Spain
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 in Off-Grid Locations, a Techno-Economic Assessment
Nov 2018
Publication
Diesel generators are currently used as an off-grid solution for backup power but this causes CO2 and GHG emissions noise emissions and the negative effects of the volatile diesel market influencing operating costs. Green hydrogen production by means of water electrolysis has been proposed as a feasible solution to fill the gaps between demand and production the main handicaps of using exclusively renewable energy in isolated applications. This manuscript presents a business case of an off-grid hydrogen production by electrolysis applied to the electrification of isolated sites. This study is part of the European Ely4off project (n◦ 700359). Under certain techno-economic hypothesis four different system configurations supplied exclusively by photovoltaic are compared to find the optimal Levelized Cost of Electricity (LCoE): photovoltaic-batteries photovoltaic-hydrogen-batteries photovoltaic-diesel generator and diesel generator; the influence of the location and the impact of different consumptions profiles is explored. Several simulations developed through specific modeling software are carried out and discussed. The main finding is that diesel-based systems still allow lower costs than any other solution although hydrogen-based solutions can compete with other technologies under certain conditions.
Challenges and Prospects of Renewable Hydrogen-based Strategies for Full Decarbonization of Stationary Power Applications
Oct 2021
Publication
The exponentially growing contribution of renewable energy sources in the electricity mix requires large systems for energy storage to tackle resources intermittency. In this context the technologies for hydrogen production offer a clean and versatile alternative to boost renewables penetration and energy security. Hydrogen production as a strategy for the decarbonization of the energy sources mix has been investigated since the beginning of the 1990s. The stationary sector i.e. all parts of the economy excluding the transportation sector accounts for almost three-quarters of greenhouse gases (GHG) emissions (mass of CO2-eq) in the world associated with power generation. While several publications focus on the hybridization of renewables with traditional energy storage systems or in different pathways of hydrogen use (mainly power-to-gas) this study provides an insightful analysis of the state of art and evolution of renewable hydrogen-based systems (RHS) to power the stationary sector. The analysis started with a thorough review of RHS deployments for power-to-power stationary applications such as in power generation industry residence commercial building and critical infrastructure. Then a detailed evaluation of relevant techno-economic parameters such as levelized cost of energy (LCOE) hydrogen roundtrip efficiency (HRE) loss of power supply probability (LPSP) self-sufficiency ratio (SSR) or renewable fraction (fRES) is provided. Subsequently lab-scale plants and pilot projects together with current market trends and commercial uptake of RHS and fuel cell systems are examined. Finally the future techno-economic barriers and challenges for short and medium-term deployment of RHS are identified and discussed.
Recent Progress and New Perspectives on Metal Amide and Imide Systems for Solid-State Hydrogen Storage
Apr 2018
Publication
Hydrogen storage in the solid state represents one of the most attractive and challenging ways to supply hydrogen to a proton exchange membrane (PEM) fuel cell. Although in the last 15 years a large variety of material systems have been identified as possible candidates for storing hydrogen further efforts have to be made in the development of systems which meet the strict targets of the Fuel Cells and Hydrogen Joint Undertaking (FCH JU) and U.S. Department of Energy (DOE). Recent projections indicate that a system possessing: (i) an ideal enthalpy in the range of 20–50 kJ/mol H2 to use the heat produced by PEM fuel cell for providing the energy necessary for desorption; (ii) a gravimetric hydrogen density of 5 wt. % H2 and (iii) fast sorption kinetics below 110 ◦C is strongly recommended. Among the known hydrogen storage materials amide and imide-based mixtures represent the most promising class of compounds for on-board applications; however some barriers still have to be overcome before considering this class of material mature for real applications. In this review the most relevant progresses made in the recent years as well as the kinetic and thermodynamic properties experimentally measured for the most promising systems are reported and properly discussed.
Finding Synergy Between Renewables and Coal: Flexible Power and Hydrogen Production from Advanced IGCC Plants with Integrated CO2 Capture
Feb 2021
Publication
Variable renewable energy (VRE) has seen rapid growth in recent years. However VRE deployment requires a fleet of dispatchable power plants to supply electricity during periods with limited wind and sunlight. These plants will operate at reduced utilization rates that pose serious economic challenges. To address this challenge this paper presents the techno-economic assessment of flexible power and hydrogen production from integrated gasification combined cycles (IGCC) employing the gas switching combustion (GSC) technology for CO2 capture and membrane assisted water gas shift (MAWGS) reactors for hydrogen production. Three GSC-MAWGS-IGCC plants are evaluated based on different gasification technologies: Shell High Temperature Winkler and GE. These advanced plants are compared to two benchmark IGCC plants one without and one with CO2 capture. All plants utilize state-of-the-art H-class gas turbines and hot gas clean-up for maximum efficiency. Under baseload operation the GSC plants returned CO2 avoidance costs in the range of 24.9–36.9 €/ton compared to 44.3 €/ton for the benchmark. However the major advantage of these plants is evident in the more realistic mid-load scenario. Due to the ability to keep operating and sell hydrogen to the market during times of abundant wind and sun the best GSC plants offer a 6–11%-point higher annual rate of return than the benchmark plant with CO2 capture. This large economic advantage shows that the flexible GSC plants are a promising option for balancing VRE provided a market for the generated clean hydrogen exists.
