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Publications

Publications by Ricardo Jorge Bessa

2014

Optimization models for an EV aggregator selling secondary reserve in the electricity market

Authors
Bessa, RJ; Matos, MA;

Publication
ELECTRIC POWER SYSTEMS RESEARCH

Abstract
Power system regulators and operators are creating conditions for encouraging the participation of the demand-side into reserve markets. The electric vehicle (EV), when aggregated by a market agent, holds sufficient flexibility for offering reserve bids. Nevertheless, due to the stochastic nature of the drivers' behavior and market variables, forecasting and optimization algorithms are necessary for supporting an EV aggregator participating in the electricity market. This paper describes a new day-ahead optimization model between energy and secondary reserve bids and an operational management algorithm that coordinates EV charging in order to minimize differences between contracted and realized values. The use of forecasts for EV and market prices is included, as well as a market settlement scheme that includes a penalty term for reserve shortage. The optimization framework is evaluated in a test case constructed with synthetic time series for EV and market data from the Iberian electricity market.

2013

Optimization Models for EV Aggregator Participation in a Manual Reserve Market

Authors
Bessa, RJ; Matos, MA;

Publication
IEEE TRANSACTIONS ON POWER SYSTEMS

Abstract
The charging flexibility of electric vehicles (EV) when aggregated by a market agent creates an opportunity for selling manual reserve in the electricity market. This paper describes a new optimization algorithm for optimizing manual reserve bids. Furthermore, two operational management algorithms covering alternative gate closures (i.e., day-ahead and hour-ahead) are also described. These operational algorithms coordinate EV charging for mitigating forecast errors. A case-study with data from the Iberian electricity market and synthetic EV time series is used for evaluating the algorithms.

2017

A Scalable Load Forecasting System for Low Voltage Grids

Authors
Reis, M; Garcia, A; Bessa, RJ;

Publication
2017 IEEE MANCHESTER POWERTECH

Abstract
A recent research trend is driven to increase the monitoring and control capabilities of low voltage networks. This paper describes a probabilistic forecasting methodology based on kernel density estimation and that makes use of distributed computing techniques to create a highly scalable forecasting system for LV networks. The results show that the proposed algorithm outperforms three benchmark models (one for point forecast and two for probabilistic forecasts) and demonstrate the applicability of the distributed in-memory computing solution for a practical operational scenario. The ultimate goal is to integrate information about net-load forecasts in power flow optimization frameworks for low voltage networks in order to solve technical constraints with the available home energy management system flexibility.

2017

Towards Improved Understanding of the Applicability of Uncertainty Forecasts in the Electric Power Industry

Authors
Bessa, RJ; Mohlen, C; Fundel, V; Siefert, M; Browell, J; El Gaidi, SH; Hodge, BM; Cali, U; Kariniotakis, G;

Publication
ENERGIES

Abstract
Around the world wind energy is starting to become a major energy provider in electricity markets, as well as participating in ancillary services markets to help maintain grid stability. The reliability of system operations and smooth integration of wind energy into electricity markets has been strongly supported by years of improvement in weather and wind power forecasting systems. Deterministic forecasts are still predominant in utility practice although truly optimal decisions and risk hedging are only possible with the adoption of uncertainty forecasts. One of the main barriers for the industrial adoption of uncertainty forecasts is the lack of understanding of its information content (e.g., its physical and statistical modeling) and standardization of uncertainty forecast products, which frequently leads to mistrust towards uncertainty forecasts and their applicability in practice. This paper aims at improving this understanding by establishing a common terminology and reviewing the methods to determine, estimate, and communicate the uncertainty in weather and wind power forecasts. This conceptual analysis of the state of the art highlights that: (i) end-users should start to look at the forecast's properties in order to map different uncertainty representations to specific wind energy-related user requirements; (ii) a multidisciplinary team is required to foster the integration of stochastic methods in the industry sector. A set of recommendations for standardization and improved training of operators are provided along with examples of best practices.

2014

An integrated approach for optimal coordination of wind power and hydro pumping storage

Authors
Castronuovo, ED; Usaola, J; Bessa, R; Matos, M; Costa, IC; Bremermann, L; Lugaro, J; Kariniotakis, G;

Publication
WIND ENERGY

Abstract
The increasing wind power penetration in power systems represents a techno-economic challenge for power producers and system operators. Because of the variability and uncertainty of wind power, system operators require new solutions to increase the controllability of wind farm output. On the other hand, producers that include wind farms in their portfolio need to find new ways to boost their profits in electricity markets. This can be done by optimizing the combination of wind farms and storage so as to make larger profits when selling power (trading) and reduce penalties from imbalances in the operation. The present work describes a new integrated approach for analysing wind-storage solutions that make use of probabilistic forecasts and optimization techniques to aid decision making on operating such systems. The approach includes a set of three complementary functions suitable for use in current systems. A real-life system is studied, comprising two wind farms and a large hydro station with pumping capacity. Economic profits and better operational features can be obtained from the proposed cooperation between the wind farms and storage. The revenues are function of the type of hydro storage used and the market characteristics, and several options are compared in this study. The results show that the use of a storage device can lead to a significant increase in revenue, up to 11% (2010 data, Iberian market). Also, the coordinated action improves the operational features of the integrated system. Copyright (c) 2013 John Wiley & Sons, Ltd.

2017

LV state estimation and TSO–DSO cooperation tools: results of the French field tests in the evolvDSO project

Authors
Viania Sebastian, M; Caujolle, M; Goncer Maraver, B; Pereira, J; Sumaili, J; Barbeiro, P; Silva, J; Bessa, R;

Publication
CIRED - Open Access Proceedings Journal

Abstract

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