I expect most modern countries are going to need to be constantly upgrading their power grids and power generation capabilities over the next few decades. Hopefully most of the new energy generation will be renewables.
We'll need more generation, but only about half as much more as a naive analysis would indicate.
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What I'm saying is that in our long term planning, we shouldn't be thinking "we have X terawatts of fossil fuel production capacity so we need to build out X terawatts of non-fossil-fuel production capacity to replace it (including storage, as needed)" We should be thinking "We probably need ~2X terawatts of additional production because we're replacing fossil fuels for electricity generation in addition to transitioning to electricity-based heating and transportation."