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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.
Techno-economic Analysis of Hydrogen Electrolysis from Off-Grid Stand-Alone Photovoltaics Incorporating Uncertainty Analysis
Oct 2020
Publication
Solar-driven electrolysis of water to generate hydrogen is emerging as a viable strategy to decarbonize the global energy economy. However this direction is more expensive than traditional fossil fuel generation of hydrogen and effective pathways to lower this cost need to be identified. Here we report a Monte Carlo approach to explore a wide range of input assumptions to identify key cost drivers targets and localized conditions necessary for competitive stand-alone dedicated PV powered hydrogen electrolysis. We determine the levelized cost of hydrogen (LCOH) considering historical weather data for specific locations to model our PV system and optimize its size compared to the electrolyzer. This analysis and its methods show the potential for green hydrogen production using off-grid PV shows the merits of remote systems in areas of high solar resource and provides cost and performance targets for electrolyzer technologies.
The Role of Hydrogen in the Transition from a Petroleum Economy to a Low-carbon Society
Jun 2021
Publication
A radical decarbonization pathway for the Norwegian society towards 2050 is presented. The paper focuses on the role of hydrogen in the transition when present Norwegian petroleum export is gradually phased out. The study is in line with EU initiatives to secure cooperation opportunities with neighbouring countries to establish an international hydrogen market. Three analytical perspectives are combined. The first uses energy models to investigate the role of hydrogen in an energy and power market perspective without considering hydrogen export. The second uses an economic equilibrium model to examine the potential role of hydrogen export in value creation. The third analysis is a socio-technical case study on the drivers and barriers for hydrogen production in Norway. Main conclusions are that access to renewable power and hydrogen are prerequisites for decarbonization of transport and industrial sectors in Norway and that hydrogen is a key to maintain a high level of economic activity. Structural changes in the economy impacts of new technologies and key enablers and barriers in this transition are discussed.
Integrating a Hydrogen Fuel Cell Electric Vehicle with Vehicle-to-grid Technology, Photovoltaic Power and a Residential Building
Feb 2018
Publication
This paper presents the results of a demonstration project including building-integrated photovoltaic (BIPV) solar panels a residential building and a hydrogen fuel cell electric vehicle (FCEV) for combined mobility and power generation aiming to achieve a net zero-energy residential building target. The experiment was conducted as part of the Car as Power Plant project at The Green Village in the Netherlands. The main objective was to assess the end-user’s potential of implementing FCEVs in vehicle-to-grid operation (FCEV2G) to act as a local energy source. FCEV2G field test performance with a Hyundai ix35 FCEV are presented. The car was adapted using a power output socket capable of delivering up to 10 kW direct current (DC) to the alternating current (AC) national grid when parked via an off-board (grid-tie) inverter. A Tank-To-AC-Grid efficiency (analogous to Tank- To-Wheel efficiency when driving) of 44% (measured on a Higher Heating Value basis) was obtained when the car was operating in vehicle-to-grid (V2G) mode at the maximum power output. By collecting and analysing real data on the FCEV power production in V2G mode and on BIPV production and household consumption two different operating modes for the FCEV offering balanced services to a residential microgrid were identified namely fixed power output and load following. Based on the data collected one-year simulations of a microgrid consisting of 10 all-electric dwellings and 5 cars with the different FCEV2G modes of operation were performed. Simulation results were evaluated on the factors of autonomy self-consumption of locally produced energy and net-energy consumption by implementing different energy indicators. The results show that utilizing an FCEV working in V2G mode can reduce the annual imported electricity from the grid by approximately 71% over one year and aiding the buildings in the microgrid to achieve a net zero-energy building target. Furthermore the simulation results show that utilizing the FCEV2G setup in both modes analysed could be economically beneficial for the end-user if hydrogen prices at the pump fall below 8.24 €/kg.
Life Cycle Assessment of Hydrogen Production and Consumption in an Isolated Territory
Apr 2018
Publication
Hydrogen produced from renewables works as an energy carrier and as energy storage medium and thus hydrogen can help to overcome the intermittency of typical renewable energy sources. However there is no comprehensive environmental performance study of hydrogen production and consumption. In this study detailed cradle to grave life cycle analyses are performed in an isolated territory. The hydrogen is produced on-site by Polymer Electrolyte Membrane (PEM) water electrolysis based on electricity from wind turbines that would otherwise have been curtailed and subsequently transported with gas cylinder by road and ferry. The hydrogen is used to provide electricity and heat through fuel cell stacks as well as hydrogen fuel for fuel cell vehicles. In order to evaluate the environmental impacts related to the hydrogen production and utilisation this work conducts an investigation of the entire life cycle of the described hydrogen production transportation and utilisation. All the processes related to the equipment manufacture operation maintenance and disposal are considered in this study.
