“Cuba’s National Electric System currently requires a structural intervention that combines recovery of generation capacity in generator sets distributed throughout the national territory, stabilization of the thermal park, continued planned incorporation of solar parks with energy storage, reconstruction and modernization of the electrical networks and demand management.”
This is the view of Víctor Puentes , an energy specialist currently residing in Madrid, with experience in managing energy companies in Cuba, who believes that the crisis cannot be resolved through a single technology or with isolated measures.
Their diagnosis is based on a system with a peak demand of around 3200 MW but with a much lower effective availability at the moment.
The difference between installed capacity and actually dispatchable capacity constitutes one of the main operational problems of the Electrical System.
Necessary steps in the short and medium term
To immediately recover a generation capacity that allows eliminating, in the short term, the long blackouts that keep the population, society, services and industry in a real crisis and while terrestrial generation is being rehabilitated, the specialist proposes that it is necessary to proceed to "immediately and temporarily incorporate a group of floating generation barges".
“These units will need to be distributed across different bays on the island and connected to substations and subtransmission or transmission networks with sufficient, reviewed capacities. Their function would be to provide stable generation to cities, industrial facilities, and priority loads almost immediately, and also cover peak demand and contingencies,” Victor Puentes points out.
“The barges should not be used as a permanent substitute for the national energy fleet, but as a shock solution during the recovery period of the land-based units,” he adds.
The expert proposes limited-term, transparent contracts linked to specific operational objectives. He also points out that their implementation, due to their high cost, will require long-term government loans and fuel supply guarantees.
The selection of sites would have to consider the evacuation capacity of the network, port infrastructure, fuel logistics and the condition of nearby substations.
Next simultaneous steps: Recover between 1500 and 2000 MW of distributed generation across the country.
The first priority should be the accelerated rehabilitation of distributed generation based on diesel and fuel oil engines.
Why? Cuba has a significant installed capacity in this type of unit, but its availability has reportedly fallen below 30% due to a lack of maintenance, spare parts, critical components, and fuel.
Therefore, Puentes proposes implementing a national program that includes engine overhauls, spare parts acquisition, auxiliary systems recovery, and maintenance contracts with specialized manufacturers and suppliers.
With fuel secured and coordinated implementation, it is estimated that it would be possible to recover more than 1500 MW of firm capacity during the coming months.
“The advantage of this alternative is that it would allow the use of existing sites, connections, substations, and infrastructure. Compared to building new power plants, rehabilitating existing assets could deliver results in considerably shorter timeframes,” he says.
“However, the recovery must be accompanied by a permanent maintenance plan, spare parts inventories, and technical support contracts. Otherwise, availability will deteriorate again in a short time,” he adds.
Another simultaneous step would be to define which thermal power plants can be brought back online. In other words, to recover the thermoelectric infrastructure vital for the stability of the National Electric System.
Several Cuban units are operating beyond their original lifespan and experience frequent downtime. Therefore, Puentes proposes abandoning a uniform strategy and conducting an individual technical evaluation of each unit.
“Units that can still provide reliability should receive selective major repairs. On the other hand, those that are structurally worn out should be incorporated into a progressive replacement program,” the interviewee mentions.
The goal would be to maintain a core of efficient and predictable thermoelectric plants capable of providing synchronous generation, inertia, frequency regulation, and continuous operation capability.
“In a system with limited reserve capacity, the unexpected shutdown of a unit can cause frequency deviations and cascading outages. Therefore, thermal recovery should not be measured solely in nominal power, but also in availability, failure rate, and actual capacity to remain in service,” Puentes adds.
And what about renewable energy? The focus should be on installing renewable energy generation facilities with storage and evacuation studies.
“The expansion of photovoltaic and other renewable energy installations is necessary to reduce fuel consumption, but it must progress according to technical integration criteria. Solar generation helps alleviate the deficit during the middle of the day, although it does not, on its own, solve the nighttime peak nor automatically provide the stability services that the grid needs,” emphasizes the energy specialist currently based in Madrid.
