Price of electricity in Finland peaks at 2.35€/kWh today. Keeping my tiny granny cottage warm costs me over 50 euros for a single day. It's negative 25C (-13F) outside.
That massive spike of 50c/kWh at the left looks tiny compared to today even though that's already insanely expensive
I have never heard of anyone that currently has a coal-heated house. I thought it was entirely dead in the developed world.
Here these heating options are common district heating, geothermal, direct electric heating, some other kind of heat pump, biofuel (like pellets), and a tiny bit of oil and gas.
The most popular by far is district heating, after that comes electric heating (which includes electricity used for geothermal heat pumps and other kinds) and then biofuel. Gas and oil are barely visible on a graph.
I just tried to find a place in my country which sells coal for heating but alas I didn't succeed. You can of course buy coal but its intended purpose is always grilling or smithing.
Your thinking of charcoal, which are chunks of wood converted into almost pure carbon by heating them above their combustion temperature in a low oxygen environment. He was talking about coal that was mined out of the ground. Plants from an ancient swamps that didn't decompose, but were converted into almost pure carbon from millions of years of heat and pressure from being buried.