My guess is a lot of folks use electric resistance heat and also folks plugging in electric space heaters.
That’s why I asked the question about nat gas earlier in the thread.
Here in Indiana, the highest peak loads come in the summer with A/C. The plant I worked at had to trim usage on hot summer afternoons because we were one of the major consumers of electricity. There never was any issue in winter because most heat is from nat gas.
Don’t know if any of your power comes from these guys, http://www.nipsco.com/Home.aspx, but as a stockholder, I hope if it does, you are well served.