Jorge de Sousa

The value of a pumping-hydro generator in a system with increasing integration of wind power

Portugal established a strong commitment to increase the installed renewable capacity in order to decrease its external energy dependency. These goals are being achieved mainly due to increasing levels of wind power. One of the main characteristics of wind power is the inherent unpredictability and variability. By allowing the energy storage, pumped-hydro units are able to cope with this drawback, promoting the match between generation and consumption. This paper presents a model based on market prices to determine the optimal bidding strategies that enable the total profit maximization of a pumped-hydro unit. It is considered that this unit participates in the Iberian day-ahead electricity market and in the portuguese ancillary services market. The optimal bids of the unit were calculated for scenarios with different levels of wind energy in the day-ahead market. The results showed that most of the income of the pumped-hydro unit was obtained from the spinning reserve market.

Emissions trading impact on the power industry with application to the Iberian Electricity Market

The purpose of this paper is to evaluate not only the impact of CO2 emissions trading on the Iberian electricity market (IBELM) power industry, but also the likelihood for the reduction in the electricity sector emissions. A simulator for electricity and carbon markets (SIMEC) was developed for that purpose. Given the system power plants characteristics, demand data and CO2 allowance prices, SIMEC computes the electricity market clearing price, power generation by technology, CO2 emissions and power industry profits. A rise in electricity prices is expected when CO2 constraints are in place with a sharp increase in off-peak hours, when normally coal power plants clear the market. Increases in electricity prices are evaluated for different scenarios of allowance prices. Producers that do not face carbon liabilities or facing less carbon liabilities than the market clearing technology will have a positive effect on profits. Moreover, due to the fact that fuel switching takes place only for higher CO2 allowance prices than the EU 2005 emissions trading market prices, a global reduction in the Iberian power industry emissions is not likely to occur.

A risk management model for trading electricity in the spot market and through bilateral contracts

This paper presents a model for evaluating the optimal strategy of a generation company (Genco) that trades electricity in a competitive market, where two possible energy transaction markets are considered: the spot market and the bilateral contract market. In this context, the Genco tries to maximize its profits and to minimize the corresponding risks by selecting the optimal balance between the two possible transaction markets (spot and bilateral). The risk considered has different sources, named risk factors, which are divided into two categories: price and volume risk factors. Numerical results are obtained using Monte Carlo simulation implemented in Matlab, which is applied to Genco that holds a diversified portfolio of generation technologies, for a time horizon of one year. The results show that the Genco can profitably take advantage of both bilateral contracts and spot market trades.

Is the electric vehicle a solution for the wind power integration in the Portuguese power system

The integration of Plug-in electric vehicles in the transportation sector has a great potential to reduce oil dependency, the GHG emissions and to contribute for the integration of renewable sources into the electricity generation mix. Portugal has a high share of wind energy, and curtailment may occur, especially during the off-peak hours with high levels of hydro generation. In this context, the electric vehicles, seen as a distributed storage system, can help to reduce the potential wind curtailments and, therefore, increase the integration of wind power into the power system. In order to assess the energy and environmental benefits of this integration, a methodology based on a unit commitment and economic dispatch is adapted and implemented. From this methodology, the thermal generation costs, the CO2 emissions and the potential wind generation curtailment are computed. Simulation results show that a 10% penetration of electric vehicles in the Portuguese fleet would increase electrical load by 3% and reduce wind curtailment by only 26%. This results from the fact that the additional generation required to supply the electric vehicles is mostly thermal. The computed CO2 emissions of the EV are 92 g CO2/kWh which become closer to those of some new ICE engines.

Strategies for the integration of wind energy into the grid: An application to the Portuguese power system

The integration of wind energy into the grid is responsible for some constraints in the operation of the power system such as power unbalances between generation and demand due to the fact that higher wind power availability occurs in periods of lower demand.

The impact of the Iberian Electricity Market on the competitive behavior of generating companies using a conjectural variations approach

The integration of the Portuguese and Spanish electricity markets came into force on the July 2007 with the creation of the Iberian Electricity Market (IBELM).

Environmental dispatch of the portuguese power system for CO 2 emissions reduction

The present paper uses the concept of the environmental dispatch minimizing the CO2 emissions associated with the thermal generation of a power system. The environmental dispatch is applied to the Portuguese system and the respective results are compared to the results of a classical economic dispatch. The environmental and economic dispatch results comparison assumes the reference emissions allowances price of 20 euro/ton CO2. However, in order to understand the influence of the CO2 emissions allowances prices on the economic dispatch results, a sensitivity analysis was performed, considering different emissions allowances prices.

Application of a conjectural variations model to analyze the competitive behavior in the Iberian electricity market

Electricity market prices can be influenced by many drivers, such as fuel costs, CO2 emission prices, hydro and other renewable production and strategic behavior of firms that participate in the market. One of the aims of the liberalization process of the electricity industry was to bring electricity prices more in line with costs. Therefore, the influence that the strategic behavior of firms might have in market prices is a concern. This paper analyzes the strategic behavior of three medium size firms acting in the Iberian electricity market (IBELM) in the first year after its implementation, that is, from July 2007 to June 2008. This strategic behavior is analyzed by computing an hourly competitive parameter which is obtained from a conjectural variation model. Then the evolution of the monthly average of this conjectural variation parameter is studied. Results showed that some of the analyzed firms did not reflect in market prices the increase in fuel costs and in CO2 emission prices that occurred in the first six months of 2008.