Applications & Pathways
Van der Waals Heterostructures - Recent Progress in Electrode Materials for Clean Energy Applications
Jul 2021
Publication
The unique layered morphology of van der Waals (vdW) heterostructures give rise to a blended set of electrochemical properties from the 2D sheet components. Herein an overview of their potential in energy storage systems in place of precious metals is conducted. The most recent progress on vdW electrocatalysis covering the last three years of research is evaluated with an emphasis on their catalytic activity towards the oxygen reduction reaction (ORR) oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). This analysis is conducted in pair with the most active Pt-based commercial catalyst currently utilized in energy systems that rely on the above-listed electrochemistry (metal–air battery fuel cells and water electrolyzers). Based on current progress in HER catalysis that employs vdW materials several recommendations can be stated. First stacking of the two types vdW materials with one being graphene or its doped derivatives results in significantly improved HER activity. The second important recommendation is to take advantage of an electronic coupling when stacking 2D materials with the metallic surface. This significantly reduces the face-to-face contact resistance and thus improves the electron transfer from the metallic surface to the vdW catalytic plane. A dual advantage can be achieved from combining the vdW heterostructure with metals containing an excess of d electrons (e.g. gold). Despite these recent and promising discoveries more studies are needed to solve the complexity of the mechanism of HER reaction in particular with respect to the electron coupling effects (metal/vdW combinations). In addition more affordable synthetic pathways allowing for a well-controlled confined HER catalysis are emerging areas.
A Hydrogen Fuelled LH2 Tanker Ship Design
May 2021
Publication
This study provides a detailed philosophical view and evaluation of a viable design for a large liquid hydrogen tanker fuelled by liquid hydrogen. Established methods for determining tank sizing ship stability and ship characteristics were used to evaluate the preliminary design and performance of the liquefied hydrogen tanker named ‘JAMILA’ designed specifically to transport liquid hydrogen. JAMILA is designed around four large liquid hydrogen tanks with a total capacity of ∼280000 m3 and uses the boil-off gas for propulsion for the loaded leg of the journey. The ship is 370 m long 75 m wide and draws 10.012 m at full load. It has a fully loaded displacement tonnage of 232000 tonnes to carry 20000 tonnes of hydrogen. Its propulsion system contains a combined-cycle gas turbine of approximately 50 MW. The volume of the hydrogen cargo pressurised to 0.5 MPa primarily determines the size and displacement of the ship.
Performance of Common Rail Direct Injection (CRDi) Engine Using Ceiba Pentandra Biodiesel and Hydrogen Fuel Combination
Nov 2021
Publication
An existing diesel engine was fitted with a common rail direct injection (CRDi) facility to inject fuel at higher pressure in CRDi mode. In the current work rotating blades were incorporated in the piston cavity to enhance turbulence. Pilot fuels used are diesel and biodiesel of Ceiba pentandra oil (BCPO) with hydrogen supply during the suction stroke. Performance evaluation and emission tests for CRDi mode were carried out under different loading conditions. In the first part of the work maximum possible hydrogen substitution without knocking was reported at an injection timing of 15◦ before top dead center (bTDC). In the second part of the work fuel injection pressure (IP) was varied with maximum hydrogen fuel substitution. Then in the third part of the work exhaust gas recirculation (EGR) was varied to study the nitrogen oxides (NOx) generated. At 900 bar HC emissions in the CRDi engine were reduced by 18.5% and CO emissions were reduced by 17% relative to the CI mode. NOx emissions from the CRDi engine were decreased by 28% relative to the CI engine mode. At 20% EGR lowered the BTE by 14.2% and reduced hydrocarbons nitrogen oxide and carbon monoxide by 6.3% 30.5% and 9% respectively compared to the CI mode of operation.
