That's exactly right. Extra electrical draw on the grid (or a loss of electrical production elsewhere) causes the turbines in power plants to physically spin sl

That's exactly right. Extra electrical draw on the grid (or a loss of electrical production elsewhere) causes the turbines in power plants to physically spin slower due to increase load on each turbine. An (imperfect) analogy would be if you and a friend were biking up a hill on a tandem bike. If a third person hopped on the handle bars (or your friend stopped pedaling) the bike's wheels would slow down, assuming you are putting a constant amount of power into the pedals.