> with solar and wind now far cheaper than nuclear ... does it even make sense for governments to go down this route?
If this works without the sun shining then, yes, it makes sense. It is always good to have multiple sources of energy even if only as a form of redundancy. Our world depends on power.
> If this works without the sun shining
HVDC lines are already mature enough that the cheapest route is to just wrap the Earth with them to form a planetary grid.
The sun always shines somewhere.
Is this true? What are the costs per km for HVDC?
Perhaps you're just talking about the Eurasian continent? What do the people of Western Europe do? Connect to the US?
Even then, we've seen with the recent Russia-Ukraine war that control of energy is a useful geopolitical tool with Europe being softer on Russia because of their reliance on their gas.
> reliance on their gas.
... and nuclear fuel and fuel rods from Russia. Which are still not being sanctioned btw. It's peanuts compared to the natural gas, admittedly, on the order of 700 million Euro per year.
Bunch of projects in the works. But building HVDC lines is not cheap.
https://en.wikipedia.org/wiki/List_of_HVDC_projects
Same goes for nuclear power plants really.
A 2.5GW undersea HVDC line costs $2.5mln/km.
The cheapest nuclear power plant in Europe is the Ostrovets power plant in Belarus, the cost of which was $11bln for a 2.4GW plant.
For that money you could buy a 2.5GW HVDC line spanning the entire EU.
If the earth was a uniform sphere without oceans and mountains, sure.