The first hydro power plant in Norway was set up in 1882, and last century it grew very quickly and was fundamental to alumin[i]um and fertiliser production in Norway. Domestic energy use has been close to a 100% hydro electric for almost just as long (and a lot of industry in addition to the above, e.g. iron smelting). Oil and gas are latecomers relative to this and the revenue from that is not behind this.