At the end he said “… keeping the grid in balance with millions of tons of spinning inertia.” Well, this is now being simulated by the electronics in the battery energy storage systems and other electronics. It’s called VMM – virtual machine mode.
Soon, there will be very few thermal power plants left after all the fossil fuel burning power plants have been shut down. There may be turbines in dams and some thermal power plants, mainly nuclear and some geothermal power plants. The wind turbines have “spinning inertia” but it’s not easily controlled since sometimes the variable wind may not be blowing. So I don’t think that wind turbines are considered spinning inertia to the grid. They are most likely matched to the grid by a MPP controller.