Preliminary Design of a Self-Sufficient Electrical Storage System Based on Electrolytic Hydrogen for Power Supply in a Residential Application
Oct 2021
Publication
The use of renewable energy and hydrogen technology is a sustainable solution for the intermittent feature of renewable energies. Hence the aim of the present work is to design a self-sufficient system for a one-family house by coupling a solar photovoltaic array and an anion exchange membrane water electrolyzer (AEMWE). The first step is the selection of the photovoltaic panel by using PV-SYST 7.0 software. Then the hydrogen production system is calculated by coupling the electrolyzer and photovoltaic panel current–potential curves. A fuel cell is selected to use the hydrogen produced when solar energy is not available. Finally the hydrogen storage tank is also estimated to store hydrogen for a design basis of four consecutive cloudy days according to the hydrogen consumption of the fuel cell. The whole system is designed by a simple procedure for a specific location in Ciudad Real (Spain) for January which is known as the coldest month of the year. The simple procedure described in this work could be used elsewhere and demonstrated that the hydrogen production at low scale is a suitable technology to use renewable energy for self-energy supporting in a residential application without any connection to the grid.
Prospective Techno-economic and Environmental Assessment of a National Hydrogen Production Mix for Road Transport
Nov 2019
Publication
Fuel cell electric vehicles arise as an alternative to conventional vehicles in the road transport sector. They could contribute to decarbonising the transport system because they have no direct CO2 emissions during the use phase. In fact the life-cycle environmental performance of hydrogen as a transportation fuel focuses on its production. In this sense through the case study of Spain this article prospectively assesses the techno-economic and environmental performance of a national hydrogen production mix by following a methodological framework based on energy systems modelling enriched with endogenous carbon footprint indicators. Taking into account the need for a hydrogen economy based on clean options alternative scenarios characterised by carbon footprint restrictions with respect to a fossil-based scenario dominated by steam methane reforming are evaluated. In these scenarios the steam reforming of natural gas still arises as the key hydrogen production technology in the short term whereas water electrolysis is the main technology in the medium and long term. Furthermore in scenarios with very restrictive carbon footprint limits biomass gasification also appears as a key hydrogen production technology in the long term. In the alternative scenarios assessed the functional substitution of hydrogen for conventional fossil fuels in the road transport sector could lead to high greenhouse gas emission savings ranging from 36 to 58 Mt CO2 eq in 2050. Overall these findings and the model structure and characterisation developed for the assessment of hydrogen energy scenarios are expected to be relevant not only to the specific case study of Spain but also to analysts and decision-makers in a large number of countries facing similar concerns.
Green Hydrogen Storage in an Underground Cavern: A Case Study in Salt Diapir of Spain
Jun 2022
Publication
The Poza de la Sal diapir is a closed circular depression with Cretaceous Mesozoic materials formed by gypsum Keuper clays and a large extension of salt in the center with intercalations of ophite. The low seismic activity of the area the reduced permeability and porosity of the salt caverns and the proximity to the Páramo de Poza wind park make it a suitable place for the construction of a facility for underground storage of green hydrogen obtained from surplus wind power. The design of a cavern for hydrogen storage at a depth of 1000 m takes into account the differences in stresses temperatures and confining pressures involved in the salt deformation process. During the 8 months of the injection phase 23.0 GWh can be stored in the form of hydrogen obtained from the wind energy surplus to be used later in the extraction phase. The injection and extraction ratio must be developed under the conditions of geomechanical safety of the cavity so as to minimize the risks to the environment and people by conditioning the gas pressure inside the cavity to remain within a given range.
