Production & Supply Chain
Design and Analysis of a New Renewable-Nuclear Hybrid Energy System for Production of Hydrogen, Fresh Water and Power
Nov 2021
Publication
This paper investigates an integrated system where solar energy system (with 75MWp bifacial PV arrays) and nuclear power plant (with 2×10MWt HTR-10 type pebble bed reactors) are hybridized and integrated with a 72MWe capacity high-temperature solid oxide electrolysis (SOE) unit to produce hydrogen fresh water and electrical power. Bifacial PV plant is integrated to system for supplying electricity with a low LCOE and zero-carbon system. A Rankine cycle is integrated to generate power from the steam that generated from nuclear heat. According to the available irradiance; the steam is diverted between steam turbine and high-temperature electrolyzer for hydrogen and power generation. Multi-effect desalination unit is integrated to exploit the excess heat to generate fresh water. A system performance assessment is carried out by energy and exergy efficiencies thermodynamically. The bifacial PV plant is analyzed in six selected latitudes in order to assess the feasibility and applicability of the system. Numerous time-dependent analyses are carried out to study the effects of varying inputs such as solar radiation intensity. For 20MWt nuclear 75MWp solar capacity; hydrogen productions are found to be between 0.036 and 0.562kg/s. Among the Northern Hemisphere latitudes the peak daily hydrogen production rate is expected to reach 25.9 tons of hydrogen per day for the 75 °N case mostly with the influence of low temperature and high albedo. The pitch distance change is increased the hydrogen production rate by 28% between 3 m and 7 m tracker spacing. The overall system energy efficiency is obtained between 21.8% and 24.2% where the overall system exergy efficiency is found between 18.6% and 21.1% under dynamic conditions for the 45°N latitude case.
Photocatalytic Production of Hydrogen from Binary Mixtures of C-3 Alcohols on Pt/TiO2: Influence of Alcohol Structure
Oct 2018
Publication
The effect of alcohol structure on photocatalytic production of H2 from C-3 alcohols was studied on 0.5% Pt/TiO2. A C-2 alcohol (ethanol) was also included for comparative purposes. For individual reactions from 10% v/v aqueous solutions of alcohols hydrogen production followed the order ethanol ≈ propan-2-ol > propan-1- ol > propane-123-triol > propane-12-diol > propane-13-diol. The process was found to be quite sensitive to the presence of additional alcohols in the reaction medium as evidenced by competitive reactions. Therefore propan-2-ol conversion was retarded in the presence of traces of the other alcohols this effect being particularly significant for vicinal diols. Additional experiments showed that adsorption of alcohols on Pt/TiO2 followed the order propane-123-triol > propane-12-diol > propane-13-diol > propan-1-ol > ethanol > propan-2-ol. Adsorption studies (DRIFT) and monitoring of reaction products showed that the main photocatalyzed process for propan-2-ol and propan-1-ol transformation is dehydrogenation to the corresponding carbonyl compound (especially for propan-2-ol both in the liquid and the gas phase). In the case of liquid-phase transformation of propan-1-ol ethane was also detected which is indicative of the dissociative mechanism to lead to the corresponding C-1 alkane. All in all competitive reactions proved to be very useful for mechanistic studies.
Optimising Onshore Wind with Energy Storage Considering Curtailment
May 2022
Publication
Operating energy storage alongside onshore wind can improve its economics whilst providing a pathway for otherwise curtailed generation. In this work we present a framework to evaluate the economic potential of onshore wind co-located with battery storage (BS) and a hydrogen electrolyser (HE). This model is applied to a case study in Great Britain using historic data and considering local network charges and the cost of using curtailed power capturing an often neglected element of competition. We use a Markov Chain to model wind curtailment and determine the optimised scheduling of the storage as we vary price parameters and storage sizing. Finally by considering storage CAPEX and comparing against the case with no storage we can determine the value added (or lost) by different sized BS and HE for an onshore wind owner as a function of power purchase agreement (PPA) and green hydrogen market price. Results show that value added increases when HE is increased and when BS is decreased. Additionally a 10 MW electrolysers uses 27% more curtailed wind than 10 MW BS.
