Article 34 1.

Transmission system operators shall establish regional cooperation within the ENTSO for Electricity to contribute to the activities referred to in Article 30(1), (2) and (3). In particular, they shall publish a regional investment plan biennially, and may take investment decisions based on that regional investment plan. The ENTSO for Electricity shall promote cooperation between transmission system operators at regional level ensuring interoperability, communication and monitoring of regional performance in those areas which have not yet been harmonised at Union level.