Optimal strategy of electricity and natural gas aggregators in the energy and balance markets

This paper presents a stochastic two-stage model for energy aggregators (EAs) in the energy and balancing markets to supply electricity and natural gas to end-users equipped with combined heat and power (CHP) units. The suggested model takes into account the battery energy storage (BES) as a self-generating unit of EA. The upper and lower subproblems determine the optimal energy supply strategy of EA and consumption of consumers, respectively. In the lower subproblem, the McCormick relaxation is used to linearize the cost function of the CHP unit. To solve the proposed model, the two-stage problem is transformed into a linear single-stage problem using the KKT conditions of the lower subproblem, the Big M method, and the strong duality theory. The performance and efficiency of the proposed model are evaluated using a case study and three scenarios. According to the simulation results, adding CHP units to the energy-scheduling problem of BES-owned aggregators increases the profit of EA by 5.96% and decreases the cost of consumers by 1.57%.This work has received funding from the EU Horizon 2020 research and innovation program under project TradeRES (grant agreement No 864276). Pedro Faria is supported by FCT, grant CEECIND/01423/2021. The authors acknowledge the work facilities and equipment provided by GECAD research center (UIDB/00760/ 2020) to the project team.info:eu-repo/semantics/publishedVersio

Towards transactive energy systems: An analysis on current trends

This paper presents a comprehensive analysis on the latest advances in transactive energy systems. The main contribution of this work is centered on the definition of transactive energy concepts and how such systems can be implemented in the smart grid paradigm. The analyzed works have been categorized into three lines of research: (i) transactive network management; (ii) transactive control; and (iii) peer-to-peer markets. It has been found that most of the current approaches for transactive energy are available as a model, lacking the real implementation to have a complete validation. For that purpose, both scientific and practical aspects of transactive energy should be studied in parallel, implementing adequate simulation platforms and tools to scrutiny the results.This work has received funding from the European Union's Horizon 2020 research and innovation programme under project DOMINOES (grant agreement No. 771066) and from FEDER Funds through COMPETE program and from National Funds through FCT under the project UID/EEA/00760/2019.info:eu-repo/semantics/publishedVersio

Complex Large-Scale Energy Resource Management Optimization Considering Demand Flexibility

As renewable energy sources penetration is increasing in the power distribution network, an energy aggregator can provide a highly flexible generation and demand as required by the smart grid paradigm. However, this energy aggregator entity needs adequate decision support tools to overcome the complex challenges and deal with a number of energy resources. So, the energy resource management is crucial for the aggregator, to increase the profits, reduce the operation costs, reduce the carbon footprint and also to improve the system stability. Thus, this paper proposes a model for a large-scale energy resource scheduling problem of aggregators in a smart grid. Also, it is compared the performance of five evolutionary algorithms to solve this kind of problem. A realistic case study is performed using a real distribution network in Zaragoza, Spain. The results show that load flexibility can contribute to the profitability improvement of the aggregators' entities.This work has received funding from Portugal 2020 under SPEAR project (NORTE-01-0247-FEDER-040224) and from National Funds through the FCT Portuguese Foundation for Science and Technology, under Project UIDB/00760/2020. Joao Soares is supported by FCT CEECIND/02814/2017 grantinfo:eu-repo/semantics/publishedVersio

DSO Contract Market for Demand Response Using Evolutionary Computation

In this article, a cost optimization problem in local energy markets is analyzed considering fixed-term flexibility contracts between the DSO and aggregators. The DSO procures flexibility while aggregators of different types (e.g., conventional demand response or thermo-load aggregators) offer the service. We solve the proposed model using evolutionary algorithms based on the well-known differential evolution (DE). First, a parameter-tuning analysis is done to assess the impact of the DE parameters on the quality of solutions to the problem. Later, after finding the best set of parameters for the "tuned" DE strategies, we compare their performance with other self-adaptive parameter algorithms, namely the HyDE, HyDE-DF, and vortex search algorithms. Results show that with the identification of the best set of parameters to be used for each strategy, the tuned DE versions lead to better results than the other tested EAs. Overall, the algorithms are able to find near-optimal solutions to the problem and can be considered an alternative solver for more complex instances of the model.This research has received funding from FEDER funds through the Operational Programme for Competitiveness and Internationalization (COMPETE 2020) and National Funds through the FCT Portuguese Foundation for Science and Technology, under Projects PTDC/EEIEEE/28983/2017(CENERGETIC), CEECIND/02814/2017 (Joao Soares grant), and UIDB/000760/2020.info:eu-repo/semantics/publishedVersio

Hybrid-adaptive differential evolution with decay function (HyDE-DF) applied to the 100-digit challenge competition on single objective numerical optimization