Prospects for the Use of Hydrogen in the Armed Forces
Oct 2021
Publication
The energy security landscape that we envisage in 2050 will be different from that of today. Meeting the future energy needs of the armed forces will be a key challenge not least for military security. The World Energy Council’s World Energy Scenarios forecast that the world’s population will rise to 10 billion by 2050 which will also necessitate an increase in the size of the armed forces. In this context energy extraction distribution and storage become essential to stabilizing the imbalance between production and demand. Among the available solutions Power to Hydrogen (P2H) is one of the most appealing options. However despite the potential many obstacles currently hinder the development of the P2H market. This article aims to identify and analyse existing barriers to the introduction of P2H technologies that use hydrogen. The holistic approach used which was based on a literature survey identified obstacles and possible strategies for overcoming them. The research conducted presents an original research contribution at the level of hydrogen strategies considered in leading countries around the world. The research findings identified unresolved regulatory issues and sources of uncertainty in the armed forces. There is a lack of knowledge in the armed forces of some countries about the process of producing hydrogen energy and its benefits which raises concerns about the consistency of its exploitation. Negative attitudes towards hydrogen fuel energy can be a significant barrier to its deployment in the armed forces. Possible approaches and solutions have also been proposed to eliminate obstacles and to support decision makers in defining and implementing a strategy for hydrogen as a clean energy carrier. There are decisive and unresolved obstacles to its deployment not only in the armed forces
An Intelligent Site Selection Model for Hydrogen Refueling Stations Based on Fuzzy Comprehensive Evaluation and Artificial Neural Network—A Case Study of Shanghai
Feb 2022
Publication
With the gradual popularization of hydrogen fuel cell vehicles (HFCVs) the construction and planning of hydrogen refueling stations (HRSs) are increasingly important. Taking operational HRSs in China’s coastal and major cities as examples we consider the main factors affecting the site selection of HRSs in China from the three aspects of economy technology and society to establish a site selection evaluation system for hydrogen refueling stations and determine the weight of each index through the analytic hierarchy process (AHP). Then combined with fuzzy comprehensive evaluation (FCE) method and artificial neural network model (ANN) FCE method is used to evaluate HRS in operation in China's coastal areas and major cities and we used the resulting data obtained from the comprehensive evaluation as the training data to train the neural network. So an intelligent site selection model for HRSs based on fuzzy comprehensive evaluation and artificial neural network model (FCE-ANN) is proposed. The planned HRSs in Shanghai are evaluated and an optimal site selection of the HRS is obtained. The results show that the optimal HRSs site selected by the FCE-ANN model is consistent with the site selection obtained by the FCE method and the accuracy of the FCE-ANN model is verified. The findings of this study may provide some guidelines for policy makers in planning the hydrogen refueling stations
Experimental Study on Tri-fuel Combustion Using Premixed Methane-hydrogen Mixtures Ignited by a Diesel Pilot
Apr 2021
Publication
A comprehensive investigation on diesel pilot spray ignited methane-hydrogen (CH4–H2) combustion tri-fuel combustion (TF) is performed in a single-cylinder compression ignition (CI) engine. The experiments provide a detailed analysis of the effect of H2 concentration (based on mole fraction MH2) and charge-air temperature (Tair) on the ignition behavior combustion stability cycle-to-cycle (CCV) and engine performance. The results indicate that adding H2 from 0 to 60% shortens the ignition delay time (IDT) and combustion duration (based on CA90) up to 33% and 45% respectively. Thereby H2 helps to increase the indicated thermal efficiency (ITE) by as much as 10%. Furthermore to gain an insight into the combustion stability and CCV the short-time Fourier transform (STFT) and continuous wavelet transform (CWT) methodologies are applied to estimate the combustion stability and CCV of the TF combustion process. The results reveal that the pressure oscillation can be reduced up to 4 dB/Hz and the CCV by 50% when MH2 < 60% and Tair < 55 °C. However when MH2 > 60% and Tair > 40 °C abnormal combustion and knocking are observed.
