board hydrogen tanks of fuel cell vehicles can be used to provide power when cars are parked. In this paper we present a community microgrid with photovoltaic systems wind turbines and fuel cell electric vehicles that are used to provide vehicle-to-grid power when renewable power generation is scarce. Excess renewable power generation is used to produce hydrogen which is stored in a refilling station. A central control system is designed to operate the system in such a way that the operational costs are minimized. To this end a hybrid model for the system is derived in which both the characteristics of the fuel cell vehicles and their traveling schedules are considered. The operational costs of the system are formulated considering the presence of uncertainty in the prediction of the load and renewable energy generation. A robust minmax model predictive control scheme is developed and finally a case study illustrates the performance of the designed system.
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.
In-Situ Hollow Sample Setup Design for Mechanical Characterisation of Gaseous Hydrogen Embrittlement of Pipeline Steels and Welds
Aug 2021
Publication
This work discusses the design and demonstration of an in-situ test setup for testing pipeline steels in a high pressure gaseous hydrogen (H2 ) environment. A miniature hollow pipe-like tensile specimen was designed that acts as the gas containment volume during the test. Specific areas of the specimen can be forced to fracture by selective notching as performed on the weldment. The volume of H2 used was minimised so the test can be performed safely without the need of specialised equipment. The setup is shown to be capable of characterising Hydrogen Embrittlement (HE) in steels through testing an X60 pipeline steel and its weldment. The percentage elongation (%El) of the base metal was found to be reduced by 40% when tested in 100 barg H2 . Reduction of cross-sectional area (%RA) was found to decrease by 28% and 11% in the base metal and weld metal respectively when tested in 100 barg H2 . Benchmark test were performed at 100 barg N2 pressure. SEM fractography further indicated a shift from normal ductile fracture mechanisms to a brittle transgranular (TG) quasi-cleavage (QC) type fracture that is characteristic of HE.
Life Cycle Assessment Integration into Energy System Models: An Application for Power-to-Methane in the EU
Nov 2019
Publication
As the EU energy system transitions to low carbon the technology choices should consider a broader set of criteria. The use of Life Cycle Assessment (LCA) prevents burden shift across life cycle stages or impact categories while the use of Energy System Models (ESM) allows evaluating alternative policies capacity evolution and covering all the sectors. This study does an ex-post LCA analysis of results from JRC-EU-TIMES and estimates the environmental impact indicators across 18 categories in scenarios that achieve 80–95% CO2 emission reduction by 2050. Results indicate that indirect CO2 emissions can be as large as direct ones for an 80% CO2 reduction target and up to three times as large for 95% CO2 reduction. Impact across most categories decreases by 20–40% as the CO2 emission target becomes stricter. However toxicity related impacts can become 35–100% higher. The integrated framework was also used to evaluate the Power-to-Methane (PtM) system to relate the electricity mix and various CO2 sources to the PtM environmental impact. To be more attractive than natural gas the climate change impact of the electricity used for PtM should be 123–181 gCO2eq/kWh when the CO2 comes from air or biogenic sources and 4–62 gCO2eq/kWh if the CO2 is from fossil fuels. PtM can have an impact up to 10 times larger for impact categories other than climate change. A system without PtM results in ~4% higher climate change impact and 9% higher fossil depletion while having 5–15% lower impact for most of the other categories. This is based on a scenario where 9 parameters favor PtM deployment and establishes the upper bound of the environmental impact PtM can have. Further studies should work towards integrating LCA feedback into ESM and standardizing the methodology.
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
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.
