What we’re showing can also be referred to as solar “self-consumption.” In short, we’re not just doing an end-of-day comparison between your total production and total consumption (in that case, you’d be right that your total consumption would be 100% covered). Instead, that “powered by solar” metric is telling you exactly, within that time window, how much of your actual consumption was covered by your solar production, rather than being sent back to the grid.
As a (way overly) simplified example: say you produced 10kWh during the daylight hours and consumed 5kWh during these hours and another 5kWh at night (a total consumption of 10kWh for the day). Only 5kWh would actually be covered by your solar production; the other 5kWh produced would be sent back to the grid as excess production and none of your night-time usage would actually be covered by your solar production.
I hope that adds some clarity! This information can then be used to better optimize your solar production. Maybe that 5kWh at night is being used to do all the dishes and the laundry? It’d be better to do that work during the day, when you have the excess solar production to cover it.