Admittedly the grandparent is somewhat ambiguous about what constitutes availability, but my point was that widely available renewable energy sources, such as wind and solar, are intermittent.

That's why we have grids and storage. Perhaps you should investigate those before making definitive statements about what renewables can and can't do.

We have very little storage and the grids require electricity generation from something. With lots of HVDC connections we could conceivably move enormous amounts of electricity around on a continental scale and thereby reduce the need for storage. That would be great...

...but it still won't be enough. We need something that can produce power when renewables can't.

Sure, they're intermittent which is a downside but they still compete away constant output sources. I didn't mention it in my previous reply but it is possible to vary the output to a certain extend (depending on the technology), the problem is that the economics assume a pretty constant output. This equation doesn't add up in certain places anymore. Therefore I expect that we will have a lot fewer constant output energy sources and a lot more variable energy sources. This will be combined with a certain amount of storage, fossil fuel backup plants, systems to timeshift our energy consumption, probably more usage of district heating/cooling systems and a lot of other stuff of course.