Optimisation-based System Designs for Deep Offshore Wind Farms including Power to Gas Technologies
Feb 2022
Publication
A large deployment of energy storage solutions will be required by the stochastic and non-controllable nature of most renewable energy sources when planning for higher penetration of renewable electricity into the energy mix. Various solutions have been suggested for dealing with medium- and long-term energy storage. Hydrogen and ammonia are two of the most frequently discussed as they are both carbon-free fuels. In this paper the authors analyse the energy and cost efficiency of hydrogen and ammonia-based pathways for the storage transportation and final use of excess electricity from an offshore wind farm. The problem is solved as a linear programming problem simultaneously optimising the size of each problem unit and the respective time-dependent operational conditions. As a case study we consider an offshore wind farm of 1.5 GW size located in a reference location North of Scotland. The energy efficiency and cost of the whole chain are evaluated and compared with competitive alternatives namely batteries and liquid hydrogen storage. The results show that hydrogen and ammonia storage can be part of the optimal solution. Moreover their use for long-term energy storage can provide a significant cost-effective contribution to an extensive penetration of renewable energy sources in national energy systems.
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.
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
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.
Carbon Capture and Biomass in Industry: A Techno-economic Analysis and Comparison of Negative Emission Options
Apr 2021
Publication
Meeting the Paris Agreement will most likely require the combination of CO2 capture and biomass in the industrial sector resulting in net negative emissions. CO2 capture within the industry has been extensively investigated. However biomass options have been poorly explored with literature alluding to technical and economic barriers. In addition a lack of consistency among studies makes comparing the performance of CO2 capture and/or biomass use between studies and sectors difficult. These inconsistencies include differences in methodology system boundaries level of integration costs greenhouse gas intensity of feedstock and energy carriers and capital cost estimations. Therefore an integrated evaluation of the techno-economic performance regarding CO2 capture and biomass use was performed for five energy-intensive industrial sub-sectors. Harmonization results indicate that CO2 mitigation potentials vary for each sub-sector resulting in reductions of 1.4–2.7 t CO2/t steel (77%–149%) 0.7 t CO2/t cement (92%) 0.2 t CO2/t crude oil (68%) 1.9 t CO2/t pulp (1663%–2548%) and 34.9 t CO2/t H2 (313%). Negative emissions can be reached in the steel paper and H2 sectors. Novel bio-based production routes might enable net negative emissions in the cement and (petro) chemical sectors as well. All the above-mentioned potentials can be reached for 100 €/t CO2 or less. Implementing mitigation options could reduce industrial CO2 emissions by 10 Gt CO2/y by 2050 easily meeting the targets of the 2 ◦C scenario by the International Energy Agency (1.8 Gt CO2/y reduction) for the industrial sector and even the Beyond 2 ◦C scenario (4.2 Gt CO2/y reduction).
Performance Analysis of a Stand-alone Integrated Solar Hydrogen Energy System for Zero Energy Buildings
Oct 2022
Publication
This study analyzes the optimal sizing design of a stand-alone solar hydrogen hybrid energy system for a house in Afyon Turkey. The house is not connected to the grid and the proposed hybrid system meets all its energy demands; therefore it is considered a zero-energy building. The designed system guarantees uninterrupted and reliable power throughout the year. Since the reliability of the power supply is crucial for the house optimal sizing of the components photovoltaic (PV) panels electrolyzer storage tank and fuel cell stack is critical. Determining the sufficient number of PV panels suitable electrolyzer model and size number of fuel cell stacks and the minimum storage tank volume to use in the proposed system can guarantee an uninterrupted energy supply to the house. In this study a stand-alone hybrid energy system is proposed. The system consists of PV panels a proton exchange membrane (PEM) electrolyzer a storage tank and a PEM fuel cell stack. It can meet the continuous energy demand of the house is sized by using 10 min of averaged solar irradiation and temperature data of the site and consumption data of the house. Present results show that the size of each component in a solar hydrogen hybrid energy system in terms of power depends on the size of each other components to meet the efficiency requirement of the whole system. Choosing the nominal electrolyzer power is critical in such energy systems
Seasonal Hydrogen Storage Decisions Under Constrained Electricity Distribution Capacity
Jun 2022
Publication
We consider a profit-maximizing renewable energy producer operating in a rural area with limited electricity distribution capacity to the grid. While maximizing profits the energy producer is responsible for the electricity supply of a local community that aims to be self-sufficient. Energy storage is required to deal with the energy productions' uncertain and intermittent character. A promising new solution is to use strategic hydrogen reserves. This provides a long-term storage option to deal with seasonal mismatches in energy production and the local community's demand. Using a Markov decision process we provide a model that determines optimal daily decisions on how much energy to store as hydrogen and buy or sell from the power grid. We explicitly consider the seasonality and uncertainty of production demand and electricity prices. We show that ignoring seasonal demand and production patterns is suboptimal and that introducing hydrogen storage transforms loss-making operations into profitable ones. Extensive numerical experiments show that the distribution capacity should not be too small to prevent local grid congestion. A higher storage capacity increases the number of buying actions from the grid thereby causing more congestion which is problematic for the grid operator. We conclude that a profit-maximizing hydrogen storage operation alone is not an alternative to grid expansion to solve congestion which is essential knowledge for policy-makers and grid operators.
