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Publicações

Publicações por CPES

2013

A long term generation expansion planning model using system dynamics - Case study using data from the Portuguese/Spanish generation system

Autores
Pereira, AJC; Saraiva, JT;

Publicação
ELECTRIC POWER SYSTEMS RESEARCH

Abstract
This paper describes a long term generation expansion model that uses system dynamics to capture the interrelations between different variables and parameters. Using this model, it is possible to estimate the long term evolution of the demand and of the electricity price that are then used by generation agents to prepare individual expansion plans. These plans are submitted to a coordination analysis to check some global indicators, as the reserve margin and the LOLE. The developed approach is illustrated using a realistic generation system based on the Portuguese/Spanish system with an installed capacity of nearly 120 GW and an yearly demand of 312 TWh in 2010. Large investments were directed in the last 20 years to the Iberian generation system both regarding traditional technologies and dispersed generation (namely wind parks and solar systems). Today, the excess of installed capacity together with the demand reduction poses a number of questions that should be addressed carefully namely to investigate the impact of several options. The planning exercise aims at identifying the most adequate expansion plans in view of the increased renewable generation (namely wind parks). For illustration purposes, we also conducted a sensitivity analysis to evaluate the impact of increasing the installed capacity in wind parks, of internalizing CO2 emission costs and of incorporating a capacity payment. These analyses are relevant in order to get more insight on the possible long term evolution of the system and to allow generation companies to take more sounded decisions.

2013

Electricity market and renewable energy integration: An agent-based conceptual model

Autores
Sousa, JC; Kokkinogenis, Z; Rossetti, RJF; Saraiva, JT;

Publicação
1st International Workshop on Simulation for Energy, Sustainable Development and Environment, SESDE 2013, Held at the International Multidisciplinary Modeling and Simulation Multiconference, I3M 2013

Abstract
The emergence of electricity markets and the opportunities consequently created have radically modified the operation planning activities of Power Systems. As direct result, there is the need for developing new methods to meet in an efficient way the requirements of generation companies, so to respond adequately to new challenges such as market competition. Agent-based models have been proposed in the literature as surrogate to equilibrium models when the problem is too complex to be addressed within a traditional equilibrium framework. Driven by this trend, this paper discusses and proposes a conceptual model following the agent paradigm that deals with the inherent complexity of electricity markets. The devised model proved to be robust enough to represent key features of our study domain and is ready to be actually developed in a computational tool to help generation companies to build their short-medium term operation decisions in a more sounded and robust way.

2013

Impact of Electric Vehicles on the electricity prices and on the load curves of the Iberian Electricity Market

Autores
Goncalves, RL; Saraiva, JT; Sousa, JC; Mendes, VT;

Publicação
International Conference on the European Energy Market, EEM

Abstract
This paper addresses the impact of the penetration of Electric Vehicles, EV's, in the electricity market prices and on the load curves of the Iberian Electricity Market, established between Portugal and Spain. These impacts are evaluated taking the year of 2011 as reference. For every day of this year, the hourly market data was downloaded from the web site of the Iberian Market Operator and then the bid curves were adequately altered considering the commissioning of new stations under construction or planned till 2020, the planned increasing presence of wind parks and PV stations and the demand increase from end consumers. Then, the hourly demand was further increased to simulate the charging of EV's, admitting several scenarios for the charging periods and for the number of EV's in 2020. Using this information, the hourly selling and buying curves were altered and the hourly market price was then estimated. The paper extensively reports the results obtained for these different scenarios for the horizon of 2020. For the analysed scenarios, the results indicate that the impact of EV's on electricity prices and load curves will depend largely on the number of EV's and in a less significant way on the charging policy that is adopted. © 2013 IEEE.

2013

Generation capacity expansion planning in restructured electricity markets using genetic algorithms

Autores
Pereira, AJC; Saraiva, JT;

Publicação
Intelligent Systems, Control and Automation: Science and Engineering

Abstract
This paper describes an approach to model and to solve the Generation Expansion Planning Problem, GEP, using Genetic Algorithms. This approach was developed in order to help investors in new generation capacity to take decisions regarding new investments. This approach was developed in the scope of the implementation of electricity markets given that they eliminated the traditional centralized planning activities leading to the creation of several generation companies competing to supply the demand. As a result, the generation activity is more risky than in the past and so it becomes important to develop new tools to help decision makers to analyze the investment alternatives, having in mind the possible behavior of the competitors. The developed model aims at maximizing the expected profits that will be obtained by an investor, while it evaluates the reliability and the security of supply and it incorporates uncertainties related with the volatility of electricity prices, with the reliability of generation groups, with the evolution of the demand, and with the operation and investment costs The developed model and the implemented solution algorithm will be applied to a Case Study to illustrate the use of the developed approach to build the expansion plans. © 2013, Springer Science+Business Media Dordrecht.

2013

Controlling Electric Vehicles in Quasi-Real-Time

Autores
Soares, FJ; Pecas Lopes, JAP;

Publicação
2013 IEEE GRENOBLE POWERTECH (POWERTECH)

Abstract
This work presents a methodology to manage Electric Vehicles (EV) charging in quasi-real-time, considering the participation of EV aggregators in electricity markets and the technical restrictions of the electricity grid components, controlled through the distribution system operator. Two methodologies are presented to manage EV charging, one to be used by the EV aggregators and the other by the Distribution System Operators (DSO). The methodology developed for the aggregator has as main objective minimizing the deviation between the energy bought in the market and the energy consumed by EV. The methodology developed for the DSO allows it to manage the grid and solve operational problems that may appear by controlling EV charging. A method to generate a synthetic EV data set is used in this work, which provides information about the EV movement, periods when EV are parked, as well as their energy requirements. This data set is used afterwards to assess the performance of the algorithms developed to manage the EV charging in quasi-real-time.

2013

Coordinated Management of Distributed Energy Resources in Electrical Distribution Systems

Autores
Madureira, A; Gouveia, C; Moreira, C; Seca, L; Lopes, JP;

Publicação
2013 IEEE PES CONFERENCE ON INNOVATIVE SMART GRID TECHNOLOGIES (ISGT LATIN AMERICA)

Abstract
Current electrical distribution systems are facing significant challenges due to the widespread deployment of Distributed Energy Resources (DER), particularly the integration of variable Renewable Energy Sources (RES). This requires a change in the paradigm of distribution grids from a purely passive perspective into fully active networks within the smart grid vision. This new paradigm involves new control and management architectures as well as advanced planning methods and operational tools for distribution systems exploiting a smart metering infrastructure. This infrastructure will enable leveraging data from smart meters and short-term forecasts of load demand and RES in order to manage the distribution system in a more efficient and cost-effective way, thus enabling large scale integration of RES. Future tests to be carried out in a new, state of the art laboratory environment will bring additional added-value to the validation of the proposed concepts and tools.

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