Production & Supply Chain
Techno-Economic Analysis of Hydrogen and Electricity Production by Biomass Calcium Looping Gasification
Feb 2022
Publication
Combined cycle biomass calcium looping gasification is proposed for a hydrogen and electricity production (CLGCC–H) system. The process simulation Aspen Plus is used to conduct techno-economic analysis of the CLGCC–H system. The appropriate detailed models are set up for the proposed system. Furthermore a dual fluidized bed is optimized for hydrogen production at 700 °C and 12 bar. For comparison calcium looping gasification with the combined cycle for electricity (CLGCC) is selected with the same parameters. The system exergy and energy efficiency of CLGCC–H reached as high as 60.79% and 64.75% while the CLGCC system had 51.22% and 54.19%. The IRR and payback period of the CLGCC–H system based on economic data are calculated as 17.43% and 7.35 years respectively. However the CLGCC system has an IRR of 11.45% and a payback period of 9.99 years respectively. The results show that the calcium looping gasification-based hydrogen and electricity coproduction system has a promising market prospect in the near future.
Development of a Viability Assessment Model for Hydrogen Production from Dedicated Offshore Wind Farms
Jun 2020
Publication
Dedicated offshore wind farms for hydrogen production are a promising option to unlock the full potential of offshore wind energy attain decarbonisation and energy security targets in electricity and other sectors and cope with grid expansion constraints. Current knowledge on these systems is limited particularly the economic aspects. Therefore a new integrated and analytical model for viability assessment of hydrogen production from dedicated offshore wind farms is developed in this paper. This includes the formulae for calculating wind power output electrolysis plant size and hydrogen production from time-varying wind speed. All the costs are projected to a specified time using both Discounted Payback (DPB) and Net Present Value (NPV) to consider the value of capital over time. A case study considers a hypothetical wind farm of 101.3 MW situated in a potential offshore wind development pipeline off the East Coast of Ireland. All the costs of the wind farm and the electrolysis plant are for 2030 based on reference costs in the literature. Proton exchange membrane electrolysers and underground storage of hydrogen are used. The analysis shows that the DPB and NPV flows for several scenarios of storage are in good agreement and that the viability model performs well. The offshore wind farm – hydrogen production system is found to be profitable in 2030 at a hydrogen price of €5/kg and underground storage capacities ranging from 2 days to 45 days of hydrogen production. The model is helpful for rapid assessment or optimisation of both economics and feasibility of dedicated offshore wind farm – hydrogen production systems.
Production of Ultra-dense Hydrogen H(0): A Novel Nuclear Fuel
Mar 2021
Publication
Condensation of hydrogen Rydberg atoms (highly electronically excited) into the lowest energy state of condensed hydrogen i.e. the ultra-dense hydrogen phase H(0) has gained increased attention not only from the fundamental aspects but also from the applied point of view. The physical properties of ultra-dense hydrogen H(0) were recently reviewed summarizing the results reported in 50 publications during the last ten years. The main application of H(0) so far is as the fuel and working medium in nuclear particle generators and nuclear fusion reactors which are under commercial development. The first fusion process showing sustained operation above break-even was published in 2015 (AIP Advances) and used ultra-dense deuterium D(0) as fuel. The first generator giving a high-intensity muon flux intended for muon-catalyzed fusion reactors was patented in 2017 using H(0) as the working medium. Here we first focus on the different nuclear processes using hydrogen isotopes for energy generation and then on the detailed processes of formation of H(0). The production of H(0) employs heterogeneous catalysts which are active in hydrogen transfer reactions. Iron oxide-based alkali promoted catalysts function well but also platinum group metals and carbon surfaces are active in this process. The clusters of highly excited Rydberg hydrogen atoms H(l) are formed upon interaction with alkali Rydberg matter. The final conversion step from ordinary hydrogen Rydberg matter H(l) to H(0) is spontaneous and does not require a solid surface. It is concluded that the exact choice of catalyst is not very important. It is also concluded that the crucial feature of the catalyst is to provide excited alkali atoms at a sufficiently high surface density and in this way enabling formation and desorption of H(0) clusters. Finally the relation to industrial catalytic processes which use H(0) formation catalysts is described and some important consequences like the muon and neutron radiation from H(0) are discussed.
