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Electric Field Effects on Photoelectrochemical Water Splitting: Perspectives and Outlook
Feb 2022
Publication
The grand challenges in renewable energy lie in our ability to comprehend efficient energy conversion systems together with dealing with the problem of intermittency via scalable energy storage systems. Relatively little progress has been made on this at grid scale and two overriding challenges still need to be addressed: (i) limiting damage to the environment and (ii) the question of environmentally friendly energy conversion. The present review focuses on a novel route for producing hydrogen the ultimate clean fuel from the Sun and renewable energy source. Hydrogen can be produced by light-driven photoelectrochemical (PEC) water splitting but it is very inefficient; rather we focus here on how electric fields can be applied to metal oxide/water systems in tailoring the interplay with their intrinsic electric fields and in how this can alter and boost PEC activity drawing both on experiment and non-equilibrium molecular simulation.
Analysis of the Polish Hydrogen Strategy in the Context of the EU’s Strategic Documents on Hydrogen
Oct 2021
Publication
In December 2019 the European Commission unveiled an ambitious project the European Green Deal which aims to lead the European Union to climate neutrality by 2050. This is a significant challenge for all EU countries and especially for Poland. The role of hydrogen in the processes of decarbonization of the economy and transport is being discussed in many countries around the world to find rational solutions to this difficult and complex problem. There is an ongoing discussion about the hydrogen economy which covers the production of hydrogen its storage transport and conversion to the desired forms of energy primarily electricity mechanical energy and new fuels. The development of the hydrogen economy can significantly support the achievement of climate neutrality. The belief that hydrogen plays an important role in the transformation of the energy sector is widespread. There are many technical and economic challenges as well as legal and logistical barriers to deal with in the transition process. The development of hydrogen technologies and a global sustainable energy system that uses hydrogen offers a real opportunity to solve the challenges facing the global energy industry: meeting the need for clean fuels increasing the efficiency of fuel and energy production and significantly reducing greenhouse gas emissions. The paper provides an in-depth analysis of the Polish Hydrogen Strategy a document that sets out the directions for the development of hydrogen use (competences and technologies) in the energy transport and industrial sectors. This analysis is presented against the background of the European Commission’s document ‘A Hydrogen Strategy for a Climate-Neutral Europe’. The draft project presented is a good basis for further discussion on the directions of development of the Polish economy. The Polish Hydrogen Strategy although it was created later than the EU document does not fully follow its guidelines. The directions for further work on the hydrogen strategy are indicated so that its final version can become a driving force for the development of the country’s economy.
Hydrogen Production in Methane Decomposition Reactor Using Solar Thermal Energy
Nov 2021
Publication
This study investigates the decomposition of methane using solar thermal energy as a heat source. Instead of the direct thermal decomposition of the methane at a temperature of 1200 ◦C or higher a catalyst coated with carbon black on a metal foam was used to lower the temperature and activation energy required for the reaction and to increase the yield. To supply solar heat during the reaction a reactor suitable for a solar concentrating system was developed. In this process a direct heating type reactor with quartz was initially applied and a number of problems were identified. An indirect heating type reactor with an insulated cavity and a rotating part was subsequently developed followed by a thermal barrier coating application. Methane decomposition experiments were conducted in a 40 kW solar furnace at the Korea Institute of Energy Research. Conversion rates of 96.7% and 82.6% were achieved when the methane flow rate was 20 L/min and 40 L/min respectively.
H21 Phase 2: Personal Protective Equipment
Dec 2020
Publication
This report is a detailed discussion related to safety shoes heat and flame personal protective equipment (PPE) and breathing apparatus (respiratory protective equipment RPE) required for working with natural gas (NG) and hydrogen (H2). This work was undertaken by HSE Science Division (SD) as part of Phase 2a of the H21 project. This report should be read alongside all the other relevant reports generated as part of this project. Recommendations made in this report are focused solely on the provision and use of PPE and should not be considered independently of recommendations made in the other relevant reports.<br/>Understanding the similarities and difference of PPE required for NG and H2 enables a deeper understanding of how the transition from NG to 100% H2 might change the way the gas distribution network is operated and managed.
