A synchronisation fault at a key coal-fired plant led to a nationwide outage after frequency plunged to 56 Hz, exposing once again the operational fragility of the country’s isolated power system, Strategic Energy website reports in its analysis of the Monday 23 February national blackout.
The Dominican Republic’s National Interconnected Electricity System (SENI) collapsed on that Monday morning after the abrupt loss of generation at strategic thermal power plants. According to official records from the grid operator, system frequency fell to 56 Hz following a sharp drop in power injected into the grid, resulting in a nationwide blackout.
Preliminary reports linked the event to a failure in the synchronisation system at the Punta Catalina power station, one of the country’s largest coal-fired plants. Technical sources confirmed that the plant’s synchronisation equipment malfunctioned. A manual intervention was attempted but failed to stabilise operations, leading to the unit’s disconnection.
The outage of this large thermal block was not contained. Its disconnection triggered the simultaneous trip of the Quisqueya 1 and Quisqueya 2 units, operated by EGE Haina, causing a sudden and significant reduction in available generation capacity.
Within seconds, the balance between supply and demand was disrupted beyond the system’s automatic response capability.
Strategic Energy explains that in islanded systems such as the Dominican Republic’s, which lacks international interconnection to buffer disturbances, the sudden loss of large thermal units can trigger a total system collapse if spinning reserve fails to compensate immediately.
The frequency drop to 56 Hz activated automatic protection schemes, further disconnecting loads and generating units. Once frequency deviates so severely from the nominal 60 Hz standard, cascading outages become increasingly difficult to contain.
The Dominican Electricity Transmission Company (ETED) confirmed that technical teams are investigating the root cause and working to restore service as quickly as possible.
On 11 November 2025, another almost total power system collapse had occurred, with the SENI going from serving approximately 3,000 MW of demand to operating with just 41 MW available.
The power outages expose structural limitations related to frequency support, protection coordination and operational resilience in the face of large-scale disturbances. Strategic Energy highlights that beyond the specific synchronisation failure, the event renews debate over the structural robustness of the Dominican electricity system. The concentration of generation capacity in high-capacity thermal units means that failures in control or protection systems can have immediate systemic consequences.
The recurrence of large-scale blackouts within a relatively short period underscores the need to strengthen operational resilience. This may include modernising protection schemes, enhancing dynamic frequency response, expanding fast-response reserves and evaluating energy storage solutions capable of improving grid stability.
Another analysis in El Caribe also looks into the urgency for energy storage solutions to enhance grid stability. Until this is down, the analysis says that the local National Interconnected Electricity System (SENI) remains at high risk for another major failure, particularly during the upcoming summer months.
Experts attribute the collapse to a high penetration of solar energy (exceeding 35% at the time of the event) without Battery Energy Storage Systems (BESS). This lack of “inertia” makes the grid unstable. The El Caribe report explains that the Monday, 23 February 2026 blackout was triggered by an incorrect maneuver of a transformer at the Los Mina substation. However, the situation escalated into a “domino effect” because protection devices were not synchronized and the Automatic Load Shedding Scheme (EDAC) failed to activate properly.
The Dominican Electricity Transmission Company (ETED) is urged to install BESS to regulate frequency and compensate for the intermittent nature of renewable energy. Likewise, authorities emphasize the need to review the “root cause” and ensure that protection schemes (EDAC) are functional and synchronized to prevent localized faults from collapsing the entire national grid.
The Dominican government recently put in place the requirement for new renewable installations to come with storage capacity.
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Noticias SIN
25 February 2026