Wholesale Market
(Day-ahead; Intraday)
Tabela comparativa dos vários Modelos de Mercados de Eletricidade ao redor do mundo - Operadores de Mercado e de Sistemas; Wholesale Market and Competitive Retailer; Formação de Preços; Capacity Market; Ancillary Services; etc.
Mercado por Custos Auditados versus o Mercado por Oferta de Preços
Na maioria dos mercados atacadistas mundiais a energia elétrica é negociada por meio de um sistema de liquidação dupla (“two-settlement system”), consistindo basicamente de um Mercado Day-Ahead (podendo possuir Mercados Intraday ou não) e de um Mercado de Tempo-real (Real-time).
Notadamente o mercado atacadista tem duas funções básicas, a primeira é precificar a energia em contratos forward bilaterias, que podem ser de longo-pazo ou de curto-prazo. Esses contratos são comumente negocidos em balcão (Over-the-Counter) ou em alguma bolsa de energia. A segunda função básica é precificar o preço spot da eletricidade através do Mercado de Tempo-real. O preço spot da eletricidade serve também como um norte para contratos forward, e até mesmo para Mercados de Derivativos de energia elétrica.
Os Mercados Day-Ahead/Intraday (1º “settlement system”) são definidos pelo livre encontro entre os produtores e os consumidores, e são “processados” antes do momento em que a energia é produzida e consumida, conforme o funcionamento já bastante conhecido dos mercados forward das commodities em geral [4].
O despacho horário dos geradores e os preços para cada hora do dia seguinte são calculados a partir do mecanismo de “market-clearing” do 1º “settlement system”. Esse par preço-quantidade é liquidado para todos os participantes do mercado, independentemente de seu desempenho real. Se um determinado gerador tiver, em tempo real de operação, uma geração maior ou menor do que foi ofertado no mercado Day-ahead, ele terá que pagar essa diferença de quantidade de energia em função do preço spot, ou seja, em função do preço do Mercado de Tempo-real, o 2º “settlement system”.
Ainda em relação ao funcionamento dos Mercados Atacadistas, é importante ressaltar a diferença entre o Mercado por Custos Auditados versus o Mercado por Oferta de Preços. O Mercado Brasileiro caracteriza-se por ser um mercado por custos auditados, onde o Operador do Sistema recebe a curva de custos de oferta e prevê uma curva horária de demanda. No Brasil a demanda não informa ao operador do sistema os seus “bids” de compra. Nos mercados por ofertas de preço os produtores e os consumidores fazem suas livres ofertas de quantidade e preço de energia e as curvas agregadas de oferta e de demanda é que caracterizam o peço de equilíbrio do mercado, como em qualquer commodity.
Os principais pontos-chaves para o funcionamento de um mercado de eletricidade eficiente são os seguintes:
(1) formação do preço spot relacionado o mais aproximadamente possível com a operação física em tempo real da rede elétrica (menor granularidade temporal possível);
(2) mecanismos regulatórios e de mercado eficazes para garantir a adequação dos recursos de geração a longo prazo;
(3) mecanismos apropriados para mitigar o poder de mercado (market power); e
(4) mecanismos que permitam o envolvimento ativo da demanda final no mercado real-time [5, 6].
Referências:
[3] - Jin Zhong, “Power System Economic and Market Operations”, 1st Edition, CRC Press, 2018.
[4] - Fernando Lopes and Helder Coelho (Editors), “Electricity Markets with Increasing Levels of Renewable Generation: Structure, Operation, Agent-based Simulation, and Emerging Designs”, Springer, 1st ed., 2018.
[5] - Ignacio J. Pérez-Arriaga (Editor), “Regulation of the Power Sector”, Springer, 2013.
[6] - Frank A. Wolak, "Wholesale Electricity Market Design", Department of Economics, Stanford University, Stanford, CA 94305-6072, Current Draft: November 20, 2019.
