The article even explains it costs him more money than using natural gas for heating.
It may be the greenest kind of heat around
No it's not. Unless you're otherwise using dumb electric resistor heating to heat your house, using electricity (without heat pump) wastes much more coal/gas/anything at the power plant than using that fuel directly to heat your house, because the power plant's efficiency is far from 100%.
If you want to be efficient: use excess heat from the power plant in block heating.