Red Eléctrica has developed an information system called the System Operator’s Information System (e•sios) to perform the tasks of information and processes management specifically related to the electricity market.

The e-sios system allows Red Eléctrica to:

  1. Communicate with the Iberian Market Operator, (the Spanish pole - OMIE), with whom the results of the matching process of the Day-ahead Market and successive Intraday Markets are exchanged.
  2. Communicate with Market Subjects who come to Spanish electricity market with offers to buy or sell energy, then to notify the acceptance or rejection of such offers, in a transparent and confidential manner.
  3. Communicate with technicians of the SO (System Operator), from whom it receives the validation of orders and the processing of offers, adjustments due to technical alterations or exceptional situations in the transmission grid, allocation of ancillary services, etc., that will lead to the definition of each of the hourly schedules.
  4. Communicate with the electricity system operators of neighbouring countries, in order to assess the technical capacity of the interconnection lines, as well as the capacity available for commercial use after applying the security criteria in both systems, and to manage grid restrictions regarding international interconnections.
  5. Publish the results of the different markets and schedules, so that each recipient of the same may act accordingly.
  6. To publish the information needed to provide the interruptibility service, service and to request the participation in the interrumpibility auctions, the auction calls and their results.
  7. Store not only the information that enters the system but also the results of the various processes in its historical database.

Under current legislation, Red Eléctrica as system operator is required to make public the results of the markets or operating system processes, ensuring at all times the confidentiality of sensitive information made ​​available by market subjects.

For this, it has developed and published two websites:

  1. Secure web access through a certificate (https://www.esios.ree.es/es/sujetos-del-mercado), in which the market subjects exchange confidential information with the system operator.
  2. e·sios public website (https://www.esios.ree.es), where Red Eléctrica makes publicly available information resulting from the operating processes under their responsibility.

Energy Identification Code (EIC)

Red Eléctrica has been designated by ETSO as the local office responsible for issuing this code.

View all the information from the website of the office.


Website of the EIC Office

The EIC code (Energy Identification Code) was implemented by ENTSO-E, with the aim of creating a unique codification, after analysing the different codification systems used by the TSOs members of the organization. The administration and maintenance of the EIC Codes is responsibility of the Central Issuing Office - ENTSO-E’s Secretariat. Moreover, Local Issuing Offices were designated, one or several for each country belonging to the European Energy Market. Red Eléctrica was designated by ENTSO-E as Local Issuing Office of EIC codes for Spain, in order to handle the requests of the applicants registered in Spain. The EIC code allows the unique identification at a national and international level, in the Energy Markets.

The outstanding characteristics of the renovated website are:

  • Improvement of the security in the connection and user registry operations, and register, cancellation and modification of EIC codes.
  • Inclusion of automatic management of the new types of EIC codes: Z codes (measurement points, connection points) and Y codes (Areas).
  • Implementation of new utilities for localizing and searching EIC codes.
  • User identification while logged.
  • It makes easier to recover a forgotten password.
  • The new process has been implemented in accordance with the ENTSO-E Reference Manual version 5.1.
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Visit the new public website of e·sios, the website of the system operator in www.esios.ree.es/en.

Voluntary price for the small consumer

Red Eléctrica publishes through its website the hourly pricing schedules of ‘energy used’.

EIC issuing office

The EIC issuing office renews its website.

Access to the new website of EIC OFFICE: https://oficinaeic.esios.ree.es