There are also proposals to place large mirrors in orbit to redirect sunlight to solar panels at night. To sustain night time power generation. Although I don't know how feasible it would be.
Cables carry better benefits to this imo. There's a lot that run under the sea between European countries already that share a power grid - this is probably the best alternative.
Is renewable power taking over? Or is it simply less efficient. Requiring greater manpower and more jobs to generate an equivalent sum of electricity? But then if it does create more jobs. Maybe that makes it a good thing.
Efficiency of both would probably be hard to measure. A lot of oil, gas and coal extraction have been automated since the mid 20th century if not before. I think there's more space for research in renewables and more work left (like making solar panels that are more efficient or making them out of different parts and for different things - steam based v silicon based v carbon/metal alternatives based). There's also different sized wind turbines and nuclear fusion research.
A nodding donkey doesn't need much manpower except an engineer to maintain it every so often (and they can probably maintain a few at once).
The highest cost for oil extraction looks to be the exploration and infrastructure imo too which might not need too many people working on either as exploration can be done by a small team and the infrastructure can be manufactured automatically (and then likely gets assembled into place by a larger team).
Renewables will probably become more efficient over time too as some become more robust (I think hydroelectric kry from dams might be close to that state as dams and "doors"/gates/locks? have existed for quite a long time for canals and seas).
