We are able to sell it back, but only at the wholesale rate, which is about 1/3 of the price we have to pay for what we buy from the grid, hence the battery so we can save it up and use it ourselves instead. Even so, for about 9 months of the year we should produce more than we use and end up selling more back, but in June, July, and August the A/C will mean we use more than we produce and have to buy.
I just found out today though that our city is considering switching to variable rate and charging more during the day and less at night, which would great for us since during the day the panels will cover our usage and then we can run on the battery through the evening and it'll be overnight and early morning when rates are low that we might need to buy.