A fusion reactor is the long term game. Sure we could use that money to add more capacity to the grid, but what we need is to take fossil fuels offline and 200 GW would barely make a dent in the production from coal if the consumption continues to increase. In 2022 it was estimated that coal produced 44000 TWh and that number increase at an alarming rate every year.
So we need to do something to meet the futures energy demands, but we also need to do something today. The smart thing is to invest in what we can do today, solar, wind and batteries, and invest what we can do in the near future, better fission reactors is one possibility, and invest in the long term, that could be fusion. It would be foolish to only invest in one of them.
If we rely on solar, we need a massive overcapacity. In large parts of the world the output of a solar panel is 50% in the winter compared to the summer, and in addition, we use significantly more power during the winter. And that will be even further exaggerated if fossils do not heat water for district heating in addition to the power produced - but perhaps that is offset by AC usage in the summer. Either way, we would need a significant overcapacity to meet demand, not to mention huge investments in battery infrastructure.
And that does not even take predictable peaks into account (think the pause of a national event with lots of viewers, where people make coffee/tea/snacks at the same time), which needs fossil peaker plants, or even more battery capacity.
So we need to do something to meet the futures energy demands, but we also need to do something today. The smart thing is to invest in what we can do today, solar, wind and batteries, and invest what we can do in the near future, better fission reactors is one possibility, and invest in the long term, that could be fusion. It would be foolish to only invest in one of them.