The Development of an Assessment Framework to Determine the Technical Hydrogen Production Potential from Wind and Solar Energy
Jun 2022
Publication
Electrolytic hydrogen produced from wind and solar energy is considered a long-term option for multi-sectoral decarbonization. The study objective is to develop a framework for assessing country-level hydrogen technical potential from wind and solar energy. We apply locational suitability and zonal statistical analyses methods in a geographic information system-based environment to derive granular insights on non-captive technically exploitable hydrogen potential in high-resource locations. Seven setback factors were considered for locational suitability and integrated with modules developed for evaluating the wind and solar resource penetration from open-source theoretical renewable resource geospatial data and electricity-to-hydrogen conversion analyses. The technique applied in this study would be a relevant contribution to determining national and regional-wide electrolytic hydrogen production potentials in other jurisdictions with requisite adjustments to data and technical constraints. The results from the case study country Canada – a major hydrogen-producing country – show that the technical hydrogen potentials from wind and solar energy are approximately 1897 and 448 million metric tonnes per year respectively at least 6.3 times greater than global hydrogen demand in 2019. When we integrated locational data on enabling infrastructure we discovered that the lack of access to power transmission lines in low-population-density areas of the country significantly reduces the exploitable wind- and solar-based hydrogen potential by over 80% and 6% respectively. The findings of this study show that in the absence of spatial data on infrastructural constraints the exploitable hydrogen potential in a jurisdiction can be overestimated leading to improper guidance for policy and decision-makers.
Proton Exchange Membrane Electrolyzer Emulator for Power Electronics Testing Applications
Mar 2021
Publication
This article aims to develop a proton exchange membrane (PEM) electrolyzer emulator. This emulator is realized through an equivalent electrical scheme. It allows taking into consideration the dynamic operation of PEM electrolyzers which is generally neglected in the literature. PEM electrolyzer dynamics are reproduced by the use of supercapacitors due to the high value of the equivalent double-layer capacitance value. Steady-state and dynamics operations are investigated in this work. The design criteria are addressed. The PEM electrolyzer emulator is validated by using a 400-W commercial PEM electrolyzer. This emulator is conceived to test new DC-DC converters to supply the PEM ELs and their control as well avoiding the risk to damage a real electrolyzer for experiment purposes. The proposed approach is valid both for a single cell and for the whole stack emulation.
Boosting the H2 Production Efficiency via Photocatalytic Organic Reforming: The Role of Additional Hole Scavenging System
Nov 2021
Publication
The simultaneous photocatalytic H2 evolution with environmental remediation over semiconducting metal oxides is a fascinating process for sustainable fuel production. However most of the previously reported photocatalytic reforming showed nonstoichiometric amounts of the evolved H2 when organic substrates were used. To explain the reasons for this phenomenon a careful analysis of the products and intermediates in gas and aqueous phases upon the photocatalytic hydrogen evolution from oxalic acid using Pt/TiO2 was performed. A quadrupole mass spectrometer (QMS) was used for the continuous flow monitoring of the evolved gases while high performance ion chromatography (HPIC) isotopic labeling and electron paramagnetic resonance (EPR) were employed to understand the reactions in the solution. The entire consumption of oxalic acid led to a ~30% lower H2 amount than theoretically expected. Due to the contribution of the photoKolbe reaction mechanism a tiny amount of formic acid was produced then disappeared shortly after the complete consumption of oxalic acid. Nevertheless a much lower concentration of formic acid was generated compared to the nonstoichiometric difference between the formed H2 and the consumed oxalic acid. Isotopic labeling measurements showed that the evolved H2 HD and/or D2 matched those of the solvent; however using D2O decreased the reaction rate. Interestingly the presence of KI as an additional hole scavenger with oxalic acid had a considerable impact on the reaction mechanism and thus the hydrogen yield as indicated by the QMS and the EPR measurements. The added KI promoted H2 evolution to reach the theoretically predictable amount and inhibited the formation of intermediates without affecting the oxalic acid degradation rate. The proposed mechanism by which KI boosts the photocatalytic performance is of great importance in enhancing the overall energy efficiency for hydrogen production via photocatalytic organic reforming.
