It's not (mostly) to salve their consciences; it's fundamental to their avoidance of the Resource Curse/"Dutch Disease". Norway, unlike just about everywhere else "blessed" (and I use those scare-quotes intentionally) with oil and gas, anticipated the value of not getting high on one's own supply: they have some of the most heavily taxed vehicle fuel in Europe, as well as strict limits on how much oil/gas tax revenue can be spent each year with the rest going into an enormous investment fund.

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.

Better than having oil and gas revenue and not using it to build hydro and wind. Like some other countries we can all name.

Interesting looking at the data, that Norway generates 4x the electricity of NZ and they are roughly the same size and population I assume it exports most.