Breakdown of energy supply systems

Cuba's electrical grid collapsed again on Sunday, the fourth such failure in 48 hours, raising fresh doubts about a quick fix on an island already suffering from severe shortages of food, fuel and medicine.
The blackout, after weeks of rolling outages, sparked some small protests around the Caribbean island, where a tropical storm threatened to hamper efforts to restore power.
Cuba's national electrical grid first crashed around midday on Friday after the island's largest power plant shut down, sowing chaos and leaving around 10 million people in the dark. The grid has collapsed three times since, underscoring the precarious state of the country's infrastructure.
The repeated failures mark a major setback in the government's efforts to quickly restore power to exhausted residents, a majority of which have already suffered from months of blackouts through the Caribbean`s sultry summer.
Cuban president Miguel Diaz-Canel appeared Sunday evening on national television dressed in olive drab military attire, encouraging Cubans to air their grievances over the situation with discipline and civility.