There absolutely are [0]. They're also used in DC's as a buffer as other energy sources spin up. Lawrence Systems did a neat walkthrough of that infra recently

There absolutely are [0]. They're also used in DC's as a buffer as other energy sources spin up. Lawrence Systems did a neat walkthrough of that infra recently [1]. [0]: https://en.wikipedia.org/wiki/Flywheel_storage_power_system#Power_grid_frequency_control https://en.wikipedia.org/wiki/Flywheel_storage_power_system#... [1]: https://youtu.be/gsN_CJJDy_o https://youtu.be/gsN_CJJDy_o