Comment by XorNot

Which they use all the time. If you did this at a district heating level, you'd just be running an electric district heating system, resistively, which you run all the time - it wouldn't be a dump load, it would just be the load and a very inefficient one at that (compared to a heat pump).

The point is all this stuff costs money to build, money to maintain, so if you don't use it most of the time the time you do needs to be incredibly valuable.