Economic Feasibility of Green Hydrogen in Providing Flexibility to Medium-voltage Distribution Grids in the Presence of Local-heat Systems
Nov 2022
Publication
The recent strong increase in the penetration of renewable energy sources (RESs) in medium-voltage distribution grids (MVDNs) has raised the need for congestion management in such grids as they were not designed for this new condition. This paper examines to what extent producing green hydrogen through electrolyzers can profitably contribute to congestion alleviation in MVDNs in the presence of high amounts of RES as well as flexible consumers of electricity and a local heat system. To address this issue an incentive-based method for improving flexibility in MVDNs is used which is based on a single-leader–multiple-followers game formulated by bi-level mathematical programming. At the upper level the distribution system operator who is the leader of this game determines dynamic prices as incentives at each node based on the levels of generation and load. Next at the lower level providers of flexibility including producers using electrolyzers price-responsive power consumers heat consumers as well as heat producers respond to these incentives by reshaping their output and consumption patterns. The model is applied to a region in the North of The Netherlands. The obtained results demonstrate that converting power to hydrogen can be an economically efficient way to reduce congestion in MVDNs when there is a high amount of RES. However the economic value of electrolyzers as providers of flexibility to MVDNs decreases when more other options for flexibility provision exist.
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.
Paving the Way: Analysing Energy Transition Pathways and Green Hydrogen Exports in Developing Countries - The Case of Algeria
Apr 2024
Publication
The measures needed to limit global warming pose a particular challenge to current fossil fuel exporters who must not only decarbonise their local energy systems but also compensate for the expected decline in fossil fuel revenues. One possibility is seen in the export of green hydrogen. Using Algeria as a case study this paper analyses how different levels of ambition in hydrogen exports energy efficiency and fuel switching affect the costoptimal expansion of the power sector for a given overall emissions reduction path. Despite falling costs for photovoltaics and wind turbines the results indicate that in countries with very low natural gas prices such as Algeria a fully renewable electricity system by 2050 is unlikely without appropriate policy measures. The expansion of renewable energy should therefore start early given the high annual growth rates required which will be reinforced by additional green hydrogen exports. In parallel energy efficiency is a key factor as it directly mitigates CO2 emissions from fossil fuels and reduces domestic electricity demand which could instead be used for hydrogen production. Integrating electrolysers into the power system could potentially help to reduce specific costs through load shifting. Overall it seems advisable to analyse hydrogen exports together with local decarbonisation in order to better understand their interactions and to reduce emissions as efficiently as possible. These results and the methodology could be transferred to other countries that want to become green hydrogen exporters in the future and are therefore a useful addition for researchers and policy makers.
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.
Renaissance of Ammonia Synthesis for Sustainable Production of Energy and Fertilizers
Feb 2021
Publication
Green ammonia synthesis via the Haber–Bosch (HB) process has become a major field of research in the recent years for production of fertilizers and seasonal energy storage due to drastic drop in cost of renewable hydrogen. While the field of catalysis and engineering has worked on this subject for many years the current process of ammonia synthesis remains essentially unaltered. As a result current industrial developments on green ammonia are based on the HB process which can only be economical at exceptionally large scales limiting implementation on financially strained economies. For green ammonia to become an economic “equalizer” that supports the energy transition around the world it is essential to facilitate the downscalability and operational robustness of the process. This contribution briefly discusses the main scientific and engineering findings that have paved the way of low-temperature and pressure ammonia synthesis using heterogeneous catalysts.
