scholarly journals An Overview of Probabilistic Dimensioning of Frequency Restoration Reserves with a Focus on the Greek Electricity Market

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5719
Author(s):  
Anthony Papavasiliou
Keyword(s):  
Electricity Market ◽  
Power Grid ◽  
Risk Profile ◽  
Skewed Distributions ◽  
Stochastic Behavior ◽  
Reserve Requirements ◽  
Potential Benefits ◽  
Adaptive Nature ◽  
Probabilistic Criteria

The dynamic dimensioning of frequency restoration reserves based on probabilistic criteria is becoming increasingly relevant in European power grid operations, following the guidelines of European legislation. This article compares dynamic dimensioning based on k-means clustering to static dimensioning on a case study of the Greek electricity market. It presents a model of system imbalances which aims to capture various realistic features of the stochastic behavior of imbalances, including skewed distributions, the dependencies of the imbalance distribution on various imbalance drivers, and the contributions of idiosyncratic noise to system imbalances. The imbalance model was calibrated in order to be consistent with historical reserve requirements in the Greek electricity market. The imbalance model was then employed in order to compare dynamic dimensioning based on probabilistic criteria to static dimensioning. The analysis revealed potential benefits of dynamic dimensioning for the Greek electricity market, which include a reduction in average reserve requirements and the preservation of a constant risk profile due to the adaptive nature of probabilistic dimensioning.

scholarly journals Prosumer Community Portfolio Optimization via Aggregator: The Case of the Iberian Electricity Market and Portuguese Retail Market

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3747
Author(s):  
Ricardo Faia ◽  
Tiago Pinto ◽  
Zita Vale ◽  
Juan Manuel Corchado
Keyword(s):  
Portfolio Optimization ◽  
Electricity Markets ◽  
Electricity Market ◽  
Retail Market ◽  
Wholesale Market ◽  
Generation Capacity ◽  
Wholesale Electricity Market ◽  
Portfolio Optimization Model ◽  
Photovoltaic Generators

The participation of household prosumers in wholesale electricity markets is very limited, considering the minimum participation limit imposed by most market participation rules. The generation capacity of households has been increasing since the installation of distributed generation from renewable sources in their facilities brings advantages for themselves and the system. Due to the growth of self-consumption, network operators have been putting aside the purchase of electricity from households, and there has been a reduction in the price of these transactions. This paper proposes an innovative model that uses the aggregation of households to reach the minimum limits of electricity volume needed to participate in the wholesale market. In this way, the Aggregator represents the community of households in market sales and purchases. An electricity transactions portfolio optimization model is proposed to enable the Aggregator reaching the decisions on which markets to participate to maximize the market negotiation outcomes, considering the day-ahead market, intra-day market, and retail market. A case study is presented, considering the Iberian wholesale electricity market and the Portuguese retail market. A community of 50 prosumers equipped with photovoltaic generators and individual storage systems is used to carry out the experiments. A cost reduction of 6–11% is achieved when the community of households buys and sells electricity in the wholesale market through the Aggregator.

Bilateral bidding strategy in joint day-ahead energy and reserve electricity markets considering techno-economic-environmental measures

2021 ◽  
pp. 0958305X2110148
Author(s):  
Mojtaba Shivaie ◽  
Mohammad Kiani-Moghaddam ◽  
Philip D Weinsier
Keyword(s):  
Electricity Market ◽  
Large Scale ◽  
Search Algorithm ◽  
Power Grid ◽  
Mathematical Formulation ◽  
Test System ◽  
Bidding Strategy ◽  
Level Problem ◽  
Optimal Bidding ◽  
Environmental Measures

In this study, a new bilateral equilibrium model was developed for the optimal bidding strategy of both price-taker generation companies (GenCos) and distribution companies (DisCos) that participate in a joint day-ahead energy and reserve electricity market. This model, from a new perspective, simultaneously takes into account such techno-economic-environmental measures as market power, security constraints, and environmental and loss considerations. The mathematical formulation of this new model, therefore, falls into a nonlinear, two-level optimization problem. The upper-level problem maximizes the quadratic profit functions of the GenCos and DisCos under incomplete information and passes the obtained optimal bidding strategies to the lower-level problem that clears a joint day-ahead energy and reserve electricity market. A locational marginal pricing mechanism was also considered for settling the electricity market. To solve this newly developed model, a competent multi-computational-stage, multi-dimensional, multiple-homogeneous enhanced melody search algorithm (MMM-EMSA), referred to as a symphony orchestra search algorithm (SOSA), was employed. Case studies using the IEEE 118-bus test system—a part of the American electrical power grid in the Midwestern U.S.—are provided in this paper in order to illustrate the effectiveness and capability of the model on a large-scale power grid. According to the simulation results, several conclusions can be drawn when comparing the unilateral bidding strategy: the competition among GenCos and DisCos facilitates; the improved performance of the electricity market; mitigation of the polluting atmospheric emission levels; and, the increase in total profits of the GenCos and DisCos.

