In an interview, ETEK member Iakovos Charalambous raises technical and financial questions regarding the GSI, as well as issues of transparency
Electrical engineer and ETEK member, Iakovos Charalambous speaks to “ALPHA on Sunday” and sheds light on many unknown aspects of electrical interconnections, particularly the interconnection between Cyprus – Greece, the Great Sea Interconnector. Expressing doubts about the project, he notes that “even if and when the interconnection is completed, it cannot be taken for granted today that Cypriot consumers will pay a lower price per kilowatt-hour.”
He therefore raises questions about “the total cost of the project, potential cost overruns, the financing costs, the degree of utilization of the cable, future electricity prices in the Cypriot and Greek markets, and the portion of the cost that will be recovered from Cypriot consumers.”
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He also asks: “The most important conclusion for the public debate surrounding the GSI is this: at what cost, with what risk, and is this the best energy investment for Cyprus?”
He also raises the issue of transparency, emphasizing that, “the Republic of Cyprus itself requested an independent review of the cost-benefit analysis, with a special emphasis on the impact on electricity prices. This confirms that the question has not been answered simply by the fact that the project is an interconnection of European interest. The first relevant tender was closed without an award, as no bidder was selected.”
What does “electricity interconnection” mean?
It is the physical connection of two different electrical systems so that electricity can flow in both directions between them. This is achieved through underground cables or overhead lines, substations, protection and control systems, and, in the case of the GSI, very large conversion stations at both ends. For the GSI, a 1,000-megawatt system is planned for the first phase, with a maximum water depth of 3,000 meters, which will be confirmed once the detailed seabed survey is completed. Interconnections increase security of supply, allow for imports when there is a shortage and exports when there is a surplus, increase competition among producers, enable better utilization of renewable energy sources, and reduce the need for each country to maintain all the reserve capacity it might need on its own. For Cyprus, the particular benefit is that it will no longer be a completely isolated power system.
Are there currently cables of the same length and depth as the GSI?
Not entirely comparable in terms of the combination of length, depth, and voltage. There are very long interconnections and there are very deep ones, but the Crete–Cyprus interconnection combines both great distance and depth. Subsea interconnection technology was developed to serve interconnections at shallower depths, and the majority of subsea interconnections are at depths of less than 750 meters. For example, when the Sicily–Sardinia interconnection—spanning 480 km at a depth of 2,150 m—is completed, it will set a world record.
Now that construction of the cable has begun, doesn’t that prove the technology exists?
It proves that the manufacturer had a technical solution it considered feasible and had assumed a contractual obligation. Nexans had already received significant payments and had been manufacturing the cable since 2025. However, this does not mean that certification of the entire system at 3,000 meters had already been completed. This was completed gradually in 2026. It is similar to the construction of a new type of aircraft: components can be manufactured before the final system has been fully certified. The big question mark concerns laying the cable at such a depth, not its construction.
Why is laying the cable such a major challenge?
Because the project combines unprecedented depth, a very long length, and difficult installation conditions:
- Enormous mechanical load: at a depth of 3,000 meters, a very long and heavy section of cable hangs from the ship. The tension must be constantly monitored to ensure that the cable does not break, snap, or bend beyond permissible limits.
- Precise route control: The ship must position the cable along a predetermined route, avoiding steep slopes, fissures, unstable sediments, undersea landslides, and other obstacles.
- Weather and sea conditions: Waves, winds, and ocean currents affect the cable’s position and mechanical stress. Earthquakes—even minor ones—occur daily in the Mediterranean Sea, accompanied by submarine landslides and faults. Suitable windows for work may be limited.
- Extremely long length: the successful testing of a section at a depth of 3,000 meters does not guarantee the successful installation of approximately 900 kilometers of cable. As the route lengthens, the duration of the work and the likelihood of technical or operational difficulties increase.
- Cable joints: Because the route usually cannot be covered by a single length of cable, extremely reliable joints are required, which must withstand both installation and decades of operation.
- Limited repair capabilities: locating, retrieving, and repairing a cable at a depth of 3,000 meters is much more difficult and expensive than in shallow waters.
- Limited number of suitable vessels: Very few vessels worldwide have the required carrying capacity, voltage testing equipment, and capability to operate in such deep waters. Their availability affects costs and the timeline.
- Geopolitical risk: a potential interruption of exploration or operations could result in the vessel’s withdrawal and redeployment, incurring significant additional costs.
Are there studies confirming that the project is feasible and technically and economically viable?
There are older studies and technical assessments suggesting that the project is feasible and may offer significant economic and energy benefits; however, these are based on outdated data for depths of 2,000 meters.
Although Nexans completed the certification of the cable system for installation in 2026, it is both the manufacturer and a contractor for the project. Consequently, the certification does not in and of itself constitute an independent assessment of the entire project. Furthermore, the cable certification does not automatically cover all the risks along the approximately 900 km route.
Regarding the project’s financial viability, the European Union approved a grant of approximately €657.9 million for the Cyprus–Crete section. However, the 2016 assessment warned that the results should be treated with caution, as they were highly sensitive to assumptions about future electricity generation. Furthermore, it was based on an older design, different costs, and a different timeline.
Inclusion in European projects and the grant are strong positive indicators, but they do not guarantee that the final cost will not increase, that the cable will be utilized to the extent projected, that revenues will cover costs, that the price per kilowatt-hour in Cyprus will decrease, and that geopolitical delays will not compromise the project’s viability.
Given these facts, do you agree that the funding requests made so far resemble putting the cart before the horse?
The fact that funding was requested before the cable’s final certification does not in itself prove that the process was irrational. Without timely funding, such a project could not even proceed to the required testing.
However, the analogy holds true if: consumers begin paying before the net benefit to them has been demonstrated, there is no up-to-date independent cost–benefit analysis, a reliable final cost has not been determined, geopolitical delays have not been quantified, it is unclear who will bear the cost overruns or the risk of non-completion, the expected impact on bills in cents per kilowatt-hour has not been presented, and alternatives, such as storage and domestic flexible generation, have not been compared on an equal footing.
A distinction must also be made between three different decisions:
- European CEF grant: reduces the cost that would otherwise have to be financed. However, it does not in itself guarantee ultimate economic viability.
- Financing from investors or banks: requires an assessment of repayment capacity and risk allocation.
- Recouping funds from consumers: This requires greater transparency, because the risk is transferred to individuals who do not decide whether to invest but are obligated to pay. In other words, if something goes wrong, the consumer will bear the cost, and this must be made clear.
Does a feasibility study not also take into account geopolitical factors, such as Turkey?
A comprehensive feasibility study must also examine the geopolitical dimensions of the project. In the case of the GSI, the risk of Turkey’s positions hindering or delaying exploration, drilling, and potential future repairs must be specifically assessed. A general reference to geopolitical risk is not sufficient. Specific scenarios for delays, route changes, or failure to complete the project are required, including a calculation of the additional costs and a clear determination of the share to be borne by each state, investor, or consumer. At the same time, the existence of geopolitical risk does not in and of itself mean that the project is unfeasible. It means that its viability cannot be reliably assessed without taking this risk into account.
In the case of the GSI, the Turkey factor must be considered at least in terms of potential obstruction or delay of surveys and cable laying, a route change—and thus additional cable length—schedule delays, increased vessel costs, insurance and financing, protection of the cable during operation and repairs, and the risk of temporary or permanent inability to complete the project.
ADMIE has publicly acknowledged that the geopolitical risk had been foreseen and that the relevant matters are now being handled at the diplomatic level, as they exceed its jurisdiction. This indicates that the risk is real and not merely theoretical.