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.
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
How Far Away is Hydrogen? Its Role in the Medium and Long-term Decarbonisation of the European Energy System
Nov 2015
Publication
Hydrogen is a promising avenue for decarbonising energy systems and providing flexibility. In this paper the JRC-EU-TIMES model – a bottom-up technology-rich model of the EU28 energy system – is used to assess the role of hydrogen in a future decarbonised Europe under two climate scenarios current policy initiative (CPI) and long-term decarbonisation (CAP). Our results indicate that hydrogen could become a viable option already in 2030 – however a long-term CO2 cap is needed to sustain the transition. In the CAP scenario the share of hydrogen in the final energy consumption of the transport and industry sectors reaches 5% and 6% by 2050. Low-carbon hydrogen production technologies dominate and electrolysers provide flexibility by absorbing electricity at times of high availability of intermittent sources. Hydrogen could also play a significant role in the industrial and transport sectors while the emergence of stationary hydrogen fuel cells for hydrogen-to-power would require significant cost improvements over and above those projected by the experts.
The New Oil? The Geopolitics and International Governance of Hydrogen
Jun 2020
Publication
While most hydrogen research focuses on the technical and cost hurdles to a full-scale hydrogen economy little consideration has been given to the geopolitical drivers and consequences of hydrogen developments. The technologies and infrastructures underpinning a hydrogen economy can take markedly different forms and the choice over which pathway to take is the object of competition between different stakeholders and countries. Over time cross-border maritime trade in hydrogen has the potential to fundamentally redraw the geography of global energy trade create a new class of energy exporters and reshape geopolitical relations and alliances between countries. International governance and investments to scale up hydrogen value chains could reduce the risk of market fragmentation carbon lock-in and intensified geo-economic rivalry.
Magnesium Based Materials for Hydrogen Based Energy Storage: Past, Present and Future
Jan 2019
Publication
Volodymyr A. Yartys,
Mykhaylo V. Lototskyy,
Etsuo Akiba,
Rene Albert,
V. E. Antonov,
Jose-Ramón Ares,
Marcello Baricco,
Natacha Bourgeois,
Craig Buckley,
José Bellosta von Colbe,
Jean-Claude Crivello,
Fermin Cuevas,
Roman V. Denys,
Martin Dornheim,
Michael Felderhoff,
David M. Grant,
Bjørn Christian Hauback,
Terry D. Humphries,
Isaac Jacob,
Petra E. de Jongh,
Jean-Marc Joubert,
Mikhail A. Kuzovnikov,
Michel Latroche,
Mark Paskevicius,
Luca Pasquini,
L. Popilevsky,
Vladimir M. Skripnyuk,
Eugene I. Rabkin,
M. Veronica Sofianos,
Alastair D. Stuart,
Gavin Walker,
Hui Wang,
Colin Webb,
Min Zhu and
Torben R. Jensen
Magnesium hydride owns the largest share of publications on solid materials for hydrogen storage. The “Magnesium group” of international experts contributing to IEA Task 32 “Hydrogen Based Energy Storage” recently published two review papers presenting the activities of the group focused on magnesium hydride based materials and on Mg based compounds for hydrogen and energy storage. This review article not only overviews the latest activities on both fundamental aspects of Mg-based hydrides and their applications but also presents a historic overview on the topic and outlines projected future developments. Particular attention is paid to the theoretical and experimental studies of Mg-H system at extreme pressures kinetics and thermodynamics of the systems based on MgH2 nanostructuring new Mg-based compounds and novel composites and catalysis in the Mg based H storage systems. Finally thermal energy storage and upscaled H storage systems accommodating MgH2 are presented.
