A casual shufti suggests this was part of a broad policy push, but that it was mainly to do with a series of purpose-built hydro projects specifically to support Alcoa’s smelting facility. [1]
It smells like there’s a story of a few strong personalities with ambitious visions somewhere in the mix here. Would any of this crowd know where I might turn to find that story?
[0] https://ourworldindata.org/grapher/energy-consumption-by-sou...
[1] https://en.m.wikipedia.org/wiki/Kárahnjúkar_Hydropower_Plant... (with a fair bit of Wikipedian NIMBY-ish color commentary in the mix there)
And Kárahnjúkar is not a case of the NIMBY, to an approximation there’s no one living in the highlands. It’s large scale environmental destruction for the benefits of a large company which the people of Iceland objected to.
Which is hardly incidental, having access to ungodly amounts of hydro power is the easiest way to run on 100% renewables. Iceland has similarly been 100% (or near enough) renewables for decades, despite more than 70% of its electricity going to aluminum smelters.
Norway similarly runs on 100% renewable electricity because it has enough hydro for pretty much all of it (Norway is the 213th country by population, but something like top 10 hydro producer)