What is the SIOS?

The System Operator's Information System (SIOS) has been drawn up by Red Eléctrica to manage and provide information on processes related specifically to the electricity market. The system offers full public information on the SIOS Internet server.

Red Eléctrica is responsible for operation of the electricity system and as such guarantees the continuity and safety of the supply and proper coordination of generation and transmission. It therefore carries out a set of processes, based on the daily matching up of the market by the market operator, leading to definition of each of the hourly programmes and allocation of complementary services allowing safe, economic operation of the system in real time.

These processes constitute the operating markets, which are managed by Red Eléctrica in order to adapt production programmes resulting from the daily and day-to-day markets to technical requirements for a high-quality, safe electricity supply.

The basic functions of the SIOS are as follows:
- To allow electricity market agents to use markets for complementary services.
- To coordinate with the market operator.
- To allow operators in the Electricity Control Centre to meet the needs of the system by allocating the bids that are required by market rules.
- To publish for the information of agents the requirements, results of the matching up process, restrictions and programmes to be followed by power stations.

According to article 28 of Royal Decree-Law 6/2000 dated 23 June:
- "The system operator shall make public the result of technical operating processes for which it is responsible."
- "The market operator and the system operator, within the scope of their respective competencies, shall publish aggregate data on volumes and prices, as well as data on commercial capacity, intra-community and international exchanges by frontier and, where appropriate, by country, as well as related aggregate curves for supply and demand."
- "Under all circumstances, the market operator and the system operator shall guarantee the secrecy of confidential information provided by market agents, as established in sections 2f) of article 27 and 2k) of article 30 of Royal Decree 2019/1997."
- "Demand forecasts produced by the system operator shall refer to full months and shall be published during the first fortnight of the month prior to that of the forecast."