Techno-Economic Evaluation of Hydrogen Production via Gasification of Vacuum Residue Integrated with Dry Methane Reforming
Dec 2021
Publication
The continuous rise of global carbon emissions demands the utilization of fossil fuels in a sustainable way. Owing to various forms of emissions our environment conditions might be affected necessitating more focus of scientists and researchers to upgrade oil processing to more efficient manner. Gasification is a potential technology that can convert fossil fuels to produce clean and environmentally friendly hydrogen fuel in an economical manner. Therefore this study analyzed and examined it critically. In this study two different routes for the production of high-purity hydrogen from vacuum residue while minimizing the carbon emissions were proposed. The first route (Case I) studied the gasification of heavy vacuum residue (VR) in series with dry methane reforming (DMR). The second route studied the gasification of VR in parallel integration with DMR (Case II). After investigating both processes a brief comparison was made between the two routes of hydrogen production in terms of their CO2 emissions energy efficiency energy consumption and environmental and economic impacts. In this study the two vacuum-residue-to-hydrogen (VRTH) processes were simulated using Aspen Plus for a hydrogen production capacity of 50 t/h with 99.9 wt.% purity. The results showed that Case II offered a process energy efficiency of 57.8% which was slightly higher than that of Case I. The unit cost of the hydrogen product for Case II was USD 15.95 per metric ton of hydrogen which was almost 9% lower than that of Case I. In terms of the environmental analysis both cases had comparably low carbon emissions of around 8.3 kg of CO2/kg of hydrogen produced; with such high purity the hydrogen could be used for production of other products further downstream or for industrial applications.
Energy Efficiency Based Control Strategy of a Three-Level Interleaved DC-DC Buck Converter Supplying a Proton Exchange Membrane Electrolyzer
Aug 2019
Publication
To face the intensive use of natural gas and other fossil fuels to generate hydrogen water electrolysis based on renewable energy sources (RES) seems to be a viable solution. Due to their fast response times and high efficiency proton exchange membrane electrolyzer (PEM EL) is the most suitable technology for long-term energy storage combined with RES. Like fuel cells the development of fit DC-DC converters is mandatory to interface the EL to the DC grid. Given that PEM EL operating voltages are quite low and to meet requirements in terms of output current ripples new emerging interleaved DC-DC converter topologies seem to be the best candidates. In this work a three-level interleaved DC-DC buck converter has been chosen to supply a PEM EL from a DC grid. Therefore the main objective of this paper is to develop a suitable control strategy of this interleaved topology connected to a PEM EL emulator. To design the control strategy investigations have been carried out on energy efficiency hydrogen flow rate and specific energy consumption. The obtained experimental results validate the performance of the converter in protecting the PEM EL during transient operations while guaranteeing correct specific energy consumption.
Techno-Economic Analysis of Low Carbon Hydrogen Production from Offshore Wind Using Battolyser Technology
Aug 2022
Publication
A battolyser is a combined battery electrolyser in one unit. It is based on flow battery technology and can be adapted to produce hydrogen at a lower efficiency than an electrolyser but without the need for rare and expensive materials. This paper presents a method of determining if a battolyser connected to a wind farm makes economic sense based on stochastic modelling. A range of cost data and operational scenarios are used to establish the impact on the NPV and LCOE of adding a battolyser to a wind farm. The results are compared to adding a battery or an electrolyser to a wind farm. Indications are that it makes economic sense to add a battolyser or battery to a wind farm to use any curtailed wind with calculated LCOE at £56/MWh to £58/MWh and positive NPV over a range of cost scenarios. However electrolysers are still too expensive to make economic sense.
