Your home is fully (100%) self-powered if all the energy you consume was generated onsite, and none was imported from your electric utility. It is possible to harvest far more energy that you are using, but still not be self-powered. This has everything to do with when you consume energy and when you harvest it.
In the snapshot below, the homeowner has exported 9.5kWh but he/she is still only 37% self-powered or energy independent. Why is this? Well, most of this family's consumption occurred during the early morning hours before solar harvest began for the day. That early energy need was met by the utility, not the solar array.
As this family continues to consume electricity in the evening, the percentage of their self-power for the day will actually decrease because they are no longer harvesting for a direct offset of their consumption.
The challenge of aligning production to consumption is an unavoidable conundrum of standard solar installations. Solar arrays produce during peak sunlight hours, but most families use electricity in the early morning before work and at the end of the day when they return home.
Enphase is at the forefront of introducing completely integrated solutions to solve this puzzle. For example, with Enphase Storage this customer could have stored the energy they generated during the day for use when the sun is not shining and electric rates are higher. In so doing, they would become completely self-powered and not reliant on their electric utility for power.