Constrained Extended Kalman Filter Design and Application for On-line State Estimation of High-order Polymer Electrolyte Membrane Fuel Cell Systems
Jun 2021
Publication
In this paper an alternative approach to extended Kalman filtering (EKF) for polymer electrolyte membrane fuel cell (FC) systems is proposed. The goal is to obtain robust real-time capable state estimations of a high-order FC model for observer applications mixed with control or fault detection. The introduced formulation resolves dependencies on operating conditions by successive linearization and constraints allowing to run the nonlinear FC model at significantly lower sampling rates than with standard approaches. The proposed method provides state estimates for challenging operating conditions such as shut-down and start-up of the fuel cell for which the unconstrained EKF fails. A detailed comparison with the unscented Kalman filter shows that the proposed EKF reconstructs the outputs equally accurate but nine times faster. An application to measured data from an FC powered passenger car is presented yielding state estimates of a real FC system which are validated based on the applied model.
Fuel Cells and Hydrogen Observatory Technology and Market Report
Sep 2021
Publication
The information in this report covers the period January 2019 – December 2019. The technology and market module of the FCHO presents a range of statistical data as an indicator of the health of the sector and the progress in market development over time. This includes statistical information on the size of the global fuel cell market including number and capacity of fuel cell systems shipped in a calendar year. For this first edition data to the end of 2019 is presented where possible alongside analysis of key sector developments. Fuel cell system shipments for each calendar year are presented both as numbers of units and total system megawatts. The data are further divided and subdivided by: • Application: Total system shipments are divided into Transport Stationary and Portable applications • Fuel cell type: Numbers are provided for each of the different fuel cell chemistry types • Region of integration: Region where the final manufacturer – usually the system integrator – integrates the fuel cell into the final product • Region of deployment: Region where the final product was shipped to for deployment The data is sourced directly from industry players as well as other relevant sources including press releases associations and other industry bodies.
Energy Saving in Public Transport Using Renewable Energy
Jan 2017
Publication
Hydrogen produced by renewable sources represents an interesting way to reduce the energetic dependence on fossil fuels in the transportation sector. This paper shows a feasibility study for the production storage and distribution of hydrogen in the western Sicilian context using three different renewable sources: wind biomass and sea wave. The objective of this study is the evaluation of the hydrogen demand needed to replace all diesel supplied buses with electrical buses equipped with fuel cells. An economic analysis is presented with the evaluation of the avoidable greenhouse gas emissions. Four different scenarios correlate the hydrogen demand for urban transport to the renewable energy resources present in the territories and to the modern technologies available for the production of hydrogen. The study focuses on the possibility of tapping into the potential of renewable energies (wind biomass and sea wave) for the production of hydrogen by electrolysis. The use of hydrogen would reduce significantly the emissions of particulate and greenhouse gases in the urban districts under analysis.
Improvement of Temperature and Humidity Control of Proton Exchange Membrane Fuel Cells
Sep 2021
Publication
Temperature and humidity are two important interconnected factors in the performance of PEMFCs (Proton Exchange Membrane Fuel Cells). The fuel and oxidant humidity and stack temperature in a fuel cell were analyzed in this study. There are many factors that affect the temperature and humidity of the stack. We adopt the fuzzy control method of multi-input and multi-output to control the temperature and humidity of the stack. A model including a driver vehicle transmission motor air feeding electrical network stack hydrogen supply and cooling system was established to study the fuel cell performance. A fuzzy controller is proven to be better in improving the output power of fuel cells. The three control objectives are the fan speed control for regulating temperature the solenoid valve on/off control of the bubble humidifier for humidity variation and the speed of the pump for regulating temperature difference. In addition the results from the PID controller stack model and the fuzzy controller stack model are compared in this research. The fuel cell bench test has been built to validate the effectiveness of the proposed fuzzy control. The maximum temperature of the stack can be reduced by 5 ◦C with the fuzzy control in this paper so the fuel cell output voltage (power) increases by an average of approximately 5.8%.
Hydrogen as a Maritime Fuel–Can Experiences with LNG Be Transferred to Hydrogen Systems?
