Primary frequency response from hydrogen-based bidirectional vector coupling storage:modelling and demonstration using power-hardware-in-the-loop simulation

To meet reduction targets for carbon emissions and improve the flexibility and security of the energy supply, future energy networks will require enhanced energy vector coupling in addition to the generation of energy from renewable sources. Increased renewable generation penetration significantly affects the electrical grid’s inertia and consequently the severity and regularity of frequency deviations from nominal values. Bidirectional Hydrogen-based Vector Coupling Storage (VCS) has been explored as a means to provide primary frequency response (PFR) services to the electrical network. This paper demonstrates the use of Power Hardware-In-the-Loop (PHIL) simulation and Digital Twin (DT) technique for such an application. This new suggested structure of VCS is composed of grid-scale electrolysers, fuel cells, and hydrogen storage. Existing works focus on unidirectional VCS, and also use simplifications or neglect the impacts of power converters on the performance of the VCS. In addition, these works do not have any control over the hydrogen storage, therefore there is no guarantee that there will be enough energy available in the storage to meet the PFR service responsibilities. This paper presents the dynamic models of electrolysis, fuel cell stacks, and hydrogen storage as a DT. The key parameters affecting the behaviours of these main components are considered. The power converters’ accurate impact on the VCS’s performance is considered through PHIL simulations. The level of stored hydrogen is also considered in the VCS controller. The DT representing the VCS is integrated with the PHIL setup representing the deployment environment. The impact of VCS is then analysed as it propagates to the deployment environment. Results of the considered case studies demonstrate that the size of the VCS plays a significant role in bringing the frequency to the statutory allowed range. In addition, more VCS capacity was installed, the nadir frequency improved. Furthermore, the VCS is fast enough to offer PFR. The response times of the VCS were 2.857 s (during under-frequency periods), corresponding to the operation of the fuel cells, and 2.252 s during over-frequency periods, corresponding to electrolyser operation.</p

Towards 2050 net zero carbon infrastructure:a critical review of key decarbonization challenges in the domestic heating sector in the UK

One of the most challenging sectors to meet “Net Zero emissions” target by 2050 in the UK is the domestic heating sector. This paper provides a comprehensive literature review of the main challenges of heating systems transition to low carbon technologies in which three distinct categories of challenges are discussed. The first challenge is of decarbonizing heat at the supply side, considering specifically the difficulties in integrating hydrogen as a low-carbon heating substitute to the dominant natural gas. The next challenge is of decarbonizing heat at the demand side, and research into the difficulties of retrofitting the existing UK housing stock, of digitalizing heating energy systems, as well as ensuring both retrofits and digitalization do not disproportionately affect vulnerable groups in society. The need for demonstrating innovative solutions to these challenges leads to the final focus, which is the challenge of modeling and demonstrating future energy systems heating scenarios. This work concludes with recommendations for the energy research community and policy makers to tackle urgent challenges facing the decarbonization of the UK heating sector.</p

Stochastic Procurement of Fast Reserve Services in Renewable Integrated Power Systems

Ensuring the security and quality of supply in a power system after a contingency event is one of the most challenging tasks for an electricity system operator. This work is initiated by this challenge and proposes a solution based on the use of provided reserves by fast generators, storage devices, and wind farms. A coordinated model is proposed in a joint energy and reserves market considering their corresponding cost to ensure the adequacy in the simultaneous deployment of reserves for the different sources of uncertainties. The Benders decomposition approach is used in the modeling of the stochastic security-constrained unit commitment, and considering the large-scale and complex nature of the model, acceleration techniques are suggested to reduce the execution time. The proposed model is tested on the 6-bus and the IEEE 118-bus test systems. Numerical results show that the optimal values of reserves successfully address contingencies in both of the critical and normal periods after the contingencies and the optimal solution is calculated in a reasonable computing time

Sizing, economic, and reliability analysis of photovoltaics and energy storage for an off‐grid power system in Jordan

Remote areas in Jordan often rely on expensive and polluting diesel generators to meet their electricity demand. This study investigates 100% renewable solutions to supply the electricity demand of off‐grid energy systems through optimal sizing of photovoltaics and energy storage systems. A linear programming approach is proposed to minimise the annualised cost of electricity supply including capital costs of equipment and their operation and maintenance costs. The optimisation determines the size of photovoltaics and energy storage required to satisfy electricity demand at every hour of a selected year. A Jordan campsite was used as a case study to assess and compare the performance of PV‐battery storage and PV‐hydrogen storage systems from economic and reliability perspectives. The results show that hydrogen storage was more economical for a 100% renewable energy system. However, introducing some diesel generation gave the battery system a significantly lower annualised cost of energy

Demand response model development for smart households using time of use tariffs and optimal control - the Isle of Wight energy autonomous community case study

