[2] On 27 June 2008, 36 European electricity transmission system operators (TSOs) signed a declaration of intent in Prague to create the ENTSO-E.[3] ENTSO-E was established on 19 December 2008 in Brussels by 42 TSOs as a successor of six regional associations of the electricity transmission system operators.

The former associations ETSO, ATSOI, UKTSOA, NORDEL, UCTE and BALTSO became a part of the ENTSO-E, while still offering data by their predecessors for public interest.

[6] Creation of ENTSO-E was initiated by the adoption of the European Union third legislative package on the gas and electricity markets.

[7] As a result, the third legislative package on the EU gas and electricity markets was adopted by the European Commission in September 2007.

[...] ENTSO-E aims to be the focal point for all technical, market and policy issues relating to TSOs and the European network, interfacing with power system users, EU institutions, regulators and national governments.

TSOs provide grid access to the electricity market players (i.e., generating companies, traders, suppliers, distributors, and directly connected customers) according to non-discriminatory and transparent rules.

[12] Due to Brexit three Great Britain based operators left and only Northern Ireland's SONI remains from the UK.

The benefits of synchronous areas include pooling of generation capacities, common provisioning of reserves, both resulting in cost-savings, and mutual assistance in the event of disturbances, resulting in cheaper reserve power costs (for instance in case of a disturbance or outage).

543/2013 [25] on submission and publication of data in electricity markets makes it mandatory for European Member State data providers and owners to submit fundamental information related to electricity generation, load, transmission, balancing, outages, and congestion management for publication through the ENTSO-E Transparency Platform.

The ten-year network development plan 2016 (TYNDP)[26] is drafted by ENTSO-E, in close cooperation with stakeholders, under scrutiny of ACER and is finally adopted by the European Commission.

[27] The list of PCIs is not fixed by ENTSO-E and is subject to a different process led by the European Commission and EU Member States.

The benefit analysis methodology[24] is developed by ENTSO-E in consultation with stakeholders and adopted by the European Commission.

The ERAA analyses resource adequacy on the decade ahead, accounting for investment and retirement decisions.

In addition, expert groups on data, network codes implementation, and EU affairs provide specific expertise and work products to the association.