It depends on the kind of meter that your utility uses and how they have it configured.

Smart meters can measure that data at higher frequencies (up to several kilohertz) and from that data you can detect signatures that identify devices inside your house and even, in some cases, what they’re doing. For example, when your washer turns on it runs a pump (which draws a specific load) for a set amount of time and then goes through a cycle of running a motor to agitate the load, which draws energy in a specific way as it turns back and forth. When you turn on an LED light, it runs at a steady rate and draws the same amount of energy. When your AC runs it draws a different amount of current than the washer or LED.

With enough data, over time, you can determine which devices are in the house and when compared to a database of known signatures you can classify the device (All Samsung Refrigerator Model 23e4234 work the same way).

Here’s some articles talking about it:

https://www.sciencedirect.com/science/article/abs/pii/S2352467719300748

https://energyinformatics.springeropen.com/articles/10.1186/s42162-019-0096-9