Technical and economical aspects of wholesale electricity markets: An international comparison and main contributions for improvements in Brazil
Luíza Ribeiro, Alexandre Street, Davi Valladão, Ana Carolina Freire, Luiz Barroso, “Technical and economical aspects of wholesale electricity markets: An international comparison and main contributions for improvements in Brazil”, Electric Power Systems Research, Volume 220, 2023, 109364, ISSN 0378-7796, https://doi.org/10.1016/j.epsr.2023.109364. (https://www.sciencedirect.com/science/article/pii/S0378779623002535)
Handbook on Electricity Markets
Edited by
Jean-Michel Glachant, Director, Florence School of Regulation, European University Institute, Italy,
Paul L. Joskow, Elizabeth and James Killiam Professor of Economics and Management, Massachusetts Institute of Technology, US and
Michael G. Pollitt, Professor of Business Economics, Judge Business School, University of Cambridge, UK
Publication Date: 2021
ISBN: 978 1 78897 994 8
Extent: 672 pp
With twenty-two chapters written by leading international experts, this volume represents the most detailed and comprehensive Handbook on electricity markets ever published.
O Preço de Equilíbrio entre o Consumidor e o Produtor de Energia Elétrica é o Preço que iguala as "Utilidades Marginais"
Ignacio J. Pérez-Arriaga (Editor), "Regulation of the Power Sector", Springer, 2013.
Wholesale Electricity Market Design
Nord Pool is the NEMO (Nominated Electricity Market Operator) in Norway, Sweden, Finland, Denmark, Estonia, Latvia, Lithuania, Germany, the Netherlands, Belgium, Austria, Luxembourg, France, and the United Kingdom with 15 price areas. It merges bids on the day-ahead spot market (Elspot) and intraday market (Elbas) and publishes the result on their website.
Other types of electricity trading are long-term contracts (future and forward contracts) operated by Nasdaq and short-term markets (balancing markets) operated by the respective TSO. Market participants who are responsible for imbalances are invoiced after the delivery day through the Imbalance Settlement which is executed by eSett Oy. In Fig. 1, the aforementioned markets and their timeline are illustrated.
A. Khodadadi, L. Herre, P. Shinde, R. Eriksson, L. Söder and M. Amelin, "Nordic Balancing Markets: Overview of Market Rules", 17th International Conference on the European Energy Market (EEM), Stockholm, Sweden, 2020, pp. 1-6, doi: 10.1109/EEM49802.2020.9221992.
Where can I find details of wholesale prices of electricity in Great Britain?
The majority of wholesale trading takes place directly between buyers and sellers of electricity at a price agreed in private. Benchmark prices for the trades are published on subscription to reference agencies.
Short term energy trading takes place on two power exchanges in GB. Both publish price data:
Although wholesale prices aren’t calculated, Energy Imbalance Price are every 30 minutes.
​
​
How are the System Sell Price and the System Buy Price Calculated?
For each half hour trading period or ‘Settlement Period’, the ‘cash-out prices’ or ‘Energy Imbalance Prices’ (System Sell Price and System Buy Price) will be calculated based on the cost incurred by National Grid – the System Operator – to bring the system into balance (based on accepted Balancing Mechanism Bids and Offers). The System Buy Price (SBP) is applied to BSC Parties that have deficit of energy and the System Sell Price (SSP) to those that have a surplus of energy.
More information about how the prices are calculated and applied can be found in the Imbalance Pricing Guidance (https://www.elexon.co.uk/guidance-note/imbalance-pricing/).
Indicative prices for each half hour trading period are reported on the Balancing Mechanism Reporting Service (BMRS) at BMReports.com (https://www.bmreports.com/bmrs/).
North American ISOs and RTOs
​
There are nine Independent System Operators (ISOs) and Regional Transmission Organizations (RTOs) in North America. ISO New England, a Regional Transmission Organization, covers the six states of Maine, Vermont, New Hampshire, Massachusetts, Connecticut and Rhode Island. Striped areas indicate interwoven transmission lines or utility service territories.
Short Term Market - Time Frames - An Overview
IRENA (2017), “Adapting market design to high shares of variable renewable energy”. International Renewable Energy Agency, Abu Dhabi.
