Towards flexibility trading at TSO-DSO-customer levels : a review

The serious problem of climate change has led the energy sector to modify its generation resources from fuel-based power plants to environmentally friendly renewable resources. However, these green resources are highly intermittent due to weather dependency and they produce increased risks of stability issues in power systems. The deployment of different flexible resources can help the system to become more resilient and secure against uncertainties caused by renewables. Flexible resources can be located at different levels in power systems like, for example, at the transmission-level (TSO), distribution-level (DSO) and customer-level. Each of these levels may have different structures of flexibility trading as well. This paper conducts a comprehensive review from the recent research related to flexible resources at various system levels in smart grids and assesses the trading structures of these resources. Finally, it analyzes the application of a newly emerged ICT technology, blockchain, in the context of flexibility trading.fi=vertaisarvioitu|en=peerReviewed

Towards Flexibility Trading at TSO-DSO-Customer Levels: A Review

The serious problem of climate change has led the energy sector to modify its generation resources from fuel-based power plants to environmentally friendly renewable resources. However, these green resources are highly intermittent due to weather dependency and they produce increased risks of stability issues in power systems. The deployment of different flexible resources can help the system to become more resilient and secure against uncertainties caused by renewables. Flexible resources can be located at different levels in power systems like, for example, at the transmission-level (TSO), distribution-level (DSO) and customer-level. Each of these levels may have different structures of flexibility trading as well. This paper conducts a comprehensive review from the recent research related to flexible resources at various system levels in smart grids and assesses the trading structures of these resources. Finally, it analyzes the application of a newly emerged ICT technology, blockchain, in the context of flexibility trading

Centralized Control of Distribution Networks with High Penetration of Renewable Energies

Distribution networks were conceived to distribute the energy received from transmission and subtransmission to supply passive loads. This approach, however, is not valid anymore due to the presence of distributed generation, which is mainly based on renewable energies, and the increased number of plug-in electric vehicles that are connected at this voltage level for domestic use. In this paper the ongoing transition that distribution networks face is addressed. Whereas distributed renewable energy sources increase nodal voltages, electric vehicles result in demand surges higher than the load predictions considered when planning these networks, leading to congestion in distribution lines and transformers. Additionally, centralized control techniques are analyzed to reduce the impact of distributed generation and electric vehicles and increase their effective integration. A classification of the different methodologies applied to the problems of voltage control and congestion management is presented.Unión Europea Convenio 764090Ministerio de Ciencia e Innovación CER-2019101

A Comprehensive Review of Congestion Management in Power System

In recent decades, restructuring has cut across all probable domains, involving the power supply industry. The restructuring has brought about considerable changes whereby electricity is now a commodity and has become a deregulated one. These competitive markets have paved the way for countless entrants. This has caused overload and congestion on transmission lines. In addition, the open access transmission network has created a more intensified congestion issue. Therefore, congestion management on power systems is relevant and central significance to the power industry. This manuscript review few congestion management techniques, consists of Reprogramming Generation (GR), Load Shedding, Optimal Distributed Generation (DG) Location, Nodal Pricing, Free Methods, Genetic Algorithm (GA), Particle Swarm Optimization (PSO), Fuzzy Logic System Method, as well as Additional Renewable Energy Sources. In this manuscript a review work is performed to unite the entire publications on congestion management

A Comprehensive Review of Congestion Management in Power System

In recent decades, restructuring has cut across all probable domains, involving the power supply industry. The restructuring has brought about considerable changes whereby electricity is now a commodity and has become a deregulated one. These competitive markets have paved the way for countless entrants. This has caused overload and congestion on transmission lines. In addition, the open access transmission network has created a more intensified congestion issue. Therefore, congestion management on power systems is relevant and central significance to the power industry. This manuscript review few congestion management techniques, consists of Reprogramming Generation (GR), Load Shedding, Optimal Distributed Generation (DG) Location, Nodal Pricing, Free Methods, Genetic Algorithm (GA), Particle Swarm Optimization (PSO), Fuzzy Logic System Method, as well as Additional Renewable Energy Sources. In this manuscript a review work is performed to unite the entire publications on congestion management

Economic feasibility of green hydrogen in providing flexibility to medium-voltage distribution grids in the presence of local-heat systems

