Consumer relief amounting to €3.7 billion is projected for the period 2026–2034 from IPTO’s electrical interconnections linking Greece’s non-interconnected islands to the mainland, according to an information note by the operator.

With the full interconnection of the Cyclades and the double interconnection of Crete with Attica and the Peloponnese, average annual savings on PSO charges for 2026–2030 are estimated at €550 million. In addition, with the integration of the Dodecanese and the islands of the North Aegean into the mainland power system from 2031, annual PSO savings are expected to nearly double to €1 billion.

The net economic benefit for consumers from the construction and operation of the new interconnections is particularly high. Average annual consumer relief is estimated at €416 million, as savings from reduced PSO charges are more than double the total System Use Charges over the same period.

It is noted that these figures take into account the cost of maintaining necessary conventional generation units in “cold reserve”, as well as the full replacement of mazut oil—currently used for local power generation on non-interconnected islands—with diesel fuel, which is nearly three times more expensive, from 2031 onward for environmental reasons. Had the islands remained non-interconnected, this change would have caused significant increases that would have been passed on to all electricity bills.

Notably, the total PSO savings from electrical interconnections—amounting to approximately €7 billion by 2034—are directly comparable to IPTO’s ten-year investment plan budget, which totals €7.5 billion through 2034, highlighting the rapid payback of these projects.