Utilities, which provide the power over the transmission lines from power producers, like power plants, are preparing for summer peak demands in various ways. Traditionally, energy producers have been required to fire up back-up power plants during extremely high peak demand periods in the summer. This summer, as more demand response and smart meters are deployed industrially, commercially and even residentially, energy consumers may regulate their own use more than ever and reduce energy consumption to smooth summer peaks. With more consumers lowering their thermostats just a few degrees, utilities will be able to provide energy more effectively for all consumers using air conditioning.

Transmission lines are like the cables that carry the power and are not generally the problem when summer peak demands cause brownouts.

San Jose hit 98 for the first day of summer.  Down the street a transformer failed and cables were smoking.  We had 110 V in part of the house, reduced power (85 V) in part of the house, and no power in part of the house (depending on which phase).  It took 3.5 hours for the first response, and the guy had to call for parts.  Finally got fixed after 12 hours.

The transmission lines are probably in no better shape than before.  To the extent that solar roofs have been installed, there should be more locally generated power.  But solar power from the Mojave Desert will need transmission lines to get to LA, and more transmission lines if power is needed in Northern California.

It's going to be a cool summer