While America's power grid has been showing signs of distress for years, the sudden warnings have surprised even those who were sounding an alarm. That's because extreme weather precipitated by climate change and the early retirement of fossil fuel plants has accelerated the destabilization of the grid - a fragile collection of transfer stations and transmission lines already challenged by a lack of investment.
The situation has unnerved energy experts, who caution an unstable grid could set back plans to move rapidly toward a climate-friendlier economy. The plans rely heavily on most of the nation shifting to electric vehicles and plug-in home appliances such as stoves and hot water heaters, which will increase demands on the power system.