Friday was the first official triple-digit temperature day for Green County.
The excessive heat triggered a PSO "energy savings event."
That allows the power company to adjust thermostats or, in some cases, shut off air conditioners to conserve electricity.
It can only happen at homes where PSO customers opt in to the program, which combines rebates and one-time savings when they adjust the air conditioning.
The PSO notice to customers said it would end at 7 p.m.