The BioSCWG Project: Understanding the Trade-Offs in the Process and Thermal Design of Hydrogen and Synthetic Natural Gas Production
Oct 2016
Publication
This article presents a summary of the main findings from a collaborative research project between Aalto University in Finland and partner universities. A comparative process synthesis modelling and thermal assessment was conducted for the production of Bio-synthetic natural gas (SNG) and hydrogen from supercritical water refining of a lipid extracted algae feedstock integrated with onsite heat and power generation. The developed reactor models for product gas composition yield and thermal demand were validated and showed conformity with reported experimental results and the balance of plant units were designed based on established technologies or state-of-the-art pilot operations. The poly-generative cases illustrated the thermo-chemical constraints and design trade-offs presented by key process parameters such as plant organic throughput supercritical water refining temperature nature of desirable coproducts downstream indirect production and heat recovery scenarios. The evaluated cases favoring hydrogen production at 5 wt. % solid content and 600 ◦C conversion temperature allowed higher gross syngas and CHP production. However mainly due to the higher utility demands the net syngas production remained lower compared to the cases favoring BioSNG production. The latter case at 450 ◦C reactor temperature 18 wt. % solid content and presence of downstream indirect production recorded 66.5% 66.2% and 57.2% energetic fuel-equivalent and exergetic efficiencies respectively
Efficient Renewable-to-Hydrogen Conversion via Decoupled Electrochemical Water Splitting
Aug 2020
Publication
Water electrolysis powered by renewables provides a green approach to hydrogen production to support the ‘‘hydrogen economy.’’ However the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are tightly coupled in both time and space in traditional water electrolysis which brings inherent operational challenges such as the mixture of H2/O2 and the limited HER rate caused by the sluggish kinetics of OER. Against this background decoupling H2 and O2 production in water electrolysis by using the auxiliary redox mediator was first proposed in 2013 in which O2 and H2 are produced at different times rates and/or locations. The decoupling strategy offers not only a new way to facilitate renewables to H2 but it can also be applied in other chemical or electrochemical processes. This review describes recent efforts to develop high-performance redox mediators optimized strategies in decoupled water electrolysis the design of electrolyzer configuration the challenges faced and the prospective directions.
Catalytic Hydrogen Production, Storage and Application
Jul 2021
Publication
Hydrogen is a clean fuel for transportation and energy storage. It has several attractive features including a higher energy content by weight use in fuel cells that produces only water as a by-product storage in small and large quantities by various methods and established transportation and infrastructures. A hydrogen economy consists of three steps i.e. hydrogen production storage and applications. All three steps involved in a hydrogen economy can be divided into catalytic and non-catalytic approaches. For catalytic processes the efficiency highly depends on the type and physico-chemical characteristics of the catalysts. Therefore for the improvement of these catalytic processes the development of highly efficient and stable catalysts is highly required.
A Review of Recent Developments in Molecular Dynamics Simulations of the Photoelectrochemical Water Splitting Process
Jun 2021
Publication
In this review we provide a short overview of the Molecular Dynamics (MD) method and how it can be used to model the water splitting process in photoelectrochemical hydrogen production. We cover classical non-reactive and reactive MD techniques as well as multiscale extensions combining classical MD with quantum chemical and continuum methods. Selected examples of MD investigations of various aqueous semiconductor interfaces with a special focus on TiO2 are discussed. Finally we identify gaps in the current state-of-the-art where further developments will be needed for better utilization of MD techniques in the field of water splitting.
Overview of Power Electronic Converter Topologies Enabling Large-Scale Hydrogen Production via Water Electrolysis
Feb 2022
Publication
Renewable power-to-hydrogen (P2H) technology is one of the most promising solutions for fulfilling the increasing global demand for hydrogen and to buffer large-scale fluctuating renewable energies. The high-power high-current ac/dc converter plays a crucial role in P2H facilities transforming medium-voltage (MV) ac power to a large dc current to supply hydrogen electrolyzers. This work introduces the general requirements and overviews several power converter topologies for P2H systems. The performances of different topologies are evaluated and compared from multiple perspectives. Moreover the future trend of eliminating the line frequency transformer (LFT) is discussed. This work can provide guidance for future designing and implementing of power-electronics-based P2H systems.
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.