The recent strong increase in the penetration of renewable energy sources (RESs) in medium-voltage distribution grids (MVDNs) has raised the need for congestion management in such grids, as they were not designed for this new condition. This paper examines to what extent producing green hydrogen through electrolyzers can profitably contribute to congestion alleviation in MVDNs in the presence of high amounts of RES, as well as flexible consumers of electricity and a local heat system. To address this issue, an incentive-based method for improving flexibility in MVDNs is used which is based on a single-leader–multiple-followers game formulated by bi-level mathematical programming. At the upper level, the distribution system operator, who is the leader of this game, determines dynamic prices as incentives at each node based on the levels of generation and load. Next, at the lower level, providers of flexibility, including producers using electrolyzers, price-responsive power consumers, heat consumers, as well as heat producers, respond to these incentives by reshaping their output and consumption patterns. The model is applied to a region in the North of The Netherlands. The obtained results demonstrate that converting power to hydrogen can be an economically efficient way to reduce congestion in MVDNs when there is a high amount of RES. However, the economic value of electrolyzers as providers of flexibility to MVDNs decreases when more other options for flexibility provision exist

Flexibility market for congestion management in smart grids

Mención Internacional en el título de doctorCurrent power systems are facing several sustainability challenges to meet the increasing demand of electricity. In addition, there is a global direction to increase the share of renewable energy sources in the power generation mix and energy efficiency. In the face of all such challenges, smart grids were incepted. Smart grids are modernized power systems that integrate state-of-the art communication and information technology to facilitate the bidirectional flow of information and electricity between the supply and demand sides. The resilience of smart grids can pave the way for having more flexibility at the distribution level of the power systems. Demand response (DR) programs are considered one of the sources of system flexibility and it is one of the main components of smart grids. DR can be defined as the willingness of customers to alter their electricity consumption profile in response to price signals. Transmission system operators have been implementing demand response programs in a straightforward fashion for several years now. For example, by having energy prices that are expensive during on-peak periods and low-priced at off-peak periods. Other type of DR programs introduces price signals when grid reliability is compromised and a reduction in energy consumption is necessary. In this way, customers can plan their activities accordingly in order to save money. Now, a new era of technology, artificial intelligence and the so-called “internet of things”, have provided new ways to explore the full potential of demand response, by allowing to alter loads in a much more dynamic and precise manner, thus optimizing the operation of grid assets. This thesis focuses on one of the main types of DR programs which is demand flexibility. Demand flexibility is the ability of the demand-side customers to adjust their load profiles in response to an external market signal. On the short- and medium-term periods, distribution system operators (DSOs) can take advantage of the flexibility of demand to mitigate network congestions caused by increased peaks or high penetration of renewable energy. On the long-term period, DSOs can include demand flexibility in their network expansion planning process for future demand growth. The optimal usage of demand flexibility can help in postponing needed investments for upgrading the networks’ capacity. Demand flexibility can be acquired through market-based solutions which can deliver cost-efficient flexibility services for several market agents by facilitating competition between different flexibility providers. Market mechanisms are considered by policy makers as the optimal solution for flexibility access. With respect to that, this thesis proposes a comprehensive framework for a distribution-level flexibility market, called “Flex-DLM” that enables and facilitates the trading of demand flexibility between the distribution system operator, as the main buyer, and aggregators, as sellers representing flexible consumers. Two types of demand flexibility services were modelled, which are: 1- Up-regulation flexibility (UREG), which corresponds to load decrease volumes, and 2- Down-regulation flexibility (DREG), which corresponds load increase volumes. In addition, the payback effect, which is a common event to the activation of demand flexibility, is considered for both types of flexibility services. Also, the distribution network constraints were modelled, which represents the power flow constraints of the network, which is key to present a realistic model for the flexibility market. In the Flex-DLM, the DSO is considered as the market operator