Implementing the largest synchronisation program project Harmony Link and preparing for the construction of the electricity connection between Lithuania and Poland, the Lithuanian electricity transmission system operator Litgrid has announced the purchase of a 700 MW High Voltage Direct Current (HVDC) cable. The construction of this cable is a key part of the Harmony Link project. 
The call for tenders published on Friday, August 13th provides that that the contractor will have to lay a HVDC cable that will connect the Žarnowiec substation in the Pomeranian region of Poland with the Darbėnai substation in the Kretinga district of Lithuania. An underground cable will be laid from Darbėnai to the Baltic Sea coast. Applications for approximately 350 km of Harmony Link cable contractors will be welcome until September 30.
“The submarine connection with Poland will ensure the reliability of electricity supply after synchronisation with the continental European networks and will significantly increase the energy security of all three Baltic States. Therefore, for the implementation of the largest synchronisation program project we are looking for a reliable, experienced and qualified contractor who will be able to implement the project on time and ensure the quality of work,” says Rokas Masiulis, CEO of Litgrid.
The terms of the procurement documents stipulate that the supplier must have manufactured in the last 8 years at least one HVDC cable system covering the sections of submarine and continental cable, also installed at least one HVDC submarine cable of 50 km or longer during this period. In addition, the supplier must have successfully completed Prequalification and Type tests for 320 kV or more submarine cables, and its average annual total operating income over the last 3 years or from the date of registration must be at least EUR 170 million.
The contract with the winner is expected to be signed in 2022, and most of the cable construction work will take place in 2023-2025. Construction work is expected to be completed by the end of 2025. The connection is planned to be put into operation after the completion of the construction of the cable installation and converter stations and the completion of a complex testing program.
Preparatory work for the Harmony Link connection is well under way: a route study has been prepared in the Baltic Sea, contracts for the connection and targeted consultations have been signed, a seabed survey and spatial planning procedures are currently underway. Litgrid also acquired a plot and announced the public procurement of the design and construction works of the switchyard in Darbėnai.
The total investment planned for the Harmony Link project is about EUR 680 million of which EUR 493 million will consist of the maximum possible support from the Connecting Europe Facility (CEF). Harmony Link will be the second electrical connection connecting the Lithuanian and Polish systems. Together with the LitPol Link land connection installed in 2016, it will allow synchronizing the electricity systems of the Baltic States with the networks of continental Europe.
The Harmony Link connection is one of 14 Government-approved projects of the synchronization program of extraordinary importance, which includes the extension of the existing LitPol Link connection by adapting it to work in synchronous mode, installation of 3 synchronous compensators, strengthening of internal networks and improvement of system management and IT.
Currently, 3 of the synchronisation projects have already been implemented. These are the extension of the 330 kV Bitėnai transformer substation, the construction of the 110 kV line Pagėgiai-Bitėnai and the reconstruction of the 330 kV line Lietuvos Elektrinė-Vilnius. In total, more than a quarter of all work required for synchronisation has now been completed.
Until now, Lithuania, Latvia and Estonia, together with Russia and Belarus, operate in the IPS/UPS system, in which the electricity frequency is centrally regulated in Russia. Connection to continental European networks and synchronous operation with Poland, Germany and other continental European countries will be ensured by 2025 at the latest.