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Publicações

Publicações por João Peças Lopes

2012

Challenges and barriers of integrating e-cars into a grid with high amount of renewable generation

Autores
Styczynski, Z; Stotzer, M; Muller, G; Komarnicki, P; Belmans, R; Driesen, J; Hansen, AB; Pecas Lopes, J; Hatziargyriou, N;

Publicação
44th International Conference on Large High Voltage Electric Systems 2012

Abstract
In this contribution international experiences concerning the integration of electrified cars (e-cars) into the grid in particular when there is a high penetration of renewable energies are presented. Future shortage of fossil fuels and concerns about security of supply derived the idea of electrified mobility which requires a new approach to design a complex system for future transportation. This system will be based on existing infrastructures (electricity system, road infrastructure, etc.) but it can also partially be considered as a "green field" approach. In the paper new strategies and global trends in the development of an e-mobility system will be presented, including strategies to combine the power system with the information and communication systems as well as a logistics. Practical experiences and data based on few projects e.g. Harz.EE-Mobility in Germany. European research as well as industry projects with these aims will be introduced and results will be presented. The main focus is twofold: integrating the upcoming mobile loads into the grid and likely storage possibilities that can operate bidirectional within the power grid. Simulations show that single-phase charging (3.7 kW) in the low and medium voltage grid does not lead to grid situations that require any significant adjustments in the power network regarding the loading of the assets. However, uncoordinated single-phase charging could create significant voltage deviations due to unbalanced loading of the three-phase low voltage grid. The different phases influence each other in unbalanced situations, through the common neutral conductor. These effects can already occur at low market penetration levels, due to the presence of local penetration levels being significantly higher than the average market level. For a significant amount of e-cars and high power charging (up to 22 kW in Germany) after 2020 the main concerns of investigation will be the forecasting of the requested charging power, the location of this demand and the impact on power grid operation security without active grid control (e.g. voltage, asset overloading). On the low-voltage grid Further, a full integration of renewable generation is also important as the amount of thermal power plants decrease, because they currently balance the intermittent, renewable generation. The future integration of e-cars into the power grid and the coordinated operation/charging with renewable energies (mobile electricity storage) will be one of the most important challenges. The conflict between mobility and the availability of storage capacity in contrast to the generation will be discussed and some recommendations based on the modeling and simulations will be presented in the paper, too.

2009

How to develop and manage a power system with more than 20% penetration of wind power?

Autores
Estanqueiro, A; Pecas Lopes, J;

Publicação
European Wind Energy Conference and Exhibition 2009, EWEC 2009

Abstract

2009

Smart charging strategies for electric vehicles: Enhancing grid performance and maximizing the use of variable renewable energy resources

Autores
Pecas Lopes, JA; Soares, FJ; Almeida, PM; Moreira Da Silva, M;

Publicação
24th International Battery, Hybrid and Fuel Cell Electric Vehicle Symposium and Exhibition 2009, EVS 24

Abstract
In this paper the behaviour of a Portuguese typical Low Voltage (LV) grid and the changes in the Portuguese global generation profile were analyzed, in a daily period, regarding different levels of Electric Vehicles (EVs) integration. The impacts provoked by EVs deployment on the network voltage profiles, branches' congestion levels, grid losses and imbalances between phases were evaluated using a three phase power flow. The first part of this work focused on the determination of the maximum share of electric vehicles, defined as the percentage of conventional vehicles replaced by EVs, which can be integrated into the selected grid, without violating the system's technical restrictions and complying with drivers' requests concerning the foreseen use of vehicles. The maximization of the EVs connected to the grid was performed using two distinct charging strategies: dumb charging and smart charging. The second task was to analyse the impacts of both charging approaches (dumb charging and smart charging) on the prevention of wasting renewable energy surplus. For the purpose of this analysis, a 2011 wet and windy day was considered, where large hydro and wind generation exists. For that specific case, in some periods of the day (mainly valley hours), the hydro and wind generation, added to the must run thermal generation units, will surpass the consumption and renewable energy can be wasted. The results obtained for the LV grid were extended to a National level and the changes in the Portuguese load/generation profiles were computed.

2012

Foreword

Autores
Filipe, J; Donnellan, B; Lopes, JP; Martins, J;

Publicação
SMARTGREENS 2012 - Proceedings of the 1st International Conference on Smart Grids and Green IT Systems

Abstract

2012

Smart grids with electric vehicles: The initial findings of project reive: A project funded by the Portuguese Ministry of Economy, Innovation and Development

Autores
Soares, FJ; Gouveia, C; Pereira Barbeiro, PN; Rocha Almeida, PM; Moreira, C; Pecas Lopes, JA;

Publicação
SMARTGREENS 2012 - Proceedings of the 1st International Conference on Smart Grids and Green IT Systems

Abstract
This paper provides a general overview of the initial developments in the REIVE project (Smart Grids with Electric Vehicles). The main focus of the project is on smart grid infrastructures for large scale integration of EV and micro-generation units. It is a natural evolution of the InovGrid project promoted by the EDP Distribuição - the Portuguese Distribution Network Operator - and allows the development of seminal concepts and enabling technological developments within the Smart Grid paradigm. This paper presents the management and control architecture developed to allow electric vehicle integration in smart grid operation. Additionally, it presents the major impacts in distribution grids of the simultaneous deployment of electric vehicles, micro-generation and smart grid technologies.

2012

The merge project: Impacts of electric vehicles on the distribution system steady-state operation

Autores
Soares, FJ; Pereira Barbeiro, PN; Gouveia, C; Rocha Almeida, PM; Moreira, C; Pecas Lopes, JA;

Publicação
SMARTGREENS 2012 - Proceedings of the 1st International Conference on Smart Grids and Green IT Systems

Abstract
This paper describes the main results of the MERGE project relative to Electric Vehicle (EV) charging strategies and the impacts of EV integration on the steady-state grid operation. MERGE is a €4.5m, collaborative research project supported by the European Commission's Seventh Framework Programme (FP7). The consortium includes utilities, regulators, commercial organisations and universities with interests in the power generation, automotive, electronic commerce and hybrid and electric vehicle sectors across the entire European Union (EU). One of the MERGE project missions is to evaluate the impacts that EV will have on EU electric power systems, exploring EV and SmartGrid/MicroGrid simultaneous deployment, together with renewable energy increase, to achieve CO 2 emission reduction through the identification of enabling technologies and advanced control approaches. The work presented proposes three charging strategies, dumb charging, multiple price tariffs and smart charging, and uses EV integration scenarios of adherence to these charging schemes. The resulting scenarios are tested using an algorithm coded with Python and using PSS/E, created within the MERGE framework to study EU grids steady-state behaviour. Additionally, the critical mass of EV adherence to smart charging schemes that brings positive impacts to the distribution grids operation was also evaluated.

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