Pathways toward a Decarbonized Future—Impact on Security of Supply and System Stability in a Sustainable German Energy System
Jan 2021
Publication
Pathways leading to a carbon neutral future for the German energy system have to deal with the expected phase-out of coal-fired power generation in addition to the shutdown of nuclear power plants and the rapid ramp-up of photovoltaics and wind power generation. An analysis of the expected impact on electricity market security of supply and system stability must consider the European context because of the strong coupling—both from an economic and a system operation point of view—through the cross-border power exchange of Germany with its neighbors. This analysis complemented by options to improve the existing development plans is the purpose of this paper. We propose a multilevel energy system modeling including electricity market network congestion management and system stability to identify challenges for the years 2023 and 2035. Out of the results we would like to highlight the positive role of innovative combined heat and power (CHP) solutions securing power and heat supply the importance of a network congestion management utilizing flexibility from sector coupling and the essential network extension plans. Network congestion and reduced security margins will become the new normal. We conclude that future energy systems require expanded flexibilities in combination with forward planning of operation.
Multi-Objective Optimization of a Hydrogen Hub for the Decarbonization of a Port Industrial Area
Feb 2022
Publication
Green hydrogen is addressed as a promising solution to decarbonize industrial and mobility sectors. In this context ports could play a key role not only as hydrogen users but also as suppliers for industrial plants with which they have strong commercial ties. The implementation of hydrogen technologies in ports has started to be addressed as a strategy for renewable energy transition but still requires a detailed evaluation of the involved costs which cannot be separated from the correct design and operation of the plant. Hence this study proposes the design and operation optimization of a hydrogen production and storage system in a typical Italian port. Multi-objective optimization is performed to determine the optimal levelized cost of hydrogen in environmental and techno-economic terms. A Polymer Electrolyte Membrane (PEM) electrolyzer powered by a grid-integrated photovoltaic (PV) plant a compression station and two-pressure level storage systems are chosen to provide hydrogen to a hydrogen refueling station for a 20-car fleet and satisfy the demand of the hydrogen batch annealing in a steel plant. The results report that a 341 kWP PV plant 89 kW electrolyzer and 17 kg hydrogen storage could provide hydrogen at 7.80 €/kgH2 potentially avoiding about 153 tCO2eq/year (120 tCO2eq/year only for the steel plant).
Hydrogen-Based Energy Storage Systems for Large-Scale Data Center Applications
Nov 2021
Publication
Global demand for data and data access has spurred the rapid growth of the data center industry. To meet demands data centers must provide uninterrupted service even during the loss of primary power. Service providers seeking ways to eliminate their carbon footprint are increasingly looking to clean and sustainable energy solutions such as hydrogen technologies as alternatives to traditional backup generators. In this viewpoint a survey of the current state of data centers and hydrogen-based technologies is provided along with a discussion of the hydrogen storage and infrastructure requirements needed for large-scale backup power applications at data centers.
FPGA-Based Implementation of an Optimization Algorithm to Maximize the Productivity of a Microbial Electrolysis Cell
Jun 2021
Publication
In this work the design of the hardware architecture to implement an algorithm for optimizing the Hydrogen Productivity Rate (HPR) in a Microbial Electrolysis Cell (MEC) is presented. The HPR in the MEC is maximized by the golden section search algorithm in conjunction with a super-twisting controller. The development of the digital architecture in the implementation step of the optimization algorithm was developed in the Very High Description Language (VHDL) and synthesized in a Field Programmable Gate Array (FPGA). Numerical simulations demonstrated the feasibility of the proposed optimization strategy embedded in an FPGA Cyclone II. Results showed that only.