Demand Side Management Based Power-to-Heat and Power-to-Gas Optimization Strategies for PV and Wind Self-Consumption in a Residential Building Cluster
Oct 2021
Publication
The volatility of renewable energy sources (RES) poses a growing problem for operation of electricity grids. In contrary the necessary decarbonisation of sectors such as heat supply and transport requires a rapid expansion of RES. Load management in the context of power-to-heat systems can help to simultaneously couple the electricity and heat sectors and stabilise the electricity grid thus enabling a higher share of RES. In addition power-to-hydrogen offers the possibility of long-term energy storage options. Within this work we present a novel optimization approach for heat pump operation with the aim to counteract the volatility and enable a higher usage of RES. For this purpose a detailed simulation model of buildings and their energy supply systems is created calibrated and validated based on a plus energy settlement. Subsequently the potential of optimized operation is determined with regard to PV and small wind turbine self-consumption. In addition the potential of seasonal hydrogen storage is examined. The results show that on a daily basis a 33% reduction of electricity demand from grid is possible. However the average optimization potential is reduced significantly by prediction inaccuracy. The addition of a hydrogen system for seasonal energy storage basically eliminates the carbon dioxide emissions of the cluster. However this comes at high carbon dioxide prevention costs of 1.76 e kg−1 .
Relevance of Optimized Low-Scale Green H2 Systems in a French Context: Two Case Studies
May 2022
Publication
Hydrogen has been identified as a very promising vector for energy storage especially for heavy mobility applications. For this reason France is making significant investments in this field and use cases need to be evaluated as they are sprouting. In this paper the relevance of H2 in two storage applications is studied: a domestic renewable electricity production system connected to the grid and a collective hydrogen production for the daily bus refill. The investigation consists of the sizing of the system and then the evaluation of its performance according to several criteria depending on case. Optimizations are made using Bayesian and gradient-based methods. Several variations around a central case are explored for both cases to give insights on the impact of the different parameters (location pricing objective etc.) on the performance of the system.Our results show that domestic power-to-power applications (case 1) do not seem to be competitive with electrochemical storage. Meanwhile without any subsidies or incentives such configuration does not allow prosumers to save money (+16% spendings compared to non-equipped dwelling). It remains interesting when self-sufficiency is the main objective (up to 68% of energy is not exchanged). The power-to-gas application (case 2 central case) with a direct use of hydrogen for mobility seems to be more relevant according to our case study we could reach a production cost of green H2 around 5 €/kg similar to the 3–10 $/kg found in literature for 182 houses involved. In both cases H2 follows a yearly cycle charging in summer and discharging in winter (long term storage) due to low conversion efficiency.
Green Hydrogen: A New Flexibility Source for Security Constrained Scheduling of Power Systems with Renewable Energies
Apr 2021
Publication
Green hydrogen i.e. the hydrogen generated from renewable energy sources (RES) will significantly contribute to a successful energy transition. Besides to facilitate the integration and storage of RES this promising energy carrier is well capable to efficiently link various energy sectors. By introduction of green hydrogen as a new flexibility source to power systems it is necessary to investigate its possible impacts on the generation scheduling and power system security. In this paper a security-constrained multi-period optimal power flow (SC-MPOPF) model is developed aiming to determine the optimal hourly dispatch of generators as well as power to hydrogen (P2H) units in the presence of large-scale renewable energy sources (RES). The proposed model characterizes the P2H demand flexibility in the proposed SC-MPOPF model taking into account the electrolyzer behavior reactive power support of P2H demands and hydrogen storage capability. The developed SC-MPOPF model is applied to IEEE 39-bus system and the obtained numerical results demonstrate the role of P2H flexibility on cost as well as RES's power curtailment reduction.
A Production and Delivery Model of Hydrogen from Solar Thermal Energy in the United Arab Emirates
May 2022
Publication
Hydrogen production from surplus solar electricity as energy storage for export purposes can push towards large-scale application of solar energy in the United Arab Emirates and the Middle East region; this region’s properties of high solar irradiance and vast empty lands provide a good fit for solar technologies such as concentrated solar power and photovoltaics. However a thorough comparison between the two solar technologies as well as investigating the infrastructure of the United Arab Emirates for a well-to-ship hydrogen pathway is yet to be fully carried out. Therefore in this study we aim to provide a full model for solar hydrogen production and delivery by evaluating the potential of concentrated solar power and photovoltaics in the UAE then comparing two different pathways for hydrogen delivery based on the location of hydrogen production sites. A Solid Oxide Cell Electrolyzer (SOEC) is used for technical comparison while the shortest routes for hydrogen transport were analyzed using Geographical Information System (GIS). The results show that CSP technology coupled with SOEC is the most favorable pathway for large-scale hydrogen from solar energy production in the UAE for export purposes. Although PV has a slightly higher electricity potential compared to CSP around 42 GWh/km2 to 41.1 GWh/km2 respectively CSP show the highest productions rates of over 6 megatons of hydrogen when the electrolyzer is placed at the same site as the CSP plant while PV generates 5.15 megatons when hydrogen is produced at the same site with PV plants; meanwhile hydrogen from PV and CSP shows similar levels of 4.8 and 4.6 megatons of hydrogen respectively when electrolyzers are placed at port sites. Even considering the constraints in the UAE’s infrastructure and suggesting new shorter electrical transmission lines that could save up to 0.1 megatons of hydrogen in the second pathway production at the same site with CSP is still the most advantageous scenario.