who is responsible of clearing the market, while making sure the network congestions are mitigated. The Flex-DLM operates on two timeframes which are day-ahead and real-time with an objective to provide the DSO with flexibility products that can help it in the congestion management process. In addition to this, the uncertainty of demand is taken into consideration to prevent the DSO from procuring inaccurate amounts of demand flexibility. A new option is introduced in the day-ahead Flex-DLM, called the right-to-use (RtU) that allows the DSO to reserve the right to activate demand flexibility during the day-ahead period for congestions that have low probability of occurrence on the following operation day. In this way, the DSO can call upon this option in real-time if the congestion takes place. Also, the uncertainty behind the customers’ commitment to the flexibility activation requests and amounts is taken into consideration. In this thesis, the decision-making process of the DSO for optimizing its choice of demand flexibility and minimizing its total cost is modelled. Two methods were carried out for the optimization model proposed in this work. The first method follows a deterministic approach, where the objective is to optimize the DSO’s cost and clear the Flex-DLM during the day-ahead period only, without taking into account the uncertainty of demand and the uncertainty of consumers’ participation. The second method follows probabilistic approach, which considers the demand uncertainty during the day-ahead and real-time periods and models the uncertainty behind the customers’ commitment. Both optimization methods were integrated with an optimal power flow (OPF) solver tool in order to check the technical validity of the activated flexibility services and to make sure that the payback effect does not cause further congestions in the network. The advantage of the proposed framework is that it requires minimum regulatory changes and it does not involve the DSO in any electricity trading. Also, the proposed optimization method can be integrated with any OPF solver tool. Different distribution feeders obtained from a distribution network located in Spain were used to check the validity of the proposed framework and the decision-making process. The case studies are divided into two parts: 1- The first part applies the proposed flexibility framework from a deterministic perspective and 2- The second part applies the Flex-DLM framework considering all uncertainties, which corresponds to the probabilistic optimization approach. Finally, to help the DSO in the long-term planning process of its local network, a cost & benefit analysis is carried out to value the economic impact of implementing demand flexibility programs as an alternate solution to conventional network upgradesLos sistemas de energía actuales se enfrentan a varios desafíos de sostenibilidad para satisfacer la creciente demanda de electricidad. Además, existe una clara tendencia a aumentar la proporción de fuentes renovables de energía en la generación de energía y así como hacia la eficiencia energética. Como parte de la respuesta a estos desafíos, se iniciaron las redes inteligentes. Las redes inteligentes son sistemas de energía modernizados que integran tecnología de comunicación e información de última generación para facilitar el flujo bidireccional de información y electricidad entre la oferta y la demanda. La utilización de las redes inteligentes pretende facilitar el empleo de la flexibilidad en la red de distribución de los sistemas eléctricos. Los programas de gestión de la demanda se consideran una de las fuentes de flexibilidad del sistema y es uno de los puntos sobre los que se apoyan las redes inteligentes. La gestión de la demanda se puede definir como la disposición de los clientes a alterar su perfil de consumo de electricidad en respuesta a las señales de precios. Los operadores de sistemas de transporte han estado implementando programas de respuesta a la demanda de manera directa desde hace varios años. Por ejemplo, la diferencia entre precios altos y bajos en el mercado mayorista introduce un incentivo para el consumo en horas de menor precio. Otro tipo de programas de gestión de la demanda introduce señales de precios cuando la fiabilidad de la red se ve comprometida y es necesaria una reducción en el consumo de energía. De esta manera, los consumidores pueden planificar sus actividades en consecuencia para ahorrar costes. Ahora, una nueva era de la tecnología, la inteligencia artificial y el llamado "internet de las cosas" han proporcionado nuevas formas de explorar el potencial completo de la respuesta de la demanda, al permitir alterar las cargas de una manera mucho más dinámica y precisa, optimizando así la utilización de los activos de red. Esta tesis se centra en uno de los principales tipos de programas de DR que es la flexibilidad de la demanda. La flexibilidad de la demanda es la capacidad de los clientes del lado de la demanda para ajustar sus perfiles de carga en respuesta a una señal del mercado externo. En los períodos a corto y mediano plazo, los operadores de sistemas de distribución pueden aprovechar la flexibilidad de la demanda para mitigar las congestiones