Test Methodologies for Hydrogen Sensor Performance Assessment: Chamber vs. Flow-through Test Apparatus
Sep 2017
Publication
Certification of hydrogen sensors to meet standards often prescribes using large-volume test chambers. However feedback from stakeholders such as sensor manufacturers and end-users indicates that chamber test methods are often viewed as too slow and expensive for routine assessment. Flow-through test methods are potentially an efficient and cost-effective alternative for sensor performance assessment. A large number of sensors can be simultaneously tested in series or in parallel with an appropriate flow-through test fixture. The recent development of sensors with response times of less than 1s mandates improvements in equipment and methodology to properly capture the performance of this new generation of fast sensors; flow methods are a viable approach for accurate response and recovery time determinations but there are potential drawbacks. According to ISO 26142 flow-through test methods may not properly simulate ambient applications. In chamber test methods gas transport to the sensor is dominated by diffusion which is viewed by some users as mimicking deployment in rooms and other confined spaces. Conversely in flow-through methods forced flow transports the gas to the sensing element. The advective flow dynamics may induce changes in the sensor behaviour relative to the quasi-quiescent condition that may prevail in chamber test methods. The aim of the current activity in the JRC and NREL sensor laboratories is to develop a validated flow-through apparatus and methods for hydrogen sensor performance testing. In addition to minimizing the impact on sensor behaviour induced by differences in flow dynamics challenges associated with flow-through methods include the ability to control environmental parameters (humidity pressure and temperature) during the test and changes in the test gas composition induced by chemical reactions with upstream sensors. Guidelines on flow-through test apparatus design and protocols for the evaluation of hydrogen sensor performance have been developed. Various commercial sensor platforms (e.g. thermal conductivity catalytic and metal semiconductor) were used to demonstrate the advantages and issues with the flow-through methodology.
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.
Parametric Study of Pt/C-Catalysed Hydrothermal Decarboxylation of Butyric Acid as a Potential Route for Biopropane Production
Jun 2021
Publication
Sustainable fuel-range hydrocarbons can be produced via the catalytic decarboxylation of biomass-derived carboxylic acids without the need for hydrogen addition. In this present study 5 wt% platinum on carbon (Pt/C) has been found to be an effective catalyst for hydrothermally decarboxylating butyric acid in order to produce mainly propane and carbon dioxide. However optimisation of the reaction conditions is required to minimise secondary reactions and increase hydrocarbon selectivity towards propane. To do this reactions using the catalyst with varying parameters such as reaction temperatures residence times feedstock loading and bulk catalyst loading were carried out in a batch reactor. The highest yield of propane obtained was 47 wt% (close to the theoretical decarboxylation yield of 50 wt% on butyric acid basis) corresponding to a 96% hydrocarbon selectivity towards propane. The results showed that the optimum parameters to produce the highest yield of propane from the range investigated were 0.5 g butyric acid (0.57 M aqueous solution) 1.0 g Pt/C (50 mg Pt content) at 300 °C for 1 h. The reusability of the catalyst was also investigated which showed little or no loss of catalytic activity after four cycles. This work has shown that Pt/C is a suitable and potentially hydrothermally stable heterogeneous catalyst for making biopropane a major component of bioLPG from aqueous butyric acid solutions which can be sourced from bio-derived feedstocks via acetone-butanol-ethanol (ABE) fermentation.
Effects of the Injector Direction on the Temperature Distribution During Filling of Hydrogen Tanks
Sep 2017
Publication
The development of the temperature field in hydrogen tanks during the filling process has been investigated with Computational Fluid Dynamics (CFD). Measurements from experiments undertaken at the JRC GasTef facility have been used to develop and validate the CFD modelling strategy; by means of the CFD calculations the effect of the injector direction on the temperature distribution has been analysed. It has been found that the dynamics of the temperature field including the development of potentially detrimental phenomena like thermal stratification and temperature inhomogeneity e.g. hot spots can be significantly affected by the injector orientation.