Jul 2021
Publication
As the use of fossil fuels becomes more and more restricted there is a need for alternative fuels also at sea. For short sea distance travel purposes batteries may be a solution. However for longer distances when there is no possibility of recharging at sea batteries do not have sufficient capacity yet. Several projects have demonstrated the use of compressed hydrogen (CH2) as a fuel for road transport. The experience with hydrogen as a maritime fuel is very limited. In this paper the similarities and differences between liquefied hydrogen (LH2) and liquefied natural gas (LNG) as a maritime fuel will be discussed based on literature data of their properties and our system knowledge. The advantages and disadvantages of the two fuels will be examined with respect to use as a maritime fuel. Our objective is to discuss if and how hydrogen could replace fossil fuels on long distance sea voyages. Due to the low temperature of LH2 and wide flammability range in air these systems have more challenges related to storage and processing onboard than LNG. These factors result in higher investment costs. All this may also imply challenges for the LH2 supply chain.
Mobility from Renewable Electricity: Infrastructure Comparison for Battery and Hydrogen Fuel Cell Vehicles
May 2018
Publication
This work presents a detailed breakdown of the energy conversion chains from intermittent electricity to a vehicle considering battery electric vehicles (BEVs) and fuel cell electric vehicles (FCEVs). The traditional well-to-wheel analysis is adapted to a grid to mobility approach by introducing the intermediate steps of useful electricity energy carrier and on-board storage. Specific attention is given to an effective coupling with renewable electricity sources and associated storage needs. Actual market data show that compared to FCEVs BEVs and their infrastructure are twice as efficient in the conversion of renewable electricity to a mobility service. A much larger difference between BEVs and FCEVs is usually reported in the literature. Focusing on recharging events this work additionally shows that the infrastructure efficiencies of both electric vehicle (EV) types are very close with 57% from grid to on-board storage for hydrogen refilling stations and 66% for fast chargers coupled with battery storage. The transfer from the energy carrier at the station to on-board storage in the vehicle accounts for 9% and 12% of the total energy losses of these two modes respectively. Slow charging modes can achieve a charging infrastructure efficiency of 78% with residential energy storage systems coupled with AC chargers.
Combined Ammonia Recovery and Solid Oxide Fuel Cell Use at Wastewater Treatment Plants for Energy and Greenhouse Gas Emission Improvements
Feb 2019
Publication
Current standard practice at wastewater treatment plants (WWTPs) involves the recycling of digestate liquor produced from the anaerobic digestion of sludge back into the treatment process. However a significant amount of energy is required to enable biological breakdown of ammonia present in the liquor. This biological processing also results in the emission of damaging quantities of greenhouse gases making diversion of liquor and recovery of ammonia a noteworthy option for improving the sustainability of wastewater treatment. This study presents a novel process which combines ammonia recovery from diverted digestate liquor for use (alongside biomethane) in a solid oxide fuel cell (SOFC) system for implementation at WWTPs. Aspen Plus V.8.8 and numerical steady state models have been developed using data from a WWTP in West Yorkshire (UK) as a reference facility (750000p.e.). Aspen Plus simulations demonstrate an ability to recover 82% of ammoniacal nitrogen present in digestate liquor produced at the WWTP. The recovery process uses a series of stripping absorption and flash separation units where water is recovered alongside ammonia. This facilitates effective internal steam methane as a case of study has the potential to make significant impacts energetically and environmentally; findings suggest the treatment facility could transform from a net consumer of electricity to a net producer. The SOFC has been demonstrated to run at an electrical efficiency of 48% with NH3 contributing 4.6% of its power output. It has also been demonstrated that 3.5 kg CO2e per person served by the WWTP could be mitigated a year due to a combination of emissions savings by diversion of ammonia from biological processing and lifecycle emissions associated with the lack of reliance on grid electricity.
