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Publicações

Publicações por CPES

2011

Models for the EV aggregation agent business

Autores
Bessa, RJ; Soares, FJ; Pecas Lopes, JA; Matos, MA;

Publicação
2011 IEEE PES Trondheim PowerTech: The Power of Technology for a Sustainable Society, POWERTECH 2011

Abstract
It is foreseeable that electricity retailers for electrical mobility will be market agents. These retailers are electric vehicle (EV) aggregation agents, which operate as a commercial middleman between electricity market and EV owners. Furthermore, with the foreseen evolution of the smart-grid concept, these agents will be able to control the EV charging rates and offer several ancillary services. This paper formulates an optimization problem for the EV aggregation agent participation in the day-ahead and secondary reserve market sessions. Forecasting issues are also discussed. The methodology was tested for two years (2009 and 2010) of the Iberian market, considering perfect and naïve forecast for all variables of the problem. © 2011 IEEE.

2011

Setting the Operating Reserve Using Probabilistic Wind Power Forecasts

Autores
Matos, MA; Bessa, RJ;

Publicação
IEEE TRANSACTIONS ON POWER SYSTEMS

Abstract
In power systems with a large integration of wind power, setting the adequate operating reserve levels is one of the main concerns of system operators (SO). The integration of large shares of wind generation in power systems led to the development of new forecasting methodologies, including probabilistic forecasting tools, but management tools able to use those forecasts to help making operational decisions are still needed. In this paper, a risk evaluation perspective is used, showing that it is possible to describe the consequences of each possible reserve level through a set of risk indices useful for decision making. The new reserve management tool (RMT) described in the paper is intended to support the SO in defining the operating reserve needs for the daily and intraday markets. Decision strategies like setting an acceptable risk level or finding a compromise between economic issues and the risk of loss of load are explored. An illustrative example based on the Portuguese power system demonstrates the usefulness and efficiency of the tool.

2011

Multicriteria decision aid for planning energy storage and sustainable mobility - The São Miguel Island case study

Autores
Da Silva, MM; Lopes, JAP; Matos, MA;

Publicação
2011 IEEE PES Trondheim PowerTech: The Power of Technology for a Sustainable Society, POWERTECH 2011

Abstract
This paper presents a Multicriteria Decision Aid methodology for planning energy storage and sustainable mobility, in an isolated system. The objective of this research is to enhance the sustainability of the analyzed case study (São Miguel Island), by comparing a set of alternatives for energy storage and sustainable mobility. The alternatives characterization and evaluation is made through the calculation of meaningful attributes, namely: carbon emissions, overall costs and reliability. An analysis of the most interesting alternatives is also performed. © 2011 IEEE.

2011

Long Term Evaluation of Operating Reserve with High Penetration of Renewable Energy Sources

Autores
Leite da Silva, AML; Rosa, MA; Sales, WS; Matos, M;

Publicação
2011 IEEE POWER AND ENERGY SOCIETY GENERAL MEETING

Abstract
Due to the high penetration of renewable energy into the energy matrix of today's power networks, the design of generating systems based only on static reserve assessment does not seem to be enough to guarantee the security of power system operation. From the wind power integration perspective, this energy source imposes additional requirements, mainly due to the inherent unpredictable characteristic of the wind. Besides the uncertainties in load and generating unit availabilities, the operating reserve needs also to deal with the fluctuation characteristic of the wind power. Therefore, more flexibility of the conventional generators (hydro and thermal) is required to provide system support services. This paper discusses a new methodology based on chronological Monte Carlo simulation to evaluate the operating reserve requirements of generating systems with large amounts of renewable energy sources, in particular, wind power.

2011

A novel fuzzy-based methodology for biogas fuelled hybrid energy systems decision making

Autores
Barin, A; Canha, LN; Magnago, KM; Matos, MA; Wottrich, B;

Publicação
Studies in Fuzziness and Soft Computing

Abstract
In response to the soaring energy crisis and the related pollution problems worldwide, it is essential to apply new technologies that use renewable energy sources in both an efficient and environmentally friendly manner. In this way, biomass offers one of the largest potential among renewable energy sources. The aim of this work is to demonstrate a novel fuzzy-based methodology for selecting hybrid energy systems fuelled by biogas. Fuzzy multi-rules and fuzzy multi-sets are used to evaluate the main operational characteristics of five types of renewable sources fuelled by biogas. The possibility of using the methodology for energy storage system evaluation is also assessed. The construction of the fuzzy multirules and fuzzy multi-sets is based on the following methods: Mamdani (fuzzification process), Max-Min (inference process), and Center of Gravity (defuzzification process). Several criteria are used: costs, efficiency, cogeneration, life-cycle, technical maturity, power application range, and environmental impacts. The methodology considers three different settings with two different constraints: costs and environment. One of the most relevant aspects presented by this work is about the previous classification of the criteria. It was created according to the different relevance observed among the attributes. The purpose of the proposed arrangement is to facilitate the understanding of the methodology and to increase the possibility of incorporating the decision makers' preferences on the decision-aid process. These aspects are essential to strengthen the final decision. © Springer-Verlag Berlin Heidelberg 2011.

2011

Photodynamic Antimicrobial Chemotherapy in Aquaculture: Photoinactivation Studies of Vibrio fischeri

Autores
Alves, E; Faustino, MAF; Tome, JPC; Neves, MGPMS; Tome, AC; Cavaleiro, JAS; Cunha, A; Gomes, NCM; Almeida, A;

Publicação
PLOS ONE

Abstract
fischeri Background: Photodynamic antimicrobial chemotherapy (PACT) combines light, a light-absorbing molecule that initiates a photochemical or photophysical reaction, and oxygen. The combined action of these three components originates reactive oxygen species that lead to microorganisms' destruction. The aim was to evaluate the efficiency of PACT on Vibrio fischeri: 1) with buffer solution, varying temperature, pH, salinity and oxygen concentration values; 2) with aquaculture water, to reproduce photoinactivation (PI) conditions in situ. Methodology/Principal Findings: To monitor the PI kinetics, the bioluminescence of V. fischeri was measured during the experiments. A tricationic meso-substituted porphyrin (Tri-Py(+)-Me-PF) was used as photosensitizer (5 mu M in the studies with buffer solution and 10-50 mu M in the studies with aquaculture water); artificial white light (4 mW cm(-2)) and solar irradiation (40 mW cm(-2)) were used as light sources; and the bacterial concentration used for all experiments was approximate to 10(7) CFU mL(-1) (corresponding to a bioluminescence level of 10(5) relative light units - RLU). The variations in pH (6.5-8.5), temperature (10-25 degrees C), salinity (20-40 g L(-1)) and oxygen concentration did not significantly affect the PI of V. fischeri, once in all tested conditions the bioluminescent signal decreased to the detection limit of the method (approximate to 7 log reduction). The assays using aquaculture water showed that the efficiency of the process is affected by the suspended matter. Total PI of V. fischeri in aquaculture water was achieved under solar light in the presence of 20 mu M of Tri-Py(+)-Me-PF. Conclusions/Significance: If PACT is to be used in environmental applications, the matrix containing target microbial communities should be previously characterized in order to establish an efficient protocol having into account the photosensitizer concentration, the light source and the total light dose delivered. The possibility of using solar light in PACT to treat aquaculture water makes this technology cost-effective and attractive.

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