In this paper, a hybrid-adaptive differential evolution with a decay function (HyDE-DF)1 is proposed for numerical function optimization. The proposed HyDE-DF is applied to the 100-Digit Challenge in a set of 10 benchmark functions. Results show that HyDE-DF can achieve a 93/100 score, proving its effectiveness for numerical optimization.This research has received funding from FEDER funds through the Operational Programme for Competitiveness and Internationalization (COMPETE 2020), under Project POCI-01-0145-FEDER-028983; by National Funds through the FCT Portuguese Foundation for Science and Technology, under Projects PTDC/EEI-EEE/28983/2017 (CENERGETIC).info:eu-repo/semantics/publishedVersio

A Statistical Analysis of Performance in the 2021 CEC-GECCO-PESGM Competition on Evolutionary Computation in the Energy Domain

Evolutionary algorithms (EAs) have emerged as an efficient alternative to deal with real-world applications with high complexity. However, due to the stochastic nature of the results obtained using EAs, the design of benchmarks and competitions where such approaches can be evaluated and compared is attracting attention in the field. In the energy domain, the “2021 CEC-GECCO-PESGM Competition on Evolutionary Computation in the Energy Domain: Smart Grid Applications” provides a platform to test and compare new EAs to solve complex problems in the field. However, the metric used to rank the algorithms is based solely on the mean fitness value (related to the objective function value only), which does not give statistical significance to the performance of the algorithms. Thus, this paper presents a statistical analysis using the Wilcoxon pair-wise comparison to study the performance of algorithms with statistical grounds. Results suggest that, for track 1 of the competition, only the winner approach (first place) is significantly different and superior to the other algorithms; in contrast, the second place is already statistically comparable to some other contestants. For track 2, all the winner approaches (first, second, and third) are statistically different from each other and the rest of the contestants. This type of analysis is important to have a deeper understanding of the stochastic performance of algorithms.This research has received funding from FEDER funds through the Operational Programme for Competitiveness and Internationalization (COMPETE 2020), under Project POCI01-0145-FEDER-028983; by National Funds through the FCT Portuguese Foundation for Science and Technology, under Projects PTDC/EEI-EEE/28983/2017(CENERGETIC),CEECIND/02814/2017, and UIDB/000760/2020.info:eu-repo/semantics/publishedVersio

Robust Energy Resource Management Incorporating Risk Analysis Using Conditional Value-at-Risk

The energy resource management (ERM) problem in today’s energy systems is complex and challenging due to the increasing penetration of distributed energy resources with uncertain behavior. Despite the improvement of forecasting tools, and the development of strategies to deal with this uncertainty (for instance, considering Monte Carlo simulation to generate a set of different possible scenarios), the risk associated with such variable resources cannot be neglected and deserves proper attention to guarantee the correct functioning of the entire system. This paper proposes a risk-based optimization approach for the centralized day-ahead ERM taking into account extreme events. Risk-neutral and risk-averse methodologies are implemented, where the risk-averse strategy considers the worst scenario costs through the conditional value-at-risk ( CVaR ) method. The model is formulated from the perspective of an aggregator that manages multiple technologies such as distributed generation, demand response, energy storage systems, among others. The case study analysis the aggregator’s management inserted in a 13-bus distribution network in the smart grid context with high penetration of renewable energy and electric vehicles. Results show an increase of nearly 4% in the day-ahead operational costs comparing the risk-neutral to the risk-averse strategy, but a reduction of up to 14% in the worst-case scenario cost. Thus, the proposed model can provide safer and more robust solutions incorporating the CVaR tool into the day-ahead management.This work was supported in part by the European Regional Development Fund (FEDER) through the Operational Program for Competitiveness and Internationalization (COMPETE 2020), under Project POCI-01-0145-FEDER-028983; and in part by the National Funds through the Fundação para a Ciância e Tecnologia (FCT) Portuguese Foundation for Science and Technology, under Project PTDC/EEI-EEE/28983/2017(CENERGETIC), Project CEECIND/02814/2017, Project UIDB/000760/2020, and Project UIDP/00760/2020.info:eu-repo/semantics/publishedVersio

Flexibility management model of home appliances to support DSO requests in smart grids

