Except that not that often. Renewables tend to be difficult to predict and then overstrain the grid.
https://www.cleanenergywire.org/news/loops-and-cracks-excess-german-power-strains-europes-grids-0
https://www.technologyreview.com/s/534266/hawaiis-solar-push-strains-the-grid/
…and more…