Analysis of Out-of-spec Events During Refueling of On-board Hydrogen Tanks
Sep 2017
Publication
For refuelling on-board hydrogen tanks table-based or formula based protocols are commonly used. These protocols are designed to achieve a tank filling close to 100% SOC (State of Charge) in s safe way: without surpassing temperature (-40°C to 85°C) and pressure limits (125% Nominal Working Pressure NWP). The ambient temperature the initial pressure and the volume category of the (compressed hydrogen storage system CHSS are used as inputs to determine the final target pressure and the pressure ramp rate (which controls the filling duration). However abnormal out-of-spec events (e.g. misinformation of storage system status and characteristics of the storage tanks) may occur and result in a refuelling in which the safety boundaries are surpassed. In the present article the possible out of specification (out-of-spec) events in a refuelling station have been analyzed. The associated hazards when refuelling on-board hydrogen tanks have been studied. Experimental results of out-of-spec event tests performed on a type 3 tank are presented. The results show that on the type 3 tank the safety temperature limit of 85°C was only surpassed under a combination of events; e.g. an unnoticed stop of the cooling of the gas combined with a wrong input of ambient temperature at a very warm environment. On the other hand under certain events (e.g. cooling the gas below the target temperature) and in particular under cold environmental conditions the 100% SOC limit established in the fuelling protocols has been surpassed. Hydrogen safety on-board tanks refuelling protocols out-of-spec events.
Fuelling the Hydrogen Economy: Scale-up of an Integrated Formic Acid-to-power System
Feb 2019
Publication
Transitioning from fossil fuels to sustainable and green energy sources in mobile applications is a difficult challenge and demands sustained and highly multidisciplinary efforts in R&D. Liquid organic hydrogen carriers (LOHC) offer several advantages over more conventional energy storage solutions but have not been yet demonstrated at scale. Herein we describe the development of an integrated and compact 25 kW formic acid-to-power system by a team of BSc and MSc students. We highlight a number of key engineering challenges encountered during scale-up of the technology and discuss several aspects commonly overlooked by academic researchers. Conclusively we provide a critical outlook and suggest a number of developmental areas currently inhibiting further implementation of the technology.
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.
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
Intensification of Hydrogen Production: Pd–Ag Membrane on Tailored Hastelloy-X Filter for Membrane-Assisted Steam Methane Reforming
Dec 2023
Publication
H2 production via membrane-assisted steam methane reforming (MA-SMR) can ensure higher energy efficiency and lower emissions compared to conventional reforming processes (SMR). Ceramic-supported Pd–Ag membranes have been extensively investigated for membrane-assisted steam methane reforming applications with outstanding performance. However costs sealings for integration in the reactor structure and resistance to solicitations remain challenging issues. In this work the surface quality of a low-cost porous Hastelloy-X filter is improved by asymmetric filling with α-Al2O3 of decreasing size and deposition of γ-Al2O3 as an interdiffusion barrier. On the modified support a thin Pd–Ag layer was deposited via electroless plating (ELP) resulting in a membrane with H2/N2 selectivity >10000. The permeation characteristics of the membrane were studied followed by testing for membrane-assisted methane steam reforming. The results showed the ability of the membrane reactor to overcome thermodynamic conversion of the conventional process for all explored operating conditions as well as ensuring 99.3% H2 purity in the permeate stream at 500 ◦C and 4 bar.
An Economic and Greenhouse Gas Footprint Assessment of International Maritime Transportation of Hydrogen Using Liquid Organic Hydrogen Carriers
Apr 2023
Publication
The supply storage and (international) transport of green hydrogen (H2) are essential for the decarbonization of the energy sector. The goal of this study was to assess the final cost-price and carbon footprint of imported green H2 in the market via maritime shipping of liquid organic hydrogen carriers (LOHCs) including dibenzyl toluene-perhydro-dibenzyltoluene (DBTPDBT) and toluene-methylcyclohexane (TOL-MCH) systems. The study focused on logistic steps in intra-European supply chains in different scenarios of future production in Portugal and demand in the Netherlands and carbon tariffs between 2030 and 2050. The case study is based on a formally accepted agreement between Portugal and the Netherlands within the Strategic Forum on Important Projects of Common European Interest (IPCEI). Under the following assumptions the results show that LOHCs are a viable technical-economic solution with logistics costs from 2030 to 2050 varying between 0.30-0.37 €/kg-H2 for DBT-PDBT and 0.28-0.34 €/kg-H2 for TOL-MCH. The associated CO2 emissions of these international H2 supply chains are between 0.46 and 2.46 kg-CO2/GJ (LHV) and 0.55-2.95 kg-CO2/GJ (LHV) for DBT-PDBT and TOL-MCH respectively.