Several initiates have been taken promoting clean energy and the use of local flexibility towards a more sustainable and green economy. From a residential point of view, flexibility can be provided to operators using home-appliances with the ability to modify their consumption profiles. These actions are part of demand response programs and can be utilized to avoid problems, such as balancing/congestion, in distribution networks. In this paper, we propose a model for aggregators flexibility provision in distribution networks. The model takes advantage of load flexibility resources allowing the re-schedule of shifting/real-time home-appliances to provision a request from a distribution system operator (DSO) or a balance responsible party (BRP). Due to the complex nature of the problem, evolutionary computation is evoked and different algorithms are implemented for solving the formulation efficiently. A case study considering 20 residential houses equipped each with seven types of home-appliances is used to test and compare the performance of evolutionary algorithms solving the proposed model. Results show that the aggregator can fulfill a flexibility request from the DSO/BRP by re-scheduling the home-appliances loads for the next 24-h horizon while minimizing the costs associated with the remuneration given to end-users.The present work has been developed under the EUREKA – ITEA2 Project M2MGrids (ITEA-13011), Project SIMOCE (ANI—P2020 17690), and has received funding from FEDER Funds through COMPETE program and from National Funds through FCT under the project UIDB/00760/2020. Joao Soares is supported by FCT under CEECIND/02814/2017 grant.info:eu-repo/semantics/publishedVersio

Acopio de los residuos sólidos urbanos y su incidencia en la estrategia de recepción de la basura en algún punto crítico de la ciudad de Cajamarca año 2017

RESUMEN La presente investigación tuvo como objeto de estudio medir la cantidad de generación de residuos sólidos y la manera más frecuente por la cual se produce, teniendo, así como objetivo principal el Evaluar la incidencia en el acopio de los residuos sólidos urbanos con el diseño de la estrategia de recepción de basura en algún punto crítico de la Ciudad de Cajamarca año 2017. Después de haber descrito el problema, se tiene como posible afirmación que, con la implementación de un Sistema de Contenedores Soterrados Urbanos, la gestión de los residuos sólidos y los impactos que estos generan, va a mejorar considerablemente. La investigación fue de carácter aplicativa, gracias a metodologías de recabación de información mediante entrevistas, encuestas, análisis de documentos en lo concerniente a la Gestión de Residuos en la ciudad de Cajamarca y observación directa en los lugares donde se puede evidenciar el acopio desmesurado de basura, posteriormente estas fueron analizadas, procesadas y contrastadas, teniendo como resultados del diagnóstico, que la ciudad no cuenta con la tecnología suficiente para poder coberturar la cantidad de residuos sólidos que son generados diariamente, además no se cuenta con un plan de mantenimiento de los buzones instalados actualmente, ni se tiene un plan de concientización profundo y eficaz para concientizar a la gente. Con la finalidad de conocer la realidad problemática en la que se encuentra la localidad actualmente, se creyó conveniente proponer el diseño de Contenedores Soterrados Urbanos y su posterior implementación en la ciudad, para mejorar las condiciones del medioambiente y el confort de las personas residentes en la localidad de Cajamarca. Se concluyó que con la implementación de nuevas tecnologías como tal es el caso de los Contenedores Soterrados Urbanos, se va a reducir los malos olores en la ciudad, minimizar el impacto ambiental y visual, generado por la agrupación descontrolada de basura en las calles, contribuyendo al equilibrio del medio ambiente, mejorando así las condiciones, del agua, suelo y aire. Por lo expuesto anteriormente, se recomienda que las municipalidades deberían promover fondos de inversión en la implementación de Contenedores Soterrados Urbanos, con la finalidad de mejorar la disposición de los residuos sólidos, y así disminuir el problema que tanto aqueja a la población.ABSTRACT The objective of this study was to measure the amount of solid waste generation and the most frequent way in which it is produced. The main objective of this study was to evaluate the incidence of solid waste disposal in urban waste Strategy to receive garbage at some critical point in the city of Cajamarca in 2017. After describing the problem, it is possible to affirm that, with the implementation of an Urban Underground Container System, the management of solid waste and Impacts that these generate, will improve considerably. The research was of an applicatory nature, thanks to methodologies of gathering information through interviews, surveys, document analysis regarding Waste Management in the city of Cajamarca and direct observation in places where it can be evidenced the excessive collection of garbage , After which they were analyzed, processed and tested, having as a result of the diagnosis, that the city does not have enough technology to cover the amount of solid waste that is generated daily, and there is no maintenance plan for the mailboxes Currently installed, nor do you have a deep and effective awareness-raising plan to raise awareness. With the purpose of knowing the problematic reality in which the locality is nowadays, it was considered convenient to propose the design of Urban Underground Containers and its subsequent implementation in the city, to improve the conditions of the environment and the comfort of the people residing in the city. Locality of Cajamarca. It was concluded that with the implementation of new technologies as such is the case of Urban Underground Containers, it will reduce the odors in the city, minimize the environmental and visual impact, generated by the uncontrolled grouping of garbage in the streets, contributing To the balance of the environment, thus improving the conditions of water, soil and air. For the above, it is recommended that municipalities should promote investment funds in the implementation of Urban Underground Containers, in order to improve the disposal of solid waste, and thus reduce the problem that so afflicts the population