My partner works in the field and we once talked about this. I think the idea is that individual consumers’ and businesses’ batteries can serve the grid as needed. For example, if your car is fully charged and you don’t need it today, it can top up local needs.
So I think the writing isn’t on the wall yet for line price going up, although I’m of course talking of a) Belgium, and b) a future that could go wrong if utilities don’t fund smart metering.
That’s how it works for us here in Australia. We have 16Wh of solar and 40KWh of battery, and pay (and receive) wholesale rates for electricity. During the say electricity prices are very low or negative, and we run off the solar and charge the car then. In the evenings when demand is high electricity prices can spike, and our system will automatically sell to the grid then. Sometimes we may need to draw from the grid in the early morning to make up for that, but the price we pay then is insignificant compared to what we make selling the day before.