R&D Status on Thermochemical IS Process for Hydrogen Production at JAEA
Nov 2012
Publication
Thermochemical hydrogen production process is one of the candidates of industrial fossil fuel free hydrogen production. Japan Atomic Energy Agency (JAEA) has been conducting R&D of the thermochemical water splitting iodine-sulfur (IS) process since the end of 1980s. This paper presents the recent study on the IS process in JAEA. In 2005-2009 test-fabrication of components collection of design database improvement of process components for higher thermal efficiency and proposition of composition measurement method were carried out. On the basis of them the integrity test of process components is carried out in 2010-2014 to examine their integrities in severe process environments. At present a Bunsen reactor which produces acids and incidental equipments has been already manufactured using corrosion resistant materials such as glass lining steel and fluoroplastic lining steel. Flow tests to examine the functionality and integrity of the materials are planned in 2012.
Hydrogen Production Methods Based on Solar and Wind Energy: A Review
Jan 2023
Publication
Several research works have investigated the direct supply of renewable electricity to electrolysis particularly from photovoltaic (PV) and wind generator (WG) systems. Hydrogen (H2 ) production based on solar energy is considered to be the newest solution for sustainable energy. Different technologies based on solar energy which allow hydrogen production are presented to study their benefits and inconveniences. The technology of water decomposition based on renewable energy sources to produce hydrogen can be achieved by different processes (photochemical systems; photocatalysis systems photo-electrolysis systems bio-photolysis systems thermolysis systems thermochemical cycles steam electrolysis hybrid processes and concentrated solar energy systems). A comparison of the different methods for hydrogen production based on PV and WG systems was given in this study. A comparative study of different types of electrolyzers was also presented and discussed. Finally an economic assessment of green hydrogen production is given. The hydrogen production cost depends on several factors such as renewable energy sources electrolysis type weather conditions installation cost and the productivity of hydrogen per day. PV/H2 and wind/H2 systems are both suitable in remote and arid areas. Minimum maintenance is required and a power cycle is not needed to produce electricity. The concentrated CSP/H2 system needs a power cycle. The hydrogen production cost is higher if using wind/H2 rather than PV/H2 . The green energy sources are useful for multiple applications such as hydrogen production cooling systems heating and water desalination.
Review on the Status of the Research on Power‐to‐Gas Experimental Activities
Aug 2022
Publication
In recent years power‐to‐gas technologies have been gaining ground and are increasingly proving their reliability. The possibility of implementing long‐term energy storage and that of being able to capture and utilize carbon dioxide are currently too important to be ignored. However sys‐ tems of this type are not yet experiencing extensive realization in practice. In this study an overview of the experimental research projects and the research and development activities that are currently part of the power‐to‐gas research line is presented. By means of a bibliographical and sitographical analysis it was possible to identify the characteristics of these projects and their distinctive points. In addition the main research targets distinguishing these projects are presented. This provides an insight into the research direction in this regard where a certain technological maturity has been achieved and where there is still work to be done. The projects found and analyzed amount to 87 mostly at laboratory scale. From these what is most noticeable is that research is currently focusing heavily on improving system efficiency and integration between components.
Two-Dimensional Photocatalysts for Energy and Environmental Applications
Jun 2022
Publication
The depletion of fossil fuels and onset of global warming dictate the achievement of efficient technologies for clean and renewable energy sources. The conversion of solar energy into chemical energy plays a vital role both in energy production and environmental protection. A photocatalytic approach for H2 production and CO2 reduction has been identified as a promising alternative for clean energy production and CO2 conversion. In this process the most critical parameter that controls efficiency is the development of a photocatalyst. Two-dimensional nanomaterials have gained considerable attention due to the unique properties that arise from their morphology. In this paper examples on the development of different 2D structures as photocatalysts in H2 production and CO2 reduction are discussed and a perspective on the challenges and required improvements is given.