en la red causadas por el aumento de los picos de demanda o la alta penetración de energía renovable. En el período a largo plazo, los distribuidores pueden incluir la flexibilidad de la demanda en su proceso de planificación de expansión de la red para el crecimiento futuro de la demanda. El uso óptimo de la flexibilidad de la demanda puede ayudar a posponer las inversiones necesarias para mejorar la capacidad de las redes. La flexibilidad de la demanda se puede conseguir mediante soluciones basadas en el mercado que pueden ofrecer servicios de flexibilidad rentables para varios agentes del mercado al facilitar la competencia entre diferentes proveedores de flexibilidad. Los reguladores suelen considerar que son los mecanismos de mercado los que dan la solución óptima para la gestión de la flexibilidad. En relación con estos temas, esta tesis propone un marco integral para un mercado de flexibilidad a en la red de distribución, denominado “Flex-DLM” que permite y facilita el comercio de flexibilidad de demanda entre el operador del sistema de distribución, como el principal comprador, y los agregadores, como vendedores que representan a los consumidores flexibles. Se han modelado dos tipos de servicios de flexibilidad de demanda, que son: 1- Flexibilidad a subir (UREG), que corresponde a un requerimiento disminución de carga, y 2- Flexibilidad a bajar (DREG), que corresponde a un requerimiento de aumento de carga. Además, el efecto de rebote, o consumo posterior al uso de la flexibilidad, que es un fenómeno común tras la activación de la flexibilidad de la demanda, se tiene en cuenta para ambos tipos de servicios de flexibilidad. Además, se han modelado las restricciones de la red de distribución, que representan las restricciones de flujo de potencia de la red, que es clave para presentar un modelo realista para el mercado de flexibilidad. En el mercado Flex-DLM propuesto, se considera al distribuidor como el operador responsable de despejar el mercado, al tiempo que se encarga de mitigar las congestiones de la red. El Flex-DLM opera en dos marcos de tiempo: el diario y el tiempo real con el objetivo de proporcionar al distribuidor productos flexibles que puedan ayudarlo en el proceso de gestión de la congestión. Además de esto, la incertidumbre de la demanda se tiene en cuenta para evitar que el distribuidor adquiera cantidades incorrectas de flexibilidad de la demanda. Se introduce una nueva opción en el Flex-DLM del día siguiente, denominado derecho de uso que le permite al distribuidor reservar el derecho de activar la flexibilidad de la demanda durante el período del día anterior para congestiones que tienen poca probabilidad de ocurrencia en el siguiente día de operación. De esta manera, el distribuidor puede recurrir a esta opción en tiempo real si se produce la congestión. Además, se tiene en cuenta la incertidumbre sobre del compromiso de cumplimiento de los clientes con los requerimientos y las cantidades de energía activadas durante el proceso de gestión de la flexibilidad. En esta tesis, se modela asimismo el proceso de toma de decisiones del DSO para optimizar su elección de flexibilidad de demanda y minimizar su costo total. Se llevaron a cabo dos métodos para el modelo de optimización propuesto en este trabajo. El primer método sigue un enfoque determinista, donde el objetivo es optimizar el coste de la flexibilidad para el distribuidor y eliminar el Flex-DLM solo durante el mercado diario , sin tener en cuenta la incertidumbre de la demanda y la de la participación de los consumidores. El segundo método sigue un enfoque probabilístico, que considera la incertidumbre de la demanda durante los períodos diarios y en tiempo real y modela la incertidumbre del compromiso de los clientes. Ambos métodos de optimización se integraron con una herramienta de solución de flujo de potencia óptimo (OPF) para verificar la validez técnica de los servicios de flexibilidad activados y asegurar que el efecto de recuperación no cause más congestiones en la red. La ventaja del marco propuesto es que requiere cambios regulatorios mínimos y no involucra al DSO en ningún comercio de electricidad. Además, el método de optimización propuesto se puede integrar con cualquier herramienta de solución OPF. Se han utiliado diferentes líneas de distribución obtenidos de una red de distribución ubicada en España para verificar la validez del marco propuesto y el proceso de toma de decisiones. Los estudios de caso se dividen en dos partes: 1- La primera parte aplica el marco de flexibilidad propuesto desde una perspectiva determinista y 2- La segunda parte aplica el marco Flex-DLM considerando todas las incertidumbres, que corresponden al enfoque de optimización probabilística. Finalmente, para ayudar al distribuidor en el proceso de planificación a largo plazo de su red local, se lleva a cabo un análisis coste - beneficio para valorar el impacto económico de la implementación de programas de flexibilidad de la demanda como una solución alternativa a las actualizaciones de red convencionales.Programa Oficial de Doctorado en Ingeniería Eléctrica, Electrónica y AutomáticaPresidente: Hortensia Elena Amaris Duarte.- Secretario: Milan Prodanovic.- Vocal: Barry Patrick Haye

