Yes, I do, albeit I fail to find why this is a prerequisite for renewables to provide most of consumed electricity. The referenced study analyzes continental-scale.

However some existing links are encouraging: https://en.wikipedia.org/wiki/NorNed

Projects: https://en.wikipedia.org/wiki/Submarine_power_cable#Proposed...

The underlying approach is not new and is rather rather quickly adopted and improved: https://en.wikipedia.org/wiki/List_of_HVDC_projects