Our current policy for grid frequency includes both manual and automated correction to keep (some) clocks ~accurate;

"Regulation of power system frequency for timekeeping accuracy was not commonplace until after 1926 and the invention of the electric clock driven by a synchronous motor (a Hammond invention). Network operators will regulate the daily average frequency so that clocks stay within a few seconds of correct time. In practice the nominal frequency is raised or lowered by a specific percentage to maintain synchronization. Over the course of a day, the average frequency is maintained at the nominal value within a few hundred parts per million. In North America, whenever the error exceeds 10 seconds for the east, 3 seconds for Texas, or 2 seconds for the west, a correction of ?0.02 Hz (0.033%) is applied. Time error corrections start and end either on the hour or on the half hour."

What isn't clear is the intent of the "experiment". If they merely discontinue the time correction efforts (which could be a sizable savings alone), the only noticeable effect will be to some of our clocks. If they loosen the overall tolerance standards, that could be a different story.