Ammonia–methane Combustion in Tangential Swirl Burners for Gas Turbine Power Generation
Feb 2016
Publication
Ammonia has been proposed as a potential energy storage medium in the transition towards a low-carbon economy. This paper details experimental results and numerical calculations obtained to progress towards optimisation of fuel injection and fluidic stabilisation in swirl burners with ammonia as the primary fuel. A generic tangential swirl burner has been employed to determine flame stability and emissions produced at different equivalence ratios using ammonia–methane blends. Experiments were performed under atmospheric and medium pressurised conditions using gas analysis and chemiluminescence to quantify emission concentrations and OH production zones respectively. Numerical calculations using GASEQ and CHEMKIN-PRO were performed to complement compare with and extend experimental findings hence improving understanding concerning the evolution of species when fuelling on ammonia blends. It is concluded that a fully premixed injection strategy is not appropriate for optimised ammonia combustion and that high flame instabilities can be produced at medium swirl numbers hence necessitating lower swirl and a different injection strategy for optimised power generation utilising ammonia fuel blends.
Methodologies for Representing the Road Transport Sector in Energy System Models
Dec 2013
Publication
Energy system models are often used to assess the potential role of hydrogen and electric powertrains for reducing transport CO2 emissions in the future. In this paper we review how different energy system models have represented both vehicles and fuel infrastructure in the past and we provide guidelines for their representation in the future. In particular we identify three key modelling decisions: the degree of car market segmentation the imposition of market share constraints and the use of lumpy investments to represent infrastructure. We examine each of these decisions in a case study using the UK MARKAL model. While disaggregating the car market principally affects only the transition rate to the optimum mix of technologies market share constraints can greatly change the optimum mix so should be chosen carefully. In contrast modelling infrastructure using lumpy investments has little impact on the model results. We identify the development of new methodologies to represent the impact of behavioural change on transport demand as a key challenge for improving energy system models in the future.
A Real-Time Load Prediction Control for Fuel Cell Hybrid Vehicle
May 2022
Publication
The development of hydrogen energy is an effective solution to the energy and environmental crisis. Hydrogen fuel cells and energy storage cells as hybrid power have broad application prospects in the field of vehicle power. Energy management strategies are key technologies for fuel cell hybrid systems. The traditional optimization strategy is generally based on optimization under the global operating conditions. The purpose of this project is to develop a power allocation optimization method based on real-time load forecasting for fuel cell/lithium battery hybrid electric vehicles which does not depend on specific working conditions or causal control methods. This paper presents an energy-management algorithm based on real-time load forecasting using GRU neural networks to predict load requirements in the short time domain and then the local optimization problem for each predictive domain is solved using a method based on Pontryagin’s minimum principle (PMP). The algorithm adopts the idea of model prediction control (MPC) to transform the global optimization problem into a series of local optimization problems. The simulation results show that the proposed strategy can achieve a good fuel-saving control effect. Compared with the rule-based strategy and equivalent hydrogen consumption strategy (ECMS) the fuel consumption is lower under two typical urban conditions. In the 1800 s driving cycle under WTCL conditions the fuel consumption under the MPC-PMP strategy is 22.4% lower than that based on the ECMS strategy and 10.3% lower than the rules-based strategy. Under CTLT conditions the fuel consumption of the MPC-PMP strategy is 13.12% lower than that of the rule-based strategy and 3.01% lower than the ECMS strategy.
Techno-economic Analysis of Freight Railway Electrification by Overhead Line, Hydrogen and Batteries: Case Studies in Norway and USA
Aug 2019
Publication
Two non-electrified railway lines one in Norway and the other in the USA are analysed for their potential to be electrified with overhead line equipment batteries hydrogen or hydrogen-battery hybrid powertrains. The energy requirements are established with single-train simulations including the altitude profiles of the lines air and rolling resistances and locomotive tractive-effort curves. The composition of the freight trains in terms of the number of locomotives battery wagons hydrogen wagons etc. is also calculated by the same model. The different technologies are compared by the criteria of equivalent annual costs benefit–cost ratio payback period and up-front investment based on the estimated techno-economic parameters for years 2020 2030 and 2050. The results indicate the potential of batteries and fuel cells to replace diesel on rail lines with low traffic volumes.