Joustotuotteet monenkeskisillä sähkömarkkinoilla

Power grids, electrical systems and liberalized zonal electricity markets are in due for major recasting as the ongoing energy transition impacts the electricity sector profoundly.This will mean new kinds of market behavior in liberalized and regulated electricity markets and increased challenges for TSOs to maintain power balance at system-level. Also, inadequacies in network capacity and flexible asset availability impact at local level. Congestions, voltage deviations and grid outages impact both TSOs and DSOs locally and the mitigation of these situations requires new types of multilateral coordination. In addition to more transmission and distribution grid capacity, future electrical systems need resilient flexible resources and intelligent control mechanisms. This thesis examines market-based control by using flexibility products. The envisioned flexibility products are expected to be implementable in the Baltic Sea area electricity markets during the regulatory period of Finnish electricity network companies beginning in 2024. Thesis includes a literature review and a qualitative empirical research consisting of industry consultation. First, the literature study examines existing products traded on future European electricity markets and other mechanisms that control networks and network connected assets. Secondly, it examines emerging flexibility products that can provide local flexibility services which the existing product structure is not covering. Industry consultation includes Finnish expert views regarding different aspects of flexibility needs,flexibility markets and opinions on the emerging flexibility products. Interviewees found the concepts of flexibility markets and products new and complex. Most of the interviewees had not experienced serious technical flexibility issues at local level in Finnish electrical networks but agreed that local flexibility challenges would be a reality in Finland within next five years. Majority of interviewees saw new enabling technologies and market-based trading of local flexibility worth considering. They had different local needs for flexibility products, if trading could be done cost-efficiently and market design would be supportive for both flexibility buyers and sellers. Outage management and voltage support with flexibility were identified as the most urgent local needs and congestion management was seen less important. According to the findings, numerous although contradictory flexibility product alternatives can solve different flexibility needs. It was concluded that market design should go forward with the development of three options: locational intraday products, locational balancing products and competitive bilateral flexibility contracts. The results show, that these recommended products are modifications of existing products. All three preferred options should be enabled due to different reasons and these options are not mutually exclusive. The compatibility of flexibility products with existing products and operational processes must be ensured, especially considering reconciliation of flexibility markets and a reactive balancing model of TSOs. Development of flexibility products should start immediately with incremental experimentation with cooperation of all network users and operators.Meneillään oleva energiamurros aiheuttaa merkittäviä muutoksia sähköverkkoihin ja-markkinoihin. Tämä johtaa uudenlaiseen käyttäytymiseen vapautetuilla ja säännellyillä sähkömarkkinoilla sekä kantaverkkoyhtiöiden lisääntyviin haasteisiin ylläpitää järjestelmätason tehotasapainoa. Myös alueelliset haasteet lisääntyvät riittämättömän verkkokapasiteetin tai joustavien resurssien puuttuessa. Paikalliset ylikuormitukset, jännite- ja loistehopoikkeamat sekä käyttökatkot voivat vaikuttaa useisiin siirto- ja jakeluverkkoyhtiöihin, jolloin ratkaisut vaativat monenkeskistä koordinointia. Tulevaisuuden sähköjärjestelmät vaativat lisää siirto- ja jakeluverkkokapasiteettia, joustavia resursseja ja älykkäitä ohjausmekanismeja. Tässä diplomityössä tutkitaan markkinaehtoisiin joustotuotteisiin perustuvia ohjausmekanismeja. Suunniteltujen joustotuotteiden on tarkoitus olla käytettävissä 2024 alkavalla suomalaisten sähköverkkoyhtiöiden sääntelykaudella Itämeren alueen sähkömarkkinoilla. Tämä diplomityö sisältää kirjallisuuskatsauksen ja empiirisen tutkimuksen, joka koostuu sähköalan asiantuntijoiden laadullisesta konsultaatiosta. Työssä tarkastellaan nykyisten sähkömarkkinoiden tuotteita, joilla verkkoja ja verkkoon kytkettyjä resursseja hallitaan. Lisäksi työ tutkii kehittyviä joustotuotteita, jotka voivat tarjota paikallisia joustopalveluita, joita nykyiset tuotteet eivät kata. Konsultaatio sisällyttää alan näkemyksiä jouston tarpeista, joustomarkkinoista ja kehittyvistä joustotuotteista tutkimukseen. Haastateltavat kokivat joustomarkkinoiden ja -tuotteiden käsitteet uusiksi ja monimutkaisiksi. Suurin osa haastatelluista ei ollut todennut suomalaisissa sähköverkoissa alueellisesti vakavia haasteita, mutta arvioivat paikallisten joustavuushaasteiden yleistyvän seuraavan viiden vuoden aikana. Merkittävä osa asiantuntijoista arvioi uudet teknologiaratkaisut ja markkinalähtöisen joustokaupankäynnin harkinnan arvoiseksi, mikäli kaupankäynti on kustannustehokasta ja kannattavaa sekä joustavuuden ostajille että myyjille. Keskeyttämätön sähkönsyöttö ja loistehon hallinta tunnistettiin kiireellisiksi paikallisiksi tarpeiksi ja siirtojenhallintaa pidettiin vähemmän kiireellisenä tarpeena. Työn mukaan lukuisat ja keskenään ristiriitaiset joustotuotevaihtoehdot voivat ratkaista erilaisia joustotarpeita. Ensisijaisesti tulisi keskittyä kolmen kategorian tuotteiden kehittämiseen: sijainnilliset päivänsisäisen markkinan tuotteet, sijainnilliset säätösähkömarkkinan tuotteet ja kilpailutetut kahdenväliset joustosopimukset. Tuloksista voidaan nähdä, että kaikki kolme vaihtoehtoa ovat olemassa olevien tuotteiden muunnoksia. Tuotteet ovat otettavissa käyttöön eri syistä, ja vaihtoehdot eivät ole toisiaan poissulkevia. Joustotuotteiden yhteensopivuus olemassa olevien tuotteiden ja toimintaprosessien kanssa on taattava, erityisesti yhteensovittaminen kantaverkkojen reaktiivisen säätötavan kanssa on varmistettava. Joustomarkkinoiden jatkokehittäminen tulisi aloittaa välittämättömästi kokeiluilla ja verkonhaltijoiden ja -käyttäjien yhteistyöllä

