Two different incidents, each with a different cause, were behind the power outages recorded last Friday and Saturday. The second incident also brought renewed attention to the way the electricity connection between the areas under the control of the Republic of Cyprus and the north operates under the framework of Confidence Building Measures, and whether this interconnection represents a risk or a safety net for the system.
Speaking to Politis, Haris Zavallis, Assistant Director of the National Energy Control Centre (NECC) of the Cyprus Transmission System Operator, stressed that the two incidents were unrelated.
Friday's incident
In Friday's case, the problem resulted from a temporary loss of communication between the Distribution Control Centre and photovoltaic parks connected to the distribution network.
The inability to control those installations triggered the automatic shedding of approximately 140 MW of consumer load, with power supply restored within about one hour.
According to Zavallis, this was an exceptionally large loss, considering that the largest conventional generating unit currently on the system has a capacity of around 120 MW.
He said the incident highlighted the need to identify the telecommunications problem involved and introduce additional safeguards.
Saturday's fault originated in the north
The cause of the outage recorded early Saturday morning was entirely different.
At around 5:51am, a fault within the electricity network in the north caused a loss of generation capacity. Because the two parts of Cyprus's electricity system are interconnected, the disturbance was immediately felt in the government-controlled areas.
Load shedding was initially activated in Part B of the system, namely the north. Shortly afterwards, automatic protection mechanisms were also triggered in the government-controlled areas, resulting in load shedding of about 20 MW.
The disruption lasted approximately 18 minutes before the system was stabilised once again.
Both Zavallis and Christina Papadopoulou, spokesperson for the Electricity Authority of Cyprus (EAC), explained that this effect is a natural consequence of the electrical connection between the two sides.
According to Papadopoulou, the two systems are linked at two separate points under Confidence Building Measures.
"When there's a problem on our side, instability can appear in their system. Likewise, when they have a problem, the network in the government controlled areas can be affected," she said.
Two parts of one system
Zavallis explained that Cyprus's electricity network essentially consists of two parts:
- Part A: the government-controlled areas
- Part B: the north
The two parts are connected at two points and, electrically speaking, operate as a single system at the same frequency of 50 Hertz.
This means that a sudden loss of a generating unit, a fault in the transmission network or a significant fluctuation in renewable energy production instantly affects frequency on both sides of the island.
To explain the concept, Zavallis compared the system to a tandem bicycle.
"To put it simply, it is like a tandem bicycle with two riders pedalling together. Because the pedals are connected, they turn at exactly the same speed for both riders. If one suddenly stops pedalling, the speed immediately drops for both, affecting the entire journey."
He added that the other rider must then exert more effort to maintain speed, while the bicycle's momentum, equivalent to inertia in an electricity system, helps slow the rate of decline.
Papadopoulou summed it up even more simply:
"We affect them and they affect us."
The relationship is therefore two-way.
Why power is cut
A critical requirement of any electricity system is the constant balance between production and consumption.
At every moment, the electricity generated must match the electricity being used.
If a significant amount of generation is suddenly lost while demand remains unchanged, system frequency begins to fall.
When frequency drops below defined safety thresholds, protection mechanisms activate within fractions of a second. These mechanisms temporarily disconnect predetermined consumer loads to reduce demand and restore balance.
This process is known as load shedding.
Without it, an uncontrolled frequency decline could lead to a cascade of generating units disconnecting, ultimately causing a full system collapse and a nationwide blackout that could take many hours to restore.
As Papadopoulou explained, the logic behind protection measures is simple: rather than have 1,000 consumers lose power, perhaps only 50 are temporarily affected.
In other words, a small controlled interruption is designed to prevent a much larger uncontrolled one.
Nobody is giving away electricity
The interconnection periodically raises questions about whether electricity is being provided free of charge to the occupied areas.
Both Zavallis and Papadopoulou rejected that claim.
"We don't give them electricity for free and they don't give us electricity for free," Papadopoulou said.
Electricity can flow in either direction depending on conditions within the system at any given time, but these quantities are recorded.
According to Zavallis, until October 2025, energy transfers between the two sides were handled through balancing arrangements under the Confidence Building Measures framework.
Since the launch of the competitive electricity market, however, financial settlements are now applied according to the amount of energy transferred.
The connection also acts as a safety net
The fact that a fault on one side can affect the other naturally raises the question of why the two systems remain connected.
The answer lies in the other side of the same interconnection. Although disturbances can be transferred between the two networks, the connection also provides greater resilience and helps prevent large-scale blackouts.
As Zavallis explained, the participation of more conventional generating units within a combined electrical system increases what engineers call inertia.
The greater the system's inertia, the more slowly frequency changes when generation is lost. This gives operators and protection mechanisms more time to react.
Using the tandem bicycle analogy again, it is similar to increasing the bicycle's mass: the greater the mass, the harder it is for speed to drop suddenly.
This is particularly important for Cyprus, which operates a relatively small and electrically isolated power system.
The automatic technical response of both sides during major faults therefore acts as a protection mechanism for overall grid stability.
While a disturbance can indeed be transmitted across the interconnection, the same connection increases reaction time and reduces the risk of a widespread blackout.
Papadopoulou summed up the situation with a simple phrase:
"More or less, each side helps save the other."