Publication Handbook for Hydrogen Fuelled Vessels
Jun 2021
Publication
Green hydrogen could play a crucial role in the maritime industry’s journey towards decarbonization. Produced through electrolysis hydrogen is emission free and could be widely available across the globe in future – as a marine fuel or a key enabler for synthetic fuels. Many in shipping recognize hydrogen’s potential as a fuel but the barriers to realizing this potential are substantial.<br/>The 1st Edition of the ‘Handbook for Hydrogen-fuelled Vessels’ offers a road map towards safe hydrogen operations using fuel cells. It details how to navigate the complex requirements for design and construction and it covers the most important aspects of hydrogen operations such as safety and risk mitigation engineering details for hydrogen systems and implementation phases for maritime applications based on the current regulatory Alternative Design process framework.<br/>This publication is the result of the 1st phase of the DNV-led Joint Industry Project MarHySafe which has brought together a consortium of 26 leading company and associations. The project is ongoing and this publication will be continually updated to reflect the latest industry expertise on hydrogen as ship fuel.
Improved VSG Control Strategy Based on the Combined Power Generation System with Hydrogen Fuel Cells and Super Capacitors
Oct 2021
Publication
Due to their environmental protection and high power generation efficiency the control technology of hydrogen fuel cells (HFCs) connected to the microgrid has become a research hotspot. However when they encounter peak demand or transient events the lack of power cannot be compensated immediately by HFCs which results in sudden changes of the voltage and frequency. The improved virtual synchronous generator (VSG) control strategy based on HFCs and supercapacitors (SCs) combined power generation system is proposed to overcome this shortcoming in this paper. The small-signal model for designing the combined system parameters is provided which are in accordance with the system loop gain phase angle margin and adjustment time requirements. Besides the voltage and current double closed-loop based on sequence control is introduced in the VSG controller. The second-order generalized integrator (SOGI) is utilized to separate the positive and negative sequence components of the output voltage. At the same time a positive and negative sequence voltage outer loop is designed to suppress the negative sequence voltage under unbalanced conditions thereby reducing the unbalance of the output voltage. Finally simulation results in MATLAB/Simulink environment verify that the proposed method has better dynamic characteristics and higher steady-state accuracy compared with the traditional VSG control
A Smart Strategy for Sizing of Hybrid Renewable Energy System to Supply Remote Loads in Saudi Arabia
Oct 2021
Publication
The use of hybrid renewable energy systems (HRES) has become the best option for supplying electricity to sites remote from the central power system because of its sustainability environmental friendliness and its low cost of energy compared to many conventional sources such as diesel generators. Due to the intermittent nature of renewable energy resources there is a need however for an energy storage system (ESS) to store the surplus energy and feed the energy deficit. Most renewable sources used battery storage systems (BSS) a green hydrogen storage system (GHSS) and a diesel generator as a backup for these sources. Batteries are very expensive and have a very short lifetime and GHSS have a very expensive initial cost and many security issues. In this paper a system consisting of wind turbines and a photovoltaic (PV) array with a pumped hydro energy storage (PHES) system as the main energy storage to replace the expensive and short lifetime batteries is proposed. The proposed system is built to feed a remote area called Dumah Aljandal in the north of Saudi Arabia. A smart grid is used via a novel demand response strategy (DRS) with a dynamic tariff to reduce the size of the components and it reduces the cost of energy compared to a flat tariff. The use of the PHES with smart DRS reduced the cost of energy by 34.2% and 41.1% compared to the use of BSS and GHSS as an ESS respectively. Moreover the use of 100% green energy sources will avoid the emission of an estimated 2.5 million tons of greenhouse gases every year. The proposed system will use a novel optimization algorithm called the gradually reduced particles of particle swarm optimization (GRP-PSO) algorithm to enhance the exploration and exploitation during the searching iterations. The GRP-PSO reduces the convergence time to 58% compared to the average convergence time of 10 optimization algorithms used for comparison. A sensitivity analysis study is introduced in this paper in which the effect of ±20% change in wind speed and solar irradiance are selected and the system showed a low effect of these resources on the Levelized cost of energy of the HRES. These outstanding results proved the superiority of using a pumped-storage system with a dynamic tariff demand response strategy compared to the other energy storage systems with flat-rate tariffs.
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