Until the year 2009, the interchange of electricity between 24 countries of continental Europe was coordinated by the Union for the Coordination of the Transmission of Electricity (UCTE).
In 2009, UCTE has been substituted by the European network of transmission system operators for electricity (ENTSO-E). As a consequence, no UCTE electricity mix should be used any longer.
For more information see: https://www.entsoe.eu/about-entso-e/inside-entso-e/a-proud-history/ucte/Pages/default.aspx
In the guidelines for ecoinvent version 3 it states that it is not possible to have markets with overlapping geographies in the ecoinvent database. Therefore it is not possible to provide a market for electricity in Europe since there are markets for all the individual countries present in the database.