At one time it was based on coal and before that on wood and wind. Technology changes, or haven't you noticed? At times Norway runs its entire grid on wind power, and imports solar and wind power from Germany to store in pumped storage Hydroelectric facilities to export later when the wind isn't blowing or the sun isn't shining.

http://spectrum.ieee.org/green-tech/wind/norway-wants-to-be-europes-battery

I have used transit for commuting since 1985. Replaced my oil tank and oil furnace with an electric heat pump in 2000. Replace my 13 litres per 100 km minivan with a 7 litre per 100 km compact in 2008. Put gas in it about once very 2 or 3 weeks.