Weather.
If you want 1KW reliably off grid (24/7 with 24kwh battery) (let’s assume 5 hrs solar insulation) you’ll need around 20kw of panels. Even then, you’ll have occasional shortages in inclement weather.
If you are on the grid (theoretically unlimited battery, just averaging over the year) you’ll need 4.8 kw of panels.
Batteries are the hard part of solar.