Insights into the Principles, Design Methodology and Applications of Electrocatalysts Towards Hydrogen Evolution Reaction
Apr 2021
Publication
The electrolysis of water for sustainable hydrogen producing is a crucial segment of various emerging clean-energy technologies. However pursuing an efficient and cheap alternative catalyst to substitute state-of-the-art platinum-group electrocatalysts remains a prerequisite for the commercialization of this technology. Typically precious-metal-free catalysts have always much lower activities towards hydrogen production than that of Pt-group catalysts. To explore high-performance catalysts maximally exposed active sites rapid charge transfer ability and desirable electronic configuration are essentially demanded. Herein the fundamentals of hydrogen evolution reaction will be briefly described and the main focus will be on the interfacial engineering strategies by means of constructing defect structure creating heterojunction phase engineering lattice strain control designing hierarchical architecture and doping heteroatoms to effectively proliferate the catalytic active sites facilitate the electron diffusion and regulate the electronic configuration of numerous transition metals and their nitrides carbides sulfides phosphides as well as oxides achieving a benchmark performance of platinum-free electrocatalysts for the hydrogen evolution reaction. This review unambiguously offers proof that the conventional cheap and earth-abundant transition metal-based substances can be translated into an active water splitting catalyst by the rational and controllable interfacial designing.
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
The Potential Role of Ammonia as Marine Fuel—Based on Energy Systems Modeling and Multi-Criteria Decision Analysis
Apr 2020
Publication
To reduce the climate impact of shipping the introduction of alternative fuels is required. There is a range of different marine fuel options but ammonia a potential zero carbon fuel has recently received a lot of attention. The purpose of this paper is to assess the prospects for ammonia as a future fuel for the shipping sector in relation to other marine fuels. The assessment is based on a synthesis of knowledge in combination with: (i) energy systems modeling including the cost-effectiveness of ammonia as marine fuel in relation to other fuels for reaching global climate targets; and (ii) a multi-criteria decision analysis (MCDA) approach ranking marine fuel options while considering estimated fuel performance and the importance of criteria based on maritime stakeholder preferences. In the long-term and to reach global GHG reduction the energy systems modeled indicate that the use of hydrogen represents a more cost-effective marine fuel option than ammonia. However in the MCDA covering more aspects we find that ammonia may be almost as interesting for shipping related stakeholders as hydrogen and various biomass-based fuels. Ammonia may to some extent be an interesting future marine fuel option but many issues remain to be solved before large-scale introduction.
Hydrogenation Production via Chemical Looping Reforming of Coke Oven Gas
Jun 2020
Publication
Coke oven gas (COG) is one of the most important by-products in the steel industry and the conversion of COG to value-added products has attracted much attention from both economic and environmental views. In this work we apply the chemical looping reforming technology to produce pure H2 from COG. A series of La1-xSrxFeO3 (x = 0 0.2 0.3 0.4 0.5 0.6) perovskite oxides were prepared as oxygen carriers for this purpose. The reduction behaviours of La1-xSrxFeO3 perovskite by different reducing gases (H2 CO CH4 and the mixed gases) are investigated to discuss the competition effect of different components in COG for reacting with the oxygen carriers. The results show that reduction temperatures of H2 and CO are much lower than that of CH4 and high temperatures (>800 °C) are requested for selective oxidation of methane to syngas. The co-existence of CO and H2 shows weak effect on the equilibrium of methane conversion at high temperatures but the oxidation of methane to syngas can inhibit the consumption of CO and H2. The doping of suitable amounts of Sr in LaFeO3 perovskite (e.g. La0.5Sr0.5FeO3) significantly promotes the reactivity for selective oxidation of methane to syngas and inhibits the formation of carbon deposition obtaining both high methane conversion in the COG oxidation step and high hydrogen yield in the water splitting step. The La0.5Sr0.5FeO3 shows the highest methane conversion (67.82%) hydrogen yield (3.34 mmol·g-1) and hydrogen purity (99.85%). The hydrogen yield in water splitting step is treble as high as the hydrogen consumption in reduction step. These results reveal that chemical looping reforming of COG to produce pure H2 is feasible and an O2-assistant chemical looping reforming process can further improve the redox stability of oxygen carrier.