The Iberian Electricity Market Schedule
A. González-Garrido, A. Saez-de-Ibarra, H. Gaztañaga, A. Milo and P. Eguia, "Comparison of market operation strategies for photovoltaic power plants with storage systems providing frequency ancillary services", 2018 Thirteenth International Conference on Ecological Vehicles and Renewable Energies (EVER), Monte Carlo, Monaco, 2018, pp. 1-8, doi: 10.1109/EVER.2018.8362386.
Participating in Markets for Electrical Energy
​
Perspective of Plants That Do Not Burn Fossil Fuels: Wind and Solar
When competing with other forms of generation, owners of wind and solar farms have the big advantage that their primary energy sources are free. [...] Wind and solar generators therefore often face an imbalance between the amount of energy that they have sold and what they have actually produced. Since the cost of covering these imbalances on the spot market can be quite significant, operators of renewable generation use several mitigation techniques. First, they strive to improve the accuracy of their generation forecasts using numerical weather forecasting (for wind generation) and satellite images of cloud covers (for solar generation). Second, they can actively trade in the short-term forward markets to cover their expected imbalances as improved forecasts become available. Third, they can partner with a flexible conventional generator or an energy storage facility. This partner then increases, decreases, or reverses its energy output to compensate for any deficit or surplus in the renewable generation. Together, these partners can enter into “firm” contracts for the delivery of energy. While energy produced by this flexible partner may not always be cheaper than purchases on the spot market, such an arrangement reduces the price risk to which the renewable generator is exposed.
Daniel S. Kirschen and Goran Strbac, “Fundamentals of Power System Economics”, 2nd Edition, 2019.
Despacho de Cascata Hidraúlica
em Mercados por Oferta de Preços
Para quem ainda acha que é impossível fazer o Despacho de uma Cascata de Usinas Hidraúlicas em Mercados por Oferta de Preços, segue uma referência muito interessante publicada em 2019.
​
Vale ressaltar, que o "International Workshop on Hydro Scheduling in Competitive Electricity Markets" teve a sua 1a ediçao em 2002, seguindo-se as edições de 2005, 2008, 2012, 2015 e a edição de 2018, que deu origem à essa publicação.
2019
Preface
​
The scheduling of generation resources is a key component of the electricity industry all over the world. In hydro-dominated systems, the generation scheduling problem becomes a very complex task due to the need to coordinate reservoirs under uncertainty in inflow. In a market environment, this complexity is compounded by uncertainties in electricity prices, the need for risk management, and integration with other markets - such as natural gas and carbon markets. The scheduling requires detailed modeling of system components and uncertainties in optimization and simulation models that run in reasonable computational times. A further complicating factor is that no hydro systems are alike. Each system is uniquely defined, e.g., by watercourse topology, man-made storages, release elements used to control the water flows, constraints imposed on the operation, and the regulatory framework governing the operation.
Either in a cost-based or profit-maximization framework, the coordination of the operation of a hydro system implies application of computer models and tools. The overall scheduling problem is normally divided into a hierarchy of scheduling problems with different planning horizons and degrees of detail in the representation of the system and of the related uncertainties. Different methodologies are utilized, including stochastic dynamic programming, decomposition-based methods, linear and nonlinear programming, and heuristics. Results from the long-term scheduling models are to be used as input to more detailed mid-term models, which in turn feed their results into the short-term scheduling procedures. The computational challenge is usually overcome by means of parallel processing and the use of computing clusters.
ABSTRACT
This report elaborates on the toolchains applied for generation scheduling in the two countries Norway and Brazil. Both countries have vast hydropower resources, with numerous geographically widespread and complex reservoir systems. Although the underlying objective of the scheduling is essentially the same, the systems are operated in different market contexts, where the different stakeholders' objectives clearly differ. This in turn leads to different uses of the scheduling models and information flow between the models.
We review the main operational scheduling models and their overarching toolchains developed and maintained by the two research institutions SINTEF Energy Research and the Brazilian Electric Energy Research Centre (CEPEL). We identify the similarities and differences and try to shed light on the original ideas that motivated the creation of the models and toolchains. We also discuss the current state of these models and how they are being developed through R&D. With the great changes both two systems are expected to see in the future, we discuss the need to improve and extend the current toolchains.