Transport grids aren’t free, and excess electricity production is bad as it requires curtailment (wastage) which isn’t free either to prevent damage to electric equipment (very expensive).
Besides, when renewables produce these excesses, this will often be the case in a very large area.
It’s the system that’s the problem. It was built for a society with a very homogenous and pacifist culture profile. That society no longer exists.
The majority in Sweden is going through a rather rude awakening right now and our systems are going to break a lot whilst our politicians struggle to bring them in line with our new reality.