The electricity generation in the article is shown per capita.

Now I'm not saying we should generate as much as humanly possible, because even with renewables that has a cost.

And some things have gotten genuinely more efficient (compare modern heat pumps to heating available in 1968).

But why shouldn't we maintain the levels our parents enjoyed? And use the extra capacity if anything for EVs, grid stabilization, medical research, etc.

So population degrowth is a pretty separate issue.