1.   California traders were willing to pay exorbitant amounts for power because other state officials told them to expect regular rolling blackouts this summer due to power shortages.

2.   The power grid is so fragile that if they shut down it may mean the difference in whether state officials call for regular blackouts.

3.   The shortage of electricity causes regular blackouts throughout the city.

4.   Police say the upsurge began last year during drought-induced electricity rationing that meant regular blackouts in cities.

5.   The past few weeks have seen a drop in electricity supplies to Nigerians with many cities complaining of regular blackouts.