The Effect of a Nuclear Baseload in a Zero-carbon Electricity System: An Analysis for the UK
Jan 2023
Publication
This paper explores the effect of having a nuclear baseload in a 100% carbon-free electricity system The study analyses numerous 8 scenarios based on different penetrations of conventional nuclear wind and solar PV power different levels of overgeneration 9 and different combinations between medium and long duration energy stores (hydrogen and compressed air respectively) to 10 determine the configuration that achieves the lowest total cost of electricity (TCoE). 11 At their current cost new baseload nuclear power plants are too expensive. Results indicate the TCoE is minimised when demand 12 is supplied entirely by renewables with no contribution from conventional nuclear. 13 However small modular reactors may achieve costs of ~£60/MWh (1.5x current wind cost) in the future. With such costs 14 supplying ~80% of the country’s electricity demand with nuclear power could minimise the TCoE. In this scenario wind provides 15 the remaining 20% plus a small percentage of overgeneration (~2.5%). Hydrogen in underground caverns provides ~30.5 TWh (81 16 days) of long-duration energy storage while CAES systems provide 2.8 TWh (~8 days) of medium-duration storage. This 17 configuration achieves costs of ~65.8 £/MWh. Batteries (required for short duration imbalances) are not included in the figure. 18 The TCoE achieved will be higher once short duration storage is accounted for.
Efficient Plasma Technology for the Production of Green Hydrogen from Ethanol and Water
Apr 2022
Publication
This study concerns the production of hydrogen from a mixture of ethanol and water. The process was conducted in plasma generated by a spark discharge. The substrates were introduced in the liquid phase into the reactor. The gaseous products formed in the spark reactor were hydrogen carbon monoxide carbon dioxide methane acetylene and ethylene. Coke was also produced. The energy efficiency of hydrogen production was 27 mol(H2 )/kWh and it was 36% of the theoretical energy efficiency. The high value of the energy efficiency of hydrogen production was obtained with relatively high ethanol conversion (63%). In the spark discharge it was possible to conduct the process under conditions in which the ethanol conversion reached 95%. However this entailed higher energy consumption and reduced the energy efficiency of hydrogen production to 8.8 mol(H2 )/kWh. Hydrogen production increased with increasing discharge power and feed stream. However the hydrogen concentration was very high under all tested conditions and ranged from 57.5 to 61.5%. This means that the spark reactor is a device that can feed fuel cells the power load of which can fluctuate.
Cotton Stalk Activated Carbon-supported Co–Ce–B Nanoparticles as Efficient Catalysts for Hydrogen Generation Through Hydrolysis of Sodium Borohydride
Nov 2019
Publication
Porous cotton stalk activated carbons (CSAC) were prepared by phosphoric acid activation of cotton stalks in a fluidized bed. The CSAC-supported Co–B and Co–Ce–B catalysts were prepared by the impregnation-chemical reduction method. The samples were characterized by the nitrogen adsorption XRD FTIR and TEM measurements. The effects of the sodium borohydride (NaBH4) and sodium hydroxide (NaOH) concentrations reaction temperature and recyclability on the rate of NaBH4 hydrolysis over the CSAC-supported Co–Ce–B catalysts were systematically investigated. The results showed that the agglomeration of the Co–Ce–B nanoclusters on the CSAC support surface was significantly reduced with the introduction of cerium. The CSAC-supported Co–Ce–B catalyst exhibited superior catalytic activity and the average hydrogen generation rate was 16.42 L min−1 g−1 Co at 25°C which is higher than the most reported cobalt-based catalysts. The catalytic hydrolysis of NaBH4 was zero order with respect to the NaBH4 concentration and the hydrogen generation rate decreased with the increase in the NaOH concentration. The activation energy of the hydrogen generation reaction on the prepared catalyst was estimated to be 48.22 kJ mol−1. A kinetic rate equation was also proposed.
JRC Reference Data from Experiments of Onboard Hydrogen Tanks Fast Filling
Sep 2013
Publication
At the JRC-IET on-board hydrogen tanks have been subjected to filling–emptying cycles to investigate their long-term mechanical and thermal behaviour and their safety performance. The local temperature history inside the tanks has been measured and compared with the temperatures outside and at the tank metallic bosses which is the measurement location identified by some standards. The outcome of these activities is a set of experimental data which will be made publicly available as reference for safety studies and validation of computational fluid dynamics.