Fuel Cell Electric Vehicle as a Power Plant and SOFC as a Natural Gas Reformer: An Exergy Analysis of Different System Designs
Apr 2016
Publication
Delft University of Technology under its ‘‘Green Village” programme has an initiative to build a power plant (car parking lot) based on the fuel cells used in vehicles for motive power. It is a trigeneration system capable of producing electricity heat and hydrogen. It comprises three main zones: a hydrogen production zone a parking zone and a pump station zone. This study focuses mainly on the hydrogen production zone which assesses four different system designs in two different operation modes of the facility: Car as Power Plant (CaPP) mode corresponding to the open period of the facility which uses fuel cell electric vehicles (FCEVs) as energy and water producers while parked; and Pump mode corresponding to the closed period which compresses the hydrogen and pumps to the vehicle’s fuel tank. These system designs differ by the reforming technology: the existing catalytic reformer (CR) and a solid oxide fuel cell operating as reformer (SOFCR); and the option of integrating a carbon capture and storage (CCS). Results reveal that the SOFCR unit significantly reduces the exergy destruction resulting in an improvement of efficiency over 20% in SOFCR-based system designs compared to CR-based system designs in both operation modes. It also mitigates the reduction in system efficiency by integration of a CCS unit achieving a value of 2% whereas in CR-based systems is 7–8%. The SOFCR-based system running in Pump mode achieves a trigeneration efficiency of 60%.
Flexibility in Great Britain
May 2021
Publication
The Flexibility in Great Britain project analysed the system-level value of deploying flexibility across the heat transport industry and power sectors in Great Britain to provide a robust evidence-base on the role and value of flexibility in a net zero system.
Overview
Findings from this groundbreaking analysis of the future net zero energy system in Great Britain are expected to have profound implications for policymakers households and the wider energy sector across Great Britain.
Key findings include:
Read the Full Report here on the Carbon Trust Website
View the interactive analysis here at the Carbon Trust Website
Watch an accompanying video here at the Carbon Trust Youtube channel
Overview
Findings from this groundbreaking analysis of the future net zero energy system in Great Britain are expected to have profound implications for policymakers households and the wider energy sector across Great Britain.
Key findings include:
- Embedding greater flexibility across the entire energy system will reduce the cost of achieving net zero for all consumers while assuring energy security.
- Investing in flexibility is a no-regrets decision as it has the potential to deliver material net savings of up to £16.7bn per annum across all scenarios analysed in 2050.
- A more flexible system will accelerate the benefits of decarbonisation supported by decentralisation and digitalisation.
- To maximise the benefits of flexibility households and businesses should play an active role in the development and operation of the country’s future energy system as energy use for transport heat and appliances becomes more integrated.
- Policymakers should preserve existing flexibility options and act now to maximise future flexibility such as by building it into ‘smart’ appliances or building standards.
Read the Full Report here on the Carbon Trust Website
View the interactive analysis here at the Carbon Trust Website
Watch an accompanying video here at the Carbon Trust Youtube channel
Loss of Integrity of Hydrogen Technologies: A Critical Review
Jul 2020
Publication
Hydrogen is one of the main candidates in replacing fossil fuels in the forthcoming years. However hydrogen technologies must deal with safety aspects due to the specific substance properties. This study aims to provide an overview on the loss of integrity (LOI) of hydrogen equipment which may lead to serious consequences such as fires and explosions. Substantial information regarding the hydrogen lifecycle its properties and safety related aspects has gathered. Furthermore focus has placed on the phenomena responsible for the LOI (e.g. hydrogen embrittlement) and material selection for hydrogen services. Moreover a systematic review on the hydrogen LOI topic has conducted to identify and connect the most relevant and active research group within the topic. In conclusion a significant dearth of knowledge in material behaviour of hydrogen technologies has highlighted. It is thought that is possible to bridge this gap by strengthening the collaborations between scientists from different research fields.