Life Cycle Environmental and Cost Comparison of Current and Future Passenger Cars under Different Energy Scenarios
Apr 2020
Publication
In this analysis life cycle environmental burdens and total costs of ownership (TCO) of current (2017) and future (2040) passenger cars with different powertrain configurations are compared. For all vehicle configurations probability distributions are defined for all performance parameters. Using these a Monte Carlo based global sensitivity analysis is performed to determine the input parameters that contribute most to overall variability of results. To capture the systematic effects of the energy transition future electricity scenarios are deeply integrated into the ecoinvent life cycle assessment background database. With this integration not only the way how future electric vehicles are charged is captured but also how future vehicles and batteries are produced. If electricity has a life cycle carbon content similar to or better than a modern natural gas combined cycle powerplant full powertrain electrification makes sense from a climate point of view and in many cases also provides reductions in TCO. In general vehicles with smaller batteries and longer lifetime distances have the best cost and climate performance. If a very large driving range is required or clean electricity is not available hybrid powertrain and compressed natural gas vehicles are good options in terms of both costs and climate change impacts. Alternative powertrains containing large batteries or fuel cells are the most sensitive to changes in the future electricity system as their life cycles are more electricity intensive. The benefits of these alternative drivetrains are strongly linked to the success of the energy transition: the more the electricity sector is decarbonized the greater the benefit of electrifying passenger vehicles.
Transportation in a 100% Renewable Energy System
Jan 2018
Publication
A 100% renewable economy would give a lasting solution to the challenges raised by climate change energy security sustainability and pollution. The conversion of the present transport system appears to be one of the most difficult aspects of such renewable transition. This study reviews the technologies and systems that are being proposed or proven as alternative to fossil-fuel based transportation and their prospects for their entry into the post-carbon era from both technological and energetic viewpoints. The energetic cost of the transition from the current transportation system into global 100% renewable transportation is estimated as well as the electrical energy required for the operation of the new renewable transportation sector. A 100% renewable transport providing the same service as global transport in 2014 would demand about 18% less energy. The main reduction is expected in road transport (69%) but the shipping and air sectors would notably increase their consumptions: 163% and 149% respectively. The analysis concludes that a 100% renewable transportation is feasible but not necessarily compatible with indefinite increase of resources consumption. The major material and energy limitations and obstacles of each transport sector for this transition are shown.
Resilience-oriented Schedule of Microgrids with Hybrid Energy Storage System using Model Predictive Control
Nov 2021
Publication
Microgrids can be regarded as a promising solution by which to increase the resilience of power systems in an energy paradigm based on renewable generation. Their main advantage is their ability to work as islanded systems under power grid outage conditions. Microgrids are usually integrated into electrical markets whose schedules are carried out according to economic aspects while resilience criteria are ignored. This paper shows the development of a resilience-oriented optimization for microgrids with hybrid Energy Storage System (ESS) which is validated via numerical simulations. A hybrid ESS composed of hydrogen and batteries is therefore considered with the objective of improving the autonomy of the microgrid while achieving a rapid transition response. The control problem is formulated using Stochastic Model Predictive Control (SMPC) techniques in order to take into account possible transitions between grid-connected and islanded modes at all the sample instants of the schedule horizon (SH). The control problem is developed by considering a healthy operation of the hybrid ESS thus avoiding degradation issues. The plant is modeled using the Mixed Logic Dynamic (MLD) framework owing to the presence of logic and dynamic control variables.
The Effect of Heat Treatments on the Constituent Materials of a Nuclear Reactor Pressure Vessel in Hydrogen Environment
Jul 2016
Publication
A nuclear reactor pressure vessel (NRPV) wall is formed by two layer of different materials: an inner layer of stainless steel (cladding material) and an outer layer of low carbon steel (base material) which is highly susceptible to corrosion related phenomena. A reduction of the mechanical properties of both materials forming the wall would appear due to the action of the harsh environment causing hydrogen embrittlement (HE) related phenomena. As a result of the manufacturing process residual stresses and strains appear in the NRPV wall thereby influencing the main stage in HE: hydrogen diffusion. A common engineering practice for reducing such states is to apply a tempering heat treatment. In this paper a numerical analysis is carried out for revealing the influence of the heat treatment parameters (tempering temperature and tempering time) on the HE of a commonly used NRPV. To achieve this goal a numerical model of hydrogen diffusion assisted by stress and strain was used considering diverse residual stress-strain states after tempering. This way the obtained hydrogen accumulation during operation time of the NRPV provides insight into the better tempering conditions from the structural integrity point of view.
