The Irony of Sanctions: How Cuba Adapted Under Pressure
For over six decades, U.S. sanctions have targeted Cuba’s energy sector as a strategic vulnerability. The approach assumed that restricting access to imported oil would strain the island’s economy. However, in recent years, that assumption faced new challenges. When sanctions intensified, Cuba responded by refining its own heavy crude—a resource that had previously been considered too difficult to process domestically. This shift followed a period of reduced fuel imports, which forced officials to reconsider how existing infrastructure could be used.
The adaptation was driven by necessity rather than preference. When petroleum sanctions were reinforced, Cuba’s access to foreign fuel declined sharply. The Hermanos Díaz refinery in Santiago de Cuba, which had previously processed imported heavy crude, faced an uncertain future. Rather than shutting down, the facility was modified to handle the thicker, more sulfur-rich crude extracted from Cuban oil fields. As Irene Barbado Lucio, the refinery’s director, explained to Granma, the adjustments involved repurposing existing equipment rather than constructing new infrastructure. The choice of the word adequó—meaning “adapted”—was deliberate, emphasizing a pragmatic response to constraints.
The outcome marked a notable change. For the first time, the island produced diesel, naphtha, and other commercial fuels from its own oil reserves. The process relied on thermoconversion technology developed by the Center for Petroleum Research (Ceinpet), which uses heat to break down complex compounds in heavy crude, reducing its viscosity. While the method is resource-intensive, it provided a way forward for a country with limited options. President Miguel Díaz-Canel later described the achievement as overcoming a long-standing assumption that Cuba’s domestic crude could not be refined effectively.
The Crude Reality: Why Cuba’s Oil Presented Both Challenges and Opportunities
Cuba’s oil reserves are diverse, ranging from light to extra-heavy crude, with the latter making up the majority of production. According to Rafael López Cordero, a senior researcher at Ceinpet, the country’s heavy and extra-heavy crude—primarily extracted from fields in Havana, Mayabeque, and Matanzas provinces—presents significant technical challenges. These varieties are dense, viscous, and prone to forming stable emulsions with water, complicating extraction, transportation, and refining. Their high sulfur content also accelerates equipment corrosion and increases air pollution when burned.
Before sanctions tightened, Cuba relied on imported lighter crude to blend with its own, mitigating some of these issues. When those imports became scarce, the country faced a choice: reduce energy production or develop ways to process its existing resources. The decision was straightforward. Currently, a meaningful share of Cuba’s electricity comes from domestically produced oil, primarily burned in older thermoelectric plants. Renewable energy sources, including solar, wind, and biomass, contribute to the grid but remain a smaller portion of the energy mix, with long-term expansion dependent on foreign investment and technological improvements.
The thermoconversion process at Hermanos Díaz offers a temporary solution rather than a permanent fix. It does not eliminate the need for imported additives or spare parts, nor does it address the inefficiencies of Cuba’s refining infrastructure. However, it provides a critical buffer. In a country where tourism has declined sharply—with arrivals in early 2025 down nearly half from the previous year—this adaptation helps maintain essential services while longer-term energy strategies are developed.
The Geopolitical Signal: How Sanctions Can Drive Adaptation
Cuba’s ability to refine its own crude carries broader implications for how sanctions are perceived as a policy tool. The U.S. embargo has long operated on the assumption that economic pressure would limit Cuba’s options. Yet recent developments suggest that isolation can sometimes accelerate local problem-solving rather than simply causing economic strain. The Hermanos Díaz refinery did not require a major financial investment to begin processing domestic crude—it required a pressing need to do so.
The example has drawn attention from other nations facing energy restrictions. Countries under similar economic pressures, including Iran and Venezuela, have taken note of Cuba’s approach. The case demonstrates that local innovation, rather than reliance on foreign capital, can sometimes provide a way forward under sanctions. It also highlights the limitations of economic warfare: when a country controls its own resources, even stringent restrictions may not achieve their intended effect, instead pushing the targeted nation toward greater self-reliance.
This does not mean Cuba’s path is without challenges. The thermoconversion process is energy-intensive, and the fuels it produces remain less efficient than modern alternatives. The country’s renewable energy goals, which aim for a significant share of electricity from clean sources in the coming years, remain difficult to achieve under current conditions. Sanctions continue to limit foreign investment in solar and wind projects, forcing Cuba to balance immediate energy needs with long-term sustainability.
The broader lesson is that in an era of disrupted supply chains and trade restrictions, energy independence has become a priority for many nations. Cuba’s refineries may be outdated, and its oil may be heavy and high in sulfur, but the ability to produce fuel domestically alters the dynamics of economic pressure. For the first time in decades, the country is not entirely dependent on imported energy, changing the strategic landscape.
What Happens Next: The Unanswered Questions
The experiment at the Hermanos Díaz refinery demonstrates feasibility but does not yet provide a scalable solution. A key question remains: can Cuba expand this process to other facilities? Most of the country’s refineries lack the infrastructure to handle heavy crude, and upgrading them would require resources that sanctions make difficult to obtain. Even if the process proves effective, its economic viability is uncertain. Heavy crude refining is costly, and the fuels produced may not be competitive if sanctions are eased and imported alternatives become available.
Environmental concerns also play a role. Cuba’s oil is among the most polluting in the world, and increasing its use could undermine the country’s renewable energy goals. The government has acknowledged this tension, presenting the refinery adaptation as a temporary measure while accelerating solar and wind projects. However, in a country where blackouts remain a frequent occurrence, immediate energy needs often take precedence over long-term environmental objectives.
The most significant variable remains U.S. policy. The current administration has not signaled plans to roll back sanctions, but future shifts in political priorities could change that. If restrictions are lifted, Cuba might return to importing lighter crude, potentially abandoning its domestic refining efforts. If sanctions persist, the country could deepen its reliance on its own resources, accepting the economic and environmental trade-offs that come with that choice.
For now, the Hermanos Díaz refinery serves as a symbol of resilience. It is not a comprehensive solution to Cuba’s energy challenges, but it demonstrates how necessity can lead to unexpected adaptations. In the complex interplay between sanctions and sovereignty, Cuba’s recent moves have altered the strategic landscape—even if the long-term consequences remain unclear.