Therefore, Puentes argues that the installation of new solar parks should continue, always accompanied by BESS systems (battery-based energy storage systems) and prior studies of energy evacuation capacity.
Storage could provide different functions:
- Shift of solar energy towards the afternoon and evening.
- Rapid frequency regulation.
- Voltage control.
- Operational reserve.
- Reduction of ramps.
- Support for the formation and synchronization of micro-islands.
- Reduction of renewable waste discharges.
Although the power and duration of each BESS should be defined according to the needs of the node and not by a uniform criterion for all projects.
“Before connecting new renewable generation, it would also be necessary to analyze the thermal capacity of the lines, short-circuit levels, voltage regulation, contingency behavior, and the available capacity of the transformers. Renewable expansion must, of course, be coordinated with investments in the grids,” he states.
“Furthermore, the development and expansion of renewable energy generation should include wind farms, some of which already exist in the north of the eastern province of Holguín, an area that has a wind potential already well studied by Cuban specialists,” he adds.
Power grids: Recovery of generation will not be enough if the grids cannot transport and distribute the energy.
Puentes identifies as priorities the reinforcement of saturated energy corridors, the modernization of substations of various voltage levels, the review and improvement of distribution circuits, along with the replacement of overloaded distribution transformers.
“Sustained overload increases losses, raises operating temperature, accelerates insulation aging, and increases the risk of failures. In addition, reconnections after prolonged blackouts produce simultaneous load inputs that can subject transformers and circuits to additional stress,” he explains.
In his view, the network plan should include
- Replacement and upgrading of transformers.
- Modernize the distribution transformer factory.
- Creation of transformer repair workshops in all provinces.
- Reinforcement of transmission and sub-transmission lines.
- Reconfiguration of saturated circuits.
- Modernization of protections.
- Reactive power compensation.
- Substation automation.
- Improvement of operational telecommunications.
What are other simultaneous steps? One of them is the use of a fully operational national supervisory control and data acquisition (SCADA) system, considering that the operation of a weakened network requires telemetry, real-time monitoring and remote control capability over substations, switches and switching equipment.
“The operator must have immediate access to power flows, voltage levels, frequency, transformer load, and the status of protection systems. In a national electrical system with limited reserve capacity, automation is essential to isolate faults, prevent their propagation, and accelerate restoration processes through electrical micro-islands,” Puentes explains.
Furthermore, the system's recovery also requires addressing electricity losses, which already exceed 13%. A reduction of just a few percentage points would free up a significant amount of energy without requiring the construction of new generation capacity.
“The program should include phase balancing, conductor renewal, replacement of inefficient transformers, voltage level correction, improved measurement, and reduction of non-technical losses,” he explains.
In parallel, Puentes outlines the idea of developing an energy efficiency plan aimed at large consumers, industries, pumping systems, air conditioning and loads capable of shifting their consumption outside of critical hours.
“Demand management should help reduce peak demand, improve the load factor, and decrease the need for emergency power generation,” the interviewee points out.
Finally, the strategy proposed by Puentes to recover Cuba's National Electric System can be summarized in a sequence of the following steps.
- Incorporate barges as immediate and temporary backup.
- Secure fuel and recover distributed generation.
- Carry out selective repairs in the thermoelectric power plant park and replace units that are no longer technically recoverable.
- Strengthen transmission, sub-transmission and distribution of the networks.
- Complete the automation and national SCADA system.
- Expand renewable energy sources in accordance with grid capacity by incorporating storage. (BESS)
- Reduce losses and manage demand.
Cuba's electricity problem is not solely a generation deficit. It is a crisis of firm capacity, reliability, fuel, grid infrastructure, and operational control. Therefore, stabilizing the National Electric System (SEN) requires integrated planning for generation, transmission, distribution, and ancillary services.
“The recovery of the Cuban electrical system does not depend on a single technology or a single decision. It is an engineering problem that requires in-depth studies, planning, operational discipline, and rigorous execution.”
Cuba has sufficient technical capacity to face these transformations, but, Puentes concludes, medium and long-term financing is required.