Your current Electric Company is a virtual battery bank. As you harvest from the sun all day and your not using all the power that is being generated, the meter would be spinning backwards. This credit can be used at night when the array is not producing power. So lets get to when the power goes out. The solar array will not produce power when there is no grid voltage. It is a safety feature built into the inverters so it will not pump power back into the grid so a line guy or girl would get hurt. It can be a grid tied system with battery backup to keep power to some critical loads. Adding batteries does increase the cost of the solar array. 90 % of all Solar arrays are grid-tied systems with no batteries.