Be careful, this is not a third of fossil fuels reduced. It is a third of fossil fuel used to generate electricity reduced. Transport , manufacturing etc would have different figures.

This is still a big deal. As you point out, with a rising amount of electric cars, it may start to convert very quickly elsewhere. With rising electric cars, we’d expect higher electricity use. So this might be less of a reduction in absolute terms, but an even bigger drop for fossil fuels overall, as transport would be much reduced.

I imagine this is part of the reason we’re seeing minimal rises in petrol pricing despite the Russian and Israeli wars. America being self sufficient and now a net exporter helps too. They’re less inclined to escalate for oil.