The cascading blackouts that have gripped Cuba since mid-October are not merely an inconvenience. For residents of the island’s high-rise buildings, they represent a structural crisis of energy poverty. In Havana’s 1970s-era tower blocks, elevators stall at the 15th floor, water pumps fall silent, and families above the sixth floor are trapped in apartments that become heat traps without ventilation. The Cuban government reports that 40% of the national grid was offline at peak blackout hours last week, leaving over 2 million people without power for 12-hour stretches.
The United Kingdom has now entered the conversation. UK Energy Secretary Ed Miliband today stated that the UK is prepared to deploy ‘renewable microgrid expertise’ to Cuba. He framed the offer not as charity but as a pragmatic response to a shared threat: the collapse of fossil-fuel-dependent grids under climate stress.
Cuba’s vulnerability is a physics problem. The island relies on aging oil-fired plants, many built in the 1980s, with a combined capacity of just 6.2 GW. When demand peaks during heatwaves, the system’s frequency drops below 49.5 Hz, causing automatic tripping. The blackouts are a predictable outcome of deferred maintenance, fuel shortages, and a lack of distributed generation.
High-rise dwellers suffer disproportionately. A 20-storey building with a single elevator and a communal water pump requires a sustained 50 kW supply. Without it, residents above the fifth floor face a daily 80-metre vertical commute on foot, carrying water and supplies. The elderly and disabled are effectively imprisoned. Dehydration and heatstroke cases at Havana’s Calixto Garcia Hospital rose 300% during this month’s blackout peaks.
The UK’s offer focuses on rooftop solar and battery microgrids. Each microgrid could power a building’s critical loads: elevators, water pumps, and one outlet per apartment. The Energy Secretary noted that similar systems were deployed in Puerto Rico after Hurricane Maria in 2017, reducing blackout times from weeks to hours for participating buildings.
This is not a humanitarian intervention. It is an energy science demonstration. Cuba sits at 23 degrees north latitude, receiving an average solar irradiance of 5.2 kWh per square metre per day. A 10-metre by 10-metre rooftop array with 40 kWh battery storage can sustain a 10-storey building’s critical systems for 8 hours. The problem is scaling. Cuba has over 12,000 high-rise residential blocks. Deploying microgrids to all would require 4.8 million solar panels and 480,000 tonnes of lithium-ion batteries, an infrastructure cost of roughly $6 billion at current prices.
The UK’s expertise lies in system design, not financing. Miliband suggested a ‘knowledge-transfer partnership’ where British engineers train Cuban technicians. This is analogous to the UK’s 2018 offer to Dominica after Hurricane Maria, where a 1 MW solar microgrid now powers the island’s main hospital.
Critics within the UK government argue that the offer is ‘experimental’ and that Cuba’s political and economic isolation complicates deployment. The US embargo restricts the sale of American-made solar panels and batteries, but British and Chinese components are available. The Cuban government has not formally responded, but energy ministry sources indicate interest in pilot projects.
Blackouts are not new to Cuba. The ‘Special Period’ of the 1990s saw 16-hour daily cuts. But the current crisis is different: it is compounded by climate change. The Caribbean has warmed by 0.8 degrees Celsius since 1980, increasing cooling demand and reducing thermal power plant efficiency. A 1 degree rise in ambient temperature reduces gas turbine output by 0.5%. Cuba’s plants are running at 80% of rated capacity.
The underlying truth is that Cuba’s grid is a fossil fuel relic in a warming world. The UK’s offer of microgrid expertise is a microcosm of a global challenge. For the residents of Havana’s high-rises, the question is not whether the technology works, but whether it arrives before the next heatwave.
Dr. Helena Vance, Science & Climate Correspondent.
