Each smart meter accumulates the energy consumed since it was installed in the home/building. It measures this is kWh. We are able to read two different values from the smart meter:
summation delivered: Accumulated kWh since the meter was installed. Indicates energy delivered from the utility to the customer.
summation received: Accumulated kWh since the meter was installed. Indicates energy delivered from the customer back to the utility. If you have generation on site, like solar on your roof, this number would increase when you are exporting power back to the utility.
Your meter is a 'net' meter, which means that it any energy generated is subtracted from any energy being used. The meter just sees the net flow of energy. Just like the odometer on your car, both numbers increase and don't ever decrease.
As an example, if your house is using 10kW, and generating 3kW, the 'net' demand would be 7kW. Over the course of an hour if this was constant, summation delivered would increase by 7kWh.
If your house was using 2kW and generating 5kW, the 'net' demand would be -3kW. Over the course of an hour, if this was constant, summation received would increase by 3kWh.