On August 14th, California electricity grid had blackouts that lasted for ~75 minutes. In round numbers, the grid was 1 gigawatt short. Thus, the blackouts. But there were lots of gigawatts around and available. Lots.
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I checked in with the Texas grid. At that moment. It had > 5 gigawatts of surplus capacity. Its prices were about $28/mwh (vs. ~$750 in California.) So, lots of electricity at a very reasonable price. 
Meanwhile, the giant SPP grid (New Mex --> Nebraska--> Arkansas) was having a windy day. Prices at the time of the blackout were about $25/mwh.
I asked the SPP grid for information on how much wind is was curtailing, and waited 24 hours. No answer yet. But I’ll bet it was a significant amount. (Power grid operations are very opaque; grid operators secretive.)
TLDR: It was very hot in the western U.S., stressing the grid with elevated, widespread power demand. But to the east, it was windy enough to generate enough excess power to share, if only….
… there was a way to share. The U.S. doesn’t have a functional national power grid. It has a bunch of regional politically controlled grids that don’t collaborate enough on reliability or market efficiency (moving the least expensive power from surplus to deficit.)
So, there’s a blackout in California. Meanwhile, wind farms in the Great Plains are curtailed and get low prices for their output. (By the way, nukes get same prices, hurting their economics.) If we wanted to, we could fix this. It is simple. Build a national interconnected grid.