Renewable Hydrogen Implementations for Combined Energy Storage, Transportation and Stationary Applications
Dec 2019
Publication
The purpose of this paper is to discuss the potential of hydrogen obtained from renewable sources for energy generation and storage systems. The first part of analysis will address such issues as various methods of green hydrogen production storage and transportation. The review of hydrogen generation methods will be followed by the critical analysis and the selection of production method. This selection is justified by the results of the comparative research on alternative green hydrogen generation technologies with focus on their environmental impacts and costs. The comparative analysis includes the biomass-based methods as well as water splitting and photo-catalysis methods while water electrolysis is taken as a benchmark. Hydrogen storage and transportation issues will be further discussed in purpose to form the list of recommended solutions. In the second part of the paper the technology readiness and technical feasibility for joint hydrogen applications will be analysed. This will include the energy storage and production systems based on renewable hydrogen in combination with hydrogen usage in mobility systems as well as the stationary applications in buildings such as combined heat and power (CHP) plants or fuel cell electric generators. Based on the analysis of the selected case studies the author will discuss the role of hydrogen for the carbon emission reduction with the stress on the real value of carbon footprint of hydrogen depending on the gas source storage transportation and applications.
Biogas Reforming as a Sustainable Solution for Hydrogen Production: Comparative Environmental Metrics with Steam-methane Reforming and Water Electrolysis in the Portuguese Context
Apr 2024
Publication
This study delves into the dynamics of hydrogen production with a specific focus on biogas reforming (BGSMR) for hydrogen generation. It compares the environmental impact of this solution with hydrogen production from natural gas-steam reforming (NGSMR) and commercial electrolysis in the Portuguese context. Various metrics including carbon footprint water depletion energy utilization and waste valorization are employed for a comprehensive comparison. The assessment explores the impact of operational parameters and different off-gas combustion scenarios incorporating water recycling practices. Due to challenges in obtaining detailed data on the actual reforming process the study relies on process simulation techniques primarily using DWSIM. Commercially available data for water electrolysers were used for comparison. In the context of decarbonizing power systems hydrogen from water electrolysis emerges as a competitive option only in a scenario where the power system is 100% reliant on renewable sources particularly with respect to the carbon footprint metric. Biogas systems characterized by near-zero carbon emissions stand out as a favourable option from the near future to the long run. This research contributes valuable insights into the dynamics of hydrogen production shedding light on environmentally viable alternatives across a range of power system scenarios.
Hydrogen Production from Sea Wave for Alternative Energy Vehicles for Public Transport in Trapani (Italy)
Oct 2016
Publication
The coupling of renewable energy and hydrogen technologies represents in the mid-term a very interesting way to match the tasks of increasing the reliable exploitation of wind and sea wave energy and introducing clean technologies in the transportation sector. This paper presents two different feasibility studies: the first proposes two plants based on wind and sea wave resource for the production storage and distribution of hydrogen for public transportation facilities in the West Sicily; the second applies the same approach to Pantelleria (a smaller island) including also some indications about solar resource. In both cases all buses will be equipped with fuel-cells. A first economic analysis is presented together with the assessment of the avoidable greenhouse gas emissions during the operation phase. The scenarios addressed permit to correlate the demand of urban transport to renewable resources present in the territories and to the modern technologies available for the production of hydrogen from renewable energies. The study focuses on the possibility of tapping the renewable energy potential (wind and sea wave) for the hydrogen production by electrolysis. The use of hydrogen would significantly reduce emissions of particulate matter and greenhouse gases in urban districts under analysis. The procedures applied in the present article as well as the main equations used are the result of previous applications made in different technical fields that show a good replicability.
Environmental Assessment of Hydrogen Utilization in Various Applications and Alternative Renewable Sources for Hydrogen Production: A Review
May 2023
Publication
Rapid industrialization is consuming too much energy and non-renewable energy resources are currently supplying the world’s majority of energy requirements. As a result the global energy mix is being pushed towards renewable and sustainable energy sources by the world’s future energy plan and climate change. Thus hydrogen has been suggested as a potential energy source for sustainable development. Currently the production of hydrogen from fossil fuels is dominant in the world and its utilization is increasing daily. As discussed in the paper a large amount of hydrogen is used in rocket engines oil refining ammonia production and many other processes. This paper also analyzes the environmental impacts of hydrogen utilization in various applications such as iron and steel production rocket engines ammonia production and hydrogenation. It is predicted that all of our fossil fuels will run out soon if we continue to consume them at our current pace of consumption. Hydrogen is only ecologically friendly when it is produced from renewable energy. Therefore a transition towards hydrogen production from renewable energy resources such as solar geothermal and wind is necessary. However many things need to be achieved before we can transition from a fossil-fuel-driven economy to one based on renewable energy
Minimizing the Cost of Hydrogen Production through Dynamic Polymer Electrolyte Membrane Electrolyzer Operation
Jun 2022
Publication
Growing imbalances between electricity demand and supply from variable renewable energy sources (VREs) create increasingly large swings in electricity prices. Polymer electrolyte membrane (PEM) electrolyzers can help to buffer against these imbalances and minimize the levelized cost of hydrogen (LCOH) by ramping up production of hydrogen through high-current-density operation when low-cost electricity is abundant and ramping down current density to operate efficiently when electricity prices are high. We introduce a technoeconomic model that optimizes current density profiles for dynamically operated electrolyzers while accounting for the potential of increased degradation rates to minimize LCOH for any given time-of-use (TOU) electricity pricing. This model is used to predict LCOH from different methods of operating a PEM electrolyzer for historical and projected electricity prices in California and Texas which were chosen due to their high penetration of VREs. Results reveal that dynamic operation could enable reductions in LCOH ranging from 2% to 63% for historical 2020 pricing and 1% to 53% for projected 2030 pricing. Moreover high-current-density operation above 2.5 A cm2 is increasingly justified at electricity prices below $0.03 kWh1 . These findings suggest an actionable means of lowering LCOH and guide PEM electrolyzer development toward devices that can operate efficiently at a range of current densities.