Examining the Role of Safety in Communication Concerning Emerging Hydrogen Technologies by Selected Groups of Stakeholders
Sep 2021
Publication
Governments and other stakeholders actively promote and facilitate the development and deployment of hydrogen and fuel cell technologies. Various strategy documents and energy forecasts outline the environmental and societal benefits of the prospective hydrogen economy. At the same time the safety related properties of hydrogen imply that it is not straightforward to achieve and document the same level of safety for hydrogen systems compared to conventional fuels. Severe accidents can have major impact on the development of energy technologies. The stakes will increase significantly as the use of hydrogen shifts from controlled environments in industrial facilities to the public domain and as the transport-related consumption extends from passenger cars and buses to trains ships and airplanes. Widespread deployment of hydrogen as an energy carrier in society will require massive investments. This implies commercial and political commitment involvement and influence on research priorities and decision-making. The legacy from accidents and the messages communicated by influential stakeholders impact not only how the public perceives hydrogen technologies but also governmental policies the development of regulations codes and standards (RCS) and ultimately the measures adopted for preventing and mitigating accidents. This paper explores whether and how selected aspects of safety are considered when distinct groups of stakeholders frame the hydrogen economy. We assess to what extent the communication is consistent with the current state-of-the-art in hydrogen safety and the contemporary strength of knowledge in risk assessments for hydrogen systems. The approach adopted entails semi-quantitative text analysis and close reading to highlight variations between diverse groups of stakeholders. The results indicate a bias in the framing of the safety-related aspects of the hydrogen economy towards procedural organisational and societal measures of risk reduction at the expense of well-known challenges and knowledge gaps associated with the implications of fundamental safety-related properties of hydrogen.
Green Hydrogen and Energy Transition: Current State and Prospects in Portugal
Jan 2023
Publication
Hydrogen is a promising commodity a renewable secondary energy source and feedstock alike to meet greenhouse gas emissions targets and promote economic decarbonization. A common goal pursued by many countries the hydrogen economy receives a blending of public and private capital. After European Green Deal state members created national policies focused on green hydrogen. This paper presents a study of energy transition considering green hydrogen production to identify Portugal’s current state and prospects. The analysis uses energy generation data hydrogen production aspects CO2 emissions indicators and based costs. A comprehensive simulation estimates the total production of green hydrogen related to the ratio of renewable generation in two different scenarios. Then a comparison between EGP goals and Portugal’s transport and energy generation prospects is made. Portugal has an essential renewable energy matrix that supports green hydrogen production and allows for meeting European green hydrogen 2030–2050 goals. Results suggest that promoting the conversion of buses and trucks into H2-based fuel is better for CO2 reduction. On the other hand given energy security thermoelectric plants fueled by H2 are the best option. The aggressive scenario implies at least 5% more costs than the moderate scenario considering economic aspects.
Water Electrolysis for the Production of Hydrogen to Be Employed in the Ironmaking and Steelmaking Industry
Nov 2021
Publication
The way to decarbonization will be characterized by the huge production of hydrogen through sustainable routes. Thus the basic production way is water electrolysis sustained by renewable energy sources allowing for obtaining “green hydrogen”. The present paper reviews the main available technologies for the water electrolysis finalized to the hydrogen production. We describe the fundamental of water electrolysis and the problems related to purification and/or desalinization of water before electrolysis. As a matter of fact we describe the energy efficiency issues with particular attention to the potential application in the steel industry. The fundamental aspects related to the choice of high-temperature or low-temperature technologies are analyzed.
Use of Hydrogen as Fuel: A Trend of the 21st Century
Jan 2022
Publication
The unbridled use of fossil fuels is a serious problem that has become increasingly evident over the years. As such fuels contribute considerably to environmental pollution there is a need to find new sustainable sources of energy with low emissions of greenhouse gases. Climate change poses a substantial challenge for the scientific community. Thus the use of renewable energy through technologies that offer maximum efficiency with minimal pollution and carbon emissions has become a major goal. Technology related to the use of hydrogen as a fuel is one of the most promising solutions for future systems of clean energy. The aim of the present review was to provide an overview of elements related to the potential use of hydrogen as an alternative energy source considering its specific chemical and physical characteristics as well as prospects for an increase in the participation of hydrogen fuel in the world energy matrix.
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