The goal of net energy exporter assumes that energy produced at one time can be exchange for energy produced at an other time for the same price, and that assumption has not been true in Europe for decades. You can be a net energy exporter and still be dependent energy imports for more than 50% of the energy a country consumes, as has been demonstrated by Denmark.

I will happily trade 10 unit of energy for just a single unit of energy, assuming I get to decide when I give the 10 units and when I can demand the 1 unit. A lot of profit in the European energy market can be made by such a "bad" deal.

The date when a country energy grid is free from fossil fuels, like coal, is when the grid has no longer any demand during the year for producing or importing energy produced by fossil fuels.