Photocatalytic Hydrogen Evolution from Biomass Conversion
Feb 2021
Publication
Biomass has incredible potential as an alternative to fossil fuels for energy production that is sustainable for the future of humanity. Hydrogen evolution from photocatalytic biomass conversion not only produces valuable carbon-free energy in the form of molecular hydrogen but also provides an avenue of production for industrially relevant biomass products. This photocatalytic conversion can be realized with efficient sustainable reaction materials (biomass) and inexhaustible sunlight as the only energy inputs. Reported herein is a general strategy and mechanism for photocatalytic hydrogen evolution from biomass and biomass-derived substrates (including ethanol glycerol formic acid glucose and polysaccharides). Recent advancements in the synthesis and fundamental physical/mechanistic studies of novel photocatalysts for hydrogen evolution from biomass conversion are summarized. Also summarized are recent advancements in hydrogen evolution efciency regarding biomass and biomass-derived substrates. Special emphasis is given to methods that utilize unprocessed biomass as a substrate or synthetic photocatalyst material as the development of such will incur greater benefts towards a sustainable route for the evolution of hydrogen and production of chemical feedstocks.
Recent Advances in Alkaline Exchange Membrane Water Electrolysis and Electrode Manufacturing
Oct 2021
Publication
Water electrolysis to obtain hydrogen in combination with intermittent renewable energy resources is an emerging sustainable alternative to fossil fuels. Among the available electrolyzer technologies anion exchange membrane water electrolysis (AEMWE) has been paid much attention because of its advantageous behavior compared to other more traditional approaches such as solid oxide electrolyzer cells and alkaline or proton exchange membrane water electrolyzers. Recently very promising results have been obtained in the AEMWE technology. This review paper is focused on recent advances in membrane electrode assembly components paying particular attention to the preparation methods for catalyst coated on gas diffusion layers which has not been previously reported in the literature for this type of electrolyzers. The most successful methodologies utilized for the preparation of catalysts including co-precipitation electrodeposition sol–gel hydrothermal chemical vapor deposition atomic layer deposition ion beam sputtering and magnetron sputtering deposition techniques have been detailed. Besides a description of these procedures in this review we also present a critical appraisal of the efficiency of the water electrolysis carried out with cells fitted with electrodes prepared with these procedures. Based on this analysis a critical comparison of cell performance is carried out and future prospects and expected developments of the AEMWE are discussed.
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.