Fuzzy Logic-based Energy Management System for Grid-connected Residential DC Microgrids with Multi-stack Fuel Cell Systems: A Multi-objective Approach
Aug 2022
Publication
Hybrid energy storage systems (HESS) are considered for use in renewable residential DC microgrids. This architecture is shown as a technically feasible solution to deal with the stochasticity of renewable energy sources however the complexity of its design and management increases inexorably. To address this problem this paper proposes a fuzzy logic-based energy management system (EMS) for use in grid-connected residential DC microgrids with HESS. It is a hydrogen-based HESS composed of batteries and multi-stack fuel cell system. The proposed EMS is based on a multivariable and multistage fuzzy logic controller specially designed to cope with a multi-objective problem whose solution increases the microgrid performance in terms of efficiency operating costs and lifespan of the HESS. The proposed EMS considers the power balance in the microgrid and its prediction the performance and degradation of its subsystems as well as the main electricity grid costs. This article assesses the performance of the developed EMS with respect to three reference EMSs present in the literature: the widely used dual-band hysteresis and two based on multi-objective model predictive control. Simulation results show an increase in the performance of the microgrid from a technical and economic point of view.
True Cost of Solar Hydrogen
Sep 2021
Publication
Green hydrogen will be an essential part of the future 100% sustainable energy and industry system. Up to one-third of the required solar and wind electricity would eventually be used for water electrolysis to produce hydrogen increasing the cumulative electrolyzer capacity to about 17 TWel by 2050. The key method applied in this research is a learning curve approach for the key technologies i.e. solar photovoltaics (PV) and water electrolyzers and levelized cost of hydrogen (LCOH). Sensitivities for the hydrogen demand and various input parameters are considered. Electrolyzer capital expenditure (CAPEX) for a large utility-scale system is expected to decrease from the current 400 €/kWel to 240 €/kWel by 2030 and to 80 €/kWel by 2050. With the continuing solar PV cost decrease this will lead to an LCOH decrease from the current 31–81 €/ MWhH2LHV (1.0–2.7 €/kgH2) to 20–54 €/MWhH2LHV (0.7–1.8 €/kgH2) by 2030 and 10–27 €/MWhH2LHV (0.3–0.9 €/kgH2) by 2050 depending on the location. The share of PV electricity cost in the LCOH will increase from the current 63% to 74% by 2050.
Value of Green Hydrogen When Curtailed to Provide Grid Balancing Services
Aug 2022
Publication
This paper evaluates the potential of grid services in France Italy Norway and Spain to provide an alternative income for electrolysers producing hydrogen from wind power. Grid services are simulated with each country's data for 2017 for energy prices grid services and wind power profiles from relevant wind parks. A novel metric is presented the value of curtailed hydrogen which is independent from several highly uncertain parameters such as electrolyser cost or hydrogen market price. Results indicate that grid services can monetise the unused spare capacity of electrolyser plants improving their economy in the critical deployment phase. For most countries up-regulation yields a value of curtailed hydrogen above 6 V/kg over 3 times higher than the EU's 2030 price target (without incentives). However countries with large hydro power resources such as Norway yield far lower results below 2 V/kg. The value of curtailed hydrogen also decreases with hydrogen production corresponding to the cases of symmetric and down-regulation.
Green Energy by Hydrogen Production from Water Splitting, Water Oxidation Catalysis and Acceptorless Dehydrogenative Coupling
Feb 2023
Publication
In this review we want to explain how the burning of fossil fuels is pushing us towards green energy. Actually for a long time we have believed that everything is profitable that resources are unlimited and there are no consequences. However the reality is often disappointing. The use of non-renewable resources the excessive waste production and the abandonment of the task of recycling has created a fragile thread that once broken may never restore itself. Metaphors aside we are talking about our planet the Earth and its unique ability to host life including ourselves. Our world has its balance; when the wind erodes a mountain a beach appears or when a fire devastates an area eventually new life emerges from the ashes. However humans have been distorting this balance for decades. Our evolving way of living has increased the number of resources that each person consumes whether food shelter or energy; we have overworked everything to exhaustion. Scientists worldwide have already said actively and passively that we are facing one of the biggest problems ever: climate change. This is unsustainable and we must try to revert it or if we are too late slow it down as much as possible. To make this happen there are many possible methods. In this review we investigate catalysts for using water as an energy source or instead of water alcohols. On the other hand the recycling of gases such as CO2 and N2O is also addressed but we also observe non-catalytic means of generating energy through solar cell production.
