Yesterday afternoon, a cascading failure of Cuba's ageing power grid left tens of thousands of residents stranded in high-rise buildings across Havana and major cities. Without functional lifts, water pumps, or ventilation, citizens face a humanitarian crisis as temperatures soar above 35°C. This event is not an isolated incident but a stark omen for nations whose infrastructure lags behind climate pressures. For the United Kingdom, the contrast could not be more pronounced: our own grid resilience is now a matter of national security, and the data demands we treat it with calm urgency.
The Cuban outage began with a failure at the Antonio Guiteras thermoelectric plant, the nation's largest. Within 90 minutes, a domino effect triggered blackouts for 10 million people. Hospitals switched to diesel generators, but fuel reserves ran low; trapped residents in 20-storey blocks faced despair. This is the physics of vulnerability: a grid without redundancy, without distributed renewables, without smart demand management, collapses under stress. Cuba's peak demand is 3.2 GW, but its generation capacity has fallen 30% since 2019 due to deferred maintenance. A single failure took down 25% of supply.
Now, transpose this to the UK. Our grid architecture is fundamentally different, thanks to two decades of strategic investment. We boast 50 GW of installed capacity, with 35% from renewables in 2025. But the crucial metric is not capacity alone: it is resilience. The UK's national security depends on the ability to keep power flowing during extreme weather, cyberattacks, or primary plant failures. The National Grid's control room uses real-time data from 300 substations to reroute power automatically. We have six interconnectors to France, Belgium, Norway, and the Netherlands, providing 8 GW of emergency backup. During Storm Eunice in 2022, when wind turbines shut down, these interconnectors imported 6 GW. The lights stayed on.
Critics argue that renewables introduce intermittency. True, but that is a solvable engineering problem, not a reason to delay transition. The UK's storage capacity has grown from 1 GWh in 2015 to 45 GWh today, using grid-scale batteries and pumped hydro. Smart meters, now in 80% of homes, allow dynamic pricing that shifts demand away from peak hours. The result: stability even when wind speeds drop or solar output fades. Compare this to Cuba, which still relies on heavy fuel oil and has no large-scale storage. When one plant fails, there is no buffer.
But complacency is our enemy. The UK's infrastructure is under strain from heatwaves and droughts. In July 2022, a 40°C day caused rail buckled and substation transformers overheated. The Climate Change Committee warns that by 2050, summer electricity demand for cooling could rise 50%. Our water cooling for thermal power stations faces scarcity. These are solvable without panic: upgrade transformers, install passive cooling, build more solar on rooftops to reduce peak loads. The cost? An estimated 1.2% of GDP per year over a decade. The cost of inaction? Look at Cuba.
To understand the urgency, consider the biosphere collapse analogy. An ecosystem loses resilience when you remove species just as a grid loses resilience when you remove diversity of supply. Cuba removed diversity by centralising generation. The UK must avoid monoculture: not all eggs in gas, or nuclear, or renewables, but a portfolio. Our current mix is 40% gas, 15% nuclear, 30% renewables, 15% imports. That is better, but gas is increasingly volatile due to global markets. We must accelerate offshore wind, which now provides 14 GW and can be paired with hydrogen storage. Delaying this by even five years locks in vulnerability.
National security extends beyond military defence. Energy security is the foundation of healthcare, communication, and food distribution. During Cuba's blackout, food spoiled, water pumps failed, and people died. In the UK, a similar event in 2019 affected only 1 million homes for less than an hour. But extreme weather events are increasing exponentially. The Met Office predicts a 40% chance of a 1-in-100-year heatwave by 2030. If that coincides with a plant failure, our resilience will be tested.
Technological solutions exist: microgrids for critical facilities like hospitals, community battery storage, and virtual power plants aggregating home batteries. The UK government's second CFiD allocation round awarded contracts for 11 TWh of new renewable capacity, but grid connection delays bottleneck progress. Reforming planning laws is not a luxury; it is a national security imperative. The modellers at the Energy Systems Catapult show that with aggressive action, the UK can maintain 99.97% grid reliability even with 80% renewables by 2035. That is the standard we must meet.
Cuba's tragedy is a data point. It shows what happens when a nation defers investment in resilience. The UK has no excuse: we have the resources, the technology, and the threat is quantified. The question is whether we have the political will to act before the cascade reaches our shores. As a scientist, I see the curves and I see the clock. Our response must be proportionate to the risk, and that response is now.
