Wrong. Natural gas is not necessary to heat a home. 

Heat pumps work great. Air pumps (air conditioners "running backwards") work great to about -10. Geothermal pumps (drilling a 30-100 m hole or laying around 300-500 m of ) work at any temperature. Sure the pumps run on electricity, but that electricity can be generated with solar, wind, or biomass (logging residues). 

check out: https://www.geothermal-energy.org/direct_uses/sweden.html