Economic Dispatch Model of Nuclear High-Temperature Reactor with Hydrogen Cogeneration in Electricity Market
Dec 2021
Publication
Hydrogen produced without carbon emissions could be a useful fuel as nations look to decarbonize their electricity transport and industry sectors. Using the iodine–sulfur (IS) cycle coupled with a nuclear heat source is one method for producing hydrogen without the use of fossil fuels. An economic dispatch model was developed for a nuclear-driven IS system to determine hydrogen sale prices that would make such a system profitable. The system studied is the HTTR GT/H2 a design for power and hydrogen cogeneration at the Japan Atomic Energy Agency’s High Temperature Engineering Test Reactor. This study focuses on the development of the economic model and the role that input data plays in the final calculated values. Using a historical price duration curve shows that the levelized cost of hydrogen (LCOH) or breakeven sale price of hydrogen would need to be 98.1 JPY/m3 or greater. Synthetic time histories were also used and found the LCOH to be 67.5 JPY/m3 . The price duration input was found to have a significant effect on the LCOH. As such great care should be used in these economic dispatch analyses to select reasonable input assumptions.
Far Off-shore Wind Energy-based Hydrogen Production: Technological Assessment and Market Valuation Designs
Jan 2020
Publication
This article provides a techno-economic study on coupled offshore wind farm and green hydrogen production via sea water electrolysis (OWF-H2). Offshore wind energy wind farms (OWF) and water electrolysis (WE) technologies are described. MHyWind (the tool used to perform simulations and optimisations of such plants) is presented as well as the models of the main components in the study. Three case studies focus on offshore wind farms either stand-alone or connected to the grid via export cables coupled with a battery and electrolysis systems either offshore or onshore. Exhaustive searches and optimisations performed allowed for rules of thumb to be derived on the sizing of coupled OWF-H2 plants that minimize costs of hydrogen production (LCoH2 in €/kgH2): Non-connected OWF-H2 coupled to a battery offers the lowest LCoH2 without the costs of H2 transportation when compared to cases where the WE is installed onshore and connected to the OWF. Using a simple power distribution heuristic increasing the number of installed WE allows the system to take advantage of more OWF energy but doesn’t improve plant efficiency whereas a battery always does. Finally within the scope of this study it is observed that power ratios of optimized plant architectures (leading to the lowest LCoH2) are between 0.8-0.9 for PWE/POWF and 0.3-0.35 for PBattery/POWF.
Co-production of Hydrogen and Power from Black Liquor Via Supercritical Water Gasification, Chemical Looping and Power Generation
Mar 2019
Publication
An integrated system to harvest efficiently the energy from the waste of pulp mill industry which is black liquor (BL) is proposed and evaluated. The proposed system consists of the supercritical water gasification (SCWG) of BL syngas chemical looping and power generation. To minimize the exergy loss throughout the system and to optimize the energy efficiency process design and integration is conducted by employing the principles of exergy recovery and process integration methods. Hydrogen is set as the main output while power is produced by utilizing the heat generated throughout the process. Process simulation is conducted using a steady state process simulator Aspen Plus. Energy efficiency is defined into three categories: hydrogen production efficiency power generation efficiency and total energy efficiency. From process simulation both of the integrated systems show very high total energy efficiency of about 73%.