Long-term Contracts for Network-supportive Flexibility in Local Flexibility Markets

With an ongoing energy transition, the electric network is increasingly challenged. Handling congestion is a major responsibility of network operators. In recent years, market-based approaches to utilize network-supportive flexibility, especially local flexibility markets (LFMs), have been discussed as possible future development of congestion management processes. LFMs are a promising opportunity for the efficient, transparent and non-discriminatory integration of new flexibility options, in particular demand-side flexibility. Despite a wide body of supporting literature and several pilot implementations, there is still no common commitment to the concept of LFMs in the European Union. Here we address decision makers in the European energy economy, especially network operators, and discuss a possible flexibility product design using a methodological approach with four steps. First, we review the theoretical background of LFMs, considering both network operators' views and the possibility of demand response as a flexibility provider. Based on this review, we formulate an interim conclusion regarding requirements for flexibility product design in general. Second, using an existing framework, we propose a concrete, capacity-based, long-term flexibility product specification. Third, we discuss compliance between the defined requirements and the proposed product design to highlight the relevance of key design parameters and identify further research needs. Finally, we derive policy implications for network operators' decision makers regarding the implementation of LFMs

Barriers and Opportunities for Residential Solar PV and Storage Markets - A Western Australian Case Study

Residents and businesses around the world are increasingly installing solar photovoltaic (PV) panels and battery storage systems, satisfying not just their interest in clean energy, but also taking advantage of reduced technology costs and mitigating against future electricity price rises. Solar PV panels coupled with storage systems present an opportunity to move towards a resilient, affordable, flexible and secure electricity network. Western Australia provides a unique set of conditions (isolated network, high solar radiation, and rising electricity prices), which has contributed to the rapid uptake of solar PV’s in the state. Yet, a number of issues are still obstructing the transition to renewables. Using Western Australia as a case study, this paper investigates the barriers inhibiting the network transformation and explores the role that solar PV and storage can play as a disruptive threat to the incumbent, centralised service model of electricity utilities