We generate more than 200KWh on a sunny day, and average about 140KWh generated per day year-round. Even on a cloudy day we generate more than 70KWh. Our whole building uses less than 100KWh per day, so we generate much more electricity than we use. That extra electricity gets fed into the power grid, so that generating stations need to make that much less (and burn less coal, oil, or natural gas).
For comparison, a typical single-family home uses something from 20-60KWh per day, depending on how many electric appliances (heat " A/C, water heater, stovetop, oven, etc.) there are.
You can see our solar panel "farm" in this Google satellite picture of our warehouse.