Stochastic control for risk under deregulated electricity market — a case study using a new formulation

2005 ◽  
Vol 32 (4) ◽  
pp. 719-725 ◽  
Author(s):  
Joyce Li Zhang ◽  
K Ponnambalam
Keyword(s):  
Electricity Market ◽  
Explicit Method ◽  
State Variables ◽  
Risk Minimization ◽  
Solution Approach ◽  
Second Moments ◽  
Deregulated Electricity Market ◽  
New Formulation ◽  
Dual Dynamic Programming

This paper describes the implementation of a new solution approach — Fletcher-Ponnambalam model (FP) — for risk management in hydropower system under deregulated electricity market. The FP model is an explicit method developed for the first and second moments of the storage state distributions in terms of moments of the inflow distributions. This method provides statistical information on the nature of random behaviour of the system state variables without any discretization and hence suitable for multi-reservoir problems. Also avoiding a scenario-based optimization makes it computationally inexpensive, as there is little growth to the size of the original problem. In this paper, the price uncertainty was introduced into the FP model in addition to the inflow uncertainty. Lake Nipigon reservoir system is chosen as the case study and FP results are compared with the stochastic dual dynamic programming (SDDP). Our studies indicate that the method could achieve optimum operations, considering risk minimization as one of the objectives in optimization.Key words: reservoir operations, explicit method, uncertainty, stochastic programming, risk.

Exuberant Life

2021 ◽  
Author(s):  
William H. Durham
Keyword(s):  
Human Impact ◽  
Charles Darwin ◽  
Ecological Systems ◽  
Social Ecological Systems ◽  
Social Ecological ◽  
History Of ◽  
Potential Benefits ◽  
Marine Iguanas ◽  
Systems Framework

Why is Galápagos so endlessly fascinating, whether to read about, to visit, or both? Reasons include its menagerie of truly unusual organisms (like tree daisies, marine iguanas, and flightless cormorants), its relatively low human impact (most of its endemic biodiversity is still extant), and its unrivalled role in the history of science ever since Charles Darwin. Exuberant Life offers a contemporary synthesis of what is known about the evolution of the curiously wonderful organisms of Galápagos, of how they are faring in the tumultuous world of human-induced change, and how evolution can guide efforts today for their conservation. In eight case-study chapters, the book looks at each organism’s ancestry, at how and when it came to Galápagos, and how and why it changed since its arrival, all with an eye to its conservation today. Such analysis often provides surprises and suggestions not previously considered, like the potential benefits to joint conservation efforts with tree daisies and tree finches, for example, or ways that a new explanation for peculiar behaviors in Nazca and blue-footed boobies can benefit both species today. In each chapter, a social-ecological systems framework is used, because human influence is always present, and because it allows an explicit link to evolution. We see how the evolutionary fitnesses of Galápagos organisms are now a product of both ecological conditions and human impact, including climate change. Historically, Galápagos has played a central role in the understanding of evolution; what it now offers to teach us about conservation may well prove indispensable for the future of the planet.

scholarly journals Aligning accreditation and academic program reviews: a Canadian case study

2017 ◽  
Vol 25 (3) ◽  
pp. 287-302 ◽  
Author(s):  
Lynne Bowker
Keyword(s):  
Professional Associations ◽  
Academic Program ◽  
Content Type ◽  
Post Secondary ◽  
Study Approach ◽  
Academic Units ◽  
Potential Benefits ◽  
Set Up ◽  
Program Reviews

Purpose This paper aims to investigate the potential benefits and limitations associated with aligning accreditation and academic program reviews in post-secondary institutions, using a descriptive case study approach. Design/methodology/approach The paper describes two Canadian graduate programs that are subject to both external professional accreditation and institutional cyclical reviews, as they underwent an aligned review. The process was developed as a collaborative effort between the academic units, the professional associations and the university’s graduate-level quality assurance office. For each program, a single self-study was developed, a single review panel was constituted, and a single site visit was conducted. The merits and challenges posed by the alignment process are discussed. Findings Initial feedback from the academic units suggests that the alignment of accreditation and program reviews is perceived as reducing the burden on programs with regard to the time and effort invested by faculty, staff and other stakeholders, as well as in terms of financial expenses. Based on this feedback, along with input from reviewers and program evaluation committee members, 14 recommendations emerged for ways in which an aligned review process can be set up for success. Practical implications The results suggest that aligned reviews are not only resource-efficient but also allow reviewers to provide more holistic feedback that faculty may be more willing to engage with for program enhancement. Originality/value The present study contributes to the existing body of knowledge about conducting aligned reviews in response to external accreditation requirements or institutional needs. It summarizes the potential benefits and limitations and offers recommendations for potential best practices for carrying out aligned reviews for policymakers and practitioners.

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