Regulator says GSI cost remains uncertain as completion estimate slips by a year

Nicosia, Cyprus. The Great Sea Interconnector (GSI) is expected to begin operating a year later than originally projected, with its ultimate cost still unclear, the energy regulator told MPs on Tuesday.

Cost estimate remains uncertain

Polis Lemonaris, who heads the energy regulatory authority (Cera), briefed parliamentarians on progress with the proposed undersea electricity connection between the grids of Cyprus and Greece.

He said a reliable final cost estimate was not yet possible. Based on comparisons with other interconnectors, he considered the €1.9 billion figure unrealistic.

Lemonaris also warned that costs would probably increase if the continuing seabed surveys indicated that the cable needed a different route.

Funding shares and operating expenses

Using €1.9 billion as the baseline, Lemonaris outlined the current allocation of costs: 63 per cent for Cyprus and 37 per cent for Greece. After deducting EU grants totalling €657 million, the respective contributions would be €749 million and €440 million.

He said the contracting parties would split operating expenses equally. Those expenses amount to €2 million a year before completion, rising to €15.5 million annually once the interconnector is operating.

Under the agreed incentives, Cyprus is to contribute €25 million annually during 2025-2029, subject to a €125 million ceiling, Lemonaris said. The initial €25 million instalment remains unpaid to Admie.

Cera review of expenditure

Admie, the independent electricity transmission operator in Greece and the GSI project promoter, submitted a filing in 2025 reporting expenditure of €302 million.

After examining the supporting documents, Cera determined that expenditure up to that point amounted to €82 million.