Grid oversupply is bad (just as any overpowered circuit is generally bad). There isn't a way to dump power or store it, so they had to dump it on other countries who then had to adjust accordingly on their grid. You might think of it as a nice gesture, but it isn't; the other country has to power off plants or otherwise adjust to handle the excess as well. There isn't an "energy garbage can" or dummy load at power grid scale.
Running a power grid is a 24x7 dance of supply and demand, which is why people that hate renewables like wind are quick to lament its variable nature. It's the same in high-capacity systems planning in our line of work; systems that have variable latency are a lot harder to plan capacity for than systems with fairly constant latency. Just substitute "supply" for "latency", and you're now a power grid operator.
Running a power grid is a 24x7 dance of supply and demand, which is why people that hate renewables like wind are quick to lament its variable nature. It's the same in high-capacity systems planning in our line of work; systems that have variable latency are a lot harder to plan capacity for than systems with fairly constant latency. Just substitute "supply" for "latency", and you're now a power grid operator.