Reuters article: In the future, maybe we'll only need power utilities for those situations when our rooftop solar panels aren't providing enough energy?

Analysis: Renewables turn utilities into dinosaurs of the energy world | Reuters

(Reuters) - Every new solar panel installed on European rooftops chips away at power utilities' centralized production model. Unless they reinvent themselves soon, these giants risk becoming the dinosaurs of the energy market.
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"In a future electricity system, the electricity network company could essentially be an insurance company, providing insurance against not having sunshine when you need power," said International Energy Agency economist Laszlo Varro.

Say it's zero degrees F. here in St. Paul on a Friday evening next January, and I'm completely off-grid, relying on my solar panels for all of my home lighting and heating. How long will I need to plug in my Tesla before I can take a worry-free drive to Duluth?