I suspect that the increased demand such as air conditioning or business-related electrical usage peaks during the daytime (business hours). In hotter climates

I suspect that the increased demand such as air conditioning or business-related electrical usage peaks during the daytime (business hours). In hotter climates, air conditioning is a substantial user of electricity, even to the point where some places have to ration their usage of it. Solar puts electricity back on the grid at the time when it's most in demand.