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.
Development of a Flashback Correlation for Burner-stabilized Hydrogen-air Premixed Flames
Feb 2022
Publication
With a growing need for replacing fossil fuels with cleaner alternatives hydrogen has emerged as a viable candidate for providing heat and power. However stable and safe combustion of hydrogen is not simple and as such a number of key issues have been identified that need to be understood for a safe design of combustion chambers. One such issue is the higher propensity of hydrogen flames to flashback compared to that for methane flames. The flashback problem is coupled with higher burner temperatures that could cause strong thermal stresses in burners and could hinder their performance. In order to systematically investigate flashback in premixed hydrogen-air flames for finding a global flashback criteria in this study we use numerical simulations as a basic tool to study flashback limits of slit burners. Flashback limits are found for varying geometrical parameters and equivalence ratios and the sensitivity of each parameter on the flashback limit and burner temperatures are identified and analyzed. It is shown that the conventional flashback correlation with critical velocity gradient does not collapse the flashback data as it does not take into account stretch induced preferential diffusion effects. A new Karlovitz number definition is introduced with physical insights that collapses the flashback data at all tested conditions in an excellent manner.
A Comparative Study for H2 –CH4 Mixture Wettability in Sandstone Porous Rocks Relevant to Underground Hydrogen Storage
Mar 2022
Publication
Characterizing the wettability of hydrogen (H2 )–methane (CH4 ) mixtures in subsurface reservoirs is the first step towards understanding containment and transport properties for underground hydrogen storage (UHS). In this study we investigate the static contact angles of H2 –CH4 mixtures in contact with brine and Bentheimer sandstone rock using a captive-bubble cell device at different pressures temperatures and brine salinity values. It is found that under the studied conditions H2 and CH4 show comparable wettability behaviour with contact angles ranging between [25◦–45◦ ]; and consequently their mixtures behave similar to the pure gas systems independent of composition pressure temperature and salinity. For the system at rest the acting buoyancy and surface forces allow for theoretical sensitivity analysis for the captive-bubble cell approach to characterize the wettability. Moreover it is theoretically validated that under similar Bond numbers and similar bubble sizes the contact angles of H2 and CH4 bubbles and their mixtures are indeed comparable. Consequently in large-scale subsurface storage systems where buoyancy and capillary are the main acting forces H2 CH4 and their mixtures will have similar wettability characteristics.
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.
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.
Model Supported Business Case Scenario Analysis for Decentral Hydrogen Conversion, Storage and Consumption within Energy Hubs
Mar 2022
Publication
Recently smart energy hubs with hydrogen conversion and storage have received increased attention in the Netherlands. The hydrogen is to be used for vehicle filling stations industrial processes and heating. The scientific problem addressed in this paper is the proper sizing of capacities for renewable energy generation hydrogen conversion and storage in relation to a feasible business case for the energy hub while achieving security of supply. Scenario analysis is often used during the early stages of the energy planning process and for this an easy-to-use analysis model is required. This paper investigates available modelling approaches and develops an algorithmic modelling method which is worked out in Microsoft Excel and offers ease of use for scenario analysis purposes. The model is applied to case study which leads to important insights such as the expected price of hydrogen and the proper sizing of electrolyser and hydrogen storage for that case. The model is made available open-source. Future work is proposed in the direction of application of the model for other project cases and comparison of results with other available modelling tools.
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