Residential variable energy price schemes can be made more effective with the use of a demand response (DR) strategy along with smart appliances. Using DR, the electricity bill of participating customers/households can be minimised, while pursuing other aims such as demand-shifting and maximising consumption of locally generated renewable-electricity. In this article, a two-stage optimization method is used to implement a price-based implicit DR scheme. The model considers a range of novel smart devices/technologies/schemes, connected to smart-meters and a local DR-Controller. A case study with various decarbonisation scenarios is used to analyse the effects of deploying the proposed DR-scheme in households located in the west area of the Isle of Wight (Southern United Kingdom). There are approximately 15,000 households, of which 3000 are not connected to the gas-network. Using a distribution network model along with a load flow software-tool, the secondary voltages and apparent-power through transformers at the relevant substations are computed. The results show that in summer, participating households could export up to 6.4 MW of power, which is 10% of installed large-scale photovoltaics (PV) capacity on the island. Average carbon dioxide equivalent (CO2e) reductions of 7.1 ktons/annum and a reduction in combined energy/transport fuel-bills of 60%/annum could be achieved by participating households

Surveillance des systèmes à événements discrets commandés: Conception et implémentation en utilisant l'automate programmable industriel

This thesis presents an approach to monitoring the controlled discrete events systems. The study is limited to the interruptible faults : intermittent and permanent. To increase the availability of a system, it is crucial to reduce the unnecessary interruptions. For that, the acceptable behavior of these systems is introduced. This behavior presents a tolerance to the intermittent faults. An approach of the construction of monitoring system is presented. We model, firstly, the behavior of the systems by a stopwatch automaton. Secondly, we apply to this automaton a synthesis procedure. This procedure is based on the forward and backward reachability analysis of the stopwatch automaton. A new model called Post- and Pre-initialized stopwatch Petri nets is also presented. This model is used to model the behavior of systems subjected to the interrupting faults. The implementation of our monitoring approach is done by using a Programmable Logic Controller. The monitoring system is translated structurally into a SFC program.Ce mémoire de thèse prèsente une approche pour la surveillance des systèmes à événements discrets commandés. L'étude se restreint aux défauts interruptibles : intermittents et permanents. Le comportement acceptable de ces systèmes est introduit afin d'accroître la disponibilité des systèmes commandés. Ce comportement présente une tolérance aux défauts intermittents. Une démarche de construction du système de surveillance est présentée. Nous modélisons, dans un premier temps, le comportement du système sujet aux défauts interruptibles par un automateà chronomètres. Nous appliquons, dans un deuxième temps, une procédure de synthèse à cet automate. Cette procédure est basée aux opérateurs d'analyse en avant et en arriérer de l'automate. Un nouveau modèle appelé réseaux de Petri à chronomètres post- et Pré-initialisés est également présenté. Ce modèle général du RdP a été utilisé, dans le cadre de ce mémoire, pour modéliser le comportement des systèmes sujets aux défauts interruptibles. L'implémentation de notre méthode de surveillance se fait par un automate programmable industriel. Pour ce faire, le système de surveillance étant sous la forme d'un automate àchronomètres est traduit structurellement en programme SFC

Réseaux de Petri à chronomètres Post et Préinitialisés

National audienceUn paradigme de modélisation appelé Réseaux de Petri à chronomètres Post et Préinitialisés SWPN est introduit. Il étend les réseaux de Petri T-temporels en incluant le concept de chronomètre dans sa sémantique. Un mécanisme d'initialisation des chronomètres appelé Post-initialisation est utilisé. Ce mécanisme repose sur l'initialisation du chronomètre après le franchissement de la transition correspondante. Le modèle résultant permet de modéliser de façon naturelle la suspension et la reprise des tâches dans les systèmes temps-réel. Nous présentons d'abord la sémantique formelle de ce modèle sous la forme d'un système de transitions temporisé. Nous proposons ensuite une méthode d'analyse temporelle de ce modèle en le traduisant en automate à chronomètres. La vérification de propriétés temporelles peut alors être effectuée en utilisant l'automate à chronomètres ainsi obtenu. L'avantage de ce modèle est qu'il combine la concision du modèle réseau de Petri et la puissance d'analyse de l'automate à chronomètres

Post and pre-initialized stopwatch Petri Nets

6 pagesInternational audienceA modeling paradigm called Post and Pre-initialized Stopwatch Petri Nets (SWPN) is introduced. It extends Time Petri Nets TPN to the concept of stopwatch with an original mechanism of stopwatches reset. SWPN makes this reset dependent on the firing of the corresponding transitions. The resulting model permits natural description of so-called preemption-resume behavior. We give the formal semantics of SWPN as a timed transition system.We propose also a method for its analysis consisting in the computation of its equivalent stopwatch automaton SWA. The advantage of Petri Nets for modeling the complex system in concise way is combined with the power analysis of SW

Design and implementation of a monitiring system using grafcet

International audienceA monitoring system based on a stopwatch automaton is proposed to detect the system faults as early as possible. Each location in the automaton corresponds to a system's situation. Its time space delimits exactly the range of the normal behavior in the corresponding system's situation. The monitoring system detects a fault when the time space corresponding to the actual system's situation is violated. The stopwatch automaton provides a formal foundation to model the system's behavior and to synthesize the exactly time space in each location. This paper aims to provide the grafcet monitor that allows to link the design of the monitoring system of a system with its implementation in a programmable logic controller