From Biogas to Hydrogen: A Techno-Economic Study on the Production of Turquoise Hydrogen and Solid Carbons
Sep 2022
Publication
Biogas is a renewable feedstock that can be used to produce hydrogen through the decomposition of biomethane. However the economics of the process are not well studied and understood especially in cases where solid carbons are also produced and which have a detrimental effect on the performance of the catalysts. The scale as well as product diversification of a biogas plant to produce hydrogen and other value-added carbons plays a crucial role in determining the feasibility of biogasto-hydrogen projects. Through a techno-economic study using the discounted cash flow method it has been shown that there are no feasible sizes of plants that can produce hydrogen at the target price of USD 3/kg or lower. However for self-funded anaerobic digestor plants retrofitting modular units for hydrogen production would only make financial sense at biogas production capacities of more than 412 m3/h. A sensitivity analysis has also shown that the cost competitiveness is dependent on the type of carbon formed and low-grade carbon black has a negative effect on economic feasibility. Hydrogen produced from biogas would thus not be able to compete with grey hydrogen production but rather with current green hydrogen production costs.
Current Legislative Framework for Green Hydrogen Production by Electrolysis Plants in Germany
Mar 2022
Publication
(1) The German energy system transformation towards an entirely renewable supply is expected to incorporate the extensive use of green hydrogen. This carbon-free fuel allows the decarbonization of end-use sectors such as industrial high-temperature processes or heavy-duty transport that remain challenging to be covered by green electricity only. However it remains unclear whether the current legislative framework supports green hydrogen production or is an obstacle to its rollout. (2) This work analyzes the relevant laws and ordinances regarding their implications on potential hydrogen production plant operators. (3) Due to unbundling-related constraints potential operators from the group of electricity transport system and distribution system operators face lacking permission to operate production plants. Moreover ownership remains forbidden for them. The same applies to natural gas transport system operators. The case is less clear for natural gas distribution system operators where explicit regulation is missing. (4) It is finally analyzed if the production of green hydrogen is currently supported in competition with fossil hydrogen production not only by the legal framework but also by the National Hydrogen Strategy and the Amendment of the Renewable Energies Act. It can be concluded that in recent amendments of German energy legislation regulatory support for green hydrogen in Germany was found. The latest legislation has clarified crucial points concerning the ownership and operation of electrolyzers and the treatment of green hydrogen as a renewable energy carrier.
Projecting the Future Cost of PEM and Alkaline Water Electrolysers; a CAPEX Model Including Electrolyser Plant Size and Technology Department
Oct 2022
Publication
The investment costs of water electrolysis represent one key challenge for the realisation of renewable hydrogen-based energy systems. This work presents a technology cost assessment and outlook towards 2030 for alkaline electrolysers (AEL) and PEM electrolysers (PEMEL) in the MW to GW range taking into consideration the effects of plant size and expected technology developments. Critical selected data was fitted to a modified power law to describe the cost of an electrolyser plant based on the overall capacity and a learning/technology development rate to derive cost estimations for different PEMEL and AEL plant capacities towards 2030. The analysis predicts that the CAPEX gap between AEL and PEMEL technologies will decrease significantly towards 2030 with plant size until 1 e10 MW range. Beyond this only marginal cost reductions can be expected with CAPEX values approaching 320e400 $/kW for large scale (greater than 100 MW) plants by 2030 with subsequent cost reductions possible. Learning rates for electrolysers were estimated at 25 e30% for both AEL and PEMEL which are significantly higher than the learning rates reported in previous literature.
HydroGenerally - Episode 1: The Colours of Hydrogen
Mar 2022
Publication
This first episode was inspired by an Innovate UK KTN perspective commenting on the UK government’s Hydrogen Strategy released by the Department of Business Energy and Industrial Strategy (BEIS) in August 2021. Following the publication of this perspective it was very evident to our Innovate UK KTN experts that the uses and challenges of ‘blue’ and ‘green’ hydrogens were generating a strong debate depending on their application areas.
Over a 20-minute discussion Simon Steffan and Sam try to answer the questions: how is hydrogen currently produced? How will it be produced in the future? And how will it fit in with the energy system?
The podcast can be found on their website
Over a 20-minute discussion Simon Steffan and Sam try to answer the questions: how is hydrogen currently produced? How will it be produced in the future? And how will it fit in with the energy system?
The podcast can be found on their website
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