Ancillary services in the Iberian Electricity market — Current situation and harmonization approaches

This paper addresses the provision of ancillary services in Portugal and Spain in the scope of the Common Iberian Electricity market. The paper reviews the definitions and the international practice regarding ancillary services with emphasis on primary, secondary and tertiary reserves and describes the procedures adopted by the Portuguese and Spanish TSO´s to procure and allocate reserve levels. On the other hand, the paper discusses the models that can be used to enlarge the integration of the reserve markets, namely regarding tertiary reserve. Using data from 2009, the paper presents the results of the simulations that were performed for several situations including an ideal unlimited interconnection capacity, the existing interconnection capacity and an interconnection capacity increased by 300 MW. The results obtained indicate that the adoption of a common tertiary reserve list would ultimately be beneficial for the consumers since the cost of tertiary reserve would be reduced. However, a larger integration and cooperation between the two TSO´s would be clearly required.