US utility firms spent big preparing power grid for storms – and still failed

Electric utilities spent billions after 2014's polar vortex to ensure power plants and the grid could handle extreme cold, but this winter it still wasn't enough

The warnings to residents in the south-east US came right before Christmas: delay washing clothes or running the dishwasher, and curb hot water use until the bitterly cold temperatures eased up.

It still wasn't enough for two of the nation's largest electric utilities.