Health-Conscious Optimization of Long-Term Operation for Hybrid PEMFC Ship Propulsion Systems
Jun 2021
Publication
The need to decarbonize the shipping sector is leading to a growing interest in fuel cell-based propulsion systems. While Polymer Electrolyte Membrane Fuel Cells (PEMFC) represent one of the most promising and mature technologies for onboard implementation they are still prone to remarkable degradation. The same problem is also affecting Lithium-ion batteries (LIB) which are usually coupled with PEMFC in hybrid powertrains. By including the combined degradation effects in an optimization strategy the best compromise between costs and PEMFC/LIB lifetime could be determined. However this is still a challenging yet crucial aspect rarely addressed in the literature and rarely yet explored. To fill this gap a health-conscious optimization is here proposed for the long-term minimization of costs and PEMFC/LIB degradation. Results show that a holistic multi-objective optimization allows a 185% increase of PEMFC/LIB lifetime with respect to a fuel-consumption-minimization-only approach. With the progressive ageing of PEMFC/LIB the hybrid propulsion system modifies the energy management strategy to limit the increase of the daily operation cost. Comparing the optimization results at the beginning and the end of the plant lifetime daily operation costs are increased by 73% and hydrogen consumption by 29%. The proposed methodology is believed to be a useful tool able to give insights into the effective costs involved in the long-term operation of this new type of propulsion system.
Alberta Hydrogen Roadmap
Nov 2021
Publication
Alberta is preparing for a lower emission future. The Hydrogen Roadmap is a key part of that future and Alberta's Recovery Plan. The roadmap is our path to building a provincial hydrogen economy and accessing global markets. It contains several policy actions that will be introduced in the coming months and years and it provides support to the sector as technology and markets develop.<br/>Alberta is already the largest hydrogen producer in Canada. We have all the resources expertise and technology needed to quickly become a global supplier of clean low-cost hydrogen. With a worldwide market estimated to be worth over $2.5 trillion a year by 2050 hydrogen can be the next great energy export that fuels jobs investment and economic opportunity across our province.
Faraday’s Efficiency Modeling of a Proton Exchange Membrane Electrolyzer Based on Experimental Data
Sep 2020
Publication
In electrolyzers Faraday’s efficiency is a relevant parameter to assess the amount of hydrogen generated according to the input energy and energy efficiency. Faraday’s efficiency expresses the faradaic losses due to the gas crossover current. The thickness of the membrane and operating conditions (i.e. temperature gas pressure) may affect the Faraday’s efficiency. The developed models in the literature are mainly focused on alkaline electrolyzers and based on the current and temperature change. However the modeling of the effect of gas pressure on Faraday’s efficiency remains a major concern. In proton exchange membrane (PEM) electrolyzers the thickness of the used membranes is very thin enabling decreasing ohmic losses and the membrane to operate at high pressure because of its high mechanical resistance. Nowadays high-pressure hydrogen production is mandatory to make its storage easier and to avoid the use of an external compressor. However when increasing the hydrogen pressure the hydrogen crossover currents rise particularly at low current densities. Therefore faradaic losses due to the hydrogen crossover increase. In this article experiments are performed on a commercial PEM electrolyzer to investigate Faraday’s efficiency based on the current and hydrogen pressure change. The obtained results have allowed modeling the effects of Faraday’s efficiency by a simple empirical model valid for the studied PEM electrolyzer stack. The comparison between the experiments and the model shows very good accuracy in replicating Faraday’s efficiency.
Extremely Halophilic Biohydrogen Producing Microbial Communities from High-Salinity Soil and Salt Evaporation Pond
Jun 2021
Publication
Extreme halophiles offer the advantage to save on the costs of sterilization and water for biohydrogen production from lignocellulosic waste after the pretreatment process with their ability to withstand extreme salt concentrations. This study identifies the dominant hydrogen-producing genera and species among the acclimatized extremely halotolerant microbial communities taken from two salt-damaged soil locations in Khon Kaen and one location from the salt evaporation pond in Samut Sakhon Thailand. The microbial communities’ V3–V4 regions of 16srRNA were analyzed using high-throughput amplicon sequencing. A total of 345 operational taxonomic units were obtained and the high-throughput sequencing confirmed that Firmicutes was the dominant phyla of the three communities. Halanaerobium fermentans and Halanaerobacter lacunarum were the dominant hydrogen-producing species of the communities. Spatial proximity was not found to be a determining factor for similarities between these extremely halophilic microbial communities. Through the study of the microbial communities strategies can be developed to increase biohydrogen molar yield.
