The Innovative Process in the Interruption of Wind Power in Portugal

Energy Purchase Department, EDP Serviço Universal SA, Portuguese Last Resort Supplier, Coimbra, Portugal

Abstract

The production of energy under a special regime of renewable origin has had a sustainable evolution in Portugal. Since the 1990s, the percentage of renewables has been growing steadily, with special emphasis being given to wind, photovoltaic, mini-hydro, biogas and high-efficiency cogeneration [1]. More recently there has been a strong push in promoting small scale production and self-consumption [2]. There are several periods of time when the country’s electricity load is 100% supplied by renewable energy. There are also periods when surplus renewable energy is exported to Spain. However, there are some periods when production exceeds consumption and it is then necessary to reduce wind power production. In Portugal there is an innovative process underway to carry out this reduction, which was systematized by the General Department of Energy and Geology in Order No. 8810/2015, of August 10. Thus, in the case of wind power plants that receive power reduction orders, the remuneration equivalent to that which is lost is paid by the other producers, through the Last Resort Supplier. Those power plants that have not been interrupted pay a percentage of their power produce to the Last Resort Supplier, to compensate those that have been interrupted. The total of the payments made to the producers whose power plants were interrupted must equal the receipts from those plants that continued to produce energy. This new concept is exemplified in this paper by the wind power cut that occurred on March 12 and 13, 2017 in Portugal. An explanation of what occurred on that day is presented, to understand why this cut was made, having been reached the limits of energy exports to Spain. To implement this new interruptible compensation model it was necessary to develop a mathematical algorithm and include it in the computer application named GPCE - Producers’ Management and Energy Purchase, that belongs to the Last Resort Supplier. When the interruption occurred in March 2017, the computer system worked correctly. The sum of the payments made equaled the sum of the receipts. It should be noted that there was a high degree of discipline shown by the producers.