Hydrogen Production from Surplus Electricity Generated by an Autonomous Renewable System: Scenario 2040 on Grand Canary Island, Spain
Sep 2022
Publication
The electrification of final energy uses is a key strategy to reach the desired scenario with zero greenhouse gas emissions. Many of them can be electrified with more or less difficulty but there is a part that is difficult to electrify at a competitive cost: heavy road transport maritime and air transport and some industrial processes are some examples. For this reason the possibility of using other energy vectors rather than electricity should be explored. Hydrogen can be considered a real alternative especially considering that this transition should not be carried out immediately because initially the electrification would be carried out in those energy uses that are considered most feasible for this conversion. The Canary Islands’ government is making considerable efforts to promote a carbon-free energy mix starting with renewable energy for electricity generation. Still in the early–mid 2030s it will be necessary to substitute heavy transport fossil fuel. For this purpose HOMER software was used to analyze the feasibility of hydrogen production using surplus electricity produced by the future electricity system. The results of previous research on the optimal generation MIX for Grand Canary Island based exclusively on renewable sources were used. This previous research considers three possible scenarios where electricity surplus is in the range of 2.3–4.9 TWh/year. Several optimized scenarios using demand-side management techniques were also studied. Therefore based on the electricity surpluses of these scenarios the optimization of hydrogen production and storage systems was carried out always covering at least the final hydrogen demand of the island. As a result it is concluded that it would be possible to produce 3.5 × 104 to 7.68 × 104 t of H2/year. In these scenarios 3.15 × 105 to 6.91 × 105 t of water per year would be required and there could be a potential production of 2.8 × 105 to 6.14 × 105 t of O2 per year.
Recent Progress in Catalysts for Hydrogen-Chlorine Regenerative Fuel Cells
Oct 2020
Publication
The increasing energy demand and the subsequent climate change consequences are supporting the search for sustainable alternatives to fossil fuels. In this scenario the link between hydrogen and renewable energy is playing a key role and unitized hydrogen-chlorine (H2-Cl2) regenerative cells (RFCs) have become promising candidates for renewable energy storage. Described herein are the recent advances in cell configurations and catalysts for the different reactions that may take place in these systems that work in both modes: electrolysis and fuel cell. It has been found that platinum (Pt)-based catalysts are the best choice for the electrode where hydrogen is involved whereas for the case of chlorine ruthenium (Ru)-based catalysts are the best candidates. Only a few studies were found where the catalysts had been tested in both modes and recent advances are focused on decreasing the amount of precious metals contained in the catalysts. Moreover the durability of the catalysts tested under realistic conditions has not been thoroughly assessed becoming a key and mandatory step to evaluate the commercial viability of the H2-Cl2 RFC technology.
Global Gas Report 2022
May 2022
Publication
This edition of the Global Gas Report covers two very turbulent years in the global gas industry and the wider global energy markets. The Covid-19 pandemic lockdowns with a brief period of excess supply and low prices gave way to tight energy markets extreme price volatility and a compounding geopolitical challenge to energy security. At the time of writing the ongoing Russia-Ukraine conflict has been affecting the flows of gas and has put Europe on a quest to diversify its energy and gas supply that is now opening a new paradigm in the energy industry. This report comes at a time when the situation for global commodity and gas markets is in a state of rapid change and the strategic path forwards for the gas industry and energy policy-makers is continually developing. One thing is clear this is a critical and decisive moment for the gas industry. How it navigates the way through this crisis and charts a path forward will shape its long-term success and the role that it will play in the energy transition and beyond. This is the moment for the gas industry to demonstrate that gas can deliver a sustainable and secure energy future for all and that natural gas and a portfolio of decarbonized low- and zero-carbon gases are key to an achievable energy transition. This year’s report assesses key gas market trends from 2020 and 2021 including Covid-19 outcomes tightness of supply price volatility investments and the upward reversal in the global emissions trend. It then turns to the main topic on the global energy agenda – security – and considers key variables impacting it from industry and policy perspectives as well as considering possible paths to reinforce it. Finally the report looks at the main decarbonization pathways for gas supply as they progressively develop to make gas itself a low or zero-carbon fuel for the future. This report seeks to deliver insights about the global gas sector and to inform its stakeholders partners and importantly global decision-makers about the state of play today and possibilities for the future. It concludes with key insights on how sustainability security and competitiveness can help to deliver a sustainable future in line with the goals of the Paris Agreement and the UN Sustainable Development Agenda.
Life Cycle Assessment of Improved High Pressure Alkaline Electrolysis
Aug 2015
Publication
This paper investigates environmental impacts of high pressure alkaline water electrolysis systems. An advanced system with membranes on polymer basis is compared to a state-of-the-art system with asbestos membranes using a Life Cycle Assessment (LCA) approach. For the advanced system a new improved membrane technology has been investigated within the EU research project “ELYGRID”. Results indicate that most environmental impacts are caused by the electricity supply necessary for operation. During the construction phase cell stacks are the main contributor to environmental impacts. New improved membranes have relatively small contributions to impacts caused by cell construction within the advanced systems. As main outcome the systems comparison illustrates a better ecological performance of the new developed system
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