Hydrogen vs. Battery in the Long-term Operation. A Comparative Between Energy Management Strategies for Hybrid Renewable Microgrids
Apr 2020
Publication
The growth of the world’s energy demand over recent decades in relation to energy intensity and demography is clear. At the same time the use of renewable energy sources is pursued to address decarbonization targets but the stochasticity of renewable energy systems produces an increasing need for management systems to supply such energy volume while guaranteeing at the same time the security and reliability of the microgrids. Locally distributed energy storage systems (ESS) may provide the capacity to temporarily decouple production and demand. In this sense the most implemented ESS in local energy districts are small–medium-scale electrochemical batteries. However hydrogen systems are viable for storing larger energy quantities thanks to its intrinsic high mass-energy density. To match generation demand and storage energy management systems (EMSs) become crucial. This paper compares two strategies for an energy management system based on hydrogen-priority vs. battery-priority for the operation of a hybrid renewable microgrid. The overall performance of the two mentioned strategies is compared in the long-term operation via a set of evaluation parameters defined by the unmet load storage efficiency operating hours and cumulative energy. The results show that the hydrogen-priority strategy allows the microgrid to be led towards island operation because it saves a higher amount of energy while the battery-priority strategy reduces the energy efficiency in the storage round trip. The main contribution of this work lies in the demonstration that conventional EMS for microgrids’ operation based on battery-priority strategy should turn into hydrogen-priority to keep the reliability and independence of the microgrid in the long-term operation.
Modeling and Statistical Analysis of the Three-side Membrane Reactor for the Optimization of Hydrocarbon Production from CO2 Hydrogenation
Feb 2020
Publication
Direct CO2 hydrogenation to hydrocarbons is a promising method of reducing CO2 emissions along with producing value-added products. However reactor design and performance have remained a challenging issue because of low olefin efficiency and high water production as a by-product. Accordingly a one-dimensional non-isothermal mathematical model is proposed to predict the membrane reactor performance and statistical analysis is used to assess the effects of important variables such as temperatures of reactor (Tr:A) shell (Ts:B) and tube (Tt:C) as well as sweep ratio (θ:D) and pressure ratio (φ:E) and their interactions on the products yields. In addition the optimized operating conditions are also obtained to achieve maximum olefin yields. Results reveal that interacting effects comprising AB (TrTs) AC (TrTt) AE (Trφ) BC (TsTt) CE (Ttφ) CD (Ttθ) and DE (θφ) play important roles on the product yields. It is concluded that higher temperatures at low sweep and pressure ratios can maximize the yields of olefins while simultaneously the yields of paraffins are minimized. In this regard optimized values for Tr Ts Tt θ and φ are determined as 325 °C 306.96 °C 325 °C 1 and 1 respectively.
Prospects of Enhancing the Understanding of Material-hydrogen Interaction by Novel In-situ and In-operando Methods
Jan 2022
Publication
A main scientific and technical challenge facing the implementation of new and sustainable energy sources is the development and improvement of materials and components. In order to provide commercial viability of these applications an intensive research in material-hydrogen (H) interaction is required. This work provides an overview of recently developed in-situ and in-operando H-charging methods and their applicability to investigate mechanical properties H-absorption characteristics and H embrittlement (HE) susceptibility of a wide range of materials employed in H-related technologies such as subsea oil and gas applications nuclear fusion and fuel cells.
Optimal Hydrogen Production in a Wind-dominated Zero-emission Energy System
May 2021
Publication
The role of hydrogen in future energy systems is widely acknowledged: from fuel for difficult-to-decarbonize applications to feedstock for chemicals synthesis to energy storage for high penetration of undispatchable renewable electricity. While several literature studies investigate such energy systems the details of how electrolysers and renewable technologies optimally behave and interact remain an open question. With this work we study the interplay between (i) renewable electricity generation through wind and solar (ii) electricity storage in batteries (iii) electricity storage via Power-to-H2 and (iv) hydrogen commodity demand. We do so by designing a cost-optimal zero-emission energy system and use the Netherlands as a case study in a mixed integer linear model with hourly resolution for a time horizon of one year. To account for the significant role of wind we also provide an elaborate approach to model broad portfolios of wind turbines. The results show that if electrolyzers can operate flexibly batteries and power-to-H2-to-power are complementary with the latter using renewable power peaks and the former using lower renewable power outputs. If the operating modes of the power-to-H2-to-power system are limited - artificially or technically - the competitive advantage over batteries decreases. The preference of electrolyzers for power peaks also leads to an increase in renewable energy utilization for increased levels of operation flexibility highlighting the importance of capturing this feature both from a technical and a modeling perspective. When adding a commodity hydrogen demand the amount of hydrogen converted to electricity decreases hence decreasing its role as electricity storage medium.
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