Design and Multi-scenario Optimization of a Hybrid Power System Based on a Working Gas Turbine: Energy, Exergy, Exergoeconomic and Environmental Evaluation
Sep 2022
Publication
The rising demand for electricity along with the need to minimize carbon footprints has motivated academics to investigate the flexible and efficient integration of energy conversion technologies. A novel hybrid power generation system based on environmentally friendly and cost-effective technologies to recover the waste heat of a working gas turbine is designed and assessed in different scenarios of multi-objective optimization from energy exergy exergoeconomic and environmental (4E) perspectives. In the proposed system a steam methane reformer and a water gas shift reactor are utilized for hydrogen production while a polymer electrolyte membrane fuel cell (PEMFC) and steam/organic Rankine cycles are run for generating additional power. Aspen Plus in conjunction with Fortran Microsoft Excel and MATLAB is used to model and simulate the designed plant. The response surface methodology (RSM) is utilized to determine accurate surrogate models to describe the evaluation criteria and the Non-dominated Sorting Genetic Algorithm II technique is employed to seek the optimal conditions. Moreover TOPSIS and LINMAP decision-making approaches are used to find the best final solution among Pareto frontiers. The analysis of variance (ANOVA) and sensitivity analysis are also applied to evaluate the importance of the design variables. In this regard three single-objective optimizations and four multi-objective optimization scenarios based on the maximization of the ecological coefficient of performance (ECOP) and the minimization of CO2 emissions and total system product cost (C˙ p) are carried out. It is demonstrated that the system’s evaluation criteria have the highest and lowest sensitivity to the variation of reformer temperature and ORC pressure respectively. From the triple-objective optimization procedure the decision variables including reformer temperature ORC pressure Rankine cycle I pressure and Rankine cycle II pressure are 544 ◦C 4.35 bar 158.12 bar and 52.82 bar respectively. At these conditions the total hybrid system’s energy efficiency exergy efficiency exergy destruction net generated power and total investment cost rate are 45.96% 46.83% 215.72 MW 203.67 MW and 9791 $/h respectively. The findings of this paper conclude that it is necessary to address all objective functions simultaneously in the system’s ultimate optimum design. Furthermore the objective of this paper becomes even more apparent when there is no choice but to cut greenhouse gas emissions while also addressing the rising global energy demand.
Energy Sustainability Analysis (ESA) of Energy-Producing Processes: A Case Study on Distributed H2 Production
Sep 2019
Publication
In the sustainability context the performance of energy-producing technologies using different energy sources needs to be scored and compared. The selective criterion of a higher level of useful energy to feed an ever-increasing demand of energy to satisfy a wide range of endo- and exosomatic human needs seems adequate. In fact surplus energy is able to cover energy services only after compensating for the energy expenses incurred to build and to run the technology itself. This paper proposes an energy sustainability analysis (ESA) methodology based on the internal and external energy use of a given technology considering the entire energy trajectory from energy sources to useful energy. ESA analysis is conducted at two levels: (i) short-term by the use of the energy sustainability index (ESI) which is the first step to establish whether the energy produced is able to cover the direct energy expenses needed to run the technology and (ii) long-term by which all the indirect energy-quotas are considered i.e. all the additional energy requirements of the technology including the energy amortization quota necessary for the replacement of the technology at the end of its operative life. The long-term level of analysis is conducted by the evaluation of two indicators: the energy return per unit of energy invested (EROI) over the operative life and the energy payback-time (EPT) as the minimum lapse at which all energy expenditures for the production of materials and their construction can be repaid to society. The ESA methodology has been applied to the case study of H2 production at small-scale (10–15 kWH2) comparing three different technologies: (i) steam-methane reforming (SMR) (ii) solar-powered water electrolysis (SPWE) and (iii) two-stage anaerobic digestion (TSAD) in order to score the technologies from an energy sustainability perspective.
Low-carbon and Cost-efficient Hydrogen Optimisation through a Grid-connected Electrolyser: The Case of GreenLab Skive
Nov 2022
Publication
Power-to-X technologies are a promising means to achieve Denmark’s carbon emission reduction targets. Water electrolysis can potentially generate carbon-neutral fuels if powered with renewable electricity. However the high variability of renewable sources threatens the Power-to-X plant’s cost-efficiency instead favouring high and constant operation rates. Therefore a diversified electricity supply is often an option to maximise the load factor of the Power-to-X systems. This paper analyses the impact of using different power sources on the cost of production and the carbon intensity of hydrogen produced by a Power-to-X system. GreenLab Skive the world’s first industrial facility with Power-to-X integrated into an industrial symbiosis network has been used as a case study. Results show that the wind/PV/grid-connected electrolyser for hydrogen and electricity production can reduce operational costs and emissions saving 30.6 × 107 kgCO2 and having a Net Present Value twice higher than a grid-connected electrolyser. In addition the carbon emission coefficient for this configuration is 3.5 × 10− 2 kgH2/kgCO2 against 7.0 gH2/gCO2 produced by Steam Methane Reforming. A sensitivity analysis detects the optimal capacity ratio between the renewables and the electrolyser. A plateau is reached for carbon emission performances suggesting a wind/grid-connected electrolyser setup with a wind farm three times the size of the electrolyser. Results demonstrate that hydrogen cost is not competitive yet with the electricity suggesting an investment cost reduction but can be competitive with the current hydrogen price